concinnity-cook 0.18.64

//! Compile stage of the build pipeline. The world is loaded, expanded, and
//! validated upstream by crate::world::prepare_world; this module takes the
//! resulting WorldJsonlAsset list and:
//! - Resolves each asset to a BlobAssetDef via asset_api::create_asset_def()
//! - Compiles payloads for assets that need compilation
//! - Packs all payloads into blobs using PayloadPacker (fills locators)
//! - Sorts: components first, then systems in declared order

use std::path::Path;

use concinnity_core::blob::{MeshBoundsRecord, PhysicsBudgetRecord, ResourceKind, SceneGroup};
use serde::Deserialize;

use crate::components::FileKind;
use crate::world::WorldJsonlAsset;

use crate::asset_api::{self, AssetRequest};
use crate::blob::PayloadPacker;
use crate::ecs::asset_id;
use crate::ecs::{AssetKind, BlobAssetDef, ResourceRecord};
use crate::registry::RegisteredType;
use crate::resource_handles::ResourceAssetCompile;

// The resource kind of a job selected by `collect_resource_jobs`. Every entry
// there was chosen by having one, so the lookup cannot fail.
fn job_resource_kind(rt: crate::registry::RegisteredType) -> crate::resource_handles::ResourceKind {
    rt.resource_kind()
        .expect("a resource job carries a resource type")
}

// The mesh kinds' declarable type names. Both are resource assets (no
// `Component` impl, so no `::NAME` const); the desugar passes and the cache
// probe match on these.
const MESH_TYPE: &str = "Mesh";
const SKINNED_MESH_TYPE: &str = "SkinnedMesh";

/// Build the world at `json_path` and write its blobs to disk, against the
/// installed state root: sources resolve under its `assets/` and the blobs land
/// in its `data/`. The one entry point anchored to the process-wide state tree;
/// a host that builds against its own directories calls
/// [`prepare_world`](crate::world::prepare_world) + [`build_compiled`].
pub fn build_from_path(json_path: &str) -> std::io::Result<()> {
    let content = std::fs::read_to_string(json_path)?;
    let assets_dir = crate::paths::assets_dir();
    let loaded = crate::world::prepare_world(&content, assets_dir.as_deref())
        .map_err(|errs| crate::check::report_validation_errors(&errs))?;

    let result = build_compiled(loaded.assets, assets_dir.as_deref(), None)?;

    let pack_result = write_build_outputs(&result, &loaded.injected, &loaded.shadowed)?;
    for (blob_idx, path) in pack_result.blob_paths.iter().enumerate() {
        let payload_bytes = result.payloads.get(blob_idx).map(|b| b.len()).unwrap_or(0);
        println!("Wrote {} ({} payload bytes)", path, payload_bytes);
    }

    if result.cache_hits + result.cache_misses > 0 {
        println!(
            "Build cache: {} reused, {} compiled",
            result.cache_hits, result.cache_misses
        );
    }

    if !loaded.injected.is_empty() {
        println!(
            "Injected {} default asset(s) (see world-lock.json)",
            loaded.injected.len()
        );
    }
    println!("Wrote world-lock.json");

    Ok(())
}

/// Write a compiled world's blob files, naming the primary blob `primary`.
/// Every overflow payload blob is written as its sibling named by index, which
/// is the layout the runtime reads back. No lock file and no thumbnails: this
/// is the blob output alone.
pub fn write_blobs_to(
    result: &PipelineResult,
    primary: &std::path::Path,
) -> std::io::Result<crate::blob::PackResult> {
    crate::blob::write_blobs(
        crate::blob::BlobStreams {
            defs: &result.defs,
            resources: &result.resources,
            scene_groups: &result.scene_groups,
            mesh_bounds: &result.mesh_bounds,
            physics_budget: result.physics_budget,
        },
        &result.payloads,
        primary,
    )
}

/// Write the blobs and world-lock.json for a compiled world: the shared build
/// tail used by the CLI and the FFI host. The lock records each asset under its
/// real name plus every injected default with its full args.
pub fn write_build_outputs(
    result: &PipelineResult,
    injected: &[crate::world::InjectedAsset],
    shadowed: &[crate::world::ShadowedAsset],
) -> std::io::Result<crate::blob::PackResult> {
    let primary = crate::blob::blob_path(0).ok_or_else(|| {
        std::io::Error::new(
            std::io::ErrorKind::NotFound,
            "no project state directory to write blobs into",
        )
    })?;
    let pack_result = write_blobs_to(result, std::path::Path::new(&primary))?;
    let named_refs: Vec<(&str, &BlobAssetDef)> = result
        .names
        .iter()
        .map(|n| n.as_str())
        .zip(result.defs.iter())
        .collect();
    crate::blob::write_lock(
        &named_refs,
        &result.resource_locks,
        injected,
        shadowed,
        &pack_result.blob_paths,
    )?;
    // Thumbnails are a best-effort side product: a bake failure must never
    // fail the build that produced valid blobs.
    match crate::thumbnail::bake_thumbnails(result) {
        Ok(r) if r.baked > 0 => println!("Baked {} thumbnail(s) ({} reused)", r.baked, r.reused),
        Ok(_) => {}
        Err(e) => println!("Thumbnail bake skipped: {e}"),
    }
    Ok(pack_result)
}

// Collapse a list of validation errors into a single io::Error. The messages
// are newline-joined so an upstream caller (e.g. the infra agentic loop) sees
// every problem from one call.
fn errors_to_io(errors: Vec<String>) -> std::io::Error {
    std::io::Error::new(std::io::ErrorKind::InvalidData, errors.join("\n"))
}

/// A texture's identity + on-disk source, in `TextureHandle` order. Now that
/// Texture is a resource (no `source`/`asset_id` on a component the renderer
/// drains), this is how a dev build hands the `cn debug` tools what they need: the
/// hot-reload watcher maps `source` -> handle, and the runtime spawn-by-name path
/// maps `name_id` -> handle. `source` is empty for a procedural texture (nothing
/// to watch). `name_id` is the interned asset name (same interner the runtime
/// shares in-process under `cn debug`), so nothing is interned at runtime.
#[derive(Debug, Clone, Default, PartialEq)]
pub struct TextureSourceInfo {
    /// The interned asset name.
    pub name_id: u32,
    /// Authored source path; empty for a procedural texture.
    pub source: String,
    /// Index of the image within the source document.
    pub image_index: u32,
}

/// A file-backed Mesh's re-import inputs, in `MeshHandle` order (the Mesh block
/// leads the shared mesh-source handle space, so Mesh handles are dense from 0).
/// Now that Mesh is a resource (no `source` on a component the renderer drains),
/// this is how a dev build hands the `cn debug` hot-reload watcher what it needs
/// to re-import a saved `.glb`/`.fbx`. `source` is empty for an inline-authored
/// mesh (nothing to watch).
#[derive(Debug, Clone, Default, PartialEq)]
pub struct MeshSourceInfo {
    /// Authored source path; empty for an inline-authored mesh.
    pub source: String,
    /// Index of the primitive within the source document.
    pub primitive_index: u32,
    /// How many LODs the mesh declares, including LOD0.
    pub lod_levels: u32,
    /// Camera distance at which each LOD past 0 takes over.
    pub lod_distances: Vec<f32>,
}

/// The in-memory result of a complete build pipeline run.
/// Defs have payload locators filled in; `payloads[i]` is the raw bytes for
/// blob i. This can be used directly without touching disk.
pub struct PipelineResult {
    /// The compiled component defs, with payload locators filled in.
    pub defs: Vec<BlobAssetDef>,
    /// Asset name of each def, index-aligned with `defs` (defs only carry the
    /// interned id; the lock file records the readable name).
    pub names: Vec<String>,
    /// The blob's resource stream: compiled resources addressed by their dense
    /// per-kind handle, carried alongside the component defs. Empty until a
    /// resource kind migrates off the component registry (AudioClip first).
    pub resources: Vec<ResourceRecord>,
    /// Per-scene exclusively-owned blob content, in scene declaration order.
    pub scene_groups: Vec<SceneGroup>,
    /// Baked AABB + counts per static mesh payload, by mesh-source handle.
    pub mesh_bounds: Vec<MeshBoundsRecord>,
    /// The world's physics reservation, or `None` when it runs no physics.
    pub physics_budget: Option<PhysicsBudgetRecord>,
    // Unified mesh-source handle -> asset name for mesh payloads compiled as
    // component defs (ProceduralMesh and friends). Resource-stream Mesh
    // handles lead the space and resolve through `resources`; these resolve
    // through `names`/`defs`. Consumed by the thumbnail baker to compose a
    // Model's sub-meshes.
    pub(crate) mesh_component_names: Vec<(u32, String)>,
    /// Raw bytes of each blob, indexed by blob number.
    pub payloads: Vec<Vec<u8>>,
    // Compiled-asset payloads served from the build cache this run.
    pub(crate) cache_hits: usize,
    // Compiled-asset payloads compiled fresh this run.
    pub(crate) cache_misses: usize,
    /// File-backed texture sources in `TextureHandle` order, for the `cn debug`
    /// hot-reload watcher. Dev-only info; not written to the shipped blob.
    pub texture_sources: Vec<TextureSourceInfo>,
    /// File-backed mesh sources in `MeshHandle` order (dense over the Mesh block
    /// of the shared mesh-source space), for the `cn debug` hot-reload watcher.
    /// Dev-only info; not written to the shipped blob.
    pub mesh_sources: Vec<MeshSourceInfo>,
    // Lock-file provenance for the resource stream, index-aligned with
    // `resources` (records only carry the kind tag + handle; the lock records
    // the readable name and args hash).
    pub(crate) resource_locks: Vec<crate::blob::LockedResource>,
}

impl PipelineResult {
    /// The interned asset name of every compiled resource of `kind`, dense by
    /// its per-kind handle: the identity a runtime that addresses resources by
    /// handle has no other way to recover (a resource record carries its kind
    /// and handle, not its name). 0 where the build recorded no id.
    pub fn resource_names(&self, kind: ResourceKind) -> Vec<u32> {
        let mut names = Vec::new();
        for (record, lock) in self.resources.iter().zip(self.resource_locks.iter()) {
            if record.resource_kind != kind as u8 {
                continue;
            }
            let slot = record.handle as usize;
            if names.len() <= slot {
                names.resize(slot + 1, 0);
            }
            names[slot] = lock.id.unwrap_or_default();
        }
        names
    }

    /// The compiled payload bytes of the resource of `kind` declared under
    /// `name`, sliced out of the in-memory blob sections. `None` when no such
    /// resource was compiled or it carries no payload. The editor's glTF
    /// export reads a SkinnedMesh's composed geometry through this.
    pub fn resource_payload(&self, kind: ResourceKind, name: &str) -> Option<&[u8]> {
        let record = self
            .resources
            .iter()
            .zip(self.resource_locks.iter())
            .find(|(r, l)| r.resource_kind == kind as u8 && l.name == name)?
            .0;
        let loc = record.payload.as_ref()?;
        let blob = self.payloads.get(loc.blob_index as usize)?;
        let start = usize::try_from(loc.offset).ok()?;
        let end = start.checked_add(usize::try_from(loc.len).ok()?)?;
        blob.get(start..end)
    }
}

/// Validate a single asset's type and generator without running the full build
/// pipeline. Called by the server on each world_add so the LLM gets per-asset
/// feedback without waiting for a WebSocket round-trip.
///
/// Checks:
///
/// - asset type is registered (via `asset_api::create_asset_def`)
/// - per-type structural checks via `crate::check`
///
/// Shader assets are not compiled here; use the validate_shader tool for that.
pub fn validate_asset(
    asset_type: &str,
    name: &str,
    args: &serde_json::Value,
) -> Result<(), String> {
    // Single-asset validation has no surrounding world to intern against; the
    // resulting ids are throwaway. Reset so calls do not accumulate entries.
    // Clear the resource handle map too: with no world there are no handles, so
    // a resource reference falls back to the interner (parses without resolving
    // to a real slot, which single-asset validation never needs).
    asset_id::reset_interner();
    crate::resource_handles::reset_resource_handles();
    let type_norm = asset_type.to_lowercase().replace('_', "");

    // Build-time types are valid in world.jsonl; they are consumed by expansion
    // functions before the runtime asset registry sees them.
    if matches!(
        type_norm.as_str(),
        "environment"
            | "lightrig"
            | "materialpalette"
            | "camerashot"
            | "prefab"
            | "sceneimport"
            | "characterschema"
            | "charactermodel"
    ) {
        return Ok(());
    }

    // A resource asset never builds a component def; validate it as a known type
    // with a structural check instead of routing through `create_asset_def`.
    if crate::registry::RegisteredType::parse(asset_type).is_some_and(|t| t.is_resource()) {
        crate::check::check_asset(&type_norm, name, args)?;
        return Ok(());
    }

    let req = AssetRequest {
        asset_type: asset_type.to_string(),
        args: Some(args.clone()),
    };
    asset_api::create_asset_def(&req).map_err(|e| format!("Asset '{}': {}", name, e))?;

    crate::check::check_asset(&type_norm, name, args)?;

    Ok(())
}

/// Run the full build pipeline on an in-memory JSONL string without writing any
/// blobs. Loads, expands, and validates the world (crate::world::prepare_world),
/// then compiles it. `assets_dir` is the asset search root a bare `source`
/// filename is searched under; `artifacts_dir` is an optional directory
/// consulted when resolving bare shader filenames not found there, so pass the
/// account's artifact directory to compile user-written shaders.
pub fn build_pipeline_from_str(
    content: &str,
    assets_dir: Option<&Path>,
    artifacts_dir: Option<&str>,
) -> std::io::Result<PipelineResult> {
    let loaded = crate::world::prepare_world(content, assets_dir).map_err(errors_to_io)?;
    build_compiled(loaded.assets, assets_dir, artifacts_dir)
}

/// A progress report from the compile pipeline: the stage's name and its
/// done / total counts. `total == 0` marks a stage that cannot count its work
/// (progress there is indeterminate).
#[derive(Debug, Clone, Copy)]
pub struct BuildProgress {
    /// The stage's name.
    pub stage: &'static str,
    /// Work completed in this stage.
    pub done: u32,
    /// Total work in this stage; 0 when the stage cannot count it.
    pub total: u32,
}

/// Compile an already-prepared world (expanded + structurally and semantically
/// validated) into in-memory blobs. This is the compile-only stage; it assumes
/// the assets have passed crate::world::prepare_world, which should have been
/// given the same `assets_dir`: an asset resolves its source the same way in
/// both halves.
pub fn build_compiled(
    assets: Vec<WorldJsonlAsset>,
    assets_dir: Option<&Path>,
    artifacts_dir: Option<&str>,
) -> std::io::Result<PipelineResult> {
    build_compiled_with_progress(assets, assets_dir, artifacts_dir, None)
}

/// [`build_compiled`] with a progress callback. The callback fires from the
/// desugar stage and, concurrently, from the parallel payload compile (hence
/// `Sync`); it must be cheap and non-blocking.
pub fn build_compiled_with_progress(
    mut assets: Vec<WorldJsonlAsset>,
    assets_dir: Option<&Path>,
    artifacts_dir: Option<&str>,
    progress: Option<&(dyn Fn(BuildProgress) + Sync)>,
) -> std::io::Result<PipelineResult> {
    if let Some(p) = progress {
        p(BuildProgress {
            stage: "desugar",
            done: 0,
            total: 0,
        });
    }

    // Cache probe runs before desugar. For every glTF-sourced Mesh /
    // SkinnedMesh, hash the un-desugared args + referenced .glb and look up
    // the compiled payload by that key. On a hit, we hold the bytes and skip
    // the .glb parse entirely (the original goal: an unchanged source file
    // means no work). On a miss, the recorded key is used when the compile
    // step stores the freshly produced payload, so the next build's probe
    // can re-use it.
    let mesh_cache = probe_mesh_payload_cache(&assets, assets_dir, artifacts_dir);

    // Expand any glTF-sourced SkinnedMesh and Mesh assets into inline geometry
    // before anything else looks at their args. Animations expand after the
    // skinned-mesh pass so an importer that wanted to share state could read
    // already-imported skeletons; today both passes parse the .glb fresh,
    // but the ordering keeps that option open without an API churn.
    desugar_gltf_skinned_meshes(&mut assets, &mesh_cache, assets_dir)?;
    desugar_fbx_skinned_meshes(&mut assets, &mesh_cache)?;
    desugar_gltf_meshes(&mut assets, &mesh_cache, assets_dir)?;
    desugar_fbx_meshes(&mut assets, &mesh_cache)?;
    desugar_animation_imports(&mut assets, assets_dir)?;
    desugar_root_motion(&mut assets)?;
    crate::character_shape::warn_unresolved(&assets);
    crate::character::bake::bake_shapes(&mut assets, |name| {
        mesh_cache.get(name).and_then(|e| e.bytes.as_deref())
    })?;

    // Intern every asset name to a dense AssetId in declaration order, then
    // resolve the scene-by-naming-convention references that the runtime can
    asset_id::reset_interner();
    let names: Vec<&str> = assets.iter().map(|a| a.name.as_str()).collect();
    asset_id::intern_all(&names);
    resolve_scene_refs(&mut assets);

    // Assign each resource its dense per-kind handle in declaration order and
    // install the map so resource references resolve during the reserialize pass
    // below: texture references (Material.albedo, Room.*_texture,
    // Decal/ParticleEmitter.texture) to a `TextureHandle`, and audio-clip
    // references (AudioEmitter.clip, AudioCue.clip, Story music/sounds) to an
    // `AudioClipHandle`. The assignment walks this same `assets` list that the
    // blob is emitted from, so a resource's handle equals the position the
    // runtime encounters it (a texture's albedo pool slot, an audio clip's drain
    // index / resource-table slot).
    crate::resource_handles::reset_resource_handles();
    let resource_assets = assets.iter().filter_map(|a| {
        crate::resource_handles::asset_resource_kind(&a.asset_type)
            .map(|kind| (asset_id::intern(&a.name), kind))
    });
    let mut resource_handles =
        crate::resource_handles::ResourceHandles::from_assets(resource_assets);
    // The mesh-source handle space spans four kinds (Mesh, ProceduralMesh,
    // VoxelChunk, mesh-kind File) and File is polymorphic, so it is assigned in a
    // second pass in the fixed block order the runtime enumerates mesh sources
    // rather than through the per-type classifier above.
    crate::resource_handles::assign_mesh_source_handles(&mut resource_handles, &assets);
    // Shader handles walk the same list, so a Material's `shader` reference
    // bakes to the position the runtime encounters that Shader at drain time.
    crate::resource_handles::assign_shader_handles(&mut resource_handles, &assets);
    // Install a clone; the original is kept to look up each resource asset's
    // handle while partitioning below.
    crate::resource_handles::install_resource_handles(resource_handles.clone());

    // Partition the world into component assets (each becomes a `BlobAssetDef`)
    // and resource assets (each becomes a resource-stream record). A resource
    // asset (AudioClip) has left the component registry, so it never goes through
    // `create_asset_def`; it is compiled + packed as a resource below. `named` is
    // therefore no longer 1:1 with `assets`, so `named_src[i]` records the source
    // asset index of each component def.
    use crate::registry::RegisteredType;
    let mut named: Vec<(String, BlobAssetDef)> = Vec::new();
    let mut named_src: Vec<usize> = Vec::new();
    let mut resource_jobs: Vec<(usize, RegisteredType, u32)> = Vec::new();
    for (i, asset) in assets.iter().enumerate() {
        if let Some((rt, kind)) =
            RegisteredType::parse(&asset.asset_type).and_then(|t| t.resource_kind().map(|k| (t, k)))
        {
            let id = asset_id::intern(&asset.name);
            let handle = resource_handles
                .get(kind, id)
                .expect("resource asset was assigned a handle above");
            resource_jobs.push((i, rt, handle));
            continue;
        }
        let req = AssetRequest {
            asset_type: asset.asset_type.clone(),
            args: Some(asset.args.clone()),
        };
        let mut def = asset_api::create_asset_def(&req).map_err(|e| {
            std::io::Error::new(
                std::io::ErrorKind::InvalidData,
                format!("Asset '{}': {}", asset.name, e),
            )
        })?;
        def.name = Some(asset_id::intern(&asset.name));
        named.push((asset.name.clone(), def));
        named_src.push(i);
    }

    // Dev-only: the file source behind each texture handle, so `cn debug`'s
    // hot-reload watcher can map a saved file back to its handle. Built in
    // handle order from the same resource jobs; a procedural texture (generator
    // set) leaves an empty source (nothing to watch).
    let texture_count = resource_jobs
        .iter()
        .filter(|(_, rt, _)| *rt == RegisteredType::Texture)
        .map(|(_, _, h)| *h as usize + 1)
        .max()
        .unwrap_or(0);
    let mut texture_sources = vec![TextureSourceInfo::default(); texture_count];
    for (asset_idx, rt, handle) in &resource_jobs {
        if *rt != RegisteredType::Texture {
            continue;
        }
        let asset = &assets[*asset_idx];
        let generator = asset
            .args
            .get("generator")
            .and_then(|v| v.as_str())
            .unwrap_or("");
        let (source, image_index) = if generator.is_empty() {
            (
                asset
                    .args
                    .get("source")
                    .and_then(|v| v.as_str())
                    .unwrap_or("")
                    .to_string(),
                asset
                    .args
                    .get("image_index")
                    .and_then(|v| v.as_u64())
                    .unwrap_or(0) as u32,
            )
        } else {
            (String::new(), 0)
        };
        texture_sources[*handle as usize] = TextureSourceInfo {
            name_id: asset_id::intern(&asset.name).0,
            source,
            image_index,
        };
    }

    // Dev-only: the file source behind each mesh handle, so `cn debug`'s
    // hot-reload watcher can re-import a saved `.glb`/`.fbx` into its draw
    // slots. Mesh handles are dense from 0 (the Mesh block leads the shared
    // mesh-source space); an inline-authored mesh leaves an empty source.
    let mesh_count = resource_jobs
        .iter()
        .filter(|(_, rt, _)| *rt == RegisteredType::Mesh)
        .map(|(_, _, h)| *h as usize + 1)
        .max()
        .unwrap_or(0);
    let mut mesh_sources = vec![MeshSourceInfo::default(); mesh_count];
    for (asset_idx, rt, handle) in &resource_jobs {
        if *rt != RegisteredType::Mesh {
            continue;
        }
        let args = &assets[*asset_idx].args;
        let str_arg = |key: &str| {
            args.get(key)
                .and_then(|v| v.as_str())
                .unwrap_or("")
                .to_string()
        };
        let u32_arg = |key: &str, default: u32| {
            args.get(key)
                .and_then(|v| v.as_u64())
                .unwrap_or(default as u64) as u32
        };
        mesh_sources[*handle as usize] = MeshSourceInfo {
            source: str_arg("source"),
            primitive_index: u32_arg("primitive_index", 0),
            lod_levels: u32_arg("lod_levels", 1),
            lod_distances: args
                .get("lod_distances")
                .and_then(|v| v.as_array())
                .map(|a| {
                    a.iter()
                        .filter_map(|d| d.as_f64())
                        .map(|d| d as f32)
                        .collect()
                })
                .unwrap_or_default(),
        };
    }

    // Scene payload ownership, derived from the resolved scene memberships and
    // the reference graph; drives the grouped packing below.
    let partition = crate::scene_partition::partition_scenes(&assets);

    // The world's physics reservation, counted from the same fully expanded
    // asset list the blob is emitted from.
    let physics_budget = crate::physics_budget::compute(&assets);
    crate::physics_budget::report_spawn_reservation(&assets);

    let compiled = compile_and_pack_payloads(
        &mut named,
        &named_src,
        PackContext {
            assets: &assets,
            resource_jobs: &resource_jobs,
            partition: &partition,
            mesh_source_handles: &resource_handles,
            max_blob_bytes: crate::blob::DEFAULT_MAX_BLOB_BYTES,
            assets_dir,
            artifacts_dir,
            mesh_cache: &mesh_cache,
            progress,
        },
    )?;

    // Lock-file provenance for the resource stream: `compiled.resources` is
    // emitted in `resource_jobs` order, so the two zip index-aligned. Texture
    // and Mesh records also carry their hot-reload source info so a blob boot
    // can reconstruct the catalogues without the authored args.
    let resource_locks: Vec<crate::blob::LockedResource> = resource_jobs
        .iter()
        .zip(compiled.resources.iter())
        .map(|((asset_idx, rt, handle), record)| {
            let asset = &assets[*asset_idx];
            crate::blob::LockedResource {
                name: asset.name.clone(),
                // Already interned by the declaration-order pass above, so
                // this is a lookup of the id the build assigned.
                id: Some(asset_id::intern(&asset.name).0),
                kind: rt.as_str().to_string(),
                handle: *handle,
                args_hash: crate::blob::checksum(asset.args.to_string().as_bytes()),
                payload_blob: record.payload.as_ref().map(|p| p.blob_index),
                texture_source: (*rt == RegisteredType::Texture).then(|| {
                    let t = &texture_sources[*handle as usize];
                    crate::blob::LockedTextureSource {
                        source: t.source.clone(),
                        image_index: t.image_index,
                    }
                }),
                mesh_source: (*rt == RegisteredType::Mesh).then(|| {
                    let m = &mesh_sources[*handle as usize];
                    crate::blob::LockedMeshSource {
                        source: m.source.clone(),
                        primitive_index: m.primitive_index,
                        lod_levels: m.lod_levels,
                        lod_distances: m.lod_distances.clone(),
                    }
                }),
            }
        })
        .collect();

    // The blob carries components (emitted in declaration order) plus the
    // resource stream. (System run order is no longer a build concern: every
    // system is internal client code ordered by the client's
    // `World::start` schedule.)
    let (names, defs): (Vec<String>, Vec<BlobAssetDef>) = named.into_iter().unzip();

    Ok(PipelineResult {
        defs,
        names,
        resources: compiled.resources,
        scene_groups: compiled.scene_groups,
        mesh_bounds: compiled.mesh_bounds,
        physics_budget,
        mesh_component_names: compiled.mesh_component_names,
        payloads: compiled.blobs,
        cache_hits: compiled.cache_hits,
        cache_misses: compiled.cache_misses,
        texture_sources,
        mesh_sources,
        resource_locks,
    })
}

// Per-asset state recorded by `probe_mesh_payload_cache`. `key` is the cache key
// computed from the asset's pre-desugar args; `bytes` is `Some` when the
// cache already held a compiled payload for that key. On a hit, the desugar
// pass skips the .glb parse for this asset; on a miss, compile_and_pack
// stores the freshly compiled payload under the same `key` so the next
// build's probe can re-use it.
#[derive(Clone)]
struct MeshCacheEntry {
    key: String,
    bytes: Option<Vec<u8>>,
}

// Hash every source-backed Mesh / SkinnedMesh asset's pre-desugar args and
// referenced source file (`.glb` or `.fbx`), then probe the content-addressed
// payload cache. Returns one entry per source-backed asset name. Assets
// without a `source` are not probed: their args don't depend on a file, so the
// regular per-asset cache path inside compile_and_pack_payloads is sufficient.
fn probe_mesh_payload_cache(
    assets: &[WorldJsonlAsset],
    assets_dir: Option<&Path>,
    artifacts_dir: Option<&str>,
) -> std::collections::HashMap<String, MeshCacheEntry> {
    use crate::resource_handles::{RegisteredType, ResourceAssetCompile};

    let mut out = std::collections::HashMap::new();
    let empty: [WorldJsonlAsset; 0] = [];
    for asset in assets {
        let has_source = asset
            .args
            .get("source")
            .and_then(|v| v.as_str())
            .map(|s| !s.is_empty())
            .unwrap_or(false);
        if !has_source && asset.args.get("character_model").is_none() {
            continue;
        }

        // Both mesh kinds are resource assets: their caches key on the
        // resource discriminant and resource source list.
        let rt = if asset.asset_type == MESH_TYPE {
            RegisteredType::Mesh
        } else if asset.asset_type == SKINNED_MESH_TYPE {
            RegisteredType::SkinnedMesh
        } else {
            continue;
        };
        let ctx = crate::asset::BuildCtx {
            name: asset.name.as_str(),
            assets_dir,
            artifacts_dir,
            all_assets: &empty,
        };
        let discriminant = RESOURCE_CACHE_DISC_BASE + job_resource_kind(rt) as u8;
        let inputs = crate::asset::CacheInputs::extra(rt.source_files(&asset.args, assets_dir));
        // A shape baked into the mesh changes its payload as much as the
        // source does, so its args join the key.
        let keyed = match crate::character::bake::baking_shape_args(assets, &asset.name) {
            Some(shape) => serde_json::json!({"mesh": asset.args, "baked_shape": shape}),
            None => asset.args.clone(),
        };
        let key = crate::cache::payload_key(discriminant, &keyed, &ctx, &inputs);
        let bytes = crate::cache::load(&key);
        out.insert(asset.name.clone(), MeshCacheEntry { key, bytes });
    }
    out
}

// Which skinned mesh of the asset's source file it selects; absent means the
// file's first.
fn skin_index_arg(asset: &WorldJsonlAsset) -> u32 {
    asset
        .args
        .get("skin_index")
        .and_then(|v| v.as_u64())
        .unwrap_or(0) as u32
}

// Skin selector per SkinnedMesh asset name. An Animation resolves its channels
// against its target's skeleton, so it inherits the target's selector rather
// than carrying its own: the two must agree or joint indices bind to a
// different skeleton and the clip silently mis-poses.
fn skin_index_by_target(assets: &[WorldJsonlAsset]) -> std::collections::HashMap<String, u32> {
    assets
        .iter()
        .filter(|a| a.asset_type == SKINNED_MESH_TYPE)
        .map(|a| (a.name.clone(), skin_index_arg(a)))
        .collect()
}

// Expand glTF-sourced SkinnedMesh assets in place: parse the referenced .glb
// and write the imported geometry + skeleton into the asset's inline
// `vertices` / `indices` / `skeleton` args. A SkinnedMesh with no `source` is
// left untouched, so an inline-authored mesh is byte-for-byte unchanged;
// `.fbx` sources belong to `desugar_fbx_skinned_meshes`.
// Skips an asset whose cache probe found a precompiled payload: there is no
// reason to parse the .glb when the bytes are already in hand.
fn desugar_gltf_skinned_meshes(
    assets: &mut [WorldJsonlAsset],
    mesh_cache: &std::collections::HashMap<String, MeshCacheEntry>,
    assets_dir: Option<&Path>,
) -> std::io::Result<()> {
    for asset in assets.iter_mut() {
        if asset.asset_type != SKINNED_MESH_TYPE {
            continue;
        }
        let source = asset
            .args
            .get("source")
            .and_then(|v| v.as_str())
            .unwrap_or("")
            .to_string();
        let character_model = asset.args.get("character_model").cloned();
        if character_model.is_none()
            && (source.is_empty() || source.to_lowercase().ends_with(".fbx"))
        {
            continue;
        }
        // Cache probe found a compiled payload for this asset, no need
        // to parse the .glb. compile_and_pack_payloads will use the bytes
        // directly. Leave the args un-desugared so they keep matching the
        // pre-desugar cache key on the next build.
        if matches!(
            mesh_cache.get(&asset.name),
            Some(MeshCacheEntry { bytes: Some(_), .. })
        ) {
            continue;
        }

        let invalid = |msg: String| std::io::Error::new(std::io::ErrorKind::InvalidData, msg);
        let imported = match character_model {
            Some(arg) => {
                let arg: crate::character::import::CharacterModelArg = serde_json::from_value(arg)
                    .map_err(|e| {
                        invalid(format!("Asset '{}': character_model: {e}", asset.name))
                    })?;
                crate::character::import::import_model(
                    &asset.name,
                    &arg.schema,
                    &arg.model,
                    assets_dir,
                )
                .map_err(invalid)?
            }
            None => crate::gltf::import_skinned_glb(&source, skin_index_arg(asset), assets_dir)
                .map_err(|e| {
                    invalid(format!("Asset '{}': glTF import failed: {}", asset.name, e))
                })?,
        };

        let name = asset.name.clone();
        let obj = asset.args.as_object_mut().ok_or_else(|| {
            std::io::Error::new(
                std::io::ErrorKind::InvalidData,
                format!("Asset '{}': args is not a JSON object", name),
            )
        })?;
        let encode = |field: &str, value: serde_json::Result<serde_json::Value>| {
            value.map_err(|e| {
                std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!(
                        "Asset '{}': failed to encode imported {}: {}",
                        name, field, e
                    ),
                )
            })
        };
        obj.insert(
            "vertices".to_string(),
            encode("vertices", serde_json::to_value(&imported.vertices))?,
        );
        obj.insert(
            "indices".to_string(),
            encode("indices", serde_json::to_value(&imported.indices))?,
        );
        obj.insert(
            "skeleton".to_string(),
            encode("skeleton", serde_json::to_value(&imported.skeleton))?,
        );
        if !imported.morph_target_names.is_empty() {
            obj.insert(
                "morph_target_names".to_string(),
                encode(
                    "morph_target_names",
                    serde_json::to_value(&imported.morph_target_names),
                )?,
            );
            obj.insert(
                "morph_deltas".to_string(),
                encode("morph_deltas", serde_json::to_value(&imported.morph_deltas))?,
            );
        }
        obj.remove("character_model");
        tracing::info!(
            "Asset '{}': imported glTF '{}': {} vertices, {} indices, {} joints, {} morph target(s)",
            asset.name,
            if source.is_empty() {
                "character model"
            } else {
                &source
            },
            imported.vertices.len(),
            imported.indices.len(),
            imported.skeleton.len(),
            imported.morph_target_names.len()
        );
    }
    Ok(())
}

// Expand FBX-sourced SkinnedMesh assets in place, mirroring the glTF pass:
// the file's first skinned geometry lands in the asset's inline `vertices` /
// `indices` / `skeleton` args.
fn desugar_fbx_skinned_meshes(
    assets: &mut [WorldJsonlAsset],
    mesh_cache: &std::collections::HashMap<String, MeshCacheEntry>,
) -> std::io::Result<()> {
    for asset in assets.iter_mut() {
        if asset.asset_type != SKINNED_MESH_TYPE {
            continue;
        }
        let source = asset
            .args
            .get("source")
            .and_then(|v| v.as_str())
            .unwrap_or("")
            .to_string();
        if !source.to_lowercase().ends_with(".fbx") {
            continue;
        }
        if matches!(
            mesh_cache.get(&asset.name),
            Some(MeshCacheEntry { bytes: Some(_), .. })
        ) {
            continue;
        }

        let imported =
            crate::fbx::import_skinned_fbx(&source, skin_index_arg(asset)).map_err(|e| {
                std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!("Asset '{}': FBX import failed: {}", asset.name, e),
                )
            })?;

        let name = asset.name.clone();
        let obj = asset.args.as_object_mut().ok_or_else(|| {
            std::io::Error::new(
                std::io::ErrorKind::InvalidData,
                format!("Asset '{}': args is not a JSON object", name),
            )
        })?;
        let encode = |field: &str, value: serde_json::Result<serde_json::Value>| {
            value.map_err(|e| {
                std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!(
                        "Asset '{}': failed to encode imported {}: {}",
                        name, field, e
                    ),
                )
            })
        };
        obj.insert(
            "vertices".to_string(),
            encode("vertices", serde_json::to_value(&imported.vertices))?,
        );
        obj.insert(
            "indices".to_string(),
            encode("indices", serde_json::to_value(&imported.indices))?,
        );
        obj.insert(
            "skeleton".to_string(),
            encode("skeleton", serde_json::to_value(&imported.skeleton))?,
        );
        tracing::info!(
            "Asset '{}': imported FBX '{}': {} vertices, {} indices, {} joints",
            asset.name,
            source,
            imported.vertices.len(),
            imported.indices.len(),
            imported.skeleton.len()
        );
    }
    Ok(())
}

// Expand glTF-sourced static `Mesh` assets in place: parse the referenced
// `.glb` and write the imported primitive geometry into the asset's inline
// `vertices` / `indices` args. A Mesh with no `source` is left untouched. The
// GLB is parsed once per unique path; ABeautifulGame fans 35+ Mesh assets out
// of one file, so memoization keeps this O(files) rather than O(primitives).
fn desugar_gltf_meshes(
    assets: &mut [WorldJsonlAsset],
    mesh_cache: &std::collections::HashMap<String, MeshCacheEntry>,
    assets_dir: Option<&Path>,
) -> std::io::Result<()> {
    use crate::components::VertexData;
    use std::collections::HashMap;

    // One split chunk: its vertices and index buffer.
    type Chunk = (Vec<VertexData>, Vec<u16>);

    let mut parsed_cache: HashMap<String, crate::gltf_source::GltfDoc> = HashMap::new();
    // Memoize the chunk split per (source, primitive_index) so an oversized
    // primitive that fans into N chunked Mesh assets is split exactly once.
    let mut chunk_cache: HashMap<(String, u32), Vec<Chunk>> = HashMap::new();

    for asset in assets.iter_mut() {
        if asset.asset_type != MESH_TYPE {
            continue;
        }
        let source = asset
            .args
            .get("source")
            .and_then(|v| v.as_str())
            .unwrap_or("")
            .to_string();
        if source.is_empty() {
            continue;
        }
        // `.fbx` sources are handled by `desugar_fbx_meshes`; this pass owns
        // only the glTF containers.
        let lower = source.to_lowercase();
        if !lower.ends_with(".glb") && !lower.ends_with(".gltf") {
            continue;
        }
        // Skip the .glb parse when the cache probe already produced bytes
        // for this asset (see `desugar_gltf_skinned_meshes` for the same
        // pattern). Args stay pre-desugar so the next build's probe hits.
        if matches!(
            mesh_cache.get(&asset.name),
            Some(MeshCacheEntry { bytes: Some(_), .. })
        ) {
            continue;
        }
        let primitive_index = asset
            .args
            .get("primitive_index")
            .and_then(|v| v.as_u64())
            .unwrap_or(0) as u32;
        let chunk_index = asset
            .args
            .get("chunk_index")
            .and_then(|v| v.as_u64())
            .map(|n| n as usize);

        if !parsed_cache.contains_key(&source) {
            let doc = crate::glb::parse_glb(&source, assets_dir).map_err(|e| {
                std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!("Asset '{}': glTF import failed: {}", asset.name, e),
                )
            })?;
            parsed_cache.insert(source.clone(), doc);
        }
        let doc = parsed_cache.get(&source).expect("just inserted");

        let (vertices, indices) = if let Some(chunk_idx) = chunk_index {
            let key = (source.clone(), primitive_index);
            if !chunk_cache.contains_key(&key) {
                let (verts, indices32) =
                    crate::glb::read_primitive_geometry(doc, &source, primitive_index).map_err(
                        |e| {
                            std::io::Error::new(
                                std::io::ErrorKind::InvalidData,
                                format!("Asset '{}': glTF import failed: {}", asset.name, e),
                            )
                        },
                    )?;
                let chunks = crate::glb::split_into_u16_chunks(&verts, &indices32);
                chunk_cache.insert(key.clone(), chunks);
            }
            let chunks = chunk_cache.get(&key).expect("just inserted");
            let chunk = chunks.get(chunk_idx).ok_or_else(|| {
                std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!(
                        "Asset '{}': chunk_index {} out of range, '{}' primitive {} \
                         splits into {} chunk(s)",
                        asset.name,
                        chunk_idx,
                        source,
                        primitive_index,
                        chunks.len(),
                    ),
                )
            })?;
            chunk.clone()
        } else {
            crate::glb::import_static_glb_primitive_from_doc(doc, &source, primitive_index)
                .map_err(|e| {
                    std::io::Error::new(
                        std::io::ErrorKind::InvalidData,
                        format!("Asset '{}': glTF import failed: {}", asset.name, e),
                    )
                })?
        };

        let name = asset.name.clone();
        let obj = asset.args.as_object_mut().ok_or_else(|| {
            std::io::Error::new(
                std::io::ErrorKind::InvalidData,
                format!("Asset '{}': args is not a JSON object", name),
            )
        })?;
        let encode = |field: &str, value: serde_json::Result<serde_json::Value>| {
            value.map_err(|e| {
                std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!(
                        "Asset '{}': failed to encode imported {}: {}",
                        name, field, e
                    ),
                )
            })
        };
        let vlen = vertices.len();
        let ilen = indices.len();
        obj.insert(
            "vertices".to_string(),
            encode("vertices", serde_json::to_value(&vertices))?,
        );
        obj.insert(
            "indices".to_string(),
            encode("indices", serde_json::to_value(&indices))?,
        );
        match chunk_index {
            Some(c) => tracing::info!(
                "Asset '{}': imported glTF '{}' primitive {} chunk {}: {} vertices, {} indices",
                asset.name,
                source,
                primitive_index,
                c,
                vlen,
                ilen,
            ),
            None => tracing::info!(
                "Asset '{}': imported glTF '{}' primitive {}: {} vertices, {} indices",
                asset.name,
                source,
                primitive_index,
                vlen,
                ilen,
            ),
        }
    }
    Ok(())
}

// Expand FBX-sourced Mesh assets in place: parse the `.fbx` into an FbxScene
// and write the imported geometry into each asset's inline `vertices` /
// `indices` args, keyed by `primitive_index` and optional `chunk_index`. A Mesh
// whose source is not a `.fbx` is left to `desugar_gltf_meshes`. The FBX is
// parsed once per unique path (Bistro fans thousands of Mesh assets out of one
// file) and each primitive's u16 chunk split is memoized.
fn desugar_fbx_meshes(
    assets: &mut [WorldJsonlAsset],
    mesh_cache: &std::collections::HashMap<String, MeshCacheEntry>,
) -> std::io::Result<()> {
    use crate::components::VertexData;
    use crate::fbx::FbxScene;
    use std::collections::HashMap;

    type Chunk = (Vec<VertexData>, Vec<u16>);

    let mut parsed_cache: HashMap<String, FbxScene> = HashMap::new();
    let mut chunk_cache: HashMap<(String, u32), Vec<Chunk>> = HashMap::new();

    for asset in assets.iter_mut() {
        if asset.asset_type != MESH_TYPE {
            continue;
        }
        let source = asset
            .args
            .get("source")
            .and_then(|v| v.as_str())
            .unwrap_or("")
            .to_string();
        if !source.to_lowercase().ends_with(".fbx") {
            continue;
        }
        // Honour the same content-addressed cache the glTF pass uses: a probe
        // hit means the compiled payload is already in hand, so skip the parse.
        if matches!(
            mesh_cache.get(&asset.name),
            Some(MeshCacheEntry { bytes: Some(_), .. })
        ) {
            continue;
        }
        let primitive_index = asset
            .args
            .get("primitive_index")
            .and_then(|v| v.as_u64())
            .unwrap_or(0) as u32;
        let chunk_index = asset
            .args
            .get("chunk_index")
            .and_then(|v| v.as_u64())
            .map(|n| n as usize)
            .unwrap_or(0);

        if !parsed_cache.contains_key(&source) {
            let scene = crate::fbx::parse_fbx(&source).map_err(|e| {
                std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!("Asset '{}': FBX import failed: {}", asset.name, e),
                )
            })?;
            parsed_cache.insert(source.clone(), scene);
        }
        let scene = parsed_cache.get(&source).expect("just inserted");

        let key = (source.clone(), primitive_index);
        if !chunk_cache.contains_key(&key) {
            let (verts, indices32) = crate::fbx::read_primitive_geometry(scene, primitive_index)
                .map_err(|e| {
                    std::io::Error::new(
                        std::io::ErrorKind::InvalidData,
                        format!("Asset '{}': FBX import failed: {}", asset.name, e),
                    )
                })?;
            let chunks = crate::glb::split_into_u16_chunks(&verts, &indices32);
            chunk_cache.insert(key.clone(), chunks);
        }
        let chunks = chunk_cache.get(&key).expect("just inserted");
        let chunk = chunks.get(chunk_index).ok_or_else(|| {
            std::io::Error::new(
                std::io::ErrorKind::InvalidData,
                format!(
                    "Asset '{}': chunk_index {} out of range, '{}' primitive {} splits into {} chunk(s)",
                    asset.name,
                    chunk_index,
                    source,
                    primitive_index,
                    chunks.len(),
                ),
            )
        })?;
        let (vertices, indices) = chunk.clone();

        let name = asset.name.clone();
        let obj = asset.args.as_object_mut().ok_or_else(|| {
            std::io::Error::new(
                std::io::ErrorKind::InvalidData,
                format!("Asset '{}': args is not a JSON object", name),
            )
        })?;
        let vlen = vertices.len();
        let ilen = indices.len();
        obj.insert(
            "vertices".to_string(),
            serde_json::to_value(&vertices).map_err(|e| {
                std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!(
                        "Asset '{}': failed to encode imported vertices: {}",
                        name, e
                    ),
                )
            })?,
        );
        obj.insert(
            "indices".to_string(),
            serde_json::to_value(&indices).map_err(|e| {
                std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!("Asset '{}': failed to encode imported indices: {}", name, e),
                )
            })?,
        );
        tracing::info!(
            "Asset '{}': imported FBX '{}' primitive {} chunk {}: {} vertices, {} indices",
            asset.name,
            source,
            primitive_index,
            chunk_index,
            vlen,
            ilen,
        );
    }
    Ok(())
}

// Expand file-sourced `Animation` assets in place, dispatching on the source
// extension: `.fbx` clips bake through the FBX importer (at the asset's
// `sample_rate`), everything else parses as glTF. The clip is picked by
// `animation_name` (preferred) or `animation_index` and the asset's
// `duration` + `tracks` are replaced with the imported data. An Animation
// with no `source` is left untouched, so inline-authored clips are
// byte-for-byte unchanged. Channels targeting non-joint nodes are dropped
// silently by the importers.
fn desugar_animation_imports(
    assets: &mut [WorldJsonlAsset],
    assets_dir: Option<&Path>,
) -> std::io::Result<()> {
    use crate::components::Animation;
    use crate::ecs::Component;

    let skin_by_target = skin_index_by_target(assets);

    for asset in assets.iter_mut() {
        if asset.asset_type != Animation::NAME {
            continue;
        }
        let source = asset
            .args
            .get("source")
            .and_then(|v| v.as_str())
            .unwrap_or("")
            .to_string();
        if source.is_empty() {
            continue;
        }
        let animation_name = asset
            .args
            .get("animation_name")
            .and_then(|v| v.as_str())
            .unwrap_or("")
            .to_string();
        let animation_index = asset
            .args
            .get("animation_index")
            .and_then(|v| v.as_u64())
            .unwrap_or(0) as usize;
        let skin_index = asset
            .args
            .get("target")
            .and_then(|v| v.as_str())
            .and_then(|t| skin_by_target.get(t))
            .copied()
            .unwrap_or(0);

        let imported = if source.to_lowercase().ends_with(".fbx") {
            let sample_rate = asset
                .args
                .get("sample_rate")
                .and_then(|v| v.as_f64())
                .unwrap_or(30.0) as f32;
            crate::fbx::import_fbx_animation(
                &source,
                animation_index as u32,
                &animation_name,
                sample_rate,
                skin_index,
            )
            .map_err(|e| {
                std::io::Error::new(
                    std::io::ErrorKind::InvalidData,
                    format!("Asset '{}': FBX import failed: {}", asset.name, e),
                )
            })?
        } else {
            // Look up by name when authored; fall back to the numeric index.
            let resolved_index = if !animation_name.is_empty() {
                let names = crate::gltf::glb_animation_names(&source, assets_dir).map_err(|e| {
                    std::io::Error::new(
                        std::io::ErrorKind::InvalidData,
                        format!("Asset '{}': glTF import failed: {}", asset.name, e),
                    )
                })?;
                names
                    .iter()
                    .position(|n| n == &animation_name)
                    .ok_or_else(|| {
                        std::io::Error::new(
                            std::io::ErrorKind::InvalidData,
                            format!(
                                "Asset '{}': glTF '{}' has no animation named '{}' \
                                 (file contains: {:?})",
                                asset.name, source, animation_name, names
                            ),
                        )
                    })?
            } else {
                animation_index
            };

            crate::gltf::import_glb_animation(&source, resolved_index, skin_index, assets_dir)
                .map_err(|e| {
                    std::io::Error::new(
                        std::io::ErrorKind::InvalidData,
                        format!("Asset '{}': glTF import failed: {}", asset.name, e),
                    )
                })?
        };

        // Convert ImportedAnimation -> the asset's serialised track shape.
        let tracks_json: Vec<serde_json::Value> = imported
            .tracks
            .iter()
            .map(|track| {
                let keyframes: Vec<serde_json::Value> = track
                    .keys
                    .iter()
                    .map(|k| {
                        serde_json::json!({
                            "time": k.time,
                            "translation": k.pose.translation,
                            "rotation_deg": k.pose.rotation_deg,
                            "scale": k.pose.scale,
                        })
                    })
                    .collect();
                serde_json::json!({
                    "joint": track.joint,
                    "keyframes": keyframes,
                })
            })
            .collect();

        let name = asset.name.clone();
        let obj = asset.args.as_object_mut().ok_or_else(|| {
            std::io::Error::new(
                std::io::ErrorKind::InvalidData,
                format!("Asset '{}': args is not a JSON object", name),
            )
        })?;
        obj.insert("duration".to_string(), serde_json::json!(imported.duration));
        obj.insert("tracks".to_string(), serde_json::Value::Array(tracks_json));
        if !imported.morph_track.is_empty() {
            let morph_json: Vec<serde_json::Value> = imported
                .morph_track
                .iter()
                .map(|k| serde_json::json!({"time": k.time, "weights": k.weights}))
                .collect();
            obj.insert(
                "morph_track".to_string(),
                serde_json::Value::Array(morph_json),
            );
        }
        tracing::info!(
            "Asset '{}': imported '{}' animation '{}': {:.3} s, {} track(s), {} morph key(s)",
            asset.name,
            source,
            imported.name,
            imported.duration,
            imported.tracks.len(),
            imported.morph_track.len(),
        );
    }
    Ok(())
}

// Bake root motion on every Animation that opted in: strip the root joint's
// travel out of the pose tracks into the asset's `root_track` (see
// `root_motion::bake_root_motion`). Runs after the glTF pass so imported
// tracks are already inline; an Animation without `root_motion` is
// untouched. A root-motion clip whose root joint has no track produces an
// empty curve, which would silently never move a character, so it warns.
fn desugar_root_motion(assets: &mut [WorldJsonlAsset]) -> std::io::Result<()> {
    use crate::components::Animation;
    use crate::ecs::Component;

    // This deserializes each flagged clip (whose `target` is a name reference),
    // so the name resolver must be installed. The full pipeline resets the
    // interner before reaching here; installing it again is a cheap no-op and
    // keeps this pass correct when called on its own.
    crate::ecs::asset_id::ensure_name_resolver();

    for asset in assets.iter_mut() {
        if asset.asset_type != Animation::NAME
            || asset.args.get("root_motion").and_then(|v| v.as_bool()) != Some(true)
        {
            continue;
        }
        let mut anim: Animation = Deserialize::deserialize(&asset.args).map_err(|e| {
            std::io::Error::new(
                std::io::ErrorKind::InvalidData,
                format!(
                    "Asset '{}': root-motion bake failed to parse args: {}",
                    asset.name, e
                ),
            )
        })?;
        crate::root_motion::bake_root_motion(&mut anim);
        if anim.root_track.is_empty() {
            tracing::warn!(
                "Asset '{}': root_motion is set but the clip has no track on the root \
                 joint; the character will not move",
                asset.name
            );
        }
        let name = asset.name.clone();
        let obj = asset.args.as_object_mut().ok_or_else(|| {
            std::io::Error::new(
                std::io::ErrorKind::InvalidData,
                format!("Asset '{}': args is not a JSON object", name),
            )
        })?;
        obj.insert(
            "tracks".to_string(),
            serde_json::to_value(&anim.tracks).expect("serialize animation tracks"),
        );
        obj.insert(
            "root_track".to_string(),
            serde_json::to_value(&anim.root_track).expect("serialize root track"),
        );
        tracing::info!(
            "Asset '{}': baked root motion ({} key(s){})",
            asset.name,
            anim.root_track.len(),
            if anim.root_motion_y { ", incl. Y" } else { "" },
        );
    }
    Ok(())
}

/// Validate world JSONL without running compilation. Runs the full front half
/// of the pipeline (load, expand, semantic checks) plus a per-asset type/args
/// resolution, but stops short of compiling payloads: intended for fast
/// server-side pre-deploy checks where shader compilation is not needed.
/// `assets_dir` is the asset search root the expansion passes resolve their
/// sources and presets against. Every problem found is reported in a single
/// newline-joined error.
pub fn validate_world_jsonl(content: &str, assets_dir: Option<&Path>) -> std::io::Result<()> {
    let loaded = crate::world::prepare_world(content, assets_dir).map_err(errors_to_io)?;

    let mut errors: Vec<String> = Vec::new();
    for asset in &loaded.assets {
        // A resource asset does not build a component def, so skip the component
        // resolution for it.
        if crate::registry::RegisteredType::parse(&asset.asset_type)
            .is_some_and(|t| t.is_resource())
        {
            continue;
        }
        let req = AssetRequest {
            asset_type: asset.asset_type.clone(),
            args: Some(asset.args.clone()),
        };
        if let Err(e) = asset_api::create_asset_def(&req) {
            errors.push(format!("Asset '{}': {}", asset.name, e));
        }
    }

    if errors.is_empty() {
        Ok(())
    } else {
        Err(errors_to_io(errors))
    }
}

// Cache-key discriminant base for resource payloads. Resource kinds are keyed
// as `128 + ResourceKind as u8` so their cache keys never collide with a
// component discriminant (all < 128, the `ComponentMask` ceiling).
const RESOURCE_CACHE_DISC_BASE: u8 = 128;

// One compiled resource awaiting packing: its kind tag + handle, the compiled
// bytes, whether those bytes are the record's inline data (a data resource like
// Material) or a blob payload, and the baked runtime data a hybrid kind
// (SkinnedMesh) carries alongside its payload (empty for everything else; it
// bakes from the authored args, so it sits outside the payload cache).
struct PendingResource {
    kind: u8,
    handle: u32,
    bytes: Vec<u8>,
    is_data: bool,
    extra_data: Vec<u8>,
}

// The output of the compile + pack pass: the packed blob payload sections, the
// resource-stream records (each with its payload locator), and cache accounting.
struct CompiledOutput {
    scene_groups: Vec<SceneGroup>,
    mesh_bounds: Vec<MeshBoundsRecord>,
    mesh_component_names: Vec<(u32, String)>,
    blobs: Vec<Vec<u8>>,
    resources: Vec<ResourceRecord>,
    cache_hits: usize,
    cache_misses: usize,
}

// Baked geometry summary of one compiled static-mesh payload, keyed by its
// unified mesh-source handle. None when the payload does not parse as a
// static mesh (VoxelChunk voxel data, a malformed payload); absence means the
// runtime decodes that payload eagerly.
fn mesh_bounds_record(handle: u32, bytes: &[u8]) -> Option<MeshBoundsRecord> {
    let (verts, idxs, _) = concinnity_core::gfx::mesh_payload::deserialise_with_lods(bytes).ok()?;
    let first = verts.first()?;
    let mut min = first.pos;
    let mut max = first.pos;
    for v in &verts {
        for axis in 0..3 {
            min[axis] = min[axis].min(v.pos[axis]);
            max[axis] = max[axis].max(v.pos[axis]);
        }
    }
    Some(MeshBoundsRecord {
        handle,
        min,
        max,
        vertex_count: verts.len() as u32,
        index_count: idxs.len() as u32,
    })
}

// Read-only inputs to the compile + pack pass: the world being packed and the
// build context, as opposed to the def stream the pass mutates.
#[derive(Clone, Copy)]
struct PackContext<'a> {
    assets: &'a [WorldJsonlAsset],
    resource_jobs: &'a [(usize, crate::registry::RegisteredType, u32)],
    partition: &'a crate::scene_partition::ScenePartition,
    mesh_source_handles: &'a crate::resource_handles::ResourceHandles,
    max_blob_bytes: u64,
    assets_dir: Option<&'a Path>,
    artifacts_dir: Option<&'a str>,
    mesh_cache: &'a std::collections::HashMap<String, MeshCacheEntry>,
    progress: Option<&'a (dyn Fn(BuildProgress) + Sync)>,
}

fn compile_and_pack_payloads(
    named: &mut [(String, BlobAssetDef)],
    named_src: &[usize],
    pack_ctx: PackContext<'_>,
) -> std::io::Result<CompiledOutput> {
    use rayon::prelude::*;
    use std::sync::atomic::{AtomicUsize, Ordering};

    let PackContext {
        assets,
        resource_jobs,
        partition,
        mesh_source_handles,
        max_blob_bytes,
        assets_dir,
        artifacts_dir,
        mesh_cache,
        progress,
    } = pack_ctx;

    let compiled_indices: Vec<usize> = named
        .iter()
        .enumerate()
        .filter(|(i, (_, def))| {
            if def.kind != AssetKind::Component {
                return false;
            }
            let Some(ct) = RegisteredType::from_discriminant(def.discriminant) else {
                return false;
            };
            if ct.as_str() == "File" {
                // only compile File assets whose kind maps to a supported payload
                // `named[i]` maps to `assets[named_src[i]]`.
                return assets[named_src[*i]]
                    .args
                    .get("kind")
                    .and_then(|k| k.as_str())
                    .and_then(FileKind::from_ext)
                    .map(|fk| fk.is_mesh())
                    .unwrap_or(false);
            }
            ct.registration().needs_compilation()
        })
        .map(|(i, _)| i)
        .collect();

    // Snapshot each job's inputs so the parallel compile borrows nothing from
    // `named`, which is mutated afterwards to record payload locators.
    let jobs: Vec<(usize, String, u8)> = compiled_indices
        .iter()
        .map(|&idx| {
            let (name, def) = &named[idx];
            (idx, name.clone(), def.discriminant)
        })
        .collect();

    // Compile assets in parallel. Each job is independent (it reads only its
    // own args and produces its own payload bytes) and the payload cache is
    // content-addressed, so concurrent hits and stores never collide. The
    // collected order follows `jobs`, so packing below stays deterministic.
    let cache_hits = AtomicUsize::new(0);
    let compile_total = jobs.len() as u32;
    let compiled_count = AtomicUsize::new(0);
    let report_one = || {
        if let Some(p) = progress {
            let done = compiled_count.fetch_add(1, Ordering::Relaxed) as u32 + 1;
            p(BuildProgress {
                stage: "compile",
                done,
                total: compile_total,
            });
        }
    };
    let pending: Vec<(usize, Vec<u8>)> = jobs
        .par_iter()
        .map(
            |(idx, name, discriminant)| -> std::io::Result<(usize, Vec<u8>)> {
                let ct = RegisteredType::from_discriminant(*discriminant).ok_or_else(|| {
                    std::io::Error::new(
                        std::io::ErrorKind::InvalidData,
                        format!("Invalid RegisteredType discriminant for asset '{}'", name),
                    )
                })?;

                // The job carries the `named` index; map it to its source asset
                // via `named_src` (`named` is not 1:1 with `assets` once resource
                // assets are partitioned out).
                let asset_args = &assets[named_src[*idx]].args;

                let ctx = crate::asset::BuildCtx {
                    name: name.as_str(),
                    assets_dir,
                    artifacts_dir,
                    all_assets: assets,
                };

                // GLB-sourced Mesh / SkinnedMesh assets are probed before
                // desugar; honor those results here so the .glb parse really
                // is skipped on cache hits. On a miss the precomputed key is
                // used at store time, keeping the next build's probe valid.
                if let Some(entry) = mesh_cache.get(name) {
                    if let Some(bytes) = &entry.bytes {
                        cache_hits.fetch_add(1, Ordering::Relaxed);
                        return Ok((*idx, bytes.clone()));
                    }
                    let compiled_bytes = compile_by_type(ct, asset_args, &ctx)?;
                    crate::cache::store(&entry.key, &compiled_bytes);
                    return Ok((*idx, compiled_bytes));
                }

                // Reuse a cached payload when the asset's inputs are unchanged;
                // otherwise compile and populate the cache for the next build.
                let inputs = cache_inputs_by_type(ct, asset_args, &ctx);
                let key = crate::cache::payload_key(*discriminant, asset_args, &ctx, &inputs);
                if let Some(bytes) = crate::cache::load(&key) {
                    cache_hits.fetch_add(1, Ordering::Relaxed);
                    return Ok((*idx, bytes));
                }
                let compiled_bytes = compile_by_type(ct, asset_args, &ctx)?;
                crate::cache::store(&key, &compiled_bytes);
                Ok((*idx, compiled_bytes))
            },
        )
        .inspect(|_| report_one())
        .collect::<std::io::Result<Vec<_>>>()?;

    let component_hits = cache_hits.into_inner();

    // Compile the resource-stream payloads (AudioClip today). Few and cheap, so
    // this stays serial; the content-addressed payload cache still short-circuits
    // an unchanged source. Bypasses the `BuildAsset`/`RegisteredType` path a
    // component takes -- a resource is no longer a component.
    let mut resource_hits = 0usize;
    let mut resource_pending: Vec<PendingResource> = Vec::new();
    for (asset_idx, rt, handle) in resource_jobs {
        let asset = &assets[*asset_idx];
        let ctx = crate::asset::BuildCtx {
            name: asset.name.as_str(),
            assets_dir,
            artifacts_dir,
            all_assets: assets,
        };
        let extra_data = rt
            .compile_data(&asset.name, &asset.args)?
            .unwrap_or_default();
        // A glTF/FBX-sourced mesh was probed before desugar; honor that result so
        // the source parse really is skipped on a hit and the pre-desugar key is
        // reused at store time (same contract as the component gltf-cache path).
        let bytes = if let Some(entry) = mesh_cache.get(&asset.name) {
            match &entry.bytes {
                Some(bytes) => {
                    resource_hits += 1;
                    bytes.clone()
                }
                None => {
                    let compiled = rt.compile_payload(&asset.args, assets_dir)?;
                    crate::cache::store(&entry.key, &compiled);
                    compiled
                }
            }
        } else {
            // Every resource asset compiles identically on every backend, so its
            // entry is shared across a DirectX and a Vulkan cook.
            let inputs = crate::asset::CacheInputs::extra(rt.source_files(&asset.args, assets_dir));
            let key = crate::cache::payload_key(
                RESOURCE_CACHE_DISC_BASE + job_resource_kind(*rt) as u8,
                &asset.args,
                &ctx,
                &inputs,
            );
            match crate::cache::load(&key) {
                Some(bytes) => {
                    resource_hits += 1;
                    bytes
                }
                None => {
                    let compiled = rt.compile_payload(&asset.args, assets_dir)?;
                    crate::cache::store(&key, &compiled);
                    compiled
                }
            }
        };
        resource_pending.push(PendingResource {
            kind: job_resource_kind(*rt) as u8,
            handle: *handle,
            bytes,
            is_data: rt.is_data(),
            extra_data,
        });
    }

    let cache_hits = component_hits + resource_hits;
    let cache_misses = (pending.len() - component_hits) + (resource_pending.len() - resource_hits);

    // Ownership of each payload, precomputed so the packing loops below can
    // mutate `named` freely. Resource jobs and `resource_pending` are
    // index-aligned.
    use crate::scene_partition::Owner;
    let comp_owners: Vec<Owner> = pending
        .iter()
        .map(|(idx, _)| partition.owner(&named[*idx].0))
        .collect();
    let res_owners: Vec<Owner> = resource_jobs
        .iter()
        .map(|(asset_idx, _, _)| partition.owner(&assets[*asset_idx].name))
        .collect();

    // Baked AABB + counts for every static mesh payload, resource-stream Mesh
    // entries first (their resource handle IS the mesh-source handle) then the
    // compiled mesh-source components, sorted by handle for determinism.
    let mut mesh_bounds: Vec<MeshBoundsRecord> = Vec::new();
    for ((_, rt, handle), res) in resource_jobs.iter().zip(&resource_pending) {
        if *rt == crate::registry::RegisteredType::Mesh
            && let Some(record) = mesh_bounds_record(*handle, &res.bytes)
        {
            mesh_bounds.push(record);
        }
    }
    let mut mesh_component_names: Vec<(u32, String)> = Vec::new();
    for (idx, bytes) in &pending {
        let asset = &assets[named_src[*idx]];
        if !crate::resource_handles::is_mesh_source(&asset.asset_type, &asset.args) {
            continue;
        }
        let id = asset_id::intern(&asset.name);
        if let Some(handle) =
            mesh_source_handles.get(crate::resource_handles::ResourceKind::Mesh, id)
        {
            // Handle -> asset name for mesh payloads riding component defs,
            // so a consumer can find any sub-mesh payload by unified handle
            // (resource-stream Mesh handles lead the space and resolve
            // through the resource records instead).
            mesh_component_names.push((handle, asset.name.clone()));
            if let Some(record) = mesh_bounds_record(handle, bytes) {
                mesh_bounds.push(record);
            }
        }
    }
    mesh_bounds.sort_unstable_by_key(|r| r.handle);

    // One group per scene (declaration order, possibly empty), carrying the
    // resource-stream entries and payload defs that scene exclusively owns.
    let scene_groups: Vec<SceneGroup> = (0..partition.scenes.len())
        .map(|s| SceneGroup {
            scene: asset_id::intern(&partition.scenes[s]),
            resources: resource_jobs
                .iter()
                .zip(&res_owners)
                .filter(|(_, o)| **o == Owner::Scene(s))
                .map(|((_, rt, handle), _)| (job_resource_kind(*rt) as u8, *handle))
                .collect(),
            defs: pending
                .iter()
                .zip(&comp_owners)
                .filter(|(_, o)| **o == Owner::Scene(s))
                .filter_map(|((idx, _), _)| named[*idx].1.name)
                .collect(),
        })
        .collect();

    if pending.is_empty() && resource_pending.is_empty() {
        return Ok(CompiledOutput {
            scene_groups,
            mesh_bounds,
            mesh_component_names,
            blobs: vec![Vec::new()],
            resources: Vec::new(),
            cache_hits: 0,
            cache_misses: 0,
        });
    }

    // Pack payloads by ownership group: the global set first (blob 0 onward),
    // then each scene's exclusive set starting at a fresh blob, so a scene's
    // payloads are contiguous and stay unread until the scene loads. Within a
    // group, component payloads pack before resource payloads, both in their
    // stream order. One packer, so every group addresses the same blob space;
    // record order in the metadata streams is unchanged (locators are
    // per-record, so packing order is independent).
    let mut packer = PayloadPacker::new(max_blob_bytes);
    let mut resource_locators: Vec<Option<concinnity_core::ecs::PayloadLocator>> =
        vec![None; resource_pending.len()];

    for group in 0..=partition.scenes.len() {
        let owner = match group {
            0 => Owner::Global,
            s => Owner::Scene(s - 1),
        };
        if group > 0 {
            packer.start_group();
        }
        for ((idx, bytes), item_owner) in pending.iter().zip(&comp_owners) {
            if *item_owner == owner {
                named[*idx].1.payload = Some(packer.push(bytes));
            }
        }
        for (i, (res, item_owner)) in resource_pending.iter().zip(&res_owners).enumerate() {
            if !res.is_data && *item_owner == owner {
                resource_locators[i] = Some(packer.push(&res.bytes));
            }
        }
    }

    let mut resources: Vec<ResourceRecord> = Vec::with_capacity(resource_pending.len());
    for (pending, locator) in resource_pending.iter().zip(resource_locators) {
        // A data resource (Material) carries its bytes inline; a payload
        // resource parks its bytes in a blob section and records the locator,
        // plus any hybrid baked data (SkinnedMesh) inline beside it.
        let (payload, data_bytes) = if pending.is_data {
            (None, pending.bytes.clone())
        } else {
            (locator, pending.extra_data.clone())
        };
        resources.push(ResourceRecord {
            resource_kind: pending.kind,
            handle: pending.handle,
            payload,
            data_bytes,
        });
    }

    Ok(CompiledOutput {
        scene_groups,
        mesh_bounds,
        mesh_component_names,
        blobs: packer.finish(),
        resources,
        cache_hits,
        cache_misses,
    })
}

// Dispatch payload compilation by RegisteredType. Every variant listed below
// has a `BuildAsset` impl in its asset file; the body of each call here is a
// one-liner that delegates to the trait. Adding a new compiled component
// means:
//   1. impl `Component` with `PAYLOAD = AssetPayload::Compiled` for the type
//   2. impl `BuildAsset` for the type in its asset file
//   3. Add one match arm here
fn compile_by_type(
    ct: RegisteredType,
    args: &serde_json::Value,
    ctx: &crate::asset::BuildCtx<'_>,
) -> std::io::Result<Vec<u8>> {
    use crate::asset::BuildAsset;
    use crate::components::{File, ProceduralMesh, Room, SdfVolume, Shader, VoxelChunk};
    match ct {
        RegisteredType::ProceduralMesh => {
            <ProceduralMesh as BuildAsset>::compile_payload(args, ctx)
        }
        RegisteredType::VoxelChunk => <VoxelChunk as BuildAsset>::compile_payload(args, ctx),
        RegisteredType::File => <File as BuildAsset>::compile_payload(args, ctx),
        RegisteredType::Room => <Room as BuildAsset>::compile_payload(args, ctx),
        RegisteredType::Shader => <Shader as BuildAsset>::compile_payload(args, ctx),
        RegisteredType::SdfVolume => <SdfVolume as BuildAsset>::compile_payload(args, ctx),
        other => Err(std::io::Error::new(
            std::io::ErrorKind::InvalidData,
            format!(
                "Asset '{}' is marked Compiled but has no BuildAsset impl (RegisteredType {:?})",
                ctx.name, other
            ),
        )),
    }
}

// Dispatch each asset's payload-cache contribution by RegisteredType. Mirrors
// `compile_by_type` so the cache layer can fold a hash of every input the
// compile reads into its payload key. Types with no `BuildAsset` impl, or with
// the trait default, contribute nothing.
//
// `source_files` and `TARGET_DEPENDENT` are read together per arm: a new
// asset whose payload differs per backend cannot pick up one without the
// other.
fn cache_inputs_by_type(
    ct: RegisteredType,
    args: &serde_json::Value,
    ctx: &crate::asset::BuildCtx<'_>,
) -> crate::asset::CacheInputs {
    use crate::asset::{BuildAsset, CacheInputs};
    use crate::components::{File, ProceduralMesh, Room, SdfVolume, Shader, VoxelChunk};
    macro_rules! inputs {
        ($t:ty) => {
            CacheInputs {
                sources: <$t as BuildAsset>::source_files(args, ctx),
                target_dependent: <$t as BuildAsset>::TARGET_DEPENDENT,
            }
        };
    }
    match ct {
        RegisteredType::ProceduralMesh => inputs!(ProceduralMesh),
        RegisteredType::VoxelChunk => inputs!(VoxelChunk),
        RegisteredType::File => inputs!(File),
        RegisteredType::Room => inputs!(Room),
        RegisteredType::Shader => inputs!(Shader),
        RegisteredType::SdfVolume => inputs!(SdfVolume),
        _ => CacheInputs::extra(Vec::new()),
    }
}

// Resolve scene + screen associations that the runtime can no longer derive
// from name strings, baking them into the asset args so they survive as
// AssetId ids.
//
// Naming-convention relationships handled:
//   - A Prop named `<scene>_*` belongs to Scene `<scene>`. The matched scene
//     name is written into the prop's `scene` arg.
//   - A UI element (Sprite, ImageOverlay, TextLabel, Text, TextInput,
//     HitRegion, ScrollPanel) named `<screen>_*` belongs to Screen `<screen>`.
//     The matched screen name is written into the asset's `screen` arg.
//   - A HitRegion or KeyBinding `action` of the form `scene:<name>`,
//     `screen:show:<name>`, `screen:push:<name>`, or `screen:toggle:<name>`
//     has its `<name>` part rewritten to the interned id, so `UiInputSystem`
//     can parse an integer at runtime instead of a name.
fn resolve_scene_refs(assets: &mut [WorldJsonlAsset]) {
    let norm = |s: &str| s.to_lowercase().replace('_', "");

    let scene_names: Vec<String> = assets
        .iter()
        .filter(|a| norm(&a.asset_type) == "scene")
        .map(|a| a.name.clone())
        .collect();

    let screen_names: Vec<String> = assets
        .iter()
        .filter(|a| norm(&a.asset_type) == "screen")
        .map(|a| a.name.clone())
        .collect();

    // Longest matching prefix wins so a nested name (e.g. `level_boss_*` under
    // both `level` and `level_boss`) binds to the most specific host.
    // Equivalent to first-match when no host name prefixes another.
    let longest_prefix_host = |name: &str, hosts: &[String]| -> Option<String> {
        hosts
            .iter()
            .filter(|h| name.starts_with(&format!("{h}_")))
            .max_by_key(|h| h.len())
            .cloned()
    };

    // Rewrite an action string, replacing the trailing `<name>` after the
    // given action prefix with its interned id. Returns Some(new_action) when
    // the action used the prefix with an unresolved name; None otherwise.
    let resolve_action = |action: &str| -> Option<String> {
        for prefix in ["scene:", "screen:show:", "screen:push:", "screen:toggle:"] {
            if let Some(rest) = action.strip_prefix(prefix) {
                if !rest.is_empty() && rest.parse::<u32>().is_err() {
                    return Some(format!("{prefix}{}", asset_id::intern(rest).0));
                }
                return None;
            }
        }
        None
    };

    for asset in assets.iter_mut() {
        let ty = norm(&asset.asset_type);

        // Host binding by name prefix: a Prop takes its Scene, a UI element
        // takes its Screen. An asset that already names its host is left alone.
        let host = match ty.as_str() {
            "prop" => Some(("scene", &scene_names)),
            "sprite" | "imageoverlay" | "textlabel" | "text" | "textinput" | "hitregion"
            | "scrollpanel" => Some(("screen", &screen_names)),
            _ => None,
        };
        if let Some((key, hosts)) = host
            && asset.args.get(key).is_none()
            && let Some(matched) = longest_prefix_host(&asset.name, hosts)
            && let serde_json::Value::Object(m) = &mut asset.args
        {
            m.insert(key.to_string(), serde_json::Value::String(matched));
        }

        // Resolve screen:* / scene:* action targets to interned ids.
        if matches!(ty.as_str(), "hitregion" | "keybinding") {
            let new_action = asset
                .args
                .get("action")
                .and_then(|v| v.as_str())
                .and_then(resolve_action);
            if let (Some(action), serde_json::Value::Object(m)) = (new_action, &mut asset.args) {
                m.insert("action".to_string(), serde_json::Value::String(action));
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    // Default-shader compilation writes intermediates to a shared
    // data path keyed by asset name, so tests whose worlds pull in
    // the default Shader (any rendering world) must not build concurrently.
    static SHADER_BUILD_LOCK: std::sync::Mutex<()> = std::sync::Mutex::new(());

    #[test]
    fn build_pipeline_interns_names_and_resolves_refs() {
        let _guard = SHADER_BUILD_LOCK.lock().unwrap_or_else(|e| e.into_inner());
        crate::shader::install_stub_toolchain();
        // box=0, day=1, day_crate=2 in declaration order.
        let world = concat!(
            r#"{"name":"box","type":"ProceduralMesh","args":{"generator":"box","half_extents":[1,1,1]}}"#,
            "\n",
            r#"{"name":"day","type":"Scene","args":{}}"#,
            "\n",
            r#"{"name":"day_crate","type":"Prop","args":{"mesh":"box"}}"#,
            "\n",
        );
        let result = build_pipeline_from_str(world, None, None).expect("build pipeline");

        // The Prop def's identity is the interned id, not a name string.
        let prop = result
            .defs
            .iter()
            .find(|d| d.name == Some(crate::ecs::asset_id::AssetId(2)))
            .expect("day_crate def present with interned id 2");

        let baked: crate::components::Prop = postcard::from_bytes(&prop.args_bytes).unwrap();
        // The `mesh` reference resolved to box's handle (0).
        assert_eq!(baked.mesh, Some(crate::ecs::MeshHandle(0)));
        // The `day_` name prefix resolved to Scene `day`'s id (1).
        assert_eq!(baked.scene, Some(crate::ecs::asset_id::AssetId(1)));
    }

    // A world with physics content but no PhysicsConfig has one injected during
    // expansion; it must compile to the same values the runtime falls back to,
    // and leave the shipped budget alone.
    #[test]
    fn an_injected_physics_config_round_trips_through_the_blob() {
        let _guard = SHADER_BUILD_LOCK.lock().unwrap_or_else(|e| e.into_inner());
        crate::shader::install_stub_toolchain();
        let world = concat!(
            r#"{"name":"box","type":"ProceduralMesh","args":{"generator":"box","half_extents":[1,1,1]}}"#,
            "\n",
            r#"{"name":"crate_a","type":"Prop","args":{"mesh":"box","collider":{"shape":"cuboid"}}}"#,
            "\n",
            r#"{"name":"crate_body","type":"PropBody","args":{"prop_name":"crate_a"}}"#,
            "\n",
        );
        let result = build_pipeline_from_str(world, None, None).expect("build pipeline");

        let index = result
            .names
            .iter()
            .position(|n| n == "physics_config")
            .expect("the injected config compiled into the blob");
        let baked: crate::components::PhysicsConfig =
            postcard::from_bytes(&result.defs[index].args_bytes).unwrap();
        let default = crate::components::PhysicsConfig::default();
        assert_eq!(baked.floor_y, default.floor_y);
        assert_eq!(baked.terrain_subdivisions, default.terrain_subdivisions);
        assert_eq!(baked.terrain_mesh, default.terrain_mesh);
        assert!(baked.layers.is_empty());
        assert!(baked.no_collide.is_empty());
        assert_eq!(baked.contact_min_impulse, default.contact_min_impulse);
        assert_eq!(baked.spawn_headroom, 0, "the strict spawn cap is untouched");

        // The reservation is the authored content plus the floor, unchanged by
        // the config becoming visible.
        let budget = result.physics_budget.expect("a physics budget");
        assert_eq!(budget.spawn_headroom, 0);
        assert_eq!(budget.dynamic, 1, "the crate");
    }

    #[test]
    fn resource_payload_slices_the_named_resource() {
        let _guard = SHADER_BUILD_LOCK.lock().unwrap_or_else(|e| e.into_inner());
        crate::shader::install_stub_toolchain();
        let world = concat!(
            r#"{"name":"prism","type":"SkinnedMesh","args":{"#,
            r#""vertices":[{"pos":[0,0,0]},{"pos":[1,0,0]},{"pos":[0,1,0]}],"#,
            r#""indices":[0,1,2],"skeleton":[{"name":"root","parent":-1}],"#,
            r#""scale":[1,1,1]}}"#,
            "\n",
        );
        let result = build_pipeline_from_str(world, None, None).expect("build");
        let bytes = result
            .resource_payload(ResourceKind::SkinnedMesh, "prism")
            .expect("named payload");
        let payload =
            concinnity_core::gfx::mesh_payload::deserialise_skinned_with_lods(bytes).unwrap();
        assert_eq!(payload.vertices.len(), 3);
        assert_eq!(payload.joints[0].name, "root");
        // The wrong name or the wrong kind finds nothing.
        assert!(
            result
                .resource_payload(ResourceKind::SkinnedMesh, "ghost")
                .is_none()
        );
        assert!(
            result
                .resource_payload(ResourceKind::Texture, "prism")
                .is_none()
        );
    }

    // A resource asset (here a Font) leaves no component def, so the lock
    // records it through `resource_locks` instead: name, kind, handle, args
    // hash, and the blob its payload landed in.
    #[test]
    fn build_pipeline_records_resource_lock_provenance() {
        let _guard = SHADER_BUILD_LOCK.lock().unwrap_or_else(|e| e.into_inner());
        crate::shader::install_stub_toolchain();
        let world = concat!(
            r#"{"name":"f","type":"Font","args":{"size_px":20}}"#,
            "\n",
            r#"{"name":"pause","type":"Screen","args":{}}"#,
            "\n",
        );
        let result = build_pipeline_from_str(world, None, None).expect("build");

        assert_eq!(result.resource_locks.len(), result.resources.len());
        let font = result
            .resource_locks
            .iter()
            .find(|r| r.name == "f")
            .expect("font provenance recorded");
        assert_eq!(font.kind, "Font");
        assert_eq!(font.handle, 0);
        assert_eq!(font.args_hash.len(), 64);
        // A payload resource records which blob holds its bytes.
        assert!(font.payload_blob.is_some());
        // The resource is not in the component asset list.
        assert!(!result.names.iter().any(|n| n == "f"));
    }

    // The visual_novel demo world (in concinnity-infra/worlds) exercises
    // Sprite + Screen + KeyBinding together. Validating it here catches asset
    // registration / pipeline regressions before we ship the world.
    #[test]
    fn visual_novel_world_validates() {
        // Inline a representative subset of the world so the test stays
        // hermetic (no infra path lookup needed). Covers: an initial Screen,
        // a Sprite under that screen's prefix, a TextLabel under it, a
        // HitRegion firing screen:show on another Screen, and a KeyBinding to
        // toggle a third (modal) Screen.
        let world = r#"{"name":"gfx","type":"GraphicsConfig","args":{}}
{"name":"f","type":"Font","args":{"size_px":20}}
{"name":"title_menu","type":"Screen","args":{"initial":true}}
{"name":"title_menu_bg","type":"Sprite","args":{"x":0,"y":0,"width":640,"height":360,"tint":[0.1,0.1,0.1,1]}}
{"name":"title_menu_lbl","type":"TextLabel","args":{"font":"f","content":"Start","x":260,"y":160}}
{"name":"title_menu_btn","type":"HitRegion","args":{"x":260,"y":156,"width":120,"height":40,"label":"title_menu_lbl","action":"screen:show:vn_page_1"}}
{"name":"vn_page_1","type":"Screen","args":{}}
{"name":"vn_page_1_text","type":"TextLabel","args":{"font":"f","content":"hello","x":40,"y":40}}
{"name":"vn_page_1_next","type":"HitRegion","args":{"x":0,"y":0,"width":640,"height":360,"action":"screen:show:title_menu"}}
{"name":"pause_menu","type":"Screen","args":{}}
{"name":"pause_menu_dim","type":"Sprite","args":{"x":0,"y":0,"width":640,"height":360,"tint":[0,0,0,0.6]}}
{"name":"esc","type":"KeyBinding","args":{"key":"Escape","action":"screen:toggle:pause_menu"}}
"#;
        validate_world_jsonl(world, None).expect("visual_novel-shaped world should validate");
    }

    // `screen:show:<name>` / `screen:toggle:<name>` action targets are
    // rewritten to interned ids at build time, like `scene:<name>`.
    #[test]
    fn build_pipeline_resolves_screen_action_refs() {
        let world = concat!(
            r#"{"name":"pause_menu","type":"Screen","args":{}}"#,
            "\n",
            r#"{"name":"btn","type":"HitRegion","args":{"x":0,"y":0,"width":10,"height":10,"action":"screen:toggle:pause_menu"}}"#,
            "\n",
            r#"{"name":"esc","type":"KeyBinding","args":{"key":"Escape","action":"screen:toggle:pause_menu"}}"#,
            "\n",
        );
        let result = build_pipeline_from_str(world, None, None).expect("build");
        // pause_menu interned id = 0 (first declared name).
        let btn = result
            .defs
            .iter()
            .find(|d| d.name == Some(crate::ecs::asset_id::AssetId(1)))
            .expect("HitRegion def");
        let baked: crate::components::HitRegion = postcard::from_bytes(&btn.args_bytes).unwrap();
        assert_eq!(baked.action, "screen:toggle:0");

        let esc = result
            .defs
            .iter()
            .find(|d| d.name == Some(crate::ecs::asset_id::AssetId(2)))
            .expect("KeyBinding def");
        let baked: crate::components::KeyBinding = postcard::from_bytes(&esc.args_bytes).unwrap();
        assert_eq!(baked.action, "screen:toggle:0");
    }

    // A Sprite/TextLabel/HitRegion named `<screen>_*` has its `screen` arg
    // resolved from the prefix at build time, mirroring Prop scene refs.
    #[test]
    fn build_pipeline_resolves_screen_prefix_on_ui_assets() {
        let _guard = SHADER_BUILD_LOCK.lock().unwrap_or_else(|e| e.into_inner());
        crate::shader::install_stub_toolchain();
        let world = concat!(
            r#"{"name":"pause_menu","type":"Screen","args":{}}"#,
            "\n",
            r#"{"name":"pause_menu_dim","type":"Sprite","args":{"x":0,"y":0,"width":10,"height":10}}"#,
            "\n",
            r#"{"name":"pause_menu_title","type":"TextLabel","args":{"font":"f","content":"x","x":0,"y":0}}"#,
            "\n",
            r#"{"name":"pause_menu_btn","type":"HitRegion","args":{"x":0,"y":0,"width":10,"height":10,"action":"screen:hide"}}"#,
            "\n",
            r#"{"name":"f","type":"Font","args":{"size_px":16}}"#,
            "\n",
        );
        let result = build_pipeline_from_str(world, None, None).expect("build");
        // pause_menu interned id = 0; the UI assets intern in declaration order.
        let baked_view = |id: u32, expect: &str| {
            let def = result
                .defs
                .iter()
                .find(|d| d.name == Some(crate::ecs::asset_id::AssetId(id)))
                .unwrap_or_else(|| panic!("expected a def for {expect}"));
            let ct = crate::registry::RegisteredType::from_discriminant(def.discriminant)
                .unwrap_or_else(|| panic!("{expect}: unknown discriminant"));
            match ct {
                crate::registry::RegisteredType::Sprite => {
                    postcard::from_bytes::<crate::components::Sprite>(&def.args_bytes)
                        .unwrap()
                        .screen
                }
                crate::registry::RegisteredType::TextLabel => {
                    postcard::from_bytes::<crate::components::TextLabel>(&def.args_bytes)
                        .unwrap()
                        .screen
                }
                crate::registry::RegisteredType::HitRegion => {
                    postcard::from_bytes::<crate::components::HitRegion>(&def.args_bytes)
                        .unwrap()
                        .screen
                }
                other => panic!("{expect}: unexpected type {other:?}"),
            }
        };
        for (id, name) in [
            (1, "pause_menu_dim"),
            (2, "pause_menu_title"),
            (3, "pause_menu_btn"),
        ] {
            assert_eq!(
                baked_view(id, name),
                Some(crate::ecs::asset_id::AssetId(0)),
                "expected {name} to have screen=0"
            );
        }
    }

    // Nested screen names resolve by longest prefix: `<menu>_settings_*` binds
    // to the `<menu>_settings` screen, not the enclosing `<menu>` screen that is
    // declared first. (Regression: first-match claimed the nested elements,
    // so a MainMenu's settings sub-screen rendered on top of the main menu.)
    #[test]
    fn resolve_scene_refs_picks_longest_screen_prefix() {
        let mk = |name: &str, ty: &str| crate::world::WorldJsonlAsset {
            name: name.to_string(),
            asset_type: ty.to_string(),
            args: serde_json::json!({}),
        };
        let mut assets = vec![
            mk("menu", "Screen"),
            mk("menu_settings", "Screen"),
            mk("menu_title", "TextLabel"),
            mk("menu_settings_title", "TextLabel"),
        ];
        super::resolve_scene_refs(&mut assets);
        let view_of = |n: &str| {
            assets
                .iter()
                .find(|a| a.name == n)
                .and_then(|a| a.args.get("screen"))
                .and_then(|v| v.as_str())
                .map(str::to_string)
        };
        assert_eq!(view_of("menu_title").as_deref(), Some("menu"));
        assert_eq!(
            view_of("menu_settings_title").as_deref(),
            Some("menu_settings")
        );
    }

    // Animation with no `source` is left byte-for-byte unchanged: the
    // inline-authored path must not regress.
    #[test]
    fn desugar_animation_imports_skips_inline_clips() {
        let original = serde_json::json!({
            "target": "flag",
            "duration": 2.0,
            "tracks": [{"joint": 0, "keyframes": [{"time": 0.0, "rotation_deg": [0,0,0]}]}],
        });
        let mut assets = vec![crate::world::WorldJsonlAsset {
            name: "wave".to_string(),
            asset_type: "Animation".to_string(),
            args: original.clone(),
        }];
        desugar_animation_imports(&mut assets, None).expect("desugar succeeds");
        assert_eq!(assets[0].args, original);
    }

    // Opting into root motion strips the root joint's X/Z travel into
    // `root_track` and anchors the pose; a clip without the flag is
    // untouched, and a second pass over already-baked args is a no-op.
    #[test]
    fn desugar_root_motion_bakes_the_root_track() {
        let walk = serde_json::json!({
            "target": "hero",
            "duration": 1.0,
            "root_motion": true,
            "tracks": [{"joint": 0, "keyframes": [
                {"time": 0.0, "translation": [0.0, 1.0, 0.0]},
                {"time": 1.0, "translation": [2.0, 1.0, 0.0]}
            ]}],
        });
        let plain = serde_json::json!({
            "target": "hero",
            "duration": 1.0,
            "tracks": [{"joint": 0, "keyframes": [
                {"time": 1.0, "translation": [2.0, 1.0, 0.0]}
            ]}],
        });
        let mut assets = vec![
            crate::world::WorldJsonlAsset {
                name: "walk".to_string(),
                asset_type: "Animation".to_string(),
                args: walk,
            },
            crate::world::WorldJsonlAsset {
                name: "plain".to_string(),
                asset_type: "Animation".to_string(),
                args: plain.clone(),
            },
        ];
        desugar_root_motion(&mut assets).expect("desugar succeeds");

        let baked = &assets[0].args;
        assert_eq!(baked["root_track"][1]["translation"][0], 2.0);
        assert_eq!(baked["root_track"][1]["translation"][1], 0.0);
        // The pose keeps Y but stays anchored on X.
        assert_eq!(baked["tracks"][0]["keyframes"][1]["translation"][0], 0.0);
        assert_eq!(baked["tracks"][0]["keyframes"][1]["translation"][1], 1.0);
        assert_eq!(assets[1].args, plain, "flag-less clip untouched");

        let after_first = assets[0].args.clone();
        desugar_root_motion(&mut assets).expect("second pass succeeds");
        assert_eq!(assets[0].args, after_first, "re-bake is a no-op");
    }

    #[test]
    fn voxel_chunk_payload_compiles_end_to_end() {
        let world = r#"{"name":"scene_shader","type":"Shader","args":{"vertex":{"source":"x.metal"},"fragment":{"source":"x.metal"}}}
{"name":"air","type":"BlockType","args":{"solid":false}}
{"name":"stone","type":"BlockType","args":{"uv_min":[0,0],"uv_max":[1,1]}}
{"name":"chunk","type":"VoxelChunk","args":{"palette":["air","stone"],"dim":[2,1,1],"blocks":[1,1]}}
"#;
        // We can't easily compile shaders here, so go through the geometry
        // entry point directly to verify the voxel chunk produces a non-empty
        // payload for two adjacent solid blocks (10 faces after interior cull).
        let chunk_args = serde_json::json!({
            "palette": ["air", "stone"],
            "dim": [2, 1, 1],
            "blocks": [1, 1],
            "block_size": 1.0,
        });
        let bt = |name: &str| -> Option<serde_json::Value> {
            match name {
                "air" => Some(serde_json::json!({"solid": false})),
                "stone" => Some(serde_json::json!({"uv_min":[0,0],"uv_max":[1,1]})),
                _ => None,
            }
        };
        let bytes = crate::geometry::compile_voxel_chunk_payload(&chunk_args, bt).unwrap();
        assert!(!bytes.is_empty());
        let _ = world; // keeps the inline jsonl reference for documentation
    }

    fn wja(name: &str, ty: &str, args: serde_json::Value) -> crate::world::WorldJsonlAsset {
        crate::world::WorldJsonlAsset {
            name: name.to_string(),
            asset_type: ty.to_string(),
            args,
        }
    }

    fn ctx() -> crate::asset::BuildCtx<'static> {
        crate::asset::BuildCtx {
            name: "test",
            assets_dir: None,
            artifacts_dir: None,
            all_assets: &[],
        }
    }

    // A cache map that claims a compiled payload is already in hand for the
    // named asset, so every desugar pass must skip its source parse.
    fn hit_cache(name: &str) -> std::collections::HashMap<String, MeshCacheEntry> {
        let mut m = std::collections::HashMap::new();
        m.insert(
            name.to_string(),
            MeshCacheEntry {
                key: "k".to_string(),
                bytes: Some(vec![1, 2, 3]),
            },
        );
        m
    }

    #[test]
    fn build_from_path_missing_world_file_errors() {
        assert!(build_from_path("/no/such/world.jsonl").is_err());
    }

    #[test]
    fn build_from_path_reports_a_malformed_world_file() {
        let dir = tempfile::tempdir().expect("tempdir");
        let world = dir.path().join("world.jsonl");
        std::fs::write(&world, "{not json\n").expect("write world");
        let err = build_from_path(world.to_str().unwrap()).expect_err("malformed world");
        assert_eq!(err.kind(), std::io::ErrorKind::InvalidData);
    }

    // A lock that cannot be written fails the build: shipping blobs without the
    // record of what went into them would leave the output unexplainable.
    #[test]
    fn write_build_outputs_fails_when_the_lock_cannot_be_written() {
        let _output = crate::blob::test_output::LOCK
            .lock()
            .unwrap_or_else(|e| e.into_inner());
        let _state = crate::blob::test_output::StateDir::new();
        let _lock_file = crate::blob::test_output::LockFile;
        // A directory where the lock file belongs makes the write fail.
        std::fs::create_dir_all(crate::blob::LOCK_PATH).expect("occupy the lock path");

        let result = PipelineResult {
            defs: Vec::new(),
            names: Vec::new(),
            resources: Vec::new(),
            scene_groups: Vec::new(),
            mesh_bounds: Vec::new(),
            physics_budget: None,
            mesh_component_names: Vec::new(),
            payloads: vec![vec![1, 2, 3]],
            cache_hits: 0,
            cache_misses: 0,
            texture_sources: Vec::new(),
            mesh_sources: Vec::new(),
            resource_locks: Vec::new(),
        };
        assert!(
            write_build_outputs(&result, &[], &[]).is_err(),
            "an unwritable lock must fail the build"
        );
    }

    // The full build tail: compile the world, ship the blobs under the state
    // root, and record every asset in the lock beside them.
    #[test]
    fn build_from_path_writes_the_blobs_and_the_lock_beside_them() {
        let _shaders = SHADER_BUILD_LOCK.lock().unwrap_or_else(|e| e.into_inner());
        crate::shader::install_stub_toolchain();
        let _output = crate::blob::test_output::LOCK
            .lock()
            .unwrap_or_else(|e| e.into_inner());
        let _state = crate::blob::test_output::StateDir::new();
        let _lock_file = crate::blob::test_output::LockFile;

        let dir = tempfile::tempdir().expect("tempdir");
        let world_path = dir.path().join("world.jsonl");
        std::fs::write(
            &world_path,
            concat!(
                r#"{"name":"gfx","type":"GraphicsConfig","args":{}}"#,
                "\n",
                r#"{"name":"f","type":"Font","args":{"size_px":20}}"#,
                "\n",
                r#"{"name":"pause","type":"Screen","args":{}}"#,
                "\n",
            ),
        )
        .expect("write world");

        build_from_path(world_path.to_str().unwrap()).expect("build");

        let raw = std::fs::read_to_string(crate::blob::LOCK_PATH).expect("lock written");
        let lock: crate::blob::BlobLock = serde_json::from_str(&raw).expect("lock is valid json");
        assert_eq!(lock.blobs.len(), 1);

        let (meta, _) = crate::blob::read_cnb(&lock.blobs[0].path).expect("blob 0 parses");
        assert_eq!(
            meta.defs.len(),
            lock.assets.len(),
            "the lock names every def the blob ships"
        );
        assert_eq!(meta.resources.len(), lock.resources.len());
        assert!(lock.assets.iter().any(|a| a.name == "pause"));

        let font = lock
            .resources
            .iter()
            .find(|r| r.name == "f")
            .expect("the font is recorded in the resource stream");
        assert_eq!(font.kind, "Font");
        assert_eq!(font.payload_blob, Some(0));
        assert!(
            !lock.injected.is_empty(),
            "engine defaults are recorded so they can be overridden"
        );
    }

    #[test]
    fn build_pipeline_from_str_rejects_malformed_jsonl() {
        let Err(err) = build_pipeline_from_str("{not json\n", None, None) else {
            panic!("malformed line must not build");
        };
        assert_eq!(err.kind(), std::io::ErrorKind::InvalidData);
    }

    #[test]
    fn build_pipeline_from_str_reports_unknown_asset_types() {
        let world = r#"{"name":"mystery","type":"NotAType","args":{}}"#;
        let Err(err) = build_pipeline_from_str(world, None, None) else {
            panic!("unknown type must not build");
        };
        assert!(
            err.to_string().contains("NotAType"),
            "error should name the unknown type: {err}"
        );
    }

    #[test]
    fn validate_asset_accepts_build_time_expansion_types() {
        // Build-time types are expanded before the runtime registry sees
        // them, so they validate structurally regardless of args.
        for ty in [
            "SceneImport",
            "Environment",
            "LightRig",
            "Prefab",
            "CharacterSchema",
            "CharacterModel",
        ] {
            validate_asset(ty, "x", &serde_json::json!({}))
                .unwrap_or_else(|e| panic!("{ty} should validate: {e}"));
        }
    }

    // A resource-only type never builds a component def, so it is validated
    // through the structural check alone rather than `create_asset_def`.
    #[test]
    fn validate_asset_routes_resource_only_types_past_the_component_registry() {
        validate_asset("AudioClip", "clip", &serde_json::json!({"source": "a.wav"}))
            .expect("a source-backed AudioClip validates");
        let err = validate_asset("Texture", "tex", &serde_json::json!({"generator": "nope"}))
            .expect_err("an unknown texture generator is rejected");
        assert!(err.contains("nope"), "got: {err}");
    }

    // A type that resolves through `create_asset_def` still has to satisfy its
    // structural check, and a clean asset returns Ok.
    #[test]
    fn validate_asset_runs_the_structural_check_after_type_resolution() {
        validate_asset("Scene", "day", &serde_json::json!({})).expect("a Scene validates");
        // A Prop resolves as a type but has no mesh source to render.
        let err = validate_asset("Prop", "empty_prop", &serde_json::json!({}))
            .expect_err("a source-less Prop is rejected");
        assert!(err.contains("empty_prop"), "got: {err}");
    }

    #[test]
    fn validate_asset_unknown_type_mentions_the_asset_name() {
        let err =
            validate_asset("Bogus", "my_thing", &serde_json::json!({})).expect_err("unknown type");
        assert!(err.contains("my_thing"), "got: {err}");
    }

    #[test]
    fn validate_asset_bad_args_mention_the_asset_name() {
        // `generator` must be a string; a number fails args deserialization.
        let err = validate_asset(
            "ProceduralMesh",
            "bad_mesh",
            &serde_json::json!({"generator": 5}),
        )
        .expect_err("bad args");
        assert!(err.contains("bad_mesh"), "got: {err}");
    }

    #[test]
    fn desugar_gltf_skinned_meshes_leaves_inline_and_cached_untouched() {
        let inline_args = serde_json::json!({"vertices": [], "indices": []});
        let cached_args = serde_json::json!({"source": "/no/such/hero.glb"});
        let mut assets = vec![
            wja("inline", SKINNED_MESH_TYPE, inline_args.clone()),
            wja("cached", SKINNED_MESH_TYPE, cached_args.clone()),
        ];
        desugar_gltf_skinned_meshes(&mut assets, &hit_cache("cached"), None).expect("desugar");
        // No source: untouched. Cache hit: the missing .glb is never parsed
        // and the args stay pre-desugar so the next probe key matches.
        assert_eq!(assets[0].args, inline_args);
        assert_eq!(assets[1].args, cached_args);
    }

    // Write a fixture container into `dir` and return its path as a string.
    fn write_fixture(dir: &tempfile::TempDir, name: &str, bytes: &[u8]) -> String {
        let path = dir.path().join(name);
        std::fs::write(&path, bytes).expect("write fixture");
        path.to_string_lossy().into_owned()
    }

    // A source-backed SkinnedMesh has its geometry and skeleton written into
    // the asset's inline args, replacing the `source` reference for the
    // compile step that follows.
    #[test]
    fn desugar_gltf_skinned_meshes_inlines_geometry_and_skeleton() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "hero.glb", &crate::glb::test_fixtures::skinned_glb());
        let mut assets = vec![wja(
            "hero",
            SKINNED_MESH_TYPE,
            serde_json::json!({"source": src}),
        )];
        desugar_gltf_skinned_meshes(&mut assets, &Default::default(), None).expect("desugar");

        let args = &assets[0].args;
        assert_eq!(args["vertices"].as_array().unwrap().len(), 3);
        assert_eq!(args["indices"].as_array().unwrap(), &vec![0, 1, 2]);
        // The two-joint skin is reordered parents-before-children, so the
        // skeleton lands with the root first.
        assert_eq!(args["skeleton"].as_array().unwrap().len(), 2);
        // The fixture carries no morph targets, so no morph args appear.
        assert!(args.get("morph_target_names").is_none());
        assert!(args.get("morph_deltas").is_none());
    }

    // The shared skinned fixture with one morph target ("bulge", +Y on every
    // vertex) and an animation channel driving its weight from 0 to 1.
    fn morphing_skinned_glb() -> Vec<u8> {
        use crate::glb::test_fixtures::{f32s, make_glb, skinned_bin, skinned_json};

        let mut bin = skinned_bin(); // 136 bytes
        bin.extend(f32s(&[0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0])); // deltas -> 172
        bin.extend(f32s(&[0.0, 1.0])); // morph weights -> 180

        let mut json = skinned_json(true, true, true);
        json["buffers"][0]["byteLength"] = 180.into();
        let views = json["bufferViews"].as_array_mut().expect("bufferViews");
        views.push(serde_json::json!({"buffer": 0, "byteOffset": 136, "byteLength": 36}));
        views.push(serde_json::json!({"buffer": 0, "byteOffset": 172, "byteLength": 8}));
        let accessors = json["accessors"].as_array_mut().expect("accessors");
        accessors.push(
            serde_json::json!({"bufferView": 6, "componentType": 5126, "count": 3, "type": "VEC3"}),
        );
        accessors.push(serde_json::json!(
            {"bufferView": 7, "componentType": 5126, "count": 2, "type": "SCALAR"}
        ));
        json["meshes"][0]["primitives"][0]["targets"] = serde_json::json!([{"POSITION": 6}]);
        json["meshes"][0]["extras"] = serde_json::json!({"targetNames": ["bulge"]});
        json["animations"][0]["samplers"]
            .as_array_mut()
            .expect("samplers")
            .push(serde_json::json!({"input": 4, "output": 7, "interpolation": "LINEAR"}));
        json["animations"][0]["channels"]
            .as_array_mut()
            .expect("channels")
            .push(serde_json::json!({"sampler": 2, "target": {"node": 0, "path": "weights"}}));

        make_glb(&json, Some(&bin))
    }

    // A source carrying morph targets writes the target names and the dense
    // delta block into the asset alongside the base geometry.
    #[test]
    fn desugar_gltf_skinned_meshes_inlines_morph_targets() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "hero.glb", &morphing_skinned_glb());
        let mut assets = vec![wja(
            "hero",
            SKINNED_MESH_TYPE,
            serde_json::json!({"source": src}),
        )];
        desugar_gltf_skinned_meshes(&mut assets, &Default::default(), None).expect("desugar");

        let args = &assets[0].args;
        assert_eq!(args["morph_target_names"], serde_json::json!(["bulge"]));
        // One target over three vertices: a dense target-major delta block.
        assert_eq!(args["morph_deltas"].as_array().unwrap().len(), 3);
    }

    // A clip that animates morph weights carries a morph track beside its
    // joint tracks.
    #[test]
    fn desugar_animation_imports_inlines_a_morph_weight_track() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "hero.glb", &morphing_skinned_glb());
        let mut assets = vec![wja(
            "wave",
            "Animation",
            serde_json::json!({"source": src, "animation_index": 0}),
        )];
        desugar_animation_imports(&mut assets, None).expect("desugar");

        let morph = assets[0].args["morph_track"]
            .as_array()
            .expect("morph track inlined");
        assert_eq!(morph.len(), 2);
        assert_eq!(morph[0], serde_json::json!({"time": 0.0, "weights": [0.0]}));
        assert_eq!(morph[1], serde_json::json!({"time": 1.0, "weights": [1.0]}));
    }

    #[test]
    fn desugar_gltf_skinned_meshes_missing_source_errors() {
        let mut assets = vec![wja(
            "hero",
            SKINNED_MESH_TYPE,
            serde_json::json!({"source": "/no/such/hero.glb"}),
        )];
        let err = desugar_gltf_skinned_meshes(&mut assets, &Default::default(), None)
            .expect_err("missing .glb");
        assert!(err.to_string().contains("Asset 'hero'"), "got: {err}");
    }

    #[test]
    fn desugar_gltf_meshes_skips_non_glb_sources_and_cache_hits() {
        let fbx_args = serde_json::json!({"source": "/no/such/scene.fbx"});
        let cached_args = serde_json::json!({"source": "/no/such/scene.glb"});
        let inline_args = serde_json::json!({"vertices": [], "indices": []});
        let mut assets = vec![
            wja("from_fbx", MESH_TYPE, fbx_args.clone()),
            wja("cached", MESH_TYPE, cached_args.clone()),
            wja("inline", MESH_TYPE, inline_args.clone()),
        ];
        desugar_gltf_meshes(&mut assets, &hit_cache("cached"), None).expect("desugar");
        assert_eq!(
            assets[0].args, fbx_args,
            ".fbx sources belong to the fbx pass"
        );
        assert_eq!(assets[1].args, cached_args, "cache hit skips the parse");
        assert_eq!(assets[2].args, inline_args, "no source: untouched");
    }

    #[test]
    fn desugar_gltf_meshes_missing_source_errors() {
        let mut assets = vec![wja(
            "crate_mesh",
            MESH_TYPE,
            serde_json::json!({"source": "/no/such/scene.glb"}),
        )];
        let err =
            desugar_gltf_meshes(&mut assets, &Default::default(), None).expect_err("missing .glb");
        assert!(err.to_string().contains("Asset 'crate_mesh'"), "got: {err}");
    }

    // The text `.gltf` container flows through the same desugar as `.glb`:
    // geometry lands inline from the external `.bin` beside the source.
    #[test]
    fn desugar_gltf_meshes_imports_a_text_gltf_with_an_external_buffer() {
        let dir = tempfile::tempdir().unwrap();
        std::fs::write(
            dir.path().join("geo.bin"),
            crate::glb::test_fixtures::static_triangle_bin(),
        )
        .unwrap();
        let mut json = crate::glb::test_fixtures::static_triangle_json();
        json["buffers"][0]["uri"] = "geo.bin".into();
        let gltf = dir.path().join("tri.gltf");
        std::fs::write(&gltf, serde_json::to_vec(&json).unwrap()).unwrap();

        let mut assets = vec![wja(
            "tri",
            MESH_TYPE,
            serde_json::json!({"source": gltf.to_str().unwrap(), "primitive_index": 0}),
        )];
        desugar_gltf_meshes(&mut assets, &Default::default(), None).expect("desugar");
        let vertices = assets[0].args.get("vertices").expect("inline vertices");
        assert_eq!(vertices.as_array().unwrap().len(), 3);
        assert_eq!(
            assets[0]
                .args
                .get("indices")
                .unwrap()
                .as_array()
                .unwrap()
                .len(),
            3
        );
    }

    // Two Mesh assets fanned out of one container parse the file once; both
    // still land with their own inline geometry.
    #[test]
    fn desugar_gltf_meshes_parses_a_shared_source_once_for_every_asset() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(
            &dir,
            "scene.glb",
            &crate::glb::test_fixtures::static_triangle_glb(),
        );
        let mut assets = vec![
            wja(
                "part_a",
                MESH_TYPE,
                serde_json::json!({"source": src, "primitive_index": 0}),
            ),
            wja(
                "part_b",
                MESH_TYPE,
                serde_json::json!({"source": src, "primitive_index": 0}),
            ),
        ];
        desugar_gltf_meshes(&mut assets, &Default::default(), None).expect("desugar");
        for asset in &assets {
            assert_eq!(asset.args["vertices"].as_array().unwrap().len(), 3);
            assert_eq!(asset.args["indices"].as_array().unwrap().len(), 3);
        }
    }

    // A primitive the container does not have fails on both the chunked and
    // the whole-primitive route, naming the asset either way.
    #[test]
    fn desugar_gltf_meshes_reports_a_primitive_the_file_does_not_have() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(
            &dir,
            "scene.glb",
            &crate::glb::test_fixtures::static_triangle_glb(),
        );
        for extra in [serde_json::json!({}), serde_json::json!({"chunk_index": 0})] {
            let mut args = serde_json::json!({"source": src, "primitive_index": 7});
            for (k, v) in extra.as_object().unwrap() {
                args[k] = v.clone();
            }
            let mut assets = vec![wja("ghost", MESH_TYPE, args)];
            let err = desugar_gltf_meshes(&mut assets, &Default::default(), None)
                .expect_err("primitive 7 does not exist");
            let msg = err.to_string();
            assert!(msg.contains("Asset 'ghost'"), "got: {msg}");
            assert!(msg.contains("glTF import failed"), "got: {msg}");
        }
    }

    // An oversized primitive fanned into several chunked Mesh assets is split
    // exactly once; every asset still gets its own inline geometry.
    #[test]
    fn desugar_gltf_meshes_splits_a_primitive_once_for_every_chunk_asset() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(
            &dir,
            "scene.glb",
            &crate::glb::test_fixtures::static_triangle_glb(),
        );
        let chunk = |name: &str| {
            wja(
                name,
                MESH_TYPE,
                serde_json::json!({"source": src, "primitive_index": 0, "chunk_index": 0}),
            )
        };
        let mut assets = vec![chunk("part_a"), chunk("part_b")];
        desugar_gltf_meshes(&mut assets, &Default::default(), None).expect("desugar");
        for asset in &assets {
            assert_eq!(asset.args["vertices"].as_array().unwrap().len(), 3);
        }
    }

    // An authored `chunk_index` routes through the u16 chunk split instead of
    // the whole-primitive import; an index past the last chunk names the file,
    // the primitive, and how many chunks it really produced.
    #[test]
    fn desugar_gltf_meshes_reads_a_chunk_and_rejects_one_out_of_range() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(
            &dir,
            "scene.glb",
            &crate::glb::test_fixtures::static_triangle_glb(),
        );
        let mut assets = vec![wja(
            "chunk0",
            MESH_TYPE,
            serde_json::json!({"source": src, "chunk_index": 0}),
        )];
        desugar_gltf_meshes(&mut assets, &Default::default(), None).expect("desugar");
        assert_eq!(assets[0].args["vertices"].as_array().unwrap().len(), 3);

        let mut past_end = vec![wja(
            "chunk9",
            MESH_TYPE,
            serde_json::json!({"source": src, "chunk_index": 9}),
        )];
        let err = desugar_gltf_meshes(&mut past_end, &Default::default(), None)
            .expect_err("chunk 9 does not exist");
        let msg = err.to_string();
        assert!(msg.contains("Asset 'chunk9'"), "got: {msg}");
        assert!(msg.contains("chunk_index 9 out of range"), "got: {msg}");
        assert!(msg.contains("1 chunk(s)"), "got: {msg}");
    }

    // Synthetic binary FBX containers. The importer walks a node tree, so the
    // fixtures are described as one and serialized by `write_fbx`; no binary
    // asset needs to live in the repo.
    enum Attr {
        Int(i64),
        Double(f64),
        Text(String),
        Doubles(Vec<f64>),
        Ints(Vec<i32>),
        Longs(Vec<i64>),
        Floats(Vec<f32>),
    }

    struct Node {
        name: &'static str,
        attrs: Vec<Attr>,
        children: Vec<Node>,
    }

    fn node(name: &'static str, attrs: Vec<Attr>, children: Vec<Node>) -> Node {
        Node {
            name,
            attrs,
            children,
        }
    }

    // An FBX object's second attribute: the authored name, the object class,
    // and the `\0\u{1}` separator between them.
    fn object_name(name: &str, class: &str) -> Attr {
        Attr::Text(format!("{name}\u{0}\u{1}{class}"))
    }

    fn connection(child: i64, parent: i64) -> Node {
        node(
            "C",
            vec![
                Attr::Text("OO".to_string()),
                Attr::Int(child),
                Attr::Int(parent),
            ],
            Vec::new(),
        )
    }

    // An object-to-property connection: the parent's named property is what
    // the child drives.
    fn property_connection(child: i64, parent: i64, property: &str) -> Node {
        node(
            "C",
            vec![
                Attr::Text("OP".to_string()),
                Attr::Int(child),
                Attr::Int(parent),
                Attr::Text(property.to_string()),
            ],
            Vec::new(),
        )
    }

    fn write_fbx(nodes: &[Node]) -> Vec<u8> {
        use fbxcel::low::FbxVersion;
        use fbxcel::writer::v7400::binary::{FbxFooter, Writer};

        fn emit<W: std::io::Write + std::io::Seek>(
            w: &mut Writer<W>,
            n: &Node,
        ) -> std::io::Result<()> {
            {
                let mut attrs = w.new_node(n.name).expect("open node");
                for a in &n.attrs {
                    match a {
                        Attr::Int(v) => attrs.append_i64(*v),
                        Attr::Double(v) => attrs.append_f64(*v),
                        Attr::Text(s) => attrs.append_string_direct(s),
                        Attr::Doubles(v) => attrs.append_arr_f64_from_iter(None, v.iter().copied()),
                        Attr::Ints(v) => attrs.append_arr_i32_from_iter(None, v.iter().copied()),
                        Attr::Longs(v) => attrs.append_arr_i64_from_iter(None, v.iter().copied()),
                        Attr::Floats(v) => attrs.append_arr_f32_from_iter(None, v.iter().copied()),
                    }
                    .expect("append attribute");
                }
            }
            for c in &n.children {
                emit(w, c)?;
            }
            w.close_node().expect("close node");
            Ok(())
        }

        let mut w =
            Writer::new(std::io::Cursor::new(Vec::new()), FbxVersion::V7_4).expect("fbx writer");
        for n in nodes {
            emit(&mut w, n).expect("emit node");
        }
        w.finalize_and_flush(&FbxFooter::default())
            .expect("finalize")
            .into_inner()
    }

    // One triangle as an FBX Geometry object. The last corner of a polygon is
    // stored bitwise-negated, which is how the importer finds polygon bounds.
    fn triangle_geometry(id: i64) -> Node {
        node(
            "Geometry",
            vec![
                Attr::Int(id),
                object_name("tri", "Geometry"),
                Attr::Text("Mesh".to_string()),
            ],
            vec![
                node(
                    "Vertices",
                    vec![Attr::Doubles(vec![
                        0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0,
                    ])],
                    Vec::new(),
                ),
                node(
                    "PolygonVertexIndex",
                    vec![Attr::Ints(vec![0, 1, !2])],
                    Vec::new(),
                ),
            ],
        )
    }

    // One Model connected to one Geometry: `parse_fbx` yields a single
    // primitive from it.
    fn static_triangle_fbx() -> Vec<u8> {
        const GEOMETRY: i64 = 1000;
        const MODEL: i64 = 2000;
        write_fbx(&[
            node(
                "Objects",
                Vec::new(),
                vec![
                    triangle_geometry(GEOMETRY),
                    node(
                        "Model",
                        vec![
                            Attr::Int(MODEL),
                            object_name("tri", "Model"),
                            Attr::Text("Mesh".to_string()),
                        ],
                        Vec::new(),
                    ),
                ],
            ),
            node("Connections", Vec::new(), vec![connection(GEOMETRY, MODEL)]),
        ])
    }

    // FBX time unit: ticks per second.
    const KTIME_PER_SEC: i64 = 46_186_158_000;

    fn skinned_triangle_fbx() -> Vec<u8> {
        skinned_fbx(false)
    }

    // The same triangle bound to a one-bone skin: a Skin deformer over the
    // geometry, a Cluster linking every control point to the bone Model at an
    // identity bind, and a unit scale of 100 so file units are already meters.
    // With `animated`, a one-second stack slides the bone 0 -> 2 along X.
    fn skinned_fbx(animated: bool) -> Vec<u8> {
        const GEOMETRY: i64 = 3000;
        const MESH_MODEL: i64 = 4000;
        const BONE: i64 = 5000;
        const SKIN: i64 = 6000;
        const CLUSTER: i64 = 7000;
        const STACK: i64 = 8000;
        const LAYER: i64 = 8100;
        const CURVE_NODE: i64 = 8200;
        const CURVE: i64 = 8300;
        let identity = vec![
            1.0, 0.0, 0.0, 0.0, //
            0.0, 1.0, 0.0, 0.0, //
            0.0, 0.0, 1.0, 0.0, //
            0.0, 0.0, 0.0, 1.0,
        ];
        let unit_scale = node(
            "GlobalSettings",
            Vec::new(),
            vec![node(
                "Properties70",
                Vec::new(),
                vec![node(
                    "P",
                    vec![
                        Attr::Text("UnitScaleFactor".to_string()),
                        Attr::Text("double".to_string()),
                        Attr::Text("Number".to_string()),
                        Attr::Text(String::new()),
                        Attr::Double(100.0),
                    ],
                    Vec::new(),
                )],
            )],
        );
        let mut objects = vec![
            triangle_geometry(GEOMETRY),
            node(
                "Model",
                vec![
                    Attr::Int(MESH_MODEL),
                    object_name("mesh", "Model"),
                    Attr::Text("Mesh".to_string()),
                ],
                Vec::new(),
            ),
            node(
                "Model",
                vec![
                    Attr::Int(BONE),
                    object_name("Root", "Model"),
                    Attr::Text("LimbNode".to_string()),
                ],
                Vec::new(),
            ),
            node(
                "Deformer",
                vec![
                    Attr::Int(SKIN),
                    object_name("skin", "Deformer"),
                    Attr::Text("Skin".to_string()),
                ],
                Vec::new(),
            ),
            node(
                "Deformer",
                vec![
                    Attr::Int(CLUSTER),
                    object_name("cluster", "SubDeformer"),
                    Attr::Text("Cluster".to_string()),
                ],
                vec![
                    node("Indexes", vec![Attr::Ints(vec![0, 1, 2])], Vec::new()),
                    node(
                        "Weights",
                        vec![Attr::Doubles(vec![1.0, 1.0, 1.0])],
                        Vec::new(),
                    ),
                    node(
                        "TransformLink",
                        vec![Attr::Doubles(identity.clone())],
                        Vec::new(),
                    ),
                    node("Transform", vec![Attr::Doubles(identity)], Vec::new()),
                ],
            ),
        ];
        let mut connections = vec![
            connection(GEOMETRY, MESH_MODEL),
            connection(SKIN, GEOMETRY),
            connection(CLUSTER, SKIN),
            connection(BONE, CLUSTER),
        ];

        if animated {
            objects.extend([
                node(
                    "AnimationStack",
                    vec![Attr::Int(STACK), object_name("wave", "AnimStack")],
                    Vec::new(),
                ),
                node(
                    "AnimationLayer",
                    vec![Attr::Int(LAYER), object_name("Base Layer", "AnimLayer")],
                    Vec::new(),
                ),
                node(
                    "AnimationCurveNode",
                    vec![Attr::Int(CURVE_NODE), object_name("T", "AnimCurveNode")],
                    Vec::new(),
                ),
                node(
                    "AnimationCurve",
                    vec![Attr::Int(CURVE), object_name("", "AnimCurve")],
                    vec![
                        node(
                            "KeyTime",
                            vec![Attr::Longs(vec![0, KTIME_PER_SEC])],
                            Vec::new(),
                        ),
                        node(
                            "KeyValueFloat",
                            vec![Attr::Floats(vec![0.0, 2.0])],
                            Vec::new(),
                        ),
                    ],
                ),
            ]);
            connections.extend([
                connection(LAYER, STACK),
                connection(CURVE_NODE, LAYER),
                property_connection(CURVE, CURVE_NODE, "d|X"),
                property_connection(CURVE_NODE, BONE, "Lcl Translation"),
            ]);
        }

        write_fbx(&[
            unit_scale,
            node("Objects", Vec::new(), objects),
            node("Connections", Vec::new(), connections),
        ])
    }

    #[test]
    fn fbx_fixture_parses_into_one_primitive() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "tri.fbx", &static_triangle_fbx());
        let scene = crate::fbx::parse_fbx(&src).expect("fixture parses");
        let (vertices, indices) =
            crate::fbx::read_primitive_geometry(&scene, 0).expect("primitive 0");
        assert_eq!(vertices.len(), 3);
        assert_eq!(indices, vec![0, 1, 2]);
    }

    // A `.fbx`-sourced Mesh lands with inline geometry, and several assets fanned
    // out of one file share a single parse and a single chunk split.
    #[test]
    fn desugar_fbx_meshes_inlines_geometry_for_every_asset_sharing_a_source() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "scene.fbx", &static_triangle_fbx());
        let mut assets = vec![
            wja(
                "part_a",
                MESH_TYPE,
                serde_json::json!({"source": src, "primitive_index": 0}),
            ),
            wja(
                "part_b",
                MESH_TYPE,
                serde_json::json!({"source": src, "primitive_index": 0, "chunk_index": 0}),
            ),
        ];
        desugar_fbx_meshes(&mut assets, &Default::default()).expect("desugar");
        for asset in &assets {
            assert_eq!(asset.args["vertices"].as_array().unwrap().len(), 3);
            assert_eq!(asset.args["indices"].as_array().unwrap(), &vec![0, 1, 2]);
        }
    }

    // The two failure modes past the parse: a primitive the file does not have,
    // and a chunk index past the split.
    #[test]
    fn desugar_fbx_meshes_rejects_an_unknown_primitive_and_chunk() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "scene.fbx", &static_triangle_fbx());

        let mut ghost = vec![wja(
            "ghost",
            MESH_TYPE,
            serde_json::json!({"source": src, "primitive_index": 7}),
        )];
        let err =
            desugar_fbx_meshes(&mut ghost, &Default::default()).expect_err("primitive 7 is absent");
        let msg = err.to_string();
        assert!(msg.contains("Asset 'ghost'"), "got: {msg}");
        assert!(msg.contains("FBX import failed"), "got: {msg}");

        let mut past_end = vec![wja(
            "chunk9",
            MESH_TYPE,
            serde_json::json!({"source": src, "chunk_index": 9}),
        )];
        let err = desugar_fbx_meshes(&mut past_end, &Default::default())
            .expect_err("chunk 9 is past the split");
        let msg = err.to_string();
        assert!(msg.contains("chunk_index 9 out of range"), "got: {msg}");
        assert!(msg.contains("1 chunk(s)"), "got: {msg}");
    }

    // A `.fbx`-sourced SkinnedMesh lands with inline geometry and a skeleton,
    // mirroring the glTF pass; the `source` reference is what the compile step
    // no longer needs.
    #[test]
    fn desugar_fbx_skinned_meshes_inlines_geometry_and_skeleton() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "hero.fbx", &skinned_triangle_fbx());
        let mut assets = vec![wja(
            "hero",
            SKINNED_MESH_TYPE,
            serde_json::json!({"source": src}),
        )];
        desugar_fbx_skinned_meshes(&mut assets, &Default::default()).expect("desugar");

        let args = &assets[0].args;
        assert_eq!(args["vertices"].as_array().unwrap().len(), 3);
        assert_eq!(args["indices"].as_array().unwrap(), &vec![0, 1, 2]);
        let skeleton = args["skeleton"].as_array().expect("skeleton inlined");
        assert_eq!(skeleton.len(), 1);
        assert_eq!(skeleton[0]["name"], "Root");
        assert_eq!(skeleton[0]["parent"], -1);
        // Every control point binds fully to the single cluster bone.
        assert_eq!(
            args["vertices"][0]["weights"],
            serde_json::json!([1.0, 0.0, 0.0, 0.0])
        );
    }

    #[test]
    fn desugar_skinned_meshes_import_the_selected_skin() {
        use crate::glb::test_fixtures::two_skin_glb;

        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "hero.glb", &two_skin_glb());
        let mut assets = vec![
            wja(
                "body",
                SKINNED_MESH_TYPE,
                serde_json::json!({"source": src, "skin_index": 0}),
            ),
            wja(
                "hair",
                SKINNED_MESH_TYPE,
                serde_json::json!({"source": src, "skin_index": 1}),
            ),
        ];
        desugar_gltf_skinned_meshes(&mut assets, &Default::default(), None).expect("desugar");

        // Each asset inlines its own part's geometry.
        assert_eq!(
            assets[0].args["vertices"][0]["pos"],
            serde_json::json!([0.0, 0.0, 0.0])
        );
        assert_eq!(
            assets[1].args["vertices"][0]["pos"],
            serde_json::json!([5.0, 0.0, 0.0])
        );
    }

    #[test]
    fn desugar_animation_imports_inherit_the_targets_skin() {
        use crate::glb::test_fixtures::two_skin_glb;

        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "hero.glb", &two_skin_glb());
        let mut assets = vec![
            wja(
                "hair",
                SKINNED_MESH_TYPE,
                serde_json::json!({"source": src, "skin_index": 1}),
            ),
            wja(
                "hair_wave",
                "Animation",
                serde_json::json!({"target": "hair", "source": src}),
            ),
        ];
        // The clip carries no selector of its own; resolving it against the
        // target's skin is what keeps the joint indices in the same space.
        assert_eq!(skin_index_by_target(&assets).get("hair"), Some(&1));
        desugar_animation_imports(&mut assets, None).expect("desugar");
        assert!(
            !assets[1].args["tracks"]
                .as_array()
                .expect("tracks")
                .is_empty()
        );
    }

    #[test]
    fn an_animation_without_a_resolvable_target_falls_back_to_the_first_skin() {
        let assets = vec![
            wja(
                "body",
                SKINNED_MESH_TYPE,
                serde_json::json!({"skin_index": 2}),
            ),
            wja("orphan", "Animation", serde_json::json!({"target": "gone"})),
        ];
        let by_target = skin_index_by_target(&assets);
        assert_eq!(by_target.get("body"), Some(&2));
        assert!(!by_target.contains_key("gone"));
    }

    // `.glb` sources belong to the glTF pass, and a probe hit means the
    // compiled payload is already in hand; neither is parsed here.
    #[test]
    fn desugar_fbx_skinned_meshes_skips_glb_sources_and_cache_hits() {
        let glb_args = serde_json::json!({"source": "/no/such/hero.glb"});
        let cached_args = serde_json::json!({"source": "/no/such/hero.fbx"});
        let mut assets = vec![
            wja("from_glb", SKINNED_MESH_TYPE, glb_args.clone()),
            wja("cached", SKINNED_MESH_TYPE, cached_args.clone()),
        ];
        desugar_fbx_skinned_meshes(&mut assets, &hit_cache("cached")).expect("desugar");
        assert_eq!(assets[0].args, glb_args);
        assert_eq!(assets[1].args, cached_args);
    }

    // A file with no skin deformer is a hard error, named against the asset.
    #[test]
    fn desugar_fbx_skinned_meshes_reports_a_file_without_a_skin() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "static.fbx", &static_triangle_fbx());
        let mut assets = vec![wja(
            "hero",
            SKINNED_MESH_TYPE,
            serde_json::json!({"source": src}),
        )];
        let err = desugar_fbx_skinned_meshes(&mut assets, &Default::default())
            .expect_err("a static file has no skin");
        let msg = err.to_string();
        assert!(msg.contains("Asset 'hero'"), "got: {msg}");
        assert!(msg.contains("FBX import failed"), "got: {msg}");
    }

    #[test]
    fn desugar_fbx_meshes_missing_source_errors() {
        let mut assets = vec![wja(
            "bistro",
            MESH_TYPE,
            serde_json::json!({"source": "/no/such/scene.fbx"}),
        )];
        let err = desugar_fbx_meshes(&mut assets, &Default::default()).expect_err("missing .fbx");
        assert!(err.to_string().contains("Asset 'bistro'"), "got: {err}");
    }

    #[test]
    fn desugar_fbx_meshes_skips_cache_hits_and_non_fbx_sources() {
        let cached_args = serde_json::json!({"source": "/no/such/scene.fbx"});
        let glb_args = serde_json::json!({"source": "/no/such/scene.glb"});
        let mut assets = vec![
            wja("cached", MESH_TYPE, cached_args.clone()),
            wja("from_glb", MESH_TYPE, glb_args.clone()),
        ];
        desugar_fbx_meshes(&mut assets, &hit_cache("cached")).expect("desugar");
        assert_eq!(assets[0].args, cached_args);
        assert_eq!(assets[1].args, glb_args);
    }

    // An `.fbx` source routes to the FBX importer, which bakes the clip at the
    // asset's `sample_rate` rather than replaying authored keys.
    #[test]
    fn desugar_animation_imports_bakes_an_fbx_clip_at_the_sample_rate() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "hero.fbx", &skinned_fbx(true));
        let mut assets = vec![wja(
            "wave",
            "Animation",
            serde_json::json!({"source": src, "sample_rate": 10.0}),
        )];
        desugar_animation_imports(&mut assets, None).expect("desugar");

        let args = &assets[0].args;
        assert!(
            (args["duration"].as_f64().expect("duration") - 1.0).abs() < 1e-3,
            "got: {}",
            args["duration"]
        );
        let tracks = args["tracks"].as_array().expect("tracks inlined");
        assert_eq!(tracks.len(), 1);
        let keys = tracks[0]["keyframes"].as_array().expect("keyframes");
        // One second at 10 samples per second, inclusive of both ends.
        assert_eq!(keys.len(), 11);
        assert_eq!(keys[0]["translation"][0], 0.0);
        assert_eq!(keys[10]["translation"][0], 2.0);
    }

    // A clip named by `animation_name` that the file does not contain fails
    // through the FBX importer too.
    #[test]
    fn desugar_animation_imports_reports_an_unknown_fbx_clip_name() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "hero.fbx", &skinned_fbx(true));
        let mut assets = vec![wja(
            "run",
            "Animation",
            serde_json::json!({"source": src, "animation_name": "sprint"}),
        )];
        let err = desugar_animation_imports(&mut assets, None).expect_err("no 'sprint' clip");
        let msg = err.to_string();
        assert!(msg.contains("Asset 'run'"), "got: {msg}");
        assert!(msg.contains("FBX import failed"), "got: {msg}");
    }

    #[test]
    fn desugar_animation_imports_missing_source_errors() {
        let mut assets = vec![wja(
            "walk",
            "Animation",
            serde_json::json!({"source": "/no/such/anim.glb"}),
        )];
        let err = desugar_animation_imports(&mut assets, None).expect_err("missing .glb");
        assert!(err.to_string().contains("Asset 'walk'"), "got: {err}");
    }

    #[test]
    fn desugar_animation_imports_missing_named_clip_errors() {
        // The by-name lookup also starts by reading the file, so a missing
        // source fails before the name search; the error still names the asset.
        let mut assets = vec![wja(
            "run",
            "Animation",
            serde_json::json!({"source": "/no/such/anim.glb", "animation_name": "Run"}),
        )];
        let err = desugar_animation_imports(&mut assets, None).expect_err("missing .glb");
        assert!(err.to_string().contains("Asset 'run'"), "got: {err}");
    }

    // A source-backed Animation is replaced by the imported clip's duration
    // and tracks. Channels targeting non-joint nodes are dropped, so the
    // fixture's two channels yield one track.
    #[test]
    fn desugar_animation_imports_inlines_the_indexed_clip() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "hero.glb", &crate::glb::test_fixtures::skinned_glb());
        let mut assets = vec![wja(
            "wave",
            "Animation",
            serde_json::json!({"source": src, "animation_index": 0}),
        )];
        desugar_animation_imports(&mut assets, None).expect("desugar");

        let args = &assets[0].args;
        assert_eq!(args["duration"], 1.0);
        let tracks = args["tracks"].as_array().expect("tracks inlined");
        assert_eq!(tracks.len(), 1, "the non-joint channel is dropped");
        let keys = tracks[0]["keyframes"].as_array().expect("keyframes");
        assert_eq!(keys.len(), 2);
        assert_eq!(keys[0]["time"], 0.0);
        assert_eq!(keys[1]["translation"], serde_json::json!([0.0, 2.0, 0.0]));
        // The fixture animates no morph weights, so no morph track appears.
        assert!(args.get("morph_track").is_none());
    }

    // `animation_name` picks the clip by name; a name the file does not carry
    // is a hard error that lists what it does contain.
    #[test]
    fn desugar_animation_imports_resolves_and_rejects_clip_names() {
        let dir = tempfile::tempdir().expect("tempdir");
        let src = write_fixture(&dir, "hero.glb", &crate::glb::test_fixtures::skinned_glb());
        let mut assets = vec![wja(
            "wave",
            "Animation",
            serde_json::json!({"source": src, "animation_name": "wave"}),
        )];
        desugar_animation_imports(&mut assets, None).expect("desugar");
        assert_eq!(assets[0].args["tracks"].as_array().unwrap().len(), 1);

        let mut missing = vec![wja(
            "run",
            "Animation",
            serde_json::json!({"source": src, "animation_name": "sprint"}),
        )];
        let err = desugar_animation_imports(&mut missing, None)
            .expect_err("the file has no 'sprint' clip");
        let msg = err.to_string();
        assert!(
            msg.contains("has no animation named 'sprint'"),
            "got: {msg}"
        );
        assert!(msg.contains("wave"), "the error lists the clips: {msg}");
    }

    #[test]
    fn desugar_root_motion_rejects_malformed_args() {
        let mut assets = vec![wja(
            "walk",
            "Animation",
            serde_json::json!({"root_motion": true, "duration": "long"}),
        )];
        let err = desugar_root_motion(&mut assets).expect_err("bad duration");
        assert!(
            err.to_string()
                .contains("root-motion bake failed to parse args"),
            "got: {err}"
        );
    }

    #[test]
    fn desugar_root_motion_tolerates_a_clip_with_no_root_track() {
        // Only joint 1 is animated: there is nothing to strip from the root,
        // so the bake warns and leaves an empty curve rather than failing.
        let mut assets = vec![wja(
            "wave",
            "Animation",
            serde_json::json!({
                "root_motion": true,
                "duration": 1.0,
                "tracks": [{"joint": 1, "keyframes": [
                    {"time": 0.0, "translation": [1.0, 0.0, 0.0]}
                ]}],
            }),
        )];
        desugar_root_motion(&mut assets).expect("bake succeeds");
        assert_eq!(assets[0].args["root_track"], serde_json::json!([]));
        // The non-root track is untouched.
        assert_eq!(
            assets[0].args["tracks"][0]["keyframes"][0]["translation"][0],
            1.0
        );
    }

    // Opting into vertical root motion keeps the Y travel in the root track
    // instead of anchoring it back into the pose.
    #[test]
    fn desugar_root_motion_keeps_y_travel_when_asked() {
        let clip = |root_motion_y: bool| {
            serde_json::json!({
                "target": "hero",
                "duration": 1.0,
                "root_motion": true,
                "root_motion_y": root_motion_y,
                "tracks": [{"joint": 0, "keyframes": [
                    {"time": 0.0, "translation": [0.0, 0.0, 0.0]},
                    {"time": 1.0, "translation": [0.0, 3.0, 0.0]}
                ]}],
            })
        };
        let mut assets = vec![
            wja("jump", "Animation", clip(true)),
            wja("walk", "Animation", clip(false)),
        ];
        desugar_root_motion(&mut assets).expect("bake succeeds");

        assert_eq!(assets[0].args["root_track"][1]["translation"][1], 3.0);
        assert_eq!(
            assets[0].args["tracks"][0]["keyframes"][1]["translation"][1],
            0.0
        );
        // Without the flag the rise stays in the pose and the root track is flat.
        assert_eq!(assets[1].args["root_track"][1]["translation"][1], 0.0);
        assert_eq!(
            assets[1].args["tracks"][0]["keyframes"][1]["translation"][1],
            3.0
        );
    }

    // An authored `screen` arg wins over the name-prefix convention, exactly
    // as an authored `scene` does on a Prop.
    #[test]
    fn resolve_scene_refs_keeps_an_authored_screen_arg() {
        let mut assets = vec![
            wja("menu", "Screen", serde_json::json!({})),
            wja("other", "Screen", serde_json::json!({})),
            wja(
                "menu_title",
                "TextLabel",
                serde_json::json!({"screen": "other"}),
            ),
        ];
        super::resolve_scene_refs(&mut assets);
        assert_eq!(assets[2].args["screen"], "other");
    }

    #[test]
    fn resolve_scene_refs_prop_scene_prefix_rules() {
        let mut assets = vec![
            wja("level", "Scene", serde_json::json!({})),
            wja("level_boss", "Scene", serde_json::json!({})),
            wja("level_boss_door", "Prop", serde_json::json!({})),
            wja("level_gate", "Prop", serde_json::json!({"scene": "other"})),
            wja("solo_thing", "Prop", serde_json::json!({})),
        ];
        super::resolve_scene_refs(&mut assets);

        // Longest scene prefix wins for the nested name.
        assert_eq!(assets[2].args["scene"], "level_boss");
        // An authored `scene` arg is never overwritten.
        assert_eq!(assets[3].args["scene"], "other");
        // No matching prefix: no `scene` arg appears.
        assert!(assets[4].args.get("scene").is_none());
    }

    #[test]
    fn resolve_scene_refs_rewrites_action_names_to_interned_ids() {
        crate::ecs::asset_id::reset_interner();
        let mut assets = vec![
            wja(
                "btn",
                "HitRegion",
                serde_json::json!({"action": "screen:show:pause"}),
            ),
            wja(
                "key",
                "KeyBinding",
                serde_json::json!({"action": "scene:day"}),
            ),
        ];
        super::resolve_scene_refs(&mut assets);

        // Names intern in resolution order on this thread's fresh interner:
        // "pause" -> 0, "day" -> 1.
        assert_eq!(assets[0].args["action"], "screen:show:0");
        assert_eq!(assets[1].args["action"], "scene:1");
    }

    #[test]
    fn resolve_scene_refs_leaves_numeric_and_foreign_actions_alone() {
        let mut assets = vec![
            wja(
                "a",
                "HitRegion",
                serde_json::json!({"action": "screen:toggle:3"}),
            ),
            wja("b", "HitRegion", serde_json::json!({"action": "quit"})),
            wja("c", "KeyBinding", serde_json::json!({"action": "scene:"})),
        ];
        super::resolve_scene_refs(&mut assets);

        // Already an id, not a recognised prefix, and an empty target: all
        // pass through unchanged.
        assert_eq!(assets[0].args["action"], "screen:toggle:3");
        assert_eq!(assets[1].args["action"], "quit");
        assert_eq!(assets[2].args["action"], "scene:");
    }

    #[test]
    fn probe_mesh_payload_cache_probes_only_source_backed_mesh_assets() {
        let assets = vec![
            wja("m", MESH_TYPE, serde_json::json!({"source": "x.glb"})),
            wja("inline", MESH_TYPE, serde_json::json!({"vertices": []})),
            wja(
                "s",
                SKINNED_MESH_TYPE,
                serde_json::json!({"source": "y.glb"}),
            ),
            wja(
                "p",
                "ProceduralMesh",
                serde_json::json!({"generator": "box"}),
            ),
        ];
        let probed = probe_mesh_payload_cache(&assets, None, None);

        let mut names: Vec<&str> = probed.keys().map(|s| s.as_str()).collect();
        names.sort_unstable();
        assert_eq!(names, vec!["m", "s"]);
        for entry in probed.values() {
            assert!(!entry.key.is_empty());
            // The payload cache is disabled under cargo test, so a probe can
            // only ever record a miss here.
            assert!(entry.bytes.is_none());
        }
    }

    // `build_compiled` runs on an already-prepared world, so a type the
    // component registry cannot resolve surfaces here rather than upstream.
    #[test]
    fn build_compiled_names_the_asset_whose_type_will_not_resolve() {
        let assets = vec![wja("mystery", "NotAType", serde_json::json!({}))];
        let Err(err) = build_compiled(assets, None, None) else {
            panic!("unknown type must not compile");
        };
        assert_eq!(err.kind(), std::io::ErrorKind::InvalidData);
        assert!(err.to_string().contains("Asset 'mystery'"), "got: {err}");
    }

    // A payload that will not compile fails the whole build; the error names
    // the asset so the author knows which line to fix.
    #[test]
    fn build_compiled_surfaces_a_payload_compile_failure() {
        let assets = vec![wja(
            "shape",
            "ProceduralMesh",
            serde_json::json!({"generator": "not_a_generator"}),
        )];
        let Err(err) = build_compiled(assets, None, None) else {
            panic!("an uncompilable payload must not build");
        };
        assert_eq!(err.kind(), std::io::ErrorKind::InvalidData);
        assert!(err.to_string().contains("not_a_generator"), "got: {err}");
    }

    // The per-asset resolution pass reports every asset that fails, not just
    // the first, and a clean world returns Ok.
    #[test]
    fn validate_world_jsonl_collects_every_resolution_failure() {
        let world = concat!(
            r#"{"name":"first","type":"ProceduralMesh","args":{"generator":"box"}}"#,
            "\n",
            r#"{"name":"clip","type":"AudioClip","args":{"source":"a.wav"}}"#,
            "\n",
        );
        validate_world_jsonl(world, None).expect("a resolvable world validates");

        // Args of the wrong shape survive the structural world checks and are
        // rejected when the def is built.
        let bad = concat!(
            r#"{"name":"t1","type":"PointLight","args":{"intensity":"soon"}}"#,
            "\n",
            r#"{"name":"t2","type":"PointLight","args":{"intensity":"later"}}"#,
            "\n",
        );
        let err = validate_world_jsonl(bad, None).expect_err("mistyped args do not resolve");
        let msg = err.to_string();
        assert!(msg.contains("Asset 't1'"), "got: {msg}");
        assert!(msg.contains("Asset 't2'"), "got: {msg}");
    }

    // An uncompressed 24-bit BGR Targa, the cheapest real image source to
    // author inline.
    fn tga_2x2() -> Vec<u8> {
        let mut v = vec![0u8; 18];
        v[2] = 2; // uncompressed true-color
        v[12..14].copy_from_slice(&2u16.to_le_bytes());
        v[14..16].copy_from_slice(&2u16.to_le_bytes());
        v[16] = 24;
        v[17] = 0x20; // top origin
        v.extend_from_slice(&[10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120]);
        v
    }

    // `cn debug`'s hot-reload watcher maps a saved file back to the handle it
    // feeds, so every file-backed texture and mesh records its source in handle
    // order. A generated asset has nothing to watch and records an empty source.
    #[test]
    fn build_compiled_records_hot_reload_sources_in_handle_order() {
        let dir = tempfile::tempdir().expect("tempdir");
        let tga = write_fixture(&dir, "wall.tga", &tga_2x2());
        let glb = write_fixture(
            &dir,
            "scene.glb",
            &crate::glb::test_fixtures::static_triangle_glb(),
        );
        let assets = vec![
            wja(
                "proc_tex",
                "Texture",
                serde_json::json!({"generator": "checker", "resolution": 8}),
            ),
            wja(
                "wall_tex",
                "Texture",
                serde_json::json!({"source": tga, "image_index": 3}),
            ),
            wja(
                "inline_mesh",
                MESH_TYPE,
                serde_json::json!({"generator": "box", "half_extents": [1, 1, 1]}),
            ),
            wja(
                "file_mesh",
                MESH_TYPE,
                serde_json::json!({
                    "source": glb,
                    "primitive_index": 0,
                    "lod_levels": 3,
                    "lod_distances": [10.0, 20.0],
                }),
            ),
        ];
        let result = build_compiled(assets, None, None).expect("build");

        assert_eq!(result.texture_sources.len(), 2);
        assert_eq!(
            result.texture_sources[0],
            TextureSourceInfo {
                name_id: 0,
                source: String::new(),
                image_index: 0,
            },
            "a generated texture has no file to watch"
        );
        assert_eq!(
            result.texture_sources[1],
            TextureSourceInfo {
                name_id: 1,
                source: tga.clone(),
                image_index: 3,
            }
        );

        assert_eq!(result.mesh_sources.len(), 2);
        assert_eq!(
            result.mesh_sources[0],
            MeshSourceInfo {
                source: String::new(),
                primitive_index: 0,
                lod_levels: 1,
                lod_distances: Vec::new(),
            },
            "a generated mesh has no file to watch"
        );
        assert_eq!(
            result.mesh_sources[1],
            MeshSourceInfo {
                source: glb.clone(),
                primitive_index: 0,
                lod_levels: 3,
                lod_distances: vec![10.0, 20.0],
            }
        );

        // The lock records mirror the catalogues so a blob boot can rebuild
        // them without the authored args.
        let lock_tex: Vec<_> = result
            .resource_locks
            .iter()
            .filter(|r| r.kind == "Texture")
            .collect();
        assert_eq!(lock_tex.len(), 2);
        assert_eq!(lock_tex[0].texture_source.as_ref().unwrap().source, "");
        let wall = lock_tex[1].texture_source.as_ref().unwrap();
        assert_eq!(wall.source, tga);
        assert_eq!(wall.image_index, 3);
        assert!(lock_tex[1].mesh_source.is_none());

        let lock_mesh: Vec<_> = result
            .resource_locks
            .iter()
            .filter(|r| r.kind == "Mesh")
            .collect();
        assert_eq!(lock_mesh.len(), 2);
        assert!(lock_mesh[0].texture_source.is_none());
        let file_mesh = lock_mesh[1].mesh_source.as_ref().unwrap();
        assert_eq!(file_mesh.source, glb);
        assert_eq!(file_mesh.lod_levels, 3);
        assert_eq!(file_mesh.lod_distances, vec![10.0, 20.0]);
    }

    // A data resource carries its bytes inline in the record rather than in a
    // blob payload section, so the lock records no payload blob for it.
    #[test]
    fn build_compiled_keeps_a_data_resource_out_of_the_payload_sections() {
        let assets = vec![
            wja("wood", "Material", serde_json::json!({})),
            wja(
                "shape",
                "ProceduralMesh",
                serde_json::json!({"generator": "box"}),
            ),
        ];
        let result = build_compiled(assets, None, None).expect("build");

        assert_eq!(result.resources.len(), 1);
        let material = &result.resources[0];
        assert!(material.payload.is_none(), "a Material rides inline");
        assert!(!material.data_bytes.is_empty());
        postcard::from_bytes::<crate::components::Material>(&material.data_bytes)
            .expect("the inline bytes decode as a Material");
        assert_eq!(result.resource_locks[0].name, "wood");
        assert_eq!(result.resource_locks[0].payload_blob, None);
        // The component's payload is what actually occupies the blob.
        assert_eq!(result.defs.len(), 1);
        assert!(result.defs[0].payload.is_some());
    }

    // Only a File whose kind maps to a mesh payload is compiled; every other
    // kind stays a plain reference with no blob bytes.
    #[test]
    fn build_compiled_compiles_only_mesh_kind_file_assets() {
        let dir = tempfile::tempdir().expect("tempdir");
        let obj = write_fixture(&dir, "tri.obj", b"v 0 0 0\nv 1 0 0\nv 0 1 0\nf 1 2 3\n");
        let png = write_fixture(&dir, "icon.png", b"not read");
        let assets = vec![
            wja(
                "model",
                "File",
                serde_json::json!({"path": obj, "kind": "obj"}),
            ),
            wja(
                "icon",
                "File",
                serde_json::json!({"path": png, "kind": "png"}),
            ),
        ];
        let result = build_compiled(assets, None, None).expect("build");

        assert_eq!(result.names, vec!["model".to_string(), "icon".to_string()]);
        let mesh_payload = result.defs[0]
            .payload
            .as_ref()
            .expect("the obj File compiles");
        assert!(mesh_payload.len > 0);
        assert!(
            result.defs[1].payload.is_none(),
            "a png File produces no blob payload"
        );
    }

    // A source-backed asset that is neither mesh kind is skipped: its payload
    // cache is handled by the per-asset path inside the compile pass.
    #[test]
    fn probe_mesh_payload_cache_skips_a_source_backed_non_mesh_asset() {
        let assets = vec![
            wja("tex", "Texture", serde_json::json!({"source": "wall.png"})),
            wja("m", MESH_TYPE, serde_json::json!({"source": "x.glb"})),
        ];
        let probed = probe_mesh_payload_cache(&assets, None, None);
        assert_eq!(probed.len(), 1);
        assert!(probed.contains_key("m"));
    }

    use crate::resource_handles::{RegisteredType, ResourceKind};

    fn procedural_mesh_def() -> BlobAssetDef {
        asset_api::create_asset_def(&AssetRequest {
            asset_type: "ProceduralMesh".to_string(),
            args: Some(serde_json::json!({"generator": "box"})),
        })
        .expect("ProceduralMesh def")
    }

    // The pre-desugar probe is the whole point of the glTF cache: when it holds
    // bytes for an asset, neither the component nor the resource path may touch
    // the source again. Both assets here name inputs that would fail to
    // compile, so a recompile would be loud.
    #[test]
    fn compile_and_pack_payloads_serves_probed_bytes_without_recompiling() {
        let assets = vec![
            wja(
                "shape",
                "ProceduralMesh",
                serde_json::json!({"generator": "not_a_generator"}),
            ),
            wja(
                "body",
                MESH_TYPE,
                serde_json::json!({"source": "/no/such/body.glb"}),
            ),
        ];
        let mut named = vec![("shape".to_string(), procedural_mesh_def())];
        let resource_jobs = vec![(1usize, RegisteredType::Mesh, 0u32)];
        let mut cache = std::collections::HashMap::new();
        cache.insert(
            "shape".to_string(),
            MeshCacheEntry {
                key: "shape-key".to_string(),
                bytes: Some(vec![1, 2, 3]),
            },
        );
        cache.insert(
            "body".to_string(),
            MeshCacheEntry {
                key: "body-key".to_string(),
                bytes: Some(vec![4, 5, 6, 7]),
            },
        );

        let out = compile_and_pack_payloads(
            &mut named,
            &[0],
            PackContext {
                assets: &assets,
                resource_jobs: &resource_jobs,
                partition: &crate::scene_partition::partition_scenes(&assets),
                mesh_source_handles: &Default::default(),
                max_blob_bytes: 1024,
                assets_dir: None,
                artifacts_dir: None,
                mesh_cache: &cache,
                progress: None,
            },
        )
        .expect("probed payloads need no compiler");

        assert_eq!(out.cache_hits, 2);
        assert_eq!(out.cache_misses, 0);
        // Components pack first, then the resource stream, into one blob.
        assert_eq!(out.blobs, vec![vec![1, 2, 3, 4, 5, 6, 7]]);
        let component = named[0].1.payload.as_ref().expect("component locator");
        assert_eq!(
            (component.blob_index, component.offset, component.len),
            (0, 0, 3)
        );
        let resource = out.resources[0].payload.as_ref().expect("resource locator");
        assert_eq!(
            (resource.blob_index, resource.offset, resource.len),
            (0, 3, 4)
        );
        assert_eq!(out.resources[0].resource_kind, ResourceKind::Mesh as u8);
        assert_eq!(out.resources[0].handle, 0);
    }

    // A scene-exclusive resource packs into its own blob after the global set,
    // and the scene group records it; record order stays resource_jobs order.
    #[test]
    fn scene_owned_payloads_pack_into_their_own_blob() {
        let assets = vec![
            wja("day", "Scene", serde_json::json!({})),
            wja(
                "day_prop",
                "Prop",
                serde_json::json!({"mesh":"day_mesh","scene":"day"}),
            ),
            wja("bg_prop", "Prop", serde_json::json!({"mesh":"bg_mesh"})),
            wja(
                "day_mesh",
                MESH_TYPE,
                serde_json::json!({"source": "/no/such/day.glb"}),
            ),
            wja(
                "bg_mesh",
                MESH_TYPE,
                serde_json::json!({"source": "/no/such/bg.glb"}),
            ),
        ];
        let mut named: Vec<(String, BlobAssetDef)> = Vec::new();
        let resource_jobs = vec![
            (3usize, RegisteredType::Mesh, 0u32),
            (4usize, RegisteredType::Mesh, 1u32),
        ];
        let cache = std::collections::HashMap::from([
            (
                "day_mesh".to_string(),
                MeshCacheEntry {
                    key: "day-key".to_string(),
                    bytes: Some(vec![0xDD; 4]),
                },
            ),
            (
                "bg_mesh".to_string(),
                MeshCacheEntry {
                    key: "bg-key".to_string(),
                    bytes: Some(vec![0xBB; 2]),
                },
            ),
        ]);

        let out = compile_and_pack_payloads(
            &mut named,
            &[],
            PackContext {
                assets: &assets,
                resource_jobs: &resource_jobs,
                partition: &crate::scene_partition::partition_scenes(&assets),
                mesh_source_handles: &Default::default(),
                max_blob_bytes: 1 << 20,
                assets_dir: None,
                artifacts_dir: None,
                mesh_cache: &cache,
                progress: None,
            },
        )
        .expect("probed payloads need no compiler");

        // Global set (bg) fills blob 0; day's exclusive mesh starts blob 1.
        assert_eq!(out.blobs, vec![vec![0xBB; 2], vec![0xDD; 4]]);
        let day = out.resources[0].payload.as_ref().expect("day locator");
        assert_eq!((day.blob_index, day.offset, day.len), (1, 0, 4));
        let bg = out.resources[1].payload.as_ref().expect("bg locator");
        assert_eq!((bg.blob_index, bg.offset, bg.len), (0, 0, 2));

        assert_eq!(out.scene_groups.len(), 1);
        assert_eq!(
            out.scene_groups[0].resources,
            vec![(ResourceKind::Mesh as u8, 0)]
        );
        assert!(out.scene_groups[0].defs.is_empty());
    }

    // Every compiled static-mesh payload gets a baked AABB + counts record
    // keyed by its mesh-source handle.
    #[test]
    fn mesh_bounds_are_baked_for_compiled_mesh_sources() {
        let assets = vec![wja(
            "shape",
            "ProceduralMesh",
            serde_json::json!({"generator": "box"}),
        )];
        let mut named = vec![("shape".to_string(), procedural_mesh_def())];
        let mut handles = crate::resource_handles::ResourceHandles::default();
        crate::resource_handles::assign_mesh_source_handles(&mut handles, &assets);
        let out = compile_and_pack_payloads(
            &mut named,
            &[0],
            PackContext {
                assets: &assets,
                resource_jobs: &[],
                partition: &crate::scene_partition::partition_scenes(&assets),
                mesh_source_handles: &handles,
                max_blob_bytes: 1 << 20,
                assets_dir: None,
                artifacts_dir: None,
                mesh_cache: &Default::default(),
                progress: None,
            },
        )
        .expect("box compiles");
        assert_eq!(out.mesh_bounds.len(), 1);
        let record = out.mesh_bounds[0];
        assert_eq!(record.handle, 0);
        assert!(record.vertex_count > 0 && record.index_count > 0);
        for axis in 0..3 {
            assert!(record.min[axis] < record.max[axis]);
        }
    }

    // A probe that recorded a miss compiles for real, on both the component and
    // the resource path, and both payloads land in the packed blob.
    #[test]
    fn compile_and_pack_payloads_compiles_a_probe_miss() {
        let assets = vec![
            wja(
                "shape",
                "ProceduralMesh",
                serde_json::json!({"generator": "box"}),
            ),
            wja(
                "body",
                MESH_TYPE,
                serde_json::json!({"generator": "sphere", "radius": 1.0}),
            ),
        ];
        let mut named = vec![("shape".to_string(), procedural_mesh_def())];
        let resource_jobs = vec![(1usize, RegisteredType::Mesh, 0u32)];
        let miss = |key: &str| MeshCacheEntry {
            key: key.to_string(),
            bytes: None,
        };
        let cache = std::collections::HashMap::from([
            ("shape".to_string(), miss("shape-key")),
            ("body".to_string(), miss("body-key")),
        ]);

        let out = compile_and_pack_payloads(
            &mut named,
            &[0],
            PackContext {
                assets: &assets,
                resource_jobs: &resource_jobs,
                partition: &crate::scene_partition::partition_scenes(&assets),
                mesh_source_handles: &Default::default(),
                max_blob_bytes: 1 << 20,
                assets_dir: None,
                artifacts_dir: None,
                mesh_cache: &cache,
                progress: None,
            },
        )
        .expect("a probe miss compiles");

        assert_eq!(out.cache_hits, 0);
        assert_eq!(out.cache_misses, 2);
        let component = named[0].1.payload.as_ref().expect("component locator");
        let resource = out.resources[0].payload.as_ref().expect("resource locator");
        assert!(component.len > 0);
        assert!(resource.len > 0);
        assert_eq!(
            out.blobs[0].len() as u64,
            component.len + resource.len,
            "both compiled payloads land in the blob"
        );
    }

    // A world whose assets all carry inline args produces no payload sections
    // at all, and still reports one (empty) blob for the metadata to ride in.
    #[test]
    fn compile_and_pack_payloads_returns_one_empty_blob_for_a_payload_less_world() {
        let assets = vec![wja("day", "Scene", serde_json::json!({}))];
        let mut named = vec![(
            "day".to_string(),
            asset_api::create_asset_def(&AssetRequest {
                asset_type: "Scene".to_string(),
                args: Some(serde_json::json!({})),
            })
            .expect("Scene def"),
        )];
        let out = compile_and_pack_payloads(
            &mut named,
            &[0],
            PackContext {
                assets: &assets,
                resource_jobs: &[],
                partition: &crate::scene_partition::partition_scenes(&assets),
                mesh_source_handles: &Default::default(),
                max_blob_bytes: 1024,
                assets_dir: None,
                artifacts_dir: None,
                mesh_cache: &Default::default(),
                progress: None,
            },
        )
        .expect("pack");

        assert_eq!(out.blobs, vec![Vec::<u8>::new()]);
        assert!(out.resources.is_empty());
        assert_eq!((out.cache_hits, out.cache_misses), (0, 0));
        assert!(named[0].1.payload.is_none());
    }

    // The compile pass selects its work by discriminant. A def carrying one the
    // component registry does not know is skipped, so an unrecognised record
    // cannot abort a build.
    #[test]
    fn compile_and_pack_payloads_skips_a_def_with_an_unknown_discriminant() {
        let assets = vec![wja("mystery", "ProceduralMesh", serde_json::json!({}))];
        let mut named = vec![(
            "mystery".to_string(),
            BlobAssetDef {
                name: None,
                kind: AssetKind::Component,
                discriminant: 200,
                args_bytes: Vec::new(),
                payload: None,
            },
        )];
        assert!(
            RegisteredType::from_discriminant(200).is_none(),
            "200 must stay outside the registered discriminant range"
        );

        let out = compile_and_pack_payloads(
            &mut named,
            &[0],
            PackContext {
                assets: &assets,
                resource_jobs: &[],
                partition: &crate::scene_partition::partition_scenes(&assets),
                mesh_source_handles: &Default::default(),
                max_blob_bytes: 1024,
                assets_dir: None,
                artifacts_dir: None,
                mesh_cache: &Default::default(),
                progress: None,
            },
        )
        .expect("pack");

        assert!(named[0].1.payload.is_none());
        assert_eq!(out.blobs, vec![Vec::<u8>::new()]);
    }

    // The blob size ceiling is packing policy, not a format limit: payloads
    // that overflow it roll into the next blob and their locators follow.
    #[test]
    fn compile_and_pack_payloads_rolls_payloads_into_overflow_blobs() {
        let assets = vec![
            wja("a", "ProceduralMesh", serde_json::json!({})),
            wja("b", "ProceduralMesh", serde_json::json!({})),
        ];
        let mut named = vec![
            ("a".to_string(), procedural_mesh_def()),
            ("b".to_string(), procedural_mesh_def()),
        ];
        let cache = std::collections::HashMap::from([
            (
                "a".to_string(),
                MeshCacheEntry {
                    key: "a".to_string(),
                    bytes: Some(vec![0xAA; 6]),
                },
            ),
            (
                "b".to_string(),
                MeshCacheEntry {
                    key: "b".to_string(),
                    bytes: Some(vec![0xBB; 6]),
                },
            ),
        ]);

        let out = compile_and_pack_payloads(
            &mut named,
            &[0, 1],
            PackContext {
                assets: &assets,
                resource_jobs: &[],
                partition: &crate::scene_partition::partition_scenes(&assets),
                mesh_source_handles: &Default::default(),
                max_blob_bytes: 8,
                assets_dir: None,
                artifacts_dir: None,
                mesh_cache: &cache,
                progress: None,
            },
        )
        .expect("pack");

        assert_eq!(out.blobs, vec![vec![0xAA; 6], vec![0xBB; 6]]);
        assert_eq!(named[0].1.payload.as_ref().unwrap().blob_index, 0);
        let second = named[1].1.payload.as_ref().unwrap();
        assert_eq!((second.blob_index, second.offset), (1, 0));
    }

    #[test]
    fn compile_by_type_without_build_impl_errors() {
        let ct = RegisteredType::parse("Prop").expect("Prop is a registered component");
        let err = compile_by_type(ct, &serde_json::json!({}), &ctx())
            .expect_err("Prop has no BuildAsset impl");
        assert!(err.to_string().contains("no BuildAsset impl"), "got: {err}");
    }

    #[test]
    fn cache_inputs_by_type_defaults_to_empty_extras() {
        use crate::asset::SourceFiles;
        let ct = RegisteredType::parse("Prop").expect("Prop is a registered component");
        let inputs = cache_inputs_by_type(ct, &serde_json::json!({}), &ctx());
        assert_eq!(inputs.sources, SourceFiles::Extra(Vec::new()));
        assert!(!inputs.target_dependent);
    }

    // The arms that take the trait default report no inputs of their own: every
    // file they read is named by an args string, which the payload cache's
    // generic walk already hashes.
    #[test]
    fn cache_inputs_by_type_covers_the_args_walk_arms() {
        use crate::asset::SourceFiles;
        for name in ["ProceduralMesh", "VoxelChunk", "File", "Room"] {
            let inputs = cache_inputs_by_type(ct(name), &serde_json::json!({}), &ctx());
            assert_eq!(
                inputs.sources,
                SourceFiles::Extra(Vec::new()),
                "{name} must not narrow the generic args walk"
            );
            assert!(
                !inputs.target_dependent,
                "{name} compiles the same everywhere"
            );
        }
    }

    // AudioClip compiles through `RegisteredType` now, not `compile_by_type`
    // (it left the component registry). Its source-less error still surfaces, and
    // its source file is folded into the payload cache key.
    #[test]
    fn resource_asset_types_compile_audio_clip_texture_cubemap_env_lut_and_font() {
        use crate::registry::RegisteredType;
        let rt = RegisteredType::parse("AudioClip").expect("AudioClip is a resource asset");
        let err = rt
            .compile_payload(&serde_json::json!({}), None)
            .expect_err("a source-less AudioClip must fail to compile");
        assert!(err.to_string().contains("missing 'source'"), "got: {err}");
        assert_eq!(
            rt.source_files(&serde_json::json!({"source": "a.wav"}), None),
            vec!["a.wav".to_string()]
        );
        assert!(rt.source_files(&serde_json::json!({}), None).is_empty());

        // Texture is also a resource asset (it left the component registry). A
        // procedural texture compiles a non-empty payload, and a file-backed one
        // folds its source into the payload cache key.
        let tex = RegisteredType::parse("Texture").expect("Texture is a resource asset");
        let bytes = tex
            .compile_payload(
                &serde_json::json!({"generator": "checker", "resolution": 32}),
                None,
            )
            .expect("a procedural texture compiles");
        assert!(!bytes.is_empty());
        assert_eq!(
            tex.source_files(&serde_json::json!({"source": "a.png"}), None),
            vec!["a.png".to_string()]
        );

        // CubemapTexture is a resource asset too. Source-less args fail, and its
        // `.hdr` source folds into the payload cache key.
        let cube =
            RegisteredType::parse("CubemapTexture").expect("CubemapTexture is a resource asset");
        let err = cube
            .compile_payload(&serde_json::json!({}), None)
            .expect_err("a source-less CubemapTexture must fail to compile");
        assert!(
            err.to_string().contains("requires a `source` path"),
            "got: {err}"
        );
        assert_eq!(
            cube.source_files(&serde_json::json!({"source": "c.hdr"}), None),
            vec!["c.hdr".to_string()]
        );

        // EnvironmentMap and ColorLut are resource assets too. Both surface their
        // source-less error through `RegisteredType::compile_payload`, and fold
        // their `source` into the payload cache key.
        let env =
            RegisteredType::parse("EnvironmentMap").expect("EnvironmentMap is a resource asset");
        let err = env
            .compile_payload(&serde_json::json!({}), None)
            .expect_err("a source-less EnvironmentMap must fail to compile");
        assert!(
            err.to_string()
                .contains("requires either `source` or `generator`"),
            "got: {err}"
        );
        assert_eq!(
            env.source_files(&serde_json::json!({"source": "e.hdr"}), None),
            vec!["e.hdr".to_string()]
        );

        let lut = RegisteredType::parse("ColorLut").expect("ColorLut is a resource asset");
        let err = lut
            .compile_payload(&serde_json::json!({}), None)
            .expect_err("a source-less ColorLut must fail to compile");
        assert!(
            err.to_string().contains("requires a `source` path"),
            "got: {err}"
        );
        assert_eq!(
            lut.source_files(&serde_json::json!({"source": "l.cube"}), None),
            vec!["l.cube".to_string()]
        );

        // Font is a resource asset. The built-in font (empty `path`) compiles a
        // non-empty atlas, and a file-backed font folds its `path` (not `source`)
        // into the payload cache key.
        let font = RegisteredType::parse("Font").expect("Font is a resource asset");
        let bytes = font
            .compile_payload(&serde_json::json!({"size_px": 20}), None)
            .expect("the built-in font compiles");
        assert!(!bytes.is_empty());
        assert_eq!(
            font.source_files(&serde_json::json!({"path": "f.ttf"}), None),
            vec!["f.ttf".to_string()]
        );
        assert!(
            font.source_files(&serde_json::json!({"source": "x.ttf"}), None)
                .is_empty()
        );
    }

    // A mesh whose source is a text `.gltf` reads sibling files the args never
    // name; `source_files` must report them so an edited external buffer or
    // image busts the payload cache.
    #[test]
    fn gltf_sources_fold_referenced_sibling_files_into_source_files() {
        use crate::registry::RegisteredType;

        let dir = tempfile::tempdir().unwrap();
        let json = serde_json::json!({
            "asset": {"version": "2.0"},
            "buffers": [{"byteLength": 4, "uri": "geo.bin"}],
            "images": [{"uri": "albedo.png"}]
        });
        let gltf_path = dir.path().join("tri.gltf");
        std::fs::write(&gltf_path, serde_json::to_vec(&json).unwrap()).unwrap();
        let src = gltf_path.to_str().unwrap().to_string();

        for rt in [RegisteredType::Mesh, RegisteredType::SkinnedMesh] {
            let files = rt.source_files(&serde_json::json!({"source": src}), None);
            assert_eq!(files.len(), 3, "{rt:?}: {files:?}");
            assert_eq!(files[0], src);
            assert!(files.iter().any(|f| f.ends_with("geo.bin")), "{files:?}");
            assert!(files.iter().any(|f| f.ends_with("albedo.png")), "{files:?}");
        }

        // A `.glb` source reports only itself.
        let glb =
            RegisteredType::Mesh.source_files(&serde_json::json!({"source": "scene.glb"}), None);
        assert_eq!(glb, vec!["scene.glb".to_string()]);
    }

    // Dispatch coverage: compile_by_type / source_files_by_type route each
    // compiled RegisteredType to its asset_impls wrapper.

    fn ct(name: &str) -> RegisteredType {
        RegisteredType::parse(name).unwrap_or_else(|| panic!("{name} is a registered component"))
    }

    // Arms whose outcome is deterministic from inline args alone: a valid
    // minimal payload for the ones that need no source file, and the expected
    // error for the ones that require a source but got none.
    #[test]
    fn compile_by_type_dispatches_deterministic_arms() {
        // Mesh is a resource asset now: it compiles through
        // `RegisteredType::compile_payload`, not the RegisteredType dispatch.
        let mesh_bytes = crate::registry::RegisteredType::Mesh
            .compile_payload(
                &serde_json::json!({"generator": "box", "half_extents": [1, 1, 1]}),
                None,
            )
            .expect("Mesh compiles through the resource path");
        assert!(!mesh_bytes.is_empty());

        let ok_cases: &[(&str, serde_json::Value)] = &[
            (
                "ProceduralMesh",
                serde_json::json!({"generator": "sphere", "radius": 1.0}),
            ),
            ("Room", serde_json::json!({})),
        ];
        for case in ok_cases {
            let name = case.0;
            let args = &case.1;
            let bytes = compile_by_type(ct(name), args, &ctx())
                .unwrap_or_else(|e| panic!("{name} should compile: {e}"));
            assert!(!bytes.is_empty(), "{name} payload should be non-empty");
        }

        let err_cases: &[(&str, serde_json::Value, &str)] =
            &[("File", serde_json::json!({}), "unsupported File kind")];
        for case in err_cases {
            let name = case.0;
            let args = &case.1;
            let needle = case.2;
            let err = compile_by_type(ct(name), args, &ctx())
                .expect_err(&format!("{name} with empty args should error"));
            assert!(
                err.to_string().contains(needle),
                "{name} error should mention '{needle}', got: {err}"
            );
        }
    }

    // The File wrapper decodes an OBJ mesh source into a non-empty payload.
    #[test]
    fn compile_by_type_file_compiles_an_obj_source() {
        let dir = tempfile::tempdir().expect("tempdir");
        let obj = dir.path().join("tri.obj");
        std::fs::write(&obj, "v 0 0 0\nv 1 0 0\nv 0 1 0\nf 1 2 3\n").expect("write obj");
        let args = serde_json::json!({"path": obj.to_str().unwrap(), "kind": "obj"});
        let bytes = compile_by_type(ct("File"), &args, &ctx()).expect("obj compiles");
        assert!(!bytes.is_empty());
    }

    // The SkinnedMesh resource compiler deserialises args + an optional
    // skeleton, then bakes geometry: one vertex is enough for a payload, no
    // vertices and a malformed skeleton are the two error arms. Its baked
    // data form carries the interned name id and drops the geometry.
    #[test]
    fn skinned_mesh_resource_compile_paths() {
        use crate::registry::RegisteredType;
        let rt = RegisteredType::SkinnedMesh;

        let ok = serde_json::json!({"vertices": [{"pos": [0.0, 0.0, 0.0]}], "indices": []});
        let bytes = rt.compile_payload(&ok, None).expect("skinned compiles");
        assert!(!bytes.is_empty());

        let no_verts = rt
            .compile_payload(&serde_json::json!({}), None)
            .expect_err("no vertices");
        assert!(
            no_verts.to_string().contains("at least one vertex"),
            "got: {no_verts}"
        );

        let bad_skeleton = rt
            .compile_payload(
                &serde_json::json!({"vertices": [{"pos": [0.0, 0.0, 0.0]}], "skeleton": 5}),
                None,
            )
            .expect_err("malformed skeleton");
        assert!(
            bad_skeleton.to_string().contains("invalid skeleton args"),
            "got: {bad_skeleton}"
        );

        // The baked data tuple: name id first, then the clamped mesh with its
        // geometry cleared.
        crate::ecs::asset_id::reset_interner();
        let name_id = crate::ecs::asset_id::intern("hero");
        let data = rt
            .compile_data(
                "hero",
                &serde_json::json!({
                    "vertices": [{"pos": [0.0, 0.0, 0.0]}],
                    "scale": [0.0, 0.0, 0.0],
                    "max_instances": 999999,
                    "capsule": {"half_height": 0.6, "radius": 0.2},
                }),
            )
            .expect("data bakes")
            .expect("skinned mesh carries baked data");
        let (baked_name, sm): (u32, crate::components::SkinnedMesh) =
            postcard::from_bytes(&data).unwrap();
        assert_eq!(baked_name, name_id.0);
        assert_eq!(sm.scale, [1.0, 1.0, 1.0], "zero scale clamps to unit");
        assert_eq!(sm.max_instances, 4096, "reserve caps at 4096");
        assert!(sm.vertices.is_empty(), "geometry rides the payload");
        assert!(sm.capsule.is_some());
    }

    // The VoxelChunk wrapper resolves its palette from sibling BlockType assets
    // in the build context.
    #[test]
    fn compile_by_type_voxel_chunk_resolves_palette_from_ctx() {
        let blocks = vec![
            wja("air", "BlockType", serde_json::json!({"solid": false})),
            wja(
                "stone",
                "BlockType",
                serde_json::json!({"uv_min": [0, 0], "uv_max": [1, 1]}),
            ),
        ];
        let vctx = crate::asset::BuildCtx {
            name: "chunk",
            assets_dir: None,
            artifacts_dir: None,
            all_assets: &blocks,
        };
        let args = serde_json::json!({
            "palette": ["air", "stone"],
            "dim": [2, 1, 1],
            "blocks": [1, 1],
            "block_size": 1.0,
        });
        let bytes = compile_by_type(ct("VoxelChunk"), &args, &vctx).expect("voxel compiles");
        assert!(!bytes.is_empty());
    }

    // The SdfVolume wrapper transports the current backend's fragment shader
    // bytes verbatim (no MSL/GLSL compilation); a missing source is a hard
    // error rather than a silent empty payload.
    #[test]
    fn compile_by_type_sdf_volume_transports_shader_bytes() {
        let dir = tempfile::tempdir().expect("tempdir");
        let shader = dir.path().join("blob.metal");
        let source = b"// sdf fragment source\n";
        std::fs::write(&shader, source).expect("write shader");
        let path = shader.to_str().unwrap();
        // Set every backend's key to the same file so the test is
        // platform-independent: only the current backend's entry is read.
        let args = serde_json::json!({
            "fragment_shaders": {"metal": path, "hlsl": path, "glsl": path}
        });
        let bytes = compile_by_type(ct("SdfVolume"), &args, &ctx()).expect("sdf reads source");
        assert_eq!(bytes, source);

        let err = compile_by_type(ct("SdfVolume"), &serde_json::json!({}), &ctx())
            .expect_err("no fragment shader source");
        assert!(
            err.to_string().contains("no fragment shader source"),
            "got: {err}"
        );
    }

    // The Shader wrapper's non-compiling arms: a missing stage source is
    // either a hard error (Metal/HLSL) or the inline-GLSL stub (Vulkan).
    // Neither shells out to a shader toolchain, so the test stays
    // backend-agnostic.
    #[test]
    fn compile_by_type_shader_missing_source_does_not_shell_out() {
        let out = compile_by_type(
            ct("Shader"),
            &serde_json::json!({"vertex": {}, "fragment": {}}),
            &ctx(),
        );
        match out {
            Ok(bytes) => {
                let payload = concinnity_core::components::ShaderPayload::decode(&bytes)
                    .expect("empty container decodes");
                assert!(payload.stages.is_empty(), "glsl stub compiles no stages");
            }
            Err(e) => assert!(e.to_string().contains("no shader source"), "got: {e}"),
        }
    }

    // cache_inputs_by_type routes to the two overriding wrappers. Both report
    // `Only` -- the complete input set the current backend reads -- so an edit
    // to a sibling backend's shader leaves this backend's payload cached.
    #[test]
    fn cache_inputs_by_type_covers_the_overriding_wrappers() {
        use crate::asset::SourceFiles;
        let dir = tempfile::tempdir().expect("tempdir");
        let shader = dir.path().join("blob.metal");
        std::fs::write(&shader, b"x").expect("write shader");
        let path = shader.to_str().unwrap();

        // SdfVolume reports the resolved path for the current backend, and
        // transports it verbatim, so the compile target is not an input.
        let sdf_args = serde_json::json!({
            "fragment_shaders": {"metal": path, "hlsl": path, "glsl": path}
        });
        let sdf = cache_inputs_by_type(ct("SdfVolume"), &sdf_args, &ctx());
        assert_eq!(sdf.sources, SourceFiles::Only(vec![path.to_string()]));
        assert!(!sdf.target_dependent);
        assert_eq!(
            cache_inputs_by_type(ct("SdfVolume"), &serde_json::json!({}), &ctx()).sources,
            SourceFiles::Only(Vec::new())
        );

        // Shader compiles its stage sources, so the target is an input.
        let no_source = cache_inputs_by_type(ct("Shader"), &serde_json::json!({}), &ctx());
        assert_eq!(no_source.sources, SourceFiles::Only(Vec::new()));
        assert!(no_source.target_dependent);
    }
}