BREP_render 0.1.0

//! History → scene: run a whole feature history through the kernel's native
//! `execute_history` (same process, same thread — the solid registry is
//! thread-local) and populate a [`RenderScene`] from the resident handles via
//! the kernel's native display payload accessor. No JSON, no typed-array
//! boundary — the R1 promise.

use crate::scene::{solid_display_from_payload, RenderScene, SolidDisplay};
use brep_kernel::{display_payload_handle_native, execute_history, HistoryRequest};
use std::collections::HashMap;

/// Non-fatal diagnostics from a scene build (mirrors the previous app's run-history
/// reporting: a failed feature halts the remaining features but the solids
/// built so far still display — seeing what a failing history DID build is the
/// point of the artifact).
#[derive(Debug, Default, Clone, serde::Serialize, serde::Deserialize)]
pub struct SceneBuildReport {
    /// Per-feature hard errors, as `"<feature id>: <message>"`.
    pub feature_errors: Vec<String>,
    /// Unresolved reference-selection names, as `"<feature id>: <name>"`.
    pub unresolved: Vec<String>,
    /// Solids whose display payload (tessellation) failed, as
    /// `"<solid name>: <message>"` — the solid is skipped, not fatal.
    pub display_errors: Vec<String>,
    /// Per-feature wall-clock execution time `(feature id, milliseconds)` in run
    /// order, carried through from the kernel's [`brep_kernel::HistoryResult`]
    /// timings — the history tree's "N ms" readout.
    pub feature_timings: Vec<(String, f64)>,
    /// Per-feature output solid names `(feature id, [solid names])` in run order —
    /// the history tree's read-only "Outputs" node.
    pub feature_outputs: Vec<(String, Vec<String>)>,
    /// Named plane FRAMES this run resolved `(frame name, frame)`, in run order —
    /// every DATUM registers three (`{id}:XY|XZ|YZ`), every PLANE one (`{id}`), and
    /// a SKETCH its own plane (`{id}`). Surfaced here so the engine can DISPLAY the
    /// construction datum/plane frames (filtered to the D/P producing features) as
    /// first-class scene citizens — the resolved frames ride
    /// [`brep_kernel::FeatureResult::frames`] straight through, no kernel change.
    pub frames: Vec<(String, brep_kernel::Frame)>,
    /// Solved sketch PROFILES this run produced `(sketch id, profile)`, in run
    /// order — every SKETCH feature publishes one under its own id. Surfaced here
    /// (exactly like [`Self::frames`]) so the engine can display each committed
    /// sketch as a SHEET SOLID (planar face + named boundary edges + corner
    /// vertices) via `sketch_profile_display_payload`, no kernel-contract change.
    pub profiles: Vec<(String, brep_kernel::SketchProfile)>,
    /// Named axis LINES this run produced `(axis name, line)`, in run order — a
    /// SKETCH publishes one per line geometry (construction included). Surfaced
    /// here (exactly like [`Self::frames`]/[`Self::profiles`]) so the engine can
    /// resolve a revolve/sweep `axis` reference to a world line at annotation-build
    /// time, fully headless. `#[serde(default)]` keeps older serialized reports
    /// (pre-`axes`) deserializing cleanly across the worker boundary.
    #[serde(default)]
    pub axes: Vec<(String, brep_kernel::Axis)>,
}

/// Execute a serialized `HistoryRequest` (the `execute_history_json` request
/// shape — a saved part file parses as one) and build the display scene from
/// the final resident solids.
pub fn scene_from_history_json(
    request_json: &str,
) -> Result<(RenderScene, SceneBuildReport), String> {
    let request: HistoryRequest = serde_json::from_str(request_json)
        .map_err(|error| format!("history request parse: {error}"))?;
    scene_from_history(&request)
}

/// Typed-request variant of [`scene_from_history_json`].
pub fn scene_from_history(
    request: &HistoryRequest,
) -> Result<(RenderScene, SceneBuildReport), String> {
    let mut scene = RenderScene::new();
    let report = update_scene_from_history(&mut scene, request, None)?;
    Ok((scene, report))
}

/// The fold of a history run into an ordered scene layout: each entry is the
/// solid's final name, its resident handle, and whether the feature that
/// produced it REPLAYED from the incremental cache (R10 — a reused solid is the
/// same resident geometry, so its display can be kept verbatim and its GPU
/// buffers reused).
struct SceneLayout {
    order: Vec<String>,
    handles: std::collections::HashMap<String, u32>,
    reused: std::collections::HashSet<String>,
    /// `name -> creating-feature id` of the FINAL resident solids (last writer
    /// wins; a `removed` name drops its entry) — the eager provenance the runner
    /// ships so the main thread never has to re-run the history to answer
    /// "what feature produced this object?". Matches the resident semantics of the
    /// old `resident_handles_and_creators`.
    creators: std::collections::HashMap<String, String>,
}

fn fold_history(result: &brep_kernel::HistoryResult, report: &mut SceneBuildReport) -> SceneLayout {
    // Removals first (a boolean result reuses a removed target's name), then
    // additions, insertion-ordered — mirrors SceneMap::apply.
    let mut order: Vec<String> = Vec::new();
    let mut handles: std::collections::HashMap<String, u32> = std::collections::HashMap::new();
    let mut reused: std::collections::HashSet<String> = std::collections::HashSet::new();
    let mut creators: std::collections::HashMap<String, String> = std::collections::HashMap::new();
    for feature in &result.results {
        for removed in &feature.removed {
            if handles.remove(removed).is_some() {
                order.retain(|name| name != removed);
            }
            reused.remove(removed);
            creators.remove(removed);
        }
        for added in &feature.added {
            if handles.insert(added.name.clone(), added.handle).is_none() {
                order.push(added.name.clone());
            }
            creators.insert(added.name.clone(), feature.id.clone());
            // A solid displays as reused only when its whole producing feature
            // replayed unchanged; a re-run feature re-tessellates.
            if feature.reused {
                reused.insert(added.name.clone());
            } else {
                reused.remove(&added.name);
            }
        }
        if let Some(error) = &feature.error {
            report.feature_errors.push(format!("{}: {error}", feature.id));
        }
        for name in &feature.unresolved {
            report.unresolved.push(format!("{}: {name}", feature.id));
        }
        // The feature's output solid name(s) — the history tree's Outputs node.
        report.feature_outputs.push((
            feature.id.clone(),
            feature.added.iter().map(|a| a.name.clone()).collect(),
        ));
        // The named plane frames this feature resolved (DATUM three / PLANE one /
        // SKETCH its own). Carried straight through so the engine can display the
        // construction datum/plane frames (it filters to the D/P producers).
        for (name, frame) in &feature.frames {
            report.frames.push((name.clone(), *frame));
        }
        // The solved sketch profile (SKETCH features publish one under `{id}`) —
        // carried straight through so the engine can synthesize its sheet solid.
        for (name, profile) in &feature.profiles {
            report.profiles.push((name.clone(), profile.clone()));
        }
        // The named axis lines this feature published (a SKETCH emits one per line
        // geometry) — carried through so the engine can resolve a revolve `axis`
        // reference to a world line for the angle gizmo.
        for (name, axis) in &feature.axes {
            report.axes.push((name.clone(), *axis));
        }
    }
    // Per-feature timing rides the kernel result straight through.
    report.feature_timings = result.timings.clone();
    SceneLayout { order, handles, reused, creators }
}

/// A stateful, SCENE-FREE history run that emits a DELTA snapshot instead of
/// mutating a scene — the M1 seam of the off-thread history runner. It remembers,
/// in [`Self::last_sent`], the resident handle it last EMITTED per solid name, so
/// a rerun can tell the applier which displays are UNCHANGED (skip re-tessellating
/// + keep their GPU buffers) vs. which are new/rebound (freshly tessellated).
///
/// Being scene-free is the point: a later milestone runs this on a background
/// thread / worker with no access to the render scene, then ships the
/// [`RunOutput`] delta back to the main thread to apply. In M1 the run is
/// immediately applied on the same thread (see `EngineState::apply_run_output`),
/// so behavior is byte-identical to the pre-seam in-place reconcile.
pub struct SceneRunner {
    /// `name -> handle` of what was last EMITTED (the delta baseline). Handles are
    /// monotonic and never recycled (the resident registry's counter only
    /// increments, and `clear_history_cache` frees solids without resetting it),
    /// so "handle unchanged since last emit" is EXACTLY the old
    /// `reused && source_handle matches` reuse condition — a re-executed feature
    /// always registers a NEW handle, so a matching handle proves a cache replay.
    last_sent: HashMap<String, u32>,
    /// The display LOD factor the current baseline was tessellated at. When a run
    /// arrives at a DIFFERENT lod (the user moved the "LOD factor" slider) every
    /// resident mesh must be rebuilt at the new chord tolerance even though its
    /// handle is unchanged — so a lod change drops `last_sent` to defeat the
    /// handle-unchanged reuse fast path. Init `1.0` (the "Normal" default) so a
    /// first run at the default lod does NOT spuriously invalidate an empty
    /// baseline's peers.
    last_lod: f64,
}

/// The delta a [`SceneRunner::run`] produces: the displayed KERNEL solids IN
/// ORDER plus the run's [`SceneBuildReport`]. The applier walks `snapshot` in
/// order, reusing or replacing each entry (see the field docs).
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
pub struct RunOutput {
    /// The displayed KERNEL solids IN ORDER. `display: Some` = freshly tessellated
    /// (new, or the handle changed since last emit); `None` = UNCHANGED — the
    /// applier keeps its existing [`SolidDisplay`] for this name, whose
    /// `source_handle` equals `handle`.
    pub snapshot: Vec<(String /* name */, u32 /* handle */, Option<SolidDisplay>)>,
    pub report: SceneBuildReport,
    /// Eager PROVENANCE: `name -> creating-feature id` for the run's FINAL resident
    /// solids (same last-writer-wins fold as the display snapshot). Shipped WITH the
    /// run so the main thread can answer object provenance (`creating_feature`, the
    /// Info tab's `creatingFeature`) without a cold `execute_history` — critical once
    /// the run lives on a background thread and the main-side registry is cold.
    pub provenance: Vec<(String, String)>,
}

impl SceneRunner {
    pub fn new() -> Self {
        Self { last_sent: HashMap::new(), last_lod: 1.0 }
    }

    /// Reset the delta baseline (call on a wholesale document switch so the next
    /// run is a full rebuild — no stale reuse across unrelated models).
    pub fn reset(&mut self) {
        self.last_sent.clear();
    }

    /// Execute `request` and fold it into an ordered delta snapshot (does NOT
    /// touch any scene). For each displayed kernel solid in order: if the handle
    /// is unchanged since the last emit, emit `(name, handle, None)` (the applier
    /// keeps its existing display); otherwise (re-)tessellate the resident handle
    /// and emit `(name, handle, Some(display))`. A display-payload error is
    /// recorded in `report.display_errors` and the entry is SKIPPED — and NOT
    /// recorded in the new baseline, so a later successful run re-tessellates it.
    ///
    /// `color_overrides` is an optional `name → sRGB [0..1;3]` map (the metadata
    /// color layer); applied to freshly built solids only (reused ones keep it).
    pub fn run(
        &mut self,
        request: &HistoryRequest,
        color_overrides: Option<&HashMap<String, [f32; 3]>>,
    ) -> RunOutput {
        let result = execute_history(request);
        let mut report = SceneBuildReport::default();
        let layout = fold_history(&result, &mut report);

        // Display LOD: a finite, positive factor (garbage from a hand-edited saved
        // file → the "Normal" 1.0, since chord = extent·1.5e-3·lod and a 0/NaN lod
        // would zero the tolerance → runaway refinement). A change since the last
        // run means every resident mesh must re-tessellate at the new chord even
        // though its handle is unchanged, so drop the reuse baseline.
        let lod = if request.display_lod.is_finite() && request.display_lod > 0.0 {
            request.display_lod
        } else {
            1.0
        };
        if lod != self.last_lod {
            self.last_sent.clear();
            self.last_lod = lod;
        }

        let mut snapshot: Vec<(String, u32, Option<SolidDisplay>)> =
            Vec::with_capacity(layout.order.len());
        let mut next_sent: HashMap<String, u32> = HashMap::with_capacity(layout.order.len());

        for name in &layout.order {
            let handle = layout.handles[name];
            if self.last_sent.get(name) == Some(&handle) {
                // Handle unchanged since last emit ⇒ same resident geometry ⇒ the
                // applier keeps its existing display. This is EXACTLY the old
                // `reused && source_handle == handle` fast path (monotonic handles):
                // the canary below verifies the implication holds.
                debug_assert!(
                    layout.reused.contains(name),
                    "handle unchanged must imply reused (monotonic handles): {name}"
                );
                snapshot.push((name.clone(), handle, None));
                next_sent.insert(name.clone(), handle);
                continue;
            }
            match display_payload_handle_native(handle, lod) {
                Ok(payload) => {
                    let mut solid = solid_display_from_payload(name, payload);
                    solid.source_handle = handle;
                    if let Some(overrides) = color_overrides {
                        solid.color_override = overrides.get(name).copied();
                    }
                    snapshot.push((name.clone(), handle, Some(solid)));
                    next_sent.insert(name.clone(), handle);
                }
                // A tessellation failure skips the solid (non-fatal) and does NOT
                // poison the baseline — dropping it lets a later successful run
                // re-tessellate from scratch.
                Err(error) => report.display_errors.push(format!("{name}: {error}")),
            }
        }

        self.last_sent = next_sent;
        // Eager provenance for the run's final resident solids (the applier stores
        // this map main-side so per-frame provenance queries never re-run history).
        let provenance: Vec<(String, String)> = layout
            .creators
            .iter()
            .map(|(name, id)| (name.clone(), id.clone()))
            .collect();
        RunOutput { snapshot, report, provenance }
    }

    /// The resident handle last EMITTED for `name` (the delta baseline), or `None`
    /// if the runner has not emitted a solid of that name. The measurement-query
    /// path resolves an object's owning-solid handle through this so the query runs
    /// against the SAME resident geometry the last run displayed (on the runner's
    /// own thread, whose registry is warm from that run).
    pub fn handle_of(&self, name: &str) -> Option<u32> {
        self.last_sent.get(name).copied()
    }
}

impl Default for SceneRunner {
    fn default() -> Self {
        Self::new()
    }
}

/// Execute the history and reconcile `scene` in place (R10 incremental update):
/// reused solids already present keep their [`SolidDisplay`] verbatim (stable
/// `revision` ⇒ the renderer reuses their GPU buffers); everything else is
/// (re-)tessellated from the resident handle; departed solids are dropped.
///
/// `color_overrides` is an optional `name → sRGB [0..1;3]` map (the metadata
/// color layer); applied to freshly built solids so the renderer picks it up.
///
/// Implemented on the M1 seam: a throwaway [`SceneRunner`] primed from the
/// CURRENT scene (`name → source_handle` of what is displayed) reproduces the
/// pre-seam reuse in a single synchronous call, and its [`RunOutput`] delta is
/// applied back to `scene` by MOVING existing displays out (via
/// [`RenderScene::drain`]) so a reused solid's mesh is never cloned.
pub fn update_scene_from_history(
    scene: &mut RenderScene,
    request: &HistoryRequest,
    color_overrides: Option<&HashMap<String, [f32; 3]>>,
) -> Result<SceneBuildReport, String> {
    let mut runner = SceneRunner::new();
    runner.last_sent = scene
        .solids()
        .iter()
        .map(|solid| (solid.name.clone(), solid.source_handle))
        .collect();
    let output = runner.run(request, color_overrides);

    // Move the current displays out, then reinsert in snapshot ORDER: a fresh
    // entry replaces, an UNCHANGED entry reuses the moved-out display (whose
    // `source_handle` equals the run's handle — guaranteed by the reuse
    // invariant). Leftovers (departed names) are dropped.
    let mut kept: HashMap<String, SolidDisplay> = scene
        .drain()
        .into_iter()
        .map(|solid| (solid.name.clone(), solid))
        .collect();
    for (name, _handle, maybe) in output.snapshot {
        match maybe {
            Some(display) => scene.insert_solid(display),
            None => scene.insert_solid(
                kept.remove(&name).expect("keep target present"),
            ),
        }
    }
    Ok(output.report)
}

/// Execute `request` and return the FINAL resident solids as `(name, handle)` in
/// display order — the export lane (STEP/STL) needs the current solids' resident
/// handles, which the scene build does not itself retain. Run right after a scene
/// build (warm incremental cache) this replays the cached features, so the
/// handles it returns are the very ones the displayed scene was built from; run
/// cold it re-executes and registers fresh (still-valid) handles. Either way the
/// handles are live in the thread-local registry when this returns, ready to
/// hand to `brep_kernel::export_step_handles`.
pub fn resident_solid_handles(request: &HistoryRequest) -> Vec<(String, u32)> {
    let result = execute_history(request);
    let mut report = SceneBuildReport::default();
    let layout = fold_history(&result, &mut report);
    layout
        .order
        .iter()
        .map(|name| (name.clone(), layout.handles[name]))
        .collect()
}

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

    fn cube_request(name: &str, size: f64) -> String {
        serde_json::json!({
            "expressions": "",
            "configurator": {},
            "features": [{
                "type": "P.CU",
                "inputParams": {
                    "id": name,
                    "sizeX": size, "sizeY": size, "sizeZ": size,
                    "transform": {
                        "position": [0.0, 0.0, 0.0],
                        "rotationEuler": [0.0, 0.0, 0.0],
                        "scale": [1.0, 1.0, 1.0]
                    },
                    "boolean": { "targets": [], "operation": "NONE" }
                },
                "persistentData": {}
            }]
        })
        .to_string()
    }

    // A DOTTED feature id (the new `{shortName}{N}` scheme yields ids like `P.CU1`)
    // must be safe as a downstream reference: the `.` is inert everywhere (scene-map
    // resolution is exact HashMap lookup — only `:` and `|` are name delimiters).
    // Prove it at RUNTIME: a boolean SUBTRACT that targets a dotted-id solid resolves
    // (nothing lands in `report.unresolved`) and builds a scene.
    #[test]
    fn dotted_feature_id_resolves_as_a_boolean_reference() {
        let request = serde_json::json!({
            "expressions": "",
            "configurator": {},
            "features": [
                {
                    "type": "P.CU",
                    "inputParams": {
                        "id": "P.CU1",
                        "sizeX": 10.0, "sizeY": 10.0, "sizeZ": 10.0,
                        "transform": { "position": [0.0, 0.0, 0.0], "rotationEuler": [0.0, 0.0, 0.0], "scale": [1.0, 1.0, 1.0] },
                        "boolean": { "targets": [], "operation": "NONE" }
                    },
                    "persistentData": {}
                },
                {
                    "type": "P.CU",
                    "inputParams": {
                        "id": "P.CU2",
                        "sizeX": 10.0, "sizeY": 10.0, "sizeZ": 10.0,
                        "transform": { "position": [5.0, 0.0, 0.0], "rotationEuler": [0.0, 0.0, 0.0], "scale": [1.0, 1.0, 1.0] },
                        // SUBTRACT referencing the DOTTED id of the first cube.
                        "boolean": { "targets": ["P.CU1"], "operation": "SUBTRACT" }
                    },
                    "persistentData": {}
                }
            ]
        })
        .to_string();
        let (scene, report) = scene_from_history_json(&request).unwrap();
        assert!(report.feature_errors.is_empty(), "{:?}", report.feature_errors);
        // The dotted reference `P.CU1` resolved — if `.` broke name matching it would
        // appear here instead.
        assert!(report.unresolved.is_empty(), "dotted ref unresolved: {:?}", report.unresolved);
        // The subtract folded the two cubes into one resident solid.
        assert_eq!(scene.solids().len(), 1);
    }

    #[test]
    fn cube_history_populates_scene() {
        let (scene, report) = scene_from_history_json(&cube_request("P.CU1", 10.0)).unwrap();
        assert!(report.feature_errors.is_empty(), "{:?}", report.feature_errors);
        assert!(report.display_errors.is_empty(), "{:?}", report.display_errors);
        assert_eq!(scene.solids().len(), 1);
        let solid = scene.solid("P.CU1").expect("solid keyed by kernel name");
        assert_eq!(solid.faces.len(), 6);
        // Cube tessellation: 2 triangles per face.
        assert_eq!(solid.mesh.indices.len(), 6 * 2 * 3);
        for face in &solid.faces {
            assert_eq!(face.tri_count, 2, "face {} range", face.name);
            assert!(!face.name.is_empty());
        }
        // 12 boundary edges, each a straight 2-point polyline, all named.
        assert_eq!(solid.edges.len(), 12);
        for edge in &solid.edges {
            assert!(edge.polyline.len() >= 2);
            assert!(!edge.name.is_empty());
        }
        assert_eq!(solid.vertices.len(), 8);
        let bbox = scene.bbox();
        assert!((bbox.size()[0] - 10.0).abs() < 1e-6);
    }

    fn sphere_request(name: &str, radius: f64, lod: f64) -> brep_kernel::HistoryRequest {
        let mut request: brep_kernel::HistoryRequest = serde_json::from_value(serde_json::json!({
            "expressions": "",
            "configurator": {},
            "features": [{
                "type": "P.S",
                "inputParams": {
                    "id": name,
                    "radius": radius,
                    "transform": {
                        "position": [0.0, 0.0, 0.0],
                        "rotationEuler": [0.0, 0.0, 0.0],
                        "scale": [1.0, 1.0, 1.0]
                    },
                    "boolean": { "targets": [], "operation": "NONE" }
                },
                "persistentData": {}
            }]
        }))
        .unwrap();
        request.display_lod = lod;
        request
    }

    // A LOD-factor change must re-tessellate every resident mesh at the new chord
    // tolerance EVEN THOUGH the solid's handle is unchanged (same geometry, replayed
    // from the incremental cache) — otherwise the "LOD factor" slider does nothing.
    #[test]
    fn lod_change_retessellates_reused_solid_coarser() {
        let mut runner = SceneRunner::new();

        // Fine mesh at lod 0.5.
        let fine = runner.run(&sphere_request("LodBall", 10.0, 0.5), None);
        let (_, fine_handle, fine_display) = &fine.snapshot[0];
        let fine_tris = fine_display.as_ref().expect("first run tessellates").mesh.indices.len();

        // SAME sphere, coarser lod 4.0: the incremental cache replays the sphere so
        // the handle is unchanged (proven below) — the ONLY reason to re-emit is the
        // lod change, and the coarser chord must drop the triangle count.
        let coarse = runner.run(&sphere_request("LodBall", 10.0, 4.0), None);
        let (_, coarse_handle, coarse_display) = &coarse.snapshot[0];
        assert_eq!(
            coarse_handle, fine_handle,
            "same sphere must replay to the same handle (reuse path) — else the test proves nothing"
        );
        let coarse_tris = coarse_display
            .as_ref()
            .expect("a lod change re-emits Some(display) despite the unchanged handle")
            .mesh
            .indices
            .len();
        assert!(
            coarse_tris < fine_tris,
            "coarser lod must shrink the mesh: fine(lod 0.5)={fine_tris} coarse(lod 4.0)={coarse_tris}"
        );

        // Re-running at the SAME lod reuses the baseline (None) — no spurious full
        // re-tessellation on every run once the lod is stable.
        let again = runner.run(&sphere_request("LodBall", 10.0, 4.0), None);
        assert!(
            again.snapshot[0].2.is_none(),
            "an unchanged lod must reuse the display baseline (None), not re-tessellate"
        );
    }

    #[test]
    fn reused_history_keeps_stable_revision() {
        let request: brep_kernel::HistoryRequest =
            serde_json::from_str(&cube_request("Keep", 8.0)).unwrap();
        let mut scene = RenderScene::new();
        update_scene_from_history(&mut scene, &request, None).unwrap();
        let first_rev = scene.solid("Keep").unwrap().revision;

        // A second identical run replays from the incremental cache; the reused
        // solid must keep its revision (so the renderer reuses its GPU buffers).
        update_scene_from_history(&mut scene, &request, None).unwrap();
        assert_eq!(scene.solid("Keep").unwrap().revision, first_rev);
    }

    #[test]
    fn color_override_applies_to_fresh_solids() {
        let request: brep_kernel::HistoryRequest =
            serde_json::from_str(&cube_request("Tinted", 5.0)).unwrap();
        let mut overrides = std::collections::HashMap::new();
        overrides.insert("Tinted".to_string(), [1.0, 0.0, 0.0]);
        let mut scene = RenderScene::new();
        update_scene_from_history(&mut scene, &request, Some(&overrides)).unwrap();
        assert_eq!(scene.solid("Tinted").unwrap().color_override, Some([1.0, 0.0, 0.0]));
    }

    #[test]
    fn scene_insert_replace_and_remove() {
        let (mut scene, _) = scene_from_history_json(&cube_request("A", 4.0)).unwrap();
        let (other, _) = scene_from_history_json(&cube_request("B", 2.0)).unwrap();
        for solid in other.solids() {
            scene.insert_solid(solid.clone());
        }
        assert_eq!(scene.solids().len(), 2);
        assert!(scene.remove_solid("A"));
        assert!(!scene.remove_solid("A"));
        assert_eq!(scene.solids().len(), 1);
        assert!(scene.solid("B").is_some());
    }

    #[test]
    fn datum_history_surfaces_three_named_frames() {
        // A single DATUM feature resolves three base-plane frames; the build report
        // surfaces them so the engine can display them as datum planes.
        let request = serde_json::json!({
            "expressions": "",
            "configurator": {},
            "features": [{
                "type": "D",
                "inputParams": { "id": "Datum" },
                "persistentData": {}
            }]
        })
        .to_string();
        let (_scene, report) = scene_from_history_json(&request).unwrap();
        let names: Vec<&str> = report.frames.iter().map(|(n, _)| n.as_str()).collect();
        assert!(names.contains(&"Datum:XY"), "{names:?}");
        assert!(names.contains(&"Datum:XZ"), "{names:?}");
        assert!(names.contains(&"Datum:YZ"), "{names:?}");
    }

    /// A `RunOutput` — the whole delta (tessellated `SolidDisplay` snapshot + the
    /// report's frames/profiles/provenance) — survives a serde JSON round trip.
    /// This is the wasm WorkerRunner (M3) message payload: the worker serializes
    /// the run result and the main thread reconstructs it byte-for-byte.
    #[test]
    fn run_output_round_trips_through_serde() {
        // A cube (→ a tessellated SolidDisplay) + a DATUM (→ frames) + a committed
        // rectangle SKETCH (→ a profile) exercise every side-channel of the report.
        let request: HistoryRequest = serde_json::from_str(
            r#"{
                "expressions": "", "configurator": {},
                "features": [
                    { "type": "P.CU", "inputParams": { "id": "Box", "sizeX": 10, "sizeY": 10, "sizeZ": 10,
                        "transform": { "position": [0,0,0], "rotationEuler": [0,0,0], "scale": [1,1,1] },
                        "boolean": { "targets": [], "operation": "NONE" } }, "persistentData": {} },
                    { "type": "D", "inputParams": { "id": "Datum" }, "persistentData": {} },
                    { "type": "S", "inputParams": { "id": "Sk" }, "persistentData": {
                        "basis": { "origin": [0,0,0], "x": [1,0,0], "y": [0,1,0], "z": [0,0,1] },
                        "sketch": { "points": [
                            {"id":0,"x":0,"y":0},{"id":1,"x":10,"y":0},{"id":2,"x":10,"y":6},{"id":3,"x":0,"y":6}],
                          "geometries": [
                            {"id":10,"type":"line","points":[0,1]},{"id":11,"type":"line","points":[1,2]},
                            {"id":12,"type":"line","points":[2,3]},{"id":13,"type":"line","points":[3,0]}],
                          "constraints": [] } } }
                ]
            }"#,
        )
        .unwrap();

        let output = SceneRunner::new().run(&request, None);
        // Sanity: the run produced the box display + the datum frames + the profile.
        assert_eq!(output.snapshot.len(), 1, "one solid (the box)");
        assert!(output.snapshot[0].2.as_ref().unwrap().mesh.positions.len() > 0);
        assert!(output.report.frames.iter().any(|(n, _)| n == "Datum:XY"));
        assert!(output.report.profiles.iter().any(|(n, _)| n == "Sk"));
        assert!(output.provenance.iter().any(|(n, id)| n == "Box" && id == "Box"));

        let json = serde_json::to_string(&output).expect("RunOutput serializes");
        let back: RunOutput = serde_json::from_str(&json).expect("RunOutput deserializes");

        assert_eq!(back.snapshot.len(), output.snapshot.len());
        assert_eq!(back.snapshot[0].0, "Box");
        assert_eq!(
            back.snapshot[0].2.as_ref().unwrap().mesh.positions.len(),
            output.snapshot[0].2.as_ref().unwrap().mesh.positions.len()
        );
        assert!(back.report.frames.iter().any(|(n, _)| n == "Datum:XY"));
        let (name, profile) = back.report.profiles.iter().find(|(n, _)| n == "Sk").unwrap();
        assert_eq!(name, "Sk");
        assert_eq!(profile.regions.len(), 1, "the rectangle profile survived");
        assert_eq!(back.provenance, output.provenance);
    }
}