brink-format 0.0.17

//! Textual (.inkt) writer for `StoryData`.
//!
//! Produces a WAT-inspired, section-based, indented mnemonic representation
//! of compiled story data for debugging and inspection.
//!
//! The output is lossless — every field in `StoryData` is represented so that
//! `read_inkt(write_inkt(story))` is an exact roundtrip.

use core::fmt;

use std::collections::HashMap;

use crate::counting::CountingFlags;
use crate::definition::{
    AddressDef, AddressPath, AliasEntry, CallAtom, CapabilityParam, ContainerDef, DebugInfoSection,
    DirectEffects, EffectRowEntry, ExternalFnDef, FileSurface, FrameShapeDef, GlobalVarDef,
    LineEntry, ListDef, ListItemDef, StructShapeDef,
};
use crate::id::DefinitionId;
use crate::line::{LineContent, LinePart, SelectKey};
use crate::opcode::{ChoiceFlags, Opcode, SequenceKind};
use crate::story::StoryData;
use crate::value::{ListValue, MapKey, ProjSegment, Value, ValueType};

/// Write the textual (.inkt) representation of a compiled story.
pub fn write_inkt(story: &StoryData, w: &mut dyn fmt::Write) -> fmt::Result {
    if story.source_checksum != 0 {
        writeln!(w, "(story checksum=0x{:08x}", story.source_checksum)?;
    } else {
        writeln!(w, "(story")?;
    }

    write_name_table(w, &story.name_table)?;
    write_globals(w, &story.variables)?;
    write_lists(w, &story.list_defs)?;
    write_list_items(w, &story.list_items)?;
    write_externals(w, &story.externals)?;
    write_addresses(w, &story.addresses)?;
    write_address_paths(w, &story.address_paths)?;
    write_list_literals(w, &story.list_literals)?;
    write_literal_pool(w, &story.literal_pool)?;
    write_struct_shapes(w, &story.struct_shapes)?;
    write_visibility(w, &story.private_defs)?;
    write_alias_table(w, &story.alias_table)?;
    write_effect_rows(w, &story.effect_rows)?;
    write_frame_shapes(w, &story.frame_shapes)?;
    write_debug_info(w, story.debug_info.as_ref())?;
    write_line_variant_groups(w, &story.line_variant_groups)?;

    // Build a lookup from scope_id → line table for writing
    let line_map: HashMap<DefinitionId, &[LineEntry]> = story
        .line_tables
        .iter()
        .map(|lt| (lt.scope_id, lt.lines.as_slice()))
        .collect();

    for container in &story.containers {
        // Only write lines on the scope-owning container (scope_id == id).
        let lines = if container.scope_id == container.id {
            line_map.get(&container.scope_id).copied().unwrap_or(&[])
        } else {
            &[]
        };
        write_container(w, container, lines)?;
    }

    write!(w, ")")
}

impl fmt::Display for StoryData {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write_inkt(self, f)
    }
}

// ── Sections ─────────────────────────────────────────────────────────────────

fn write_name_table(w: &mut dyn fmt::Write, names: &[String]) -> fmt::Result {
    if names.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (name_table")?;
    for (i, name) in names.iter().enumerate() {
        writeln!(w, "    {i} \"{}\"", escape_string(name))?;
    }
    writeln!(w, "  )")
}

fn write_globals(w: &mut dyn fmt::Write, globals: &[GlobalVarDef]) -> fmt::Result {
    if globals.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (globals")?;
    for g in globals {
        write!(
            w,
            "    (global {} :{} ",
            g.id,
            value_type_name(g.value_type)
        )?;
        write_value(w, &g.default_value)?;
        if g.mutable {
            write!(w, " mutable")?;
        }
        if g.local {
            write!(w, " local")?;
        }
        writeln!(w)?;
        writeln!(w, "      (name {}))", g.name.0)?;
    }
    writeln!(w, "  )")
}

fn write_visibility(w: &mut dyn fmt::Write, private_defs: &[DefinitionId]) -> fmt::Result {
    if private_defs.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (visibility")?;
    for id in private_defs {
        writeln!(w, "    (private {id})")?;
    }
    writeln!(w, "  )")
}

fn write_lists(w: &mut dyn fmt::Write, list_defs: &[ListDef]) -> fmt::Result {
    if list_defs.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (lists")?;
    for ld in list_defs {
        writeln!(w, "    (list {}", ld.id)?;
        writeln!(w, "      (name {})", ld.name.0)?;
        for (item_name, ordinal) in &ld.items {
            writeln!(w, "      (item name={} ordinal={ordinal})", item_name.0)?;
        }
        writeln!(w, "    )")?;
    }
    writeln!(w, "  )")
}

fn write_list_items(w: &mut dyn fmt::Write, list_items: &[ListItemDef]) -> fmt::Result {
    if list_items.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (list_items")?;
    for li in list_items {
        writeln!(
            w,
            "    (list_item {} (origin {}) (ordinal {}) (name {}))",
            li.id, li.origin, li.ordinal, li.name.0
        )?;
    }
    writeln!(w, "  )")
}

fn write_list_literals(w: &mut dyn fmt::Write, list_literals: &[ListValue]) -> fmt::Result {
    if list_literals.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (list_literals")?;
    for lv in list_literals {
        write!(w, "    (list (items")?;
        for item in &lv.items {
            write!(w, " {item}")?;
        }
        write!(w, ") (origins")?;
        for origin in &lv.origins {
            write!(w, " {origin}")?;
        }
        writeln!(w, "))")?;
    }
    writeln!(w, "  )")
}

/// Write the T1b literal pool section (`docs/format-v4-rfc.md` §2) —
/// printed only when present, matching the RFC's section discipline.
fn write_literal_pool(w: &mut dyn fmt::Write, literal_pool: &[Value]) -> fmt::Result {
    if literal_pool.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (literal_pool")?;
    for v in literal_pool {
        write!(w, "    ")?;
        write_value(w, v)?;
        writeln!(w)?;
    }
    writeln!(w, "  )")
}

/// TM-4 (`docs/format-v4-rfc.md` §1): mirrors the `.inkb` `StructShapes`
/// section — shape id, name, then its ordered field `NameId`s. The reader
/// lands with the writer in the same PR (the #742/#883 lesson): this
/// section used to round-trip through `.inkb` only, with `.inkt` silently
/// dropping it entirely.
fn write_struct_shapes(w: &mut dyn fmt::Write, struct_shapes: &[StructShapeDef]) -> fmt::Result {
    if struct_shapes.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (struct_shapes")?;
    for shape in struct_shapes {
        writeln!(w, "    (struct {}", shape.id.0)?;
        writeln!(w, "      (name {})", shape.name.0)?;
        for field in &shape.fields {
            writeln!(w, "      (field {})", field.0)?;
        }
        writeln!(w, "    )")?;
    }
    writeln!(w, "  )")
}

fn write_externals(w: &mut dyn fmt::Write, externals: &[ExternalFnDef]) -> fmt::Result {
    if externals.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (externals")?;
    for ext in externals {
        write!(w, "    (extern {} argc={}", ext.id, ext.arg_count)?;
        writeln!(w)?;
        writeln!(w, "      (name {})", ext.name.0)?;
        if let Some(fb) = ext.fallback {
            writeln!(w, "      (fallback {fb})")?;
        }
        writeln!(w, "    )")?;
    }
    writeln!(w, "  )")
}

fn write_addresses(w: &mut dyn fmt::Write, addresses: &[AddressDef]) -> fmt::Result {
    if addresses.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (addresses")?;
    for addr in addresses {
        writeln!(
            w,
            "    (address {} -> {} +{})",
            addr.id, addr.container_id, addr.byte_offset
        )?;
    }
    writeln!(w, "  )")
}

fn write_address_paths(w: &mut dyn fmt::Write, address_paths: &[AddressPath]) -> fmt::Result {
    if address_paths.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (address_paths")?;
    for ap in address_paths {
        writeln!(w, "    (path {} -> {})", ap.path.0, ap.target)?;
    }
    writeln!(w, "  )")
}

/// M-3 (`docs/modules-spec.md` §5): `#@was`-derived old→new `DefinitionId`
/// rename records. Mirrors [`write_addresses`]'s `id -> target` shape.
fn write_alias_table(w: &mut dyn fmt::Write, aliases: &[AliasEntry]) -> fmt::Result {
    if aliases.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (alias_table")?;
    for a in aliases {
        writeln!(w, "    (alias {} -> {})", a.old, a.new)?;
    }
    writeln!(w, "  )")
}

/// T2-3 (`docs/effects-spec.md` §11): the factored `EffectRows` table. Written
/// only when non-empty, mirroring the other optional sections. The reader lands
/// with the writer in the same PR (the #742 lesson) — this section is fully
/// round-tripped through `.inkt`.
fn write_effect_rows(w: &mut dyn fmt::Write, rows: &[EffectRowEntry]) -> fmt::Result {
    if rows.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (effect_rows")?;
    for row in rows {
        // #882 freeze bit: `internal` prints only when the row is NOT a host
        // entry point (`#@private` — see `EffectRowEntry::is_entry`'s doc).
        let internal = if row.is_entry { "" } else { " internal" };
        writeln!(w, "    (row {}{internal}", row.def)?;
        write_direct_effects(w, &row.direct, 6)?;
        for d in &row.dispatches {
            let narrowable = if d.narrowable { " narrowable" } else { "" };
            writeln!(w, "      (dispatch {}{}", d.cell, narrowable)?;
            write_direct_effects(w, &d.fallback, 8)?;
            writeln!(w, "      )")?;
        }
        writeln!(w, "    )")?;
    }
    writeln!(w, "  )")
}

/// FS-3 (`docs/flow-suspension-spec.md` §4/§11): the `FrameShapes` table.
/// Written only when non-empty, mirroring the other optional sections. The
/// reader lands with the writer in the same PR (the #742 lesson) — this
/// section is fully round-tripped through `.inkt`. Each entry is the `await`
/// site's stable `DefinitionId` (the synthesized continuation container id)
/// followed by its name-keyed crossing-local slots (interned `NameId`s).
fn write_frame_shapes(w: &mut dyn fmt::Write, shapes: &[FrameShapeDef]) -> fmt::Result {
    if shapes.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (frame_shapes")?;
    for shape in shapes {
        write!(w, "    (frame {}", shape.site)?;
        for slot in &shape.slots {
            write!(w, " {}", slot.0)?;
        }
        writeln!(w, ")")?;
    }
    writeln!(w, "  )")
}

/// D6 `DebugInfo` (`docs/debugger-spec.md` §2, issue #3184): the section-local
/// file table plus one per-container entry/locals table, in `Containers`
/// order. Written only when `Some` (debug info was requested at compile
/// time) — distinct from every other optional section here, which key on
/// #3273: render `(line_variant_groups (group $id base (dims d0 d1 ...)) ...)`.
/// Skipped entirely when empty, mirroring the `.inkb` section's
/// omitted-when-empty contract, so stories without variant groups render
/// byte-identically to before the section existed.
fn write_line_variant_groups(
    w: &mut dyn fmt::Write,
    groups: &[crate::LineVariantGroup],
) -> fmt::Result {
    if groups.is_empty() {
        return Ok(());
    }
    writeln!(w)?;
    writeln!(w, "  (line_variant_groups")?;
    for group in groups {
        write!(w, "    (group {} {} (dims", group.scope_id, group.base)?;
        for dim in &group.dims {
            write!(w, " {dim}")?;
        }
        writeln!(w, "))")?;
    }
    writeln!(w, "  )")?;
    Ok(())
}

/// emptiness rather than `Option`, matching [`crate::StoryData::debug_info`]'s
/// own "presence tracks whether it was requested" semantics. The reader
/// lands with the writer in this same PR (the #742 lesson).
fn write_debug_info(w: &mut dyn fmt::Write, debug_info: Option<&DebugInfoSection>) -> fmt::Result {
    let Some(debug_info) = debug_info else {
        return Ok(());
    };
    writeln!(w)?;
    writeln!(w, "  (debug_info")?;
    if !debug_info.files.is_empty() {
        writeln!(w, "    (files")?;
        for (idx, file) in debug_info.files.iter().enumerate() {
            // #3261: `source_hash` and the line index ride along, so an
            // `.inkt` dump stays a lossless view of the section rather than
            // a lossy one — the round-trip proptest depends on it.
            write!(
                w,
                "      (file {idx} {} \"{}\" {}",
                debug_file_surface_name(file.surface),
                escape_string(&file.path),
                file.source_hash
            )?;
            if !file.line_starts.is_empty() {
                write!(w, " (lines")?;
                for start in &file.line_starts {
                    write!(w, " {start}")?;
                }
                write!(w, ")")?;
            }
            writeln!(w, ")")?;
        }
        writeln!(w, "    )")?;
    }
    for (container_idx, table) in debug_info.containers.iter().enumerate() {
        writeln!(w, "    (dcontainer {container_idx}")?;
        for entry in &table.entries {
            writeln!(
                w,
                "      (entry {} {} {} {} {} {})",
                entry.bytecode_offset,
                entry.file_idx,
                entry.range_start,
                entry.range_len,
                entry.kind_token,
                entry.flags
            )?;
        }
        if !table.locals.is_empty() {
            writeln!(w, "      (locals")?;
            for local in &table.locals {
                write!(
                    w,
                    "        (local {} \"{}\"",
                    local.slot,
                    escape_string(&local.name)
                )?;
                if local.synthetic {
                    write!(w, " synthetic")?;
                }
                if let Some((file_idx, range_start, range_len)) = local.declaring_range {
                    write!(w, " (range {file_idx} {range_start} {range_len})")?;
                }
                writeln!(w, ")")?;
            }
            writeln!(w, "      )")?;
        }
        writeln!(w, "    )")?;
    }
    writeln!(w, "  )")
}

fn debug_file_surface_name(surface: FileSurface) -> &'static str {
    match surface {
        FileSurface::Synthetic => "synthetic",
        FileSurface::Ink => "ink",
        FileSurface::Native => "native",
    }
}

/// Write a [`DirectEffects`] block (`(reads …) (writes …) (calls …) opaque?`)
/// at the given indent.
fn write_direct_effects(
    w: &mut dyn fmt::Write,
    direct: &DirectEffects,
    indent: usize,
) -> fmt::Result {
    let pad = " ".repeat(indent);
    write!(w, "{pad}(reads")?;
    for id in &direct.reads {
        write!(w, " {id}")?;
    }
    writeln!(w, ")")?;
    write!(w, "{pad}(writes")?;
    for id in &direct.writes {
        write!(w, " {id}")?;
    }
    writeln!(w, ")")?;
    write!(w, "{pad}(calls")?;
    for atom in &direct.calls {
        write_call_atom(w, atom)?;
    }
    writeln!(w, ")")?;
    if direct.opaque {
        writeln!(w, "{pad}opaque")?;
    }
    // NS-A2 (issue #1108): the emits/tags/faults dimension flags, printed
    // as bare optional tokens like `opaque`.
    if direct.emits {
        writeln!(w, "{pad}emits")?;
    }
    if direct.tags {
        writeln!(w, "{pad}tags")?;
    }
    if direct.faults {
        writeln!(w, "{pad}faults")?;
    }
    Ok(())
}

/// Write a single [`CallAtom`]: `(call <name> any)`. The capability-parameter
/// slot renders as `any` (the v1 value); the reserved handle-parameter slot is
/// `None` in v1 and therefore omitted.
fn write_call_atom(w: &mut dyn fmt::Write, atom: &CallAtom) -> fmt::Result {
    let cap = match atom.capability {
        CapabilityParam::Any => "any",
    };
    write!(w, " (call {} {cap})", atom.name.0)
}

fn write_container(w: &mut dyn fmt::Write, c: &ContainerDef, lines: &[LineEntry]) -> fmt::Result {
    writeln!(w)?;
    writeln!(w, "  (container {}", c.id)?;

    // Scope (only when different from container id)
    if c.scope_id != c.id {
        writeln!(w, "    (scope {})", c.scope_id)?;
    }

    // Container name (for scope-owning containers)
    if let Some(name_id) = c.name {
        writeln!(w, "    (name {})", name_id.0)?;
    }

    // Counting flags
    if !c.counting_flags.is_empty() {
        write!(w, "    (flags")?;
        if c.counting_flags.contains(CountingFlags::VISITS) {
            write!(w, " visits")?;
        }
        if c.counting_flags.contains(CountingFlags::TURNS) {
            write!(w, " turns")?;
        }
        if c.counting_flags.contains(CountingFlags::COUNT_START_ONLY) {
            write!(w, " start_only")?;
        }
        if c.counting_flags.contains(CountingFlags::INVISIBLE) {
            write!(w, " invisible")?;
        }
        writeln!(w, ")")?;
    }

    // Path hash (for shuffle RNG seeding)
    if c.path_hash != 0 {
        writeln!(w, "    (path_hash {})", c.path_hash)?;
    }

    // Declared parameter count (parameterized knots/stitches/functions).
    // When per-param name/mode metadata is present (T1c, #700 — carried so
    // rehydration can validate function values), dump it too for parity.
    if c.param_count != 0 {
        if c.params.is_empty() {
            writeln!(w, "    (params {})", c.param_count)?;
        } else {
            write!(w, "    (params {}", c.param_count)?;
            for p in &c.params {
                let mode = if p.is_ref { "ref" } else { "val" };
                write!(w, " ({mode} {} {})", p.name.0, p.slot)?;
            }
            writeln!(w, ")")?;
        }
    }

    // Flow-private scope default (`#@local` knot/stitch)
    if c.local {
        writeln!(w, "    local")?;
    }

    // Line table
    if !lines.is_empty() {
        writeln!(w, "    (lines")?;
        for (i, entry) in lines.iter().enumerate() {
            write!(w, "      {i} ")?;
            write_line_content(w, &entry.content)?;
            write!(w, " @{:016x}", entry.source_hash)?;
            if let Some(audio) = &entry.audio_ref {
                write!(w, " (audio \"{}\")", escape_string(audio))?;
            }
            if !entry.slot_info.is_empty() {
                write!(w, " (slots")?;
                for slot in &entry.slot_info {
                    write!(w, " {}:\"{}\"", slot.index, escape_string(&slot.name))?;
                }
                write!(w, ")")?;
            }
            if let Some(loc) = &entry.source_location {
                write!(
                    w,
                    " (source \"{}\" {}..{})",
                    escape_string(&loc.file),
                    loc.range_start,
                    loc.range_end,
                )?;
            }
            writeln!(w)?;
        }
        writeln!(w, "    )")?;
    }

    // Bytecode
    if !c.bytecode.is_empty() {
        writeln!(w, "    (code")?;
        write_bytecode(w, &c.bytecode)?;
        writeln!(w, "    )")?;
    }

    writeln!(w, "  )")
}

// ── Line content ─────────────────────────────────────────────────────────────

fn write_line_content(w: &mut dyn fmt::Write, content: &LineContent) -> fmt::Result {
    match content {
        LineContent::Plain(s) => write!(w, "\"{}\"", escape_string(s)),
        LineContent::Template(parts) => {
            write!(w, "(template")?;
            for part in parts {
                write!(w, " ")?;
                write_line_part(w, part)?;
            }
            write!(w, ")")
        }
    }
}

fn write_line_part(w: &mut dyn fmt::Write, part: &LinePart) -> fmt::Result {
    match part {
        LinePart::Literal(s) => write!(w, "(lit \"{}\")", escape_string(s)),
        LinePart::Slot(idx) => write!(w, "(slot {idx})"),
        LinePart::Select {
            slot,
            variants,
            default,
        } => {
            write!(w, "(select slot={slot}")?;
            for (key, text) in variants {
                write!(w, " (")?;
                write_select_key(w, key)?;
                write!(w, " \"{}\")", escape_string(text))?;
            }
            write!(w, " (default \"{}\"))", escape_string(default))
        }
        LinePart::Span {
            name,
            attrs,
            children,
        } => {
            write!(w, "(span \"{}\"", escape_string(name))?;
            for (k, v) in attrs {
                write!(
                    w,
                    " (attr \"{}\" \"{}\")",
                    escape_string(k),
                    escape_string(v)
                )?;
            }
            for child in children {
                write!(w, " ")?;
                write_line_part(w, child)?;
            }
            write!(w, ")")
        }
    }
}

fn write_select_key(w: &mut dyn fmt::Write, key: &SelectKey) -> fmt::Result {
    match key {
        SelectKey::Cardinal(cat) => write!(w, "cardinal:{cat:?}"),
        SelectKey::Ordinal(cat) => write!(w, "ordinal:{cat:?}"),
        SelectKey::Exact(n) => write!(w, "={n}"),
        SelectKey::Keyword(k) => write!(w, "keyword:{k}"),
    }
}

// ── Bytecode disassembly ─────────────────────────────────────────────────────

fn write_bytecode(w: &mut dyn fmt::Write, bytecode: &[u8]) -> fmt::Result {
    let mut offset = 0;
    while offset < bytecode.len() {
        match Opcode::decode(bytecode, &mut offset) {
            Ok(op) => {
                write!(w, "      ")?;
                write_opcode(w, &op)?;
                writeln!(w)?;
            }
            Err(e) => {
                writeln!(w, "      <decode error: {e}>")?;
                break;
            }
        }
    }
    Ok(())
}

#[expect(clippy::too_many_lines)]
fn write_opcode(w: &mut dyn fmt::Write, op: &Opcode) -> fmt::Result {
    match op {
        // Stack & literals
        Opcode::PushInt(v) => write!(w, "push_int {v}"),
        Opcode::PushFloat(v) => write!(w, "push_float {v}"),
        Opcode::PushBool(v) => write!(w, "push_bool {v}"),
        Opcode::PushString(idx) => write!(w, "push_string {idx}"),
        Opcode::PushList(idx) => write!(w, "push_list {idx}"),
        Opcode::PushDivertTarget(id) => write!(w, "push_divert_target {id}"),
        Opcode::PushNull => write!(w, "push_null"),
        Opcode::Pop => write!(w, "pop"),
        Opcode::Duplicate => write!(w, "duplicate"),

        // Arithmetic
        Opcode::Add => write!(w, "add"),
        Opcode::Subtract => write!(w, "subtract"),
        Opcode::Multiply => write!(w, "multiply"),
        Opcode::Divide => write!(w, "divide"),
        Opcode::Modulo => write!(w, "modulo"),
        Opcode::Negate => write!(w, "negate"),

        // Comparison
        Opcode::Equal => write!(w, "equal"),
        Opcode::NotEqual => write!(w, "not_equal"),
        Opcode::Greater => write!(w, "greater"),
        Opcode::GreaterOrEqual => write!(w, "greater_or_equal"),
        Opcode::Less => write!(w, "less"),
        Opcode::LessOrEqual => write!(w, "less_or_equal"),

        // Logic
        Opcode::Not => write!(w, "not"),
        Opcode::And => write!(w, "and"),
        Opcode::Or => write!(w, "or"),

        // Global vars
        Opcode::GetGlobal(id) => write!(w, "get_global {id}"),
        Opcode::SetGlobal(id) => write!(w, "set_global {id}"),

        // Temp vars
        Opcode::DeclareTemp(idx) => write!(w, "declare_temp {idx}"),
        Opcode::GetTemp(idx) => write!(w, "get_temp {idx}"),
        Opcode::SetTemp(idx) => write!(w, "set_temp {idx}"),
        Opcode::GetTempRaw(idx) => write!(w, "get_temp_raw {idx}"),

        // Variable pointers
        Opcode::PushVarPointer(id) => write!(w, "push_var_pointer {id}"),
        Opcode::PushTempPointer(slot) => write!(w, "push_temp_pointer {slot}"),

        // Control flow
        Opcode::Jump(off) => write!(w, "jump {off}"),
        Opcode::JumpIfFalse(off) => write!(w, "jump_if_false {off}"),
        Opcode::Goto(id) => write!(w, "goto {id}"),
        Opcode::GotoIf(id) => write!(w, "goto_if {id}"),
        Opcode::GotoVariable => write!(w, "goto_variable"),

        // Container flow
        Opcode::EnterContainer(id) => write!(w, "enter_container {id}"),
        Opcode::ExitContainer => write!(w, "exit_container"),

        // Functions / tunnels
        Opcode::Call(id) => write!(w, "call {id}"),
        Opcode::Return => write!(w, "return"),
        Opcode::TunnelCall(id) => write!(w, "tunnel_call {id}"),
        Opcode::TunnelReturn => write!(w, "tunnel_return"),
        Opcode::TunnelCallVariable => write!(w, "tunnel_call_variable"),
        Opcode::CallVariable(argc) => write!(w, "call_variable argc={argc}"),

        // Threads
        Opcode::ThreadCall(id) => write!(w, "thread_call {id}"),
        Opcode::ThreadStart => write!(w, "thread_start"),
        Opcode::ThreadDone => write!(w, "thread_done"),

        // Output
        Opcode::EmitLine(idx, slots) => write!(w, "emit_line {idx} {slots}"),
        Opcode::EmitValue => write!(w, "emit_value"),
        Opcode::EmitNewline => write!(w, "emit_newline"),
        Opcode::EmitLineNl(idx, slots) => write!(w, "emit_line_nl {idx} {slots}"),
        // `kind=` rather than a bare word: a bare `add` would parse as a trailing
        // operand of the previous instruction and swallow the `add` mnemonic on
        // the next line (#3273's hazard); `kv_operand` is the grammar's safe
        // form for word-valued operands.
        Opcode::BinaryImm(kind, imm) => write!(w, "binary_imm kind={} {imm}", kind.mnemonic()),
        Opcode::BinaryJumpIfFalse(kind, rel) => {
            write!(w, "binary_jump_if_false kind={} {rel}", kind.mnemonic())
        }
        Opcode::BinaryImmJumpIfFalse(kind, imm, rel) => {
            write!(
                w,
                "binary_imm_jump_if_false kind={} {imm} {rel}",
                kind.mnemonic()
            )
        }
        Opcode::GetTempBinaryImm(slot, kind, imm) => {
            write!(
                w,
                "get_temp_binary_imm {slot} kind={} {imm}",
                kind.mnemonic()
            )
        }
        Opcode::GetTempBinaryImmJumpIfFalse(slot, kind, imm, rel) => write!(
            w,
            "get_temp_binary_imm_jump_if_false {slot} kind={} {imm} {rel}",
            kind.mnemonic()
        ),
        Opcode::DuplicateBinaryImmJumpIfFalse(kind, imm, rel) => write!(
            w,
            "duplicate_binary_imm_jump_if_false kind={} {imm} {rel}",
            kind.mnemonic()
        ),
        Opcode::Spring => write!(w, "spring"),
        Opcode::Glue => write!(w, "glue"),
        Opcode::BeginTag => write!(w, "begin_tag"),
        Opcode::EndTag => write!(w, "end_tag"),
        Opcode::EvalLine(idx, slots) => write!(w, "eval_line {idx} {slots}"),
        Opcode::BeginFragment => write!(w, "begin_fragment"),
        Opcode::EndFragment => write!(w, "end_fragment"),
        Opcode::AttachElement => write!(w, "attach_element"),
        Opcode::EndElementRun => write!(w, "end_element_run"),

        // Choices
        Opcode::BeginChoice(flags, target) => {
            write!(w, "begin_choice {} {target}", format_choice_flags(*flags))
        }
        Opcode::EndChoice => write!(w, "end_choice"),

        // Sequences
        Opcode::Sequence(kind, count) => {
            write!(w, "sequence {} {count}", format_sequence_kind(*kind))
        }
        Opcode::SequenceBranch(off) => write!(w, "sequence_branch {off}"),

        // Intrinsics
        Opcode::VisitCount => write!(w, "visit_count"),
        Opcode::TurnsSince => write!(w, "turns_since"),
        Opcode::TurnIndex => write!(w, "turn_index"),
        Opcode::ChoiceCount => write!(w, "choice_count"),
        Opcode::Random => write!(w, "random"),
        Opcode::SeedRandom => write!(w, "seed_random"),

        // Casts / math
        Opcode::CastToInt => write!(w, "cast_to_int"),
        Opcode::CastToFloat => write!(w, "cast_to_float"),
        Opcode::Floor => write!(w, "floor"),
        Opcode::Ceiling => write!(w, "ceiling"),
        Opcode::Pow => write!(w, "pow"),
        Opcode::Min => write!(w, "min"),
        Opcode::Max => write!(w, "max"),

        // External fns
        Opcode::CallExternal(id, argc) => write!(w, "call_external {id} argc={argc}"),

        // List ops
        Opcode::ListContains => write!(w, "list_contains"),
        Opcode::ListNotContains => write!(w, "list_not_contains"),
        Opcode::ListIntersect => write!(w, "list_intersect"),
        Opcode::ListAll => write!(w, "list_all"),
        Opcode::ListInvert => write!(w, "list_invert"),
        Opcode::ListCount => write!(w, "list_count"),
        Opcode::ListMin => write!(w, "list_min"),
        Opcode::ListMax => write!(w, "list_max"),
        Opcode::ListValue => write!(w, "list_value"),
        Opcode::ListRange => write!(w, "list_range"),
        Opcode::ListFromInt => write!(w, "list_from_int"),
        Opcode::ListRandom => write!(w, "list_random"),

        // Collections (T1b)
        Opcode::ArrayNew(n) => write!(w, "array_new {n}"),
        Opcode::MapNew(n) => write!(w, "map_new {n}"),
        Opcode::IndexGet => write!(w, "index_get"),
        Opcode::IndexSet => write!(w, "index_set"),
        Opcode::CollectionLen => write!(w, "collection_len"),
        Opcode::MapGet => write!(w, "map_get"),
        Opcode::MapInsert => write!(w, "map_insert"),
        Opcode::MapRemove => write!(w, "map_remove"),
        Opcode::MapContains => write!(w, "map_contains"),
        Opcode::CollectionKeys => write!(w, "collection_keys"),
        Opcode::CollectionValues => write!(w, "collection_values"),
        Opcode::PushLiteral(idx) => write!(w, "push_literal {idx}"),

        // Sharing discipline (T1b-4)
        Opcode::TakeGlobal(id) => write!(w, "take_global {id}"),
        Opcode::TakeTemp(idx) => write!(w, "take_temp {idx}"),

        // Lifecycle
        Opcode::Done => write!(w, "done"),
        Opcode::Yield => write!(w, "yield"),
        Opcode::End => write!(w, "end"),
        Opcode::Nop => write!(w, "nop"),

        // String eval
        Opcode::BeginStringEval => write!(w, "begin_string_eval"),
        Opcode::EndStringEval => write!(w, "end_string_eval"),

        // Visit
        Opcode::CurrentVisitCount => write!(w, "current_visit_count"),
        Opcode::TouchVisit => write!(w, "touch_visit"),
        Opcode::ShuffleIndexOf => write!(w, "shuffle_index_of"),

        // Records (TM-4)
        Opcode::RecordNew(shape_id) => write!(w, "record_new {shape_id}"),
        Opcode::RecordGetDyn(name_id) => write!(w, "record_get_dyn {name_id}"),
        Opcode::RecordSetDyn(name_id) => write!(w, "record_set_dyn {name_id}"),
        Opcode::RecordGet(offset) => write!(w, "record_get {offset}"),
        Opcode::RecordSet(offset) => write!(w, "record_set {offset}"),

        // Conversion intrinsics (TM-3 completion, #659)
        Opcode::ConvertInt => write!(w, "convert_int"),
        Opcode::ConvertFloat => write!(w, "convert_float"),
        Opcode::ConvertString => write!(w, "convert_string"),

        // Function values (T1c, #700)
        Opcode::PushFnRef(id) => write!(w, "push_fn_ref {id}"),
        Opcode::MakeClosure {
            target,
            bound_count,
        } => write!(w, "make_closure {target} bound={bound_count}"),
        Opcode::CallValue(argc) => write!(w, "call_value argc={argc}"),
        Opcode::BindValue(argc) => write!(w, "bind_value argc={argc}"),

        // Path projections (T1e)
        Opcode::MakeProjection {
            root,
            segment_count,
        } => write!(w, "make_projection {root} segments={segment_count}"),
        Opcode::ProjRead => write!(w, "proj_read"),
        Opcode::ProjWrite => write!(w, "proj_write"),

        // Stdlib slice 1 completion (#857)
        Opcode::CharAt => write!(w, "char_at"),

        // NS-A1 Option + stdlib flips
        Opcode::PushNone => write!(w, "push_none"),
        Opcode::MakeSome => write!(w, "make_some"),
        Opcode::StrFind => write!(w, "str_find"),
        Opcode::SeqIndexOf => write!(w, "seq_index_of"),
        Opcode::SeqMin => write!(w, "seq_min"),
        Opcode::SeqMax => write!(w, "seq_max"),
        Opcode::SeqFirst => write!(w, "seq_first"),
        Opcode::SeqLast => write!(w, "seq_last"),
        Opcode::SeqPop => write!(w, "seq_pop"),
        Opcode::MapGetOpt => write!(w, "map_get_opt"),
        Opcode::MapContainsValue => write!(w, "map_contains_value"),
        Opcode::MapClear => write!(w, "map_clear"),
        // B1 `or`-coalescing, short-circuited (issue #1471).
        Opcode::CoalesceSome(off) => write!(w, "coalesce_some {off}"),
        Opcode::OptionBind(slot) => write!(w, "option_bind {slot}"),
        // Seq `remove_at` (issue #1484).
        Opcode::SeqRemoveAt => write!(w, "seq_remove_at"),
        // NS-A6 rand verbs (#1112).
        Opcode::RandFloat => write!(w, "rand_float"),
        Opcode::RandChance => write!(w, "rand_chance"),
        Opcode::RandPick => write!(w, "rand_pick"),
        Opcode::RandShuffle => write!(w, "rand_shuffle"),
        Opcode::RangeMakeExcl => write!(w, "range_make_excl"),
        Opcode::RangeMakeIncl => write!(w, "range_make_incl"),
        Opcode::RangeNonEmpty => write!(w, "range_non_empty"),
        // NS-A4 ordering verbs (#1110).
        Opcode::SeqSorted => write!(w, "seq_sorted"),
        Opcode::SeqSortedBy => write!(w, "seq_sorted_by"),

        // NS-A8 numeric tower: the kind's own mnemonic IS the instruction
        // word (`make_vec2` … `tower_lerp`) — one wire opcode, thirteen
        // spellings, `TowerOp::mnemonic`/`from_mnemonic` the single pairing.
        Opcode::Tower(op) => write!(w, "{}", op.mnemonic()),

        // NS-A7 collections+: same one-opcode-per-kind-mnemonic pattern as
        // the tower — `CollectOp::mnemonic`/`from_mnemonic` the single
        // pairing (`weighted_new` … `heap_peek`).
        Opcode::Collect(op) => write!(w, "{}", op.mnemonic()),

        // The fn-value verbs (issue #1679): same one-opcode-per-kind-
        // mnemonic pattern — the mnemonic IS the source spelling, for all
        // six kinds (`map`/`filter`/`fold`/`filter_map`/`each`/`map_each`),
        // `SeqVerbOp::mnemonic`/`from_mnemonic` the single pairing.
        Opcode::SeqVerb(op) => write!(w, "{}", op.mnemonic()),
    }
}

// ── Helpers ──────────────────────────────────────────────────────────────────

fn format_choice_flags(flags: ChoiceFlags) -> String {
    let mut parts = Vec::new();
    if flags.has_condition {
        parts.push("cond");
    }
    if flags.has_start_content {
        parts.push("start");
    }
    if flags.has_choice_only_content {
        parts.push("choice_only");
    }
    if flags.once_only {
        parts.push("once");
    }
    if flags.is_invisible_default {
        parts.push("invis_default");
    }
    if parts.is_empty() {
        "none".to_owned()
    } else {
        parts.join("+")
    }
}

fn format_sequence_kind(kind: SequenceKind) -> &'static str {
    match kind {
        SequenceKind::Cycle => "cycle",
        SequenceKind::Stopping => "stopping",
        SequenceKind::OnceOnly => "once_only",
        SequenceKind::Shuffle => "shuffle",
    }
}

fn value_type_name(vt: ValueType) -> &'static str {
    match vt {
        ValueType::Int => "int",
        ValueType::Float => "float",
        ValueType::Bool => "bool",
        ValueType::String => "string",
        ValueType::List => "list",
        ValueType::DivertTarget => "divert_target",
        ValueType::VariablePointer => "var_pointer",
        ValueType::TempPointer => "temp_pointer",
        ValueType::Null => "null",
        ValueType::FragmentRef => "fragment_ref",
        ValueType::Array => "array",
        ValueType::Map => "map",
        ValueType::Record => "record",
        ValueType::FnRef => "fn_ref",
        ValueType::Closure => "closure",
        ValueType::Handle => "handle",
        ValueType::Projection => "projection",
        ValueType::Option => "option",
        ValueType::Range => "range",
        ValueType::Vec2 => "vec2",
        ValueType::Vec3 => "vec3",
        ValueType::Vec4 => "vec4",
        ValueType::Quat => "quat",
        ValueType::Mat2 => "mat2",
        ValueType::Mat3 => "mat3",
        ValueType::Mat4 => "mat4",
        ValueType::Weighted => "weighted",
    }
}

#[expect(
    clippy::too_many_lines,
    reason = "one atom arm per Value variant — the NS-A7 Weighted arm pushed this past 100"
)]
fn write_value(w: &mut dyn fmt::Write, v: &Value) -> fmt::Result {
    match v {
        Value::Int(n) => write!(w, "{n}"),
        Value::Float(n) => write_float_atom(w, *n),
        Value::Bool(b) => write!(w, "{b}"),
        Value::String(s) => write!(w, "\"{}\"", escape_string(s)),
        Value::List(lv) => {
            write!(w, "(list (items")?;
            for item in &lv.items {
                write!(w, " {item}")?;
            }
            write!(w, ") (origins")?;
            for origin in &lv.origins {
                write!(w, " {origin}")?;
            }
            write!(w, "))")
        }
        Value::DivertTarget(id) => write!(w, "{id}"),
        Value::VariablePointer(id) => write!(w, "(var_pointer {id})"),
        Value::TempPointer { slot, frame_depth } => {
            write!(w, "(temp_pointer {slot} {frame_depth})")
        }
        Value::Null => write!(w, "null"),
        Value::FragmentRef(idx) => write!(w, "(fragment_ref {idx})"),
        // Array/Map render as nested s-expressions — the textual mirror of the
        // v4 `.inkb`/transcript tree encoding (`docs/format-v4-rfc.md` §1). A
        // collection reaches the dump whenever a binding/external return value
        // (which since #525 can be a collection) is stored or emitted.
        Value::Array(items) => {
            write!(w, "(array")?;
            for item in items.iter() {
                write!(w, " ")?;
                write_value(w, item)?;
            }
            write!(w, ")")
        }
        Value::Map(map) => {
            write!(w, "(map")?;
            for (key, value) in map.iter() {
                write!(w, " (")?;
                write_map_key(w, key)?;
                write!(w, " ")?;
                write_value(w, value)?;
                write!(w, ")")?;
            }
            write!(w, ")")
        }
        Value::Record { shape, fields } => {
            write!(w, "(record {}", shape.0)?;
            for field in fields.iter() {
                write!(w, " ")?;
                write_value(w, field)?;
            }
            write!(w, ")")
        }
        // Function values (T1c, #700): a fn value can reach the dump as a
        // binding/global default value the same way a collection can.
        Value::FnRef(target) => write!(w, "(fn_ref {target})"),
        Value::Closure(c) => {
            write!(w, "(closure {}", c.target)?;
            for entry in &c.env {
                let mode = if entry.is_ref { "ref" } else { "val" };
                write!(w, " ({mode} {} ", entry.name.0)?;
                write_value(w, &entry.payload)?;
                write!(w, ")")?;
            }
            write!(w, ")")
        }
        // Handle values (T1d, `docs/t1d-spec.md` §2): `(handle <kind> <id>)`
        // — kind as its raw NameId (the human-readable kind name lives in the
        // name table, resolved by tooling that has it, not by this dump).
        Value::Handle { kind, id } => write!(w, "(handle {} {id})", kind.0),
        // Projection values (T1e, `docs/t1e-spec.md` §3): `(projection <cell>
        // (segments <seg>…))`, each segment `(index <n>)` or `(key <value>)`
        // — the reader parity this dump exists for (dump/reader parity, the
        // #742 lesson).
        Value::Projection(p) => {
            write!(w, "(projection {} (segments", p.cell)?;
            for seg in &p.segments {
                write!(w, " ")?;
                write_proj_segment(w, seg)?;
            }
            write!(w, "))")
        }
        // Option values (NS-A1, `docs/stdlib-spec.md` §1.4): `(some
        // <value>)` / `(option_none)` — reader lands with the writer in this
        // same PR (the #742 dump/reader parity lesson). `option_none`, not
        // bare `none`, because `none` is already a choice-flags token in the
        // grammar.
        Value::OptionVal(inner) => match inner {
            None => write!(w, "(option_none)"),
            Some(v) => {
                write!(w, "(some ")?;
                write_value(w, v)?;
                write!(w, ")")
            }
        },
        // Range values (NS-A5, `docs/stdlib-spec.md` §7, F7): `(range
        // <start> <end> incl|excl)` — the written form is preserved via the
        // incl/excl token; reader lands with the writer in this same PR
        // (the #742 dump/reader parity lesson).
        Value::Range {
            start,
            end,
            inclusive,
        } => {
            let form = if *inclusive { "incl" } else { "excl" };
            write!(w, "(range {start} {end} {form})")
        }
        // Tower values (NS-A8, `docs/tower-mini-spec.md` T5): `(vec2 <x>
        // <y>)` … `(mat4 <16 column-major lanes>)` — the textual mirror of
        // the VAL_VEC2..VAL_MAT4 wire tags, reader landing with the writer
        // in this same PR (the #742 dump/reader parity lesson). Lanes come
        // from glam's explicit array conversions, never its memory layout.
        Value::Vec2(v) => write_tower_lanes(w, "vec2", &v.to_array()),
        Value::Vec3(v) => write_tower_lanes(w, "vec3", &v.to_array()),
        Value::Vec4(v) => write_tower_lanes(w, "vec4", &v.to_array()),
        Value::Quat(q) => write_tower_lanes(w, "quat", &q.to_array()),
        Value::Mat2(m) => write_tower_lanes(w, "mat2", &m.to_cols_array()),
        Value::Mat3(m) => write_tower_lanes(w, "mat3", &m.to_cols_array()),
        Value::Mat4(m) => write_tower_lanes(w, "mat4", &m.to_cols_array()),
        // Weighted tables (NS-A7, `docs/stdlib-spec.md` §8): `(weighted
        // (<weight> <value>)+)`, entries in construction order.
        Value::Weighted(wt) => {
            write!(w, "(weighted")?;
            for (weight, value) in &wt.entries {
                write!(w, " ({weight} ")?;
                write_value(w, value)?;
                write!(w, ")")?;
            }
            write!(w, ")")
        }
    }
}

/// Write one f32 with a guaranteed decimal point (unambiguous float atom) —
/// the exact convention `write_value`'s `Float` arm has always used, shared
/// with the NS-A8 tower lanes.
fn write_float_atom(w: &mut dyn fmt::Write, n: f32) -> fmt::Result {
    let s = format!("{n}");
    if s.contains('.') || s.contains("inf") || s.contains("NaN") {
        write!(w, "{s}")
    } else {
        write!(w, "{s}.0")
    }
}

/// NS-A8 tower atom body: the tag word then the flat lanes in the pinned
/// order (`docs/tower-mini-spec.md` T5 — vec/quat `x y (z w)`, matrices
/// column-major), each lane through [`write_float_atom`].
fn write_tower_lanes(w: &mut dyn fmt::Write, tag: &str, lanes: &[f32]) -> fmt::Result {
    write!(w, "({tag}")?;
    for lane in lanes {
        write!(w, " ")?;
        write_float_atom(w, *lane)?;
    }
    write!(w, ")")
}

fn write_proj_segment(w: &mut dyn fmt::Write, seg: &ProjSegment) -> fmt::Result {
    match seg {
        ProjSegment::Index(n) => write!(w, "(index {n})"),
        ProjSegment::Key(v) => {
            write!(w, "(key ")?;
            write_value(w, v)?;
            write!(w, ")")
        }
    }
}

fn write_map_key(w: &mut dyn fmt::Write, key: &MapKey) -> fmt::Result {
    match key {
        MapKey::Int(n) => write!(w, "{n}"),
        MapKey::Str(s) => write!(w, "\"{}\"", escape_string(s)),
        MapKey::Bool(b) => write!(w, "{b}"),
    }
}

pub(crate) fn escape_string(s: &str) -> String {
    let mut out = String::with_capacity(s.len());
    for c in s.chars() {
        match c {
            '\\' => out.push_str("\\\\"),
            '"' => out.push_str("\\\""),
            '\n' => out.push_str("\\n"),
            '\t' => out.push_str("\\t"),
            '\r' => out.push_str("\\r"),
            other => out.push(other),
        }
    }
    out
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::id::{DefinitionId, DefinitionTag};

    #[test]
    fn definition_id_display() {
        let id = DefinitionId::new(DefinitionTag::Address, 0xDEAD_BEEF);
        assert_eq!(format!("{id}"), "$01_000000deadbeef");
    }

    #[test]
    fn escape_special_chars() {
        assert_eq!(escape_string("hello"), "hello");
        assert_eq!(escape_string("a\"b"), "a\\\"b");
        assert_eq!(escape_string("a\\b"), "a\\\\b");
        assert_eq!(escape_string("a\nb"), "a\\nb");
        assert_eq!(escape_string("a\tb"), "a\\tb");
    }

    #[test]
    fn empty_story() {
        let story = StoryData {
            containers: vec![],
            line_tables: vec![],
            variables: vec![],
            list_defs: vec![],
            list_items: vec![],
            externals: vec![],
            addresses: vec![],
            address_paths: vec![],
            name_table: vec![],
            list_literals: vec![],
            literal_pool: vec![],
            struct_shapes: vec![],
            private_defs: vec![],
            alias_table: vec![],
            effect_rows: vec![],
            frame_shapes: Vec::new(),
            debug_info: None,
            line_variant_groups: Vec::new(),
            source_checksum: 0,
        };
        let mut buf = String::new();
        write_inkt(&story, &mut buf).unwrap();
        assert_eq!(buf, "(story\n)");
    }

    #[test]
    fn choice_flags_formatting() {
        let flags = ChoiceFlags {
            has_condition: true,
            has_start_content: false,
            has_choice_only_content: false,
            once_only: true,
            is_invisible_default: false,
        };
        assert_eq!(format_choice_flags(flags), "cond+once");

        let empty = ChoiceFlags {
            has_condition: false,
            has_start_content: false,
            has_choice_only_content: false,
            once_only: false,
            is_invisible_default: false,
        };
        assert_eq!(format_choice_flags(empty), "none");
    }
}