feuerwerk/src/core/store/serialize.ts

// Importing the graph package index is what registers the built-in nodes.
import {
  ANNOTATION_KINDS,
  annotationList,
  createEmptyGraph,
  type DeclaredPort,
  type GraphAnnotation,
  MIN_ANNOTATION_SIZE,
  type DeclaredPortKind,
  type Graph,
  type GraphEdge,
  type GraphNode,
  type PortSplit,
  isValidPortName,
  fixedPortKeys,
  type NodeDef,
  nodeDef,
  STATE,
} from '../graph';
import { isParticleNodeDef } from '../particles/nodes';
import { isShaderNodeDef } from '../shader/nodes';
import { isKeyInterpolation, normalizeKeys } from '../model/animation';
import type {
  AnimationKey,
  AnimationTrack,
  Asset,
  BehaviorAsset,
  ContainerAsset,
  PictureCut,
  PixelArtAsset,
  PixelFrame,
  PixelLayer,
  SceneAsset,
  StateMachineAsset,
  TextureFrame,
  GradientStop,
  TilemapLayer,
  VariablesAsset,
  VectorArtAsset,
  VectorGradient,
  VectorPaint,
  VectorPoint,
  VectorRing,
  VectorItem,
  VectorLayer,
  VectorShape,
} from '../model/Asset';
import { parseCellKey } from '../model/tilemap';
import { pluginsOf } from './projectPlugins';
import { collisionLayersOf } from '../model/collisionLayers';
import { renderLayersOf } from '../model/renderLayers';
import { gameLinkZoomOf, gameScaleOf, playFromOf, whilePlayingOf } from '../model/playSettings';
import { sceneVisibilityOf } from '../model/sceneVisibility';
import { symbolScaleOf } from '../model/symbolScale';
import { decodeCells, encodeCells } from './tilemapCells';
import { isAssetType } from '../model/AssetTypes';
import { isFontFile } from '../model/font';
import { isSoundFile } from '../model/sound';
import { emptyEdit, type InstanceEdit, isEmptyEdit } from '../model/instance';
import { type PropertyBag, type PropertyValue, tagOf, type Vec2 } from '../model/Properties';
import { PROJECT_FORMAT_VERSION, type Project } from '../model/Project';
import { readScope, readSharedScope } from '../model/Scope';
import type { ObjectGroup, SceneObject } from '../model/SceneObject';
import {
  type CutSize,
  DEFAULT_FILL,
  isTextureFile,
  normalizeFrameRect,
  setCutSlice,
  setCutSortLine,
  setFrameCollision,
} from '../model/texture';
import { drawnCutSize } from '../model/cutTarget';
import { pointsOf } from '../model/polygon';
import { canvasSide, PALETTE_MAX } from '../model/pixelart';
import { isCelFile } from '../model/pixelCel';
import { newId } from '../ids';
import { SHAPE_FILL_DEFAULT } from '../model/vectorart';
import { sanitizedCurve } from '../model/curve';
import { hasParentCycle } from '../model/walk';
import { syncStructTypes } from '../model/structTypes';
import { Recorder } from '../util/recorder';
import {
  DECLARED_PORT_KINDS,
  FIELD_KINDS,
  type FieldKind,
  isTaggedKind,
  VARIABLE_KINDS,
  type VariableKind,
} from '../properties/kinds';
import { makeItem } from '../properties/listItems';
import {
  coerceValue,
  initialOf,
  isValidFieldName,
  isValidVariableName,
  type PropertyDef,
  type PropertySchema,
  rowsNotClaimedBy,
  schemaFor,
  sourceRows,
  type StructFieldDef,
  variableDef,
} from '../properties/PropertySchema';
import { FIELD_SHADER_KEY, particleParamDefs } from '../properties/particles';
import { SHADER_KEY, shaderParamDefs } from '../properties/shaders';

/**
 * Turns untrusted JSON (server file, import) into a well-formed Project: unknown keys are dropped,
 * missing ones get defaults, values are coerced against the schema, dangling objects are removed.
 */
export function deserializeProject(raw: unknown, fallbackId = ''): Project {
  const r = asRecord(raw);
  const rawAssets = (Array.isArray(r.assets) ? r.assets : []).map(asRecord);

  // Pass 1: asset ids and their effective schemas, needed to coerce overrides in pass 2.
  const schemas = new Map<string, PropertySchema>();
  const variables = new Map<string, PropertyDef[]>();
  const rawProps = new Map<string, Record<string, unknown>>();
  const shaderGraphs = new Map<string, Graph>();
  const shaderRows = new Map<string, PropertyDef[]>();
  const particleGraphs = new Map<string, Graph>();
  const wearers = new Map<string, 'sprite' | 'particles' | 'text' | 'camera'>();
  for (const a of rawAssets) {
    if (typeof a.id !== 'string' || !a.id || !isAssetType(a.type)) continue;
    rawProps.set(a.id, asRecord(a.props));
    if (a.type === 'sprite' || a.type === 'particles' || a.type === 'text' || a.type === 'camera')
      wearers.set(a.id, a.type);
    if (a.type === 'behavior' || a.type === 'variables' || a.type === 'struct') {
      const vars = normalizeVariables(a.variables);
      variables.set(a.id, vars);
      // The full schema, not just the common rows: this is what pass 2 coerces `props` against, and
      // a behavior's own `runInEditor` would be dropped as undeclared.
      schemas.set(a.id, [...schemaFor(a.type), ...vars]);
    } else if (a.type === 'particles') {
      // A source's rows end with its own graph's parameters, so the graph is needed before the
      // overrides of the objects placed from it can be coerced.
      const graph = normalizeGraph(a.graph, isParticleNodeDef);
      particleGraphs.set(a.id, graph);
      schemas.set(a.id, [...schemaFor('particles'), ...particleParamDefs(graph)]);
    } else {
      if (a.type === 'shader') {
        const graph = normalizeGraph(a.graph, isShaderNodeDef);
        shaderGraphs.set(a.id, graph);
        shaderRows.set(a.id, shaderParamDefs(graph));
      }
      if (a.type === 'shaderfunction') shaderGraphs.set(a.id, normalizeGraph(a.graph, isShaderNodeDef));
      schemas.set(a.id, schemaFor(a.type));
    }
  }
  /**
   * A sprite's, source's, text's or camera's rows end with the parameters of the shader its bag names –
   * an override's, else the asset's. Only a sprite's rows yield to none: a name the others have stays
   * theirs.
   */
  const schemaOf = (assetId: string, bag: Record<string, unknown>): PropertySchema | undefined => {
    const schema = schemas.get(assetId);
    const wearer = wearers.get(assetId);
    if (!schema || !wearer) return schema;
    const rowsOf = (key: string): PropertySchema => {
      const own = bag[key];
      const shader = typeof own === 'string' ? own : rawProps.get(assetId)?.[key];
      return shaderRows.get(typeof shader === 'string' ? shader : '') ?? [];
    };
    const rows = rowsOf(SHADER_KEY);
    if (wearer === 'sprite') return [...schema, ...rows];
    if (wearer === 'particles') return sourceRows(schema, rows, rowsOf(FIELD_SHADER_KEY));
    return [...schema, ...rowsNotClaimedBy(rows, schema)];
  };

  // Pass 2: build assets. Frame ids share the reference space with asset ids, so `normalizeTexture`
  // is handed the ids already spoken for.
  const assets: Asset[] = [];
  const takenIds = new Set(schemas.keys());
  for (const a of rawAssets) {
    const id = typeof a.id === 'string' ? a.id : '';
    const schema = schemaOf(id, asRecord(a.props));
    if (!schema || !isAssetType(a.type)) continue;
    const type = a.type;
    const name = typeof a.name === 'string' ? a.name : type;
    const props = normalizeBag(a.props, schema, false);
    if (type === 'scene' || type === 'container') {
      const holder: SceneAsset | ContainerAsset = {
        id,
        type,
        name,
        props,
        objects: normalizeObjects(a.objects, schemaOf),
      };
      normalizeGroups(holder, a.groups);
      assets.push(holder);
    } else if (type === 'behavior') {
      const declared = variables.get(id) ?? [];
      const behavior: BehaviorAsset = {
        id,
        type,
        name,
        props,
        variables: declared,
        graph: normalizeGraph(a.graph),
      };
      // Only names that are declared, each once, in declaration order.
      const declaredOf = (list: unknown): string[] => {
        const named = new Set(Array.isArray(list) ? list : []);
        return declared.map((v) => v.key).filter((key) => named.has(key));
      };
      const keptVariables = declaredOf(a.keptVariables);
      if (keptVariables.length > 0) behavior.keptVariables = keptVariables;
      const privateVariables = declaredOf(a.privateVariables);
      if (privateVariables.length > 0) behavior.privateVariables = privateVariables;
      assets.push(behavior);
    } else if (type === 'variables') {
      const shared: VariablesAsset = { id, type, name, props, variables: variables.get(id) ?? [] };
      // Scope first: a `scene` asset is never persistent, so the switch that cannot apply is dropped.
      if (readSharedScope(a.scope) === 'scene') shared.scope = 'scene';
      else if (a.persistent === true) shared.persistent = true;
      assets.push(shared);
    } else if (type === 'struct') {
      assets.push({ id, type, name, props, variables: variables.get(id) ?? [] });
    } else if (type === 'statemachine') {
      const machine: StateMachineAsset = {
        id,
        type,
        name,
        props,
        graph: normalizeGraph(a.graph, (def) => def.type === STATE),
      };
      const scope = readScope(a.scope);
      if (scope !== 'local') machine.scope = scope;
      // Kept as written even where it names no state any more: the same as a deleted start.
      if (typeof a.start === 'string' && a.start !== '') machine.start = a.start;
      assets.push(machine);
    } else if (type === 'shader' || type === 'shaderfunction') {
      assets.push({ id, type, name, props, graph: shaderGraphs.get(id) ?? createEmptyGraph() });
    } else if (type === 'particles') {
      assets.push({ id, type, name, props, graph: particleGraphs.get(id) ?? createEmptyGraph() });
    } else if (type === 'texture') {
      assets.push({ id, type, name, props, ...normalizeTexture(a, takenIds) });
    } else if (type === 'font') {
      const file = typeof a.file === 'string' && isFontFile(a.file) ? a.file : '';
      assets.push({ id, type, name, props, file });
    } else if (type === 'sound') {
      const file = typeof a.file === 'string' && isSoundFile(a.file) ? a.file : '';
      assets.push({ id, type, name, props, file });
    } else if (type === 'tile') {
      // A picture naming nothing is kept, like an animation's dangling root: it reads as missing
      // in the tab and comes back when the texture it named is restored by an undo.
      const pictures = (Array.isArray(a.pictures) ? a.pictures : []).filter(
        (id): id is string => typeof id === 'string' && id !== '',
      );
      assets.push({ id, type, name, props, pictures });
    } else if (type === 'tilemap') {
      assets.push({ id, type, name, props, layers: normalizeLayers(a.layers) });
    } else if (type === 'vectorart') {
      const drawing: VectorArtAsset = { id, type, name, props, layers: normalizeVectorLayers(a) };
      readCut(drawing, drawnCutSize(drawing), a);
      assets.push(drawing);
    } else if (type === 'pixelart') {
      const drawing: PixelArtAsset = { id, type, name, props, ...normalizePixelArt(a, takenIds) };
      readCut(drawing, drawnCutSize(drawing), a);
      assets.push(drawing);
    } else if (type === 'palette') {
      assets.push({ id, type, name, props, colors: normalizePalette(a.colors) });
    } else if (type === 'curve') {
      assets.push({ id, type, name, props, points: sanitizedCurve(normalizePoints(a.points)) });
    } else if (type === 'animation') {
      // A root or row aiming at something gone is kept: it reads as missing and keeps its keys.
      const root = typeof a.root === 'string' ? a.root : '';
      assets.push({ id, type, name, props, root, tracks: normalizeTracks(a.tracks) });
    } else {
      assets.push({ id, type, name, props });
    }
  }

  let activeSceneId = typeof r.activeSceneId === 'string' ? r.activeSceneId : '';
  if (!assets.some((a) => a.type === 'scene' && a.id === activeSceneId)) {
    const first = assets.find((a) => a.type === 'scene');
    activeSceneId = first ? first.id : '';
  }

  // A dangling start scene reads as none at all – the run then falls back to the active scene,
  // which is also what every project written before there was such a field does.
  const startSceneId =
    typeof r.startSceneId === 'string' && assets.some((a) => a.type === 'scene' && a.id === r.startSceneId)
      ? r.startSceneId
      : '';

  const project: Project = {
    formatVersion: PROJECT_FORMAT_VERSION,
    id: typeof r.id === 'string' && r.id ? r.id : fallbackId,
    name: typeof r.name === 'string' ? r.name : 'Untitled',
    assets,
    activeSceneId,
    startSceneId,
    // The same reading the editor did before it loaded the plugins (#119), so the model says what
    // is actually running.
    plugins: pluginsOf(r),
    collisionLayers: collisionLayersOf(r),
    renderLayers: renderLayersOf(r),
    symbolScale: symbolScaleOf(r),
    playFrom: playFromOf(r),
    whilePlaying: whilePlayingOf(r),
    gameScale: gameScaleOf(r),
    gameLinkZoom: gameLinkZoomOf(r),
    sceneVisibility: sceneVisibilityOf(r),
  };
  // A hand-edited file may have copies that no longer match their Struct asset.
  syncStructTypes(project, new Recorder());
  return project;
}

/**
 * Plain JSON-ready copy of the project (deep clone, stable key order for readable diffs). The cells
 * of a tilemap are the one thing written differently from how they are held: see `tilemapCells.ts`.
 */
export function serializeProject(project: Project): unknown {
  const copy = JSON.parse(JSON.stringify(project)) as Project;
  for (const asset of copy.assets)
    if (asset.type === 'tilemap')
      (asset as { layers: unknown[] }).layers = asset.layers.map(({ cells, ...layer }) => ({
        ...layer,
        ...encodeCells(cells),
      }));
  return copy;
}

function normalizeObjects(
  raw: unknown,
  schemaOf: (assetId: string, overrides: Record<string, unknown>) => PropertySchema | undefined,
): SceneObject[] {
  const objects: SceneObject[] = [];
  for (const item of Array.isArray(raw) ? raw : []) {
    const o = asRecord(item);
    if (typeof o.id !== 'string' || !o.id || typeof o.assetId !== 'string') continue;
    const schema = schemaOf(o.assetId, asRecord(o.overrides));
    if (!schema || schema === schemaFor('scene')) continue; // dangling reference or illegal scene-in-scene
    const p = asRecord(o.position);
    const offset = asRecord(o.editorOffset);
    objects.push({
      id: o.id,
      assetId: o.assetId,
      name: typeof o.name === 'string' ? o.name : '',
      position: { x: toNumber(p.x), y: toNumber(p.y), z: toNumber(p.z) },
      editorOffset: { x: toNumber(offset.x), y: toNumber(offset.y) },
      overrides: normalizeBag(o.overrides, schema, true),
      parentId: typeof o.parentId === 'string' ? o.parentId : '',
      instanceEdits: normalizeInstanceEdits(o.instanceEdits),
      ...(typeof o.groupId === 'string' && o.groupId ? { groupId: o.groupId } : {}),
    });
  }
  // Parents must exist in the same scene, differ from the object itself and not form cycles.
  const byId = new Map(objects.map((o) => [o.id, o]));
  for (const o of objects) if (o.parentId && (o.parentId === o.id || !byId.has(o.parentId))) o.parentId = '';
  // Cut one link per cycle: an object already unlinked here is a root for the objects checked after it.
  const parentOf = (o: SceneObject) => (o.parentId ? byId.get(o.parentId) : undefined);
  for (const o of objects) if (hasParentCycle(o, parentOf)) o.parentId = '';
  return objects;
}

/**
 * Hierarchy folders (#241): only those with a member are kept, and a member is a top-level object
 * naming one of them – anything else loses its `groupId`.
 */
function normalizeGroups(holder: SceneAsset | ContainerAsset, raw: unknown): void {
  const groups = new Map<string, ObjectGroup>();
  for (const item of Array.isArray(raw) ? raw : []) {
    const g = asRecord(item);
    if (typeof g.id !== 'string' || !g.id || groups.has(g.id)) continue;
    groups.set(g.id, { id: g.id, name: typeof g.name === 'string' ? g.name : '' });
  }
  const used = new Set<string>();
  for (const object of holder.objects) {
    if (object.groupId === undefined) continue;
    if (!object.parentId && groups.has(object.groupId)) used.add(object.groupId);
    else delete object.groupId;
  }
  const kept = [...groups.values()].filter((g) => used.has(g.id));
  if (kept.length > 0) holder.groups = kept;
}

/**
 * Deviations of container content, keyed by template path. Values are not coerced against a schema:
 * which asset a path leads to depends on container assets that may not be built yet, and resolving
 * drops what the schema does not declare anyway.
 */
function normalizeInstanceEdits(raw: unknown): Record<string, InstanceEdit> {
  const edits: Record<string, InstanceEdit> = {};
  for (const [path, value] of Object.entries(asRecord(raw))) {
    if (!path) continue;
    const e = asRecord(value);
    const edit = emptyEdit();
    if (typeof e.name === 'string') edit.name = e.name;
    const position = asRecord(e.position);
    for (const axis of ['x', 'y', 'z'] as const)
      if (typeof position[axis] === 'number' && Number.isFinite(position[axis]))
        edit.position[axis] = position[axis];
    const offset = asRecord(e.editorOffset);
    if (typeof offset.x === 'number' || typeof offset.y === 'number')
      edit.editorOffset = { x: toNumber(offset.x), y: toNumber(offset.y) };
    for (const [key, v] of Object.entries(asRecord(e.overrides))) {
      const value = asStoredValue(v);
      if (value !== undefined) edit.overrides[key] = value;
    }
    if (!isEmptyEdit(edit)) edits[path] = edit;
  }
  return edits;
}

function normalizeVariables(raw: unknown): PropertyDef[] {
  const defs: PropertyDef[] = [];
  const seen = new Set<string>();
  for (const item of Array.isArray(raw) ? raw : []) {
    const v = asRecord(item);
    const key = typeof v.key === 'string' ? v.key : '';
    const kind = (VARIABLE_KINDS as readonly string[]).includes(String(v.kind))
      ? (v.kind as VariableKind)
      : 'number';
    // Common property keys are reserved – a variable of that name would shadow the switch.
    if (!isValidVariableName(key) || seen.has(key)) continue;
    seen.add(key);
    const fields = normalizeStructFields(v.fields);
    const def = variableDef(key, kind, undefined, fields);
    def.default = coerceValue(def, (v.default ?? def.default) as PropertyValue);
    if (def.kind === 'struct') readStructType(def, v.structType);
    if (def.kind === 'list') readItemType(def, v.itemType);
    defs.push(def);
  }
  return defs;
}

/** An unreadable field is dropped rather than defaulted: an invented key would claim a value. */
function normalizeStructFields(raw: unknown): StructFieldDef[] {
  const fields: StructFieldDef[] = [];
  const seen = new Set<string>();
  for (const item of Array.isArray(raw) ? raw : []) {
    const f = asRecord(item);
    const key = typeof f.key === 'string' ? f.key : '';
    if (!isValidFieldName(key) || seen.has(key)) continue;
    const field = readField(key, f);
    if (!field) continue;
    seen.add(key);
    fields.push(field);
  }
  return fields;
}

function readField(key: string, f: Record<string, unknown>): StructFieldDef | null {
  const isFieldKind = (value: unknown) => (FIELD_KINDS as readonly string[]).includes(String(value));
  if (f.kind === 'list') {
    const field: StructFieldDef = { key, kind: 'list' };
    readItemType(field, f.itemType);
    return field;
  }
  if (f.kind === 'struct') {
    const field: StructFieldDef = { key, kind: 'struct', fields: normalizeStructFields(f.fields) };
    readStructType(field, f.structType);
    return field;
  }
  return isFieldKind(f.kind) ? { key, kind: f.kind as FieldKind } : null;
}

/** A dangling id is kept, as a curve's is: the struct keeps the fields it last had (#253). */
function readStructType(def: { structType?: string }, raw: unknown): void {
  if (typeof raw === 'string' && raw !== '') def.structType = raw;
}

/** The same for a typed list (#254): gone, it is a mixed list whose items keep their marks. */
function readItemType(def: { itemType?: string }, raw: unknown): void {
  if (typeof raw === 'string' && raw !== '') def.itemType = raw;
}

function normalizePorts(raw: unknown, fixed: readonly string[], writable: boolean): DeclaredPort[] {
  const ports: DeclaredPort[] = [];
  const seen = new Set(fixed);
  for (const item of Array.isArray(raw) ? raw : []) {
    const p = asRecord(item);
    const key = typeof p.key === 'string' ? p.key : '';
    if (!isValidPortName(key) || seen.has(key)) continue;
    seen.add(key);
    const kind = (DECLARED_PORT_KINDS as readonly string[]).includes(String(p.kind))
      ? (p.kind as DeclaredPortKind)
      : 'number';
    ports.push(writable && p.write === true ? { key, kind, write: true } : { key, kind });
  }
  return ports;
}

/** One split per output; its fields are checked like declared ports, the type is kept even when gone. */
function normalizeSplits(raw: unknown): PortSplit[] {
  const splits: PortSplit[] = [];
  for (const item of Array.isArray(raw) ? raw : []) {
    const s = asRecord(item);
    const port = typeof s.port === 'string' ? s.port : '';
    if (!port || splits.some((other) => other.port === port)) continue;
    const structType = typeof s.structType === 'string' ? s.structType : '';
    splits.push({ port, structType, fields: normalizePorts(s.fields, [], false) });
  }
  return splits;
}

/** `keep` restricts the node types kept: a state machine's graph holds states, a shader's shader nodes, and nothing else. */
function normalizeGraph(raw: unknown, keep?: (def: NodeDef) => boolean): Graph {
  const g = asRecord(raw);
  const graph = createEmptyGraph();
  const nodeIds = new Set<string>();
  for (const item of Array.isArray(g.nodes) ? g.nodes : []) {
    const n = asRecord(item);
    const id = typeof n.id === 'string' ? n.id : '';
    const type = typeof n.type === 'string' ? n.type : '';
    const def = nodeDef(type);
    if (!id || nodeIds.has(id) || !def || (keep !== undefined && !keep(def))) continue;
    nodeIds.add(id);
    // Params carry both settings and inline input values, so there is no schema to coerce against.
    const params: PropertyBag = {};
    for (const [key, value] of Object.entries(asRecord(n.params))) {
      const stored = asStoredValue(value);
      if (stored !== undefined) params[key] = stored;
    }
    const node: GraphNode = { id, type, x: toNumber(n.x), y: toNumber(n.y), params };
    const ports = normalizePorts(n.ports, fixedPortKeys(def), def.declaresPorts === 'both');
    if (ports.length > 0) node.ports = ports;
    const splits = normalizeSplits(n.splits);
    if (splits.length > 0) node.splits = splits;
    if (n.collapsed === true) node.collapsed = true;
    graph.nodes.push(node);
  }
  const edgeIds = new Set<string>();
  for (const item of Array.isArray(g.edges) ? g.edges : []) {
    const e = asRecord(item);
    const from = asRecord(e.from);
    const to = asRecord(e.to);
    const id = typeof e.id === 'string' ? e.id : '';
    if (!id || edgeIds.has(id)) continue;
    if (
      typeof from.node !== 'string' ||
      typeof from.port !== 'string' ||
      typeof to.node !== 'string' ||
      typeof to.port !== 'string'
    )
      continue;
    if (!nodeIds.has(from.node) || !nodeIds.has(to.node)) continue;
    edgeIds.add(id);
    const edge: GraphEdge = {
      id,
      from: { node: from.node, port: from.port },
      to: { node: to.node, port: to.port },
    };
    if (e.folded === true) edge.folded = true;
    const label = typeof e.label === 'string' ? e.label.trim() : '';
    if (label) edge.label = label;
    graph.edges.push(edge);
  }
  for (const kind of ANNOTATION_KINDS) {
    const list = normalizeAnnotations(g[kind === 'group' ? 'groups' : 'notes'], nodeIds);
    if (list.length > 0) annotationList(graph, kind).push(...list);
  }
  return graph;
}

/**
 * Annotations share the id space with nodes and with each other: a duplicate would make one
 * selection mean two boxes. A size below the minimum is raised rather than dropped – a box nobody
 * can see is worse than one that is a little larger than it was written.
 */
function normalizeAnnotations(raw: unknown, takenIds: Set<string>): GraphAnnotation[] {
  const list: GraphAnnotation[] = [];
  for (const item of Array.isArray(raw) ? raw : []) {
    const a = asRecord(item);
    const id = typeof a.id === 'string' ? a.id : '';
    if (!id || takenIds.has(id)) continue;
    takenIds.add(id);
    const annotation: GraphAnnotation = {
      id,
      x: toNumber(a.x),
      y: toNumber(a.y),
      w: Math.max(toNumber(a.w), MIN_ANNOTATION_SIZE.w),
      h: Math.max(toNumber(a.h), MIN_ANNOTATION_SIZE.h),
      text: typeof a.text === 'string' ? a.text : '',
    };
    if (typeof a.color === 'number' && Number.isFinite(a.color))
      annotation.color = Math.max(0, Math.min(0xffffff, Math.floor(a.color)));
    list.push(annotation);
  }
  return list;
}

/**
 * Layers need a unique id and keep their order; a frame id shares the reference space with asset ids,
 * as a texture frame's does. A cel naming a layer that is gone, or no cel file, falls away. An asset
 * left without a layer or a frame gets an empty one, the way a new asset starts.
 */
function normalizePixelArt(
  raw: Record<string, unknown>,
  takenIds: Set<string>,
): { width: number; height: number; layers: PixelLayer[]; frames: PixelFrame[] } {
  const layers: PixelLayer[] = [];
  const layerIds = new Set<string>();
  for (const item of Array.isArray(raw.layers) ? raw.layers : []) {
    const l = asRecord(item);
    const id = typeof l.id === 'string' ? l.id : '';
    if (!id || layerIds.has(id)) continue;
    layerIds.add(id);
    const opacity = asFinite(l.opacity);
    const layer: PixelLayer = {
      id,
      name: typeof l.name === 'string' ? l.name : '',
      opacity: opacity === null ? 1 : Math.max(0, Math.min(1, opacity)),
    };
    if (l.hidden === true) layer.hidden = true;
    layers.push(layer);
  }
  if (layers.length === 0) {
    const layer = { id: newId(), name: 'Layer 1', opacity: 1 };
    layers.push(layer);
    layerIds.add(layer.id);
  }
  const frames: PixelFrame[] = [];
  for (const item of Array.isArray(raw.frames) ? raw.frames : []) {
    const f = asRecord(item);
    const id = typeof f.id === 'string' ? f.id : '';
    if (!id || takenIds.has(id)) continue;
    takenIds.add(id);
    const cels: Record<string, string> = {};
    for (const [layerId, file] of Object.entries(asRecord(f.cels)))
      if (layerIds.has(layerId) && typeof file === 'string' && isCelFile(file)) cels[layerId] = file;
    frames.push({ id, cels });
  }
  if (frames.length === 0) {
    let id = newId();
    while (takenIds.has(id)) id = newId();
    takenIds.add(id);
    frames.push({ id, cels: {} });
  }
  return { width: canvasSide(raw.width), height: canvasSide(raw.height), layers, frames };
}

/** Colours as 0xRRGGBB, at most `PALETTE_MAX`; anything that is no colour falls away. */
function normalizePalette(raw: unknown): number[] {
  const colors: number[] = [];
  for (const item of Array.isArray(raw) ? raw : []) {
    const color = asFinite(item);
    if (color !== null && colors.length < PALETTE_MAX)
      colors.push(Math.max(0, Math.min(0xffffff, Math.floor(color))));
  }
  return colors;
}

/**
 * A file name that is not the server's content-addressed form is dropped: a request built from it
 * would 404, and the texture then loads as "no picture".
 */
function normalizeTexture(
  raw: Record<string, unknown>,
  takenIds: Set<string>,
): { file: string; width: number; height: number; frames: TextureFrame[] } {
  const file = typeof raw.file === 'string' && isTextureFile(raw.file) ? raw.file : '';
  const size = (value: unknown): number =>
    typeof value === 'number' && Number.isFinite(value) && value > 0 ? Math.floor(value) : 0;
  const width = size(raw.width);
  const height = size(raw.height);
  const frames: TextureFrame[] = [];
  for (const item of Array.isArray(raw.frames) ? raw.frames : []) {
    const f = asRecord(item);
    const id = typeof f.id === 'string' ? f.id : '';
    // Frame ids share the reference space with asset ids, so a duplicate would make one
    // reference mean two pictures.
    if (!id || takenIds.has(id)) continue;
    takenIds.add(id);
    const rect = normalizeFrameRect(
      { x: toNumber(f.x), y: toNumber(f.y), w: toNumber(f.w), h: toNumber(f.h) },
      width,
      height,
    );
    const frame: TextureFrame = { id, name: typeof f.name === 'string' ? f.name : '', ...rect };
    // Against the frame, not the image: the borders are distances inside the cut-out.
    readCut(frame, rect, f);
    // Corners that are no numbers fall away; what is left is kept only as an outline (#141).
    const outlines = collisionOutlines(f.collision).filter((outline) => outline.length >= 3);
    if (outlines.length > 0) setFrameCollision(frame, outlines);
    frames.push(frame);
  }
  return { file, width, height, frames };
}

/**
 * The nine-slice and the sort line of a texture frame or a drawing (#308), measured against `size`.
 * A picture without them is one nobody sliced, and keeps saying so.
 */
function readCut(cut: PictureCut, size: CutSize, raw: Record<string, unknown>): void {
  const border = asRecord(raw.border);
  setCutSlice(cut, size, {
    border: {
      left: toNumber(border.left),
      top: toNumber(border.top),
      right: toNumber(border.right),
      bottom: toNumber(border.bottom),
    },
    fill: raw.fill === 'stretch' ? 'stretch' : DEFAULT_FILL,
  });
  setCutSortLine(cut, size, toNumber(raw.sortLine));
}

/**
 * A frame's stored outlines: a list of corner lists, or – as saved before a frame held several –
 * one corner list, which is one outline.
 */
function collisionOutlines(raw: unknown): Vec2[][] {
  if (!Array.isArray(raw)) return [];
  if (raw.some((item) => !Array.isArray(item))) return [pointsOf(raw as PropertyValue)];
  return raw.map((outline) => pointsOf(outline as PropertyValue));
}

/**
 * The rows of an animation. Keys hold flat values only – a row animates one property – and are
 * sorted onto whole frames; a second row on the same target and property, or with an id already
 * taken, is dropped like a doubled node.
 */
function normalizeTracks(raw: unknown): AnimationTrack[] {
  const tracks: AnimationTrack[] = [];
  for (const item of Array.isArray(raw) ? raw : []) {
    const t = asRecord(item);
    if (typeof t.id !== 'string' || !t.id || typeof t.property !== 'string' || !t.property) continue;
    const target = typeof t.target === 'string' ? t.target : '';
    if (tracks.some((o) => o.id === t.id || (o.target === target && o.property === t.property))) continue;
    const keys: AnimationKey[] = [];
    for (const k of Array.isArray(t.keys) ? t.keys : []) {
      const key = asRecord(k);
      const frame = Number(key.frame);
      if (!Number.isFinite(frame) || !isPrimitive(key.value)) continue;
      const kept: AnimationKey = { frame, value: key.value };
      // `linear` is what no field means, so it is not kept; an unknown one reads as linear, too.
      if (isKeyInterpolation(key.interpolation) && key.interpolation !== 'linear')
        kept.interpolation = key.interpolation;
      keys.push(kept);
    }
    const track: AnimationTrack = { id: t.id, target, property: t.property, keys: normalizeKeys(keys) };
    if (t.relative === true) track.relative = true;
    tracks.push(track);
  }
  return tracks;
}

/**
 * The layers of a tilemap. A cell whose key is not a pair of whole numbers, or which names nothing,
 * is dropped; one naming a deleted tile is kept, like an animation's dangling row, so an undo
 * brings the drawing back. A doubled layer id is dropped as a doubled node is.
 */
function normalizeLayers(raw: unknown): TilemapLayer[] {
  const layers: TilemapLayer[] = [];
  for (const item of Array.isArray(raw) ? raw : []) {
    const l = asRecord(item);
    if (typeof l.id !== 'string' || !l.id || layers.some((o) => o.id === l.id)) continue;
    const stored = decodeCells(l);
    const cells: Record<string, string> = {};
    for (const [key, value] of Object.entries(stored))
      if (parseCellKey(key) && typeof value === 'string' && value !== '') cells[key] = value;
    const layer: TilemapLayer = { id: l.id, name: typeof l.name === 'string' ? l.name : 'Layer', cells };
    if (l.hidden === true) layer.hidden = true;
    if (typeof l.z === 'number' && Number.isFinite(l.z) && l.z !== 0) layer.z = l.z;
    if (l.sortByY === true) layer.sortByY = true;
    layers.push(layer);
  }
  return layers;
}

/**
 * The layers of a vector art asset (#190). A drawing saved before there were layers holds a flat
 * list of `shapes`; they become its one layer. A layer or an item whose id is taken is dropped, as a
 * doubled tilemap layer is, and so is a group with nothing in it – a group is never empty. A
 * drawing left without a layer gets one, since there has to be somewhere to draw.
 */
function normalizeVectorLayers(asset: Record<string, unknown>): VectorLayer[] {
  const taken = new Set<string>();
  const layers: VectorLayer[] = [];
  for (const item of Array.isArray(asset.layers) ? asset.layers : []) {
    const l = asRecord(item);
    if (typeof l.id !== 'string' || !l.id || taken.has(l.id)) continue;
    taken.add(l.id);
    const layer: VectorLayer = {
      id: l.id,
      name: typeof l.name === 'string' && l.name ? l.name : 'Layer',
      items: normalizeVectorItems(l.items, taken),
    };
    if (l.hidden === true) layer.hidden = true;
    layers.push(layer);
  }
  if (layers.length === 0)
    layers.push({ id: newId(), name: 'Layer 1', items: normalizeVectorItems(asset.shapes, taken) });
  return layers;
}

/** Shapes and groups; whatever carries `items` is a group. */
function normalizeVectorItems(raw: unknown, taken: Set<string>): VectorItem[] {
  const items: VectorItem[] = [];
  for (const item of Array.isArray(raw) ? raw : []) {
    const record = asRecord(item);
    if (typeof record.id !== 'string' || !record.id || taken.has(record.id)) continue;
    taken.add(record.id);
    if (!Array.isArray(record.items)) {
      items.push(normalizeShape(record, record.id));
      continue;
    }
    const inner = normalizeVectorItems(record.items, taken);
    if (inner.length > 0)
      items.push({
        id: record.id,
        name: typeof record.name === 'string' ? record.name : 'Group',
        items: inner,
      });
  }
  return items;
}

/**
 * One shape of a vector art asset (#129). A point whose coordinates are no numbers falls away, as
 * a frame's outline corners do, and so does a handle that is not a pair of numbers – the point then
 * reads as a corner, which is what a shape drawn without handles says anyway. A shape left without
 * any drawable ring is kept: it is an outline someone is still drawing, and the rasteriser passes
 * over it.
 */
function normalizeShape(s: Record<string, unknown>, id: string): VectorShape {
  const rings: VectorRing[] = [];
  for (const r of Array.isArray(s.rings) ? s.rings : []) {
    const ring = asRecord(r);
    // Closed is what a shape usually is, and what every ring written by the editor says.
    rings.push({ points: normalizePoints(ring.points), closed: ring.closed !== false });
  }
  const shape: VectorShape = {
    id,
    name: typeof s.name === 'string' ? s.name : 'Shape',
    rings,
    fill: normalizeColor(s.fill, SHAPE_FILL_DEFAULT),
    opacity: normalizeOpacity(s.opacity),
  };
  const paint = normalizePaint(s.paint);
  if (paint) shape.paint = paint;
  const stroke = asRecord(s.stroke);
  const width = asFinite(stroke.width);
  if (width !== null && width > 0) {
    shape.stroke = { color: normalizeColor(stroke.color, 0), width };
    const line = normalizePaint(stroke.paint);
    if (line && line.type !== 'texture') shape.stroke.paint = line;
  }
  return shape;
}

/** The points of a ring or of a curve (#247); the rules are those of `normalizeShape`. */
function normalizePoints(raw: unknown): VectorPoint[] {
  const points: VectorPoint[] = [];
  for (const p of Array.isArray(raw) ? raw : []) {
    const point = asRecord(p);
    const x = asFinite(point.x);
    const y = asFinite(point.y);
    if (x === null || y === null) continue;
    const kept: VectorPoint = { x, y };
    for (const side of ['in', 'out'] as const) {
      const handle = normalizeHandle(point[side]);
      if (handle) kept[side] = handle;
    }
    if (point.mode === 'smooth' || point.mode === 'symmetric') kept.mode = point.mode;
    points.push(kept);
  }
  return points;
}

/**
 * A number as written, or null – unlike `toNumber`, which reads anything unusable as 0. A coordinate
 * of 0 is a place on the canvas, so "broken" and "the left edge" must not come out the same.
 */
function asFinite(value: unknown): number | null {
  return typeof value === 'number' && Number.isFinite(value) ? value : null;
}

/**
 * A gradient or picture fill (#186). One that cannot be drawn as written – no ends, an unknown type,
 * fewer than two stops – is dropped and the shape reads as the solid colour it kept all along. A
 * texture id is kept even when nothing answers to it: the drawing falls back to its colour and
 * shows it, as a sprite shows a texture that has gone.
 */
function normalizePaint(raw: unknown): VectorPaint | null {
  const p = asRecord(raw);
  const from = normalizeHandle(p.from);
  const to = normalizeHandle(p.to);
  if (!from || !to) return null;
  if (p.type === 'texture')
    return typeof p.texture === 'string' ? { type: 'texture', from, to, texture: p.texture } : null;
  if (p.type !== 'linear' && p.type !== 'radial') return null;
  const stops: GradientStop[] = [];
  for (const item of Array.isArray(p.stops) ? p.stops : []) {
    const stop = asRecord(item);
    const offset = asFinite(stop.offset);
    if (offset === null) continue;
    stops.push({
      offset: Math.max(0, Math.min(1, offset)),
      color: normalizeColor(stop.color, 0),
      alpha: normalizeOpacity(stop.alpha),
    });
  }
  const gradient: VectorGradient = { type: p.type, from, to, stops };
  return stops.length >= 2 ? gradient : null;
}

function normalizeHandle(raw: unknown): Vec2 | undefined {
  const handle = asRecord(raw);
  const x = asFinite(handle.x);
  const y = asFinite(handle.y);
  return x !== null && y !== null ? { x, y } : undefined;
}

function normalizeColor(raw: unknown, fallback: number): number {
  const value = asFinite(raw);
  return value === null ? fallback : Math.max(0, Math.min(0xffffff, Math.floor(value)));
}

function normalizeOpacity(raw: unknown): number {
  const value = asFinite(raw);
  return value === null ? 1 : Math.max(0, Math.min(1, value));
}

function normalizeBag(raw: unknown, schema: PropertySchema, sparse: boolean): PropertyBag {
  const r = asRecord(raw);
  const bag: PropertyBag = {};
  for (const def of schema) {
    const value = r[def.key];
    if (value === undefined || value === null) {
      // A key with its own `initial` stays missing: written out, the old reading would count as
      // a deviation from what a new asset starts with, and mark every older asset gold.
      if (!sparse && initialOf(def) === def.default) bag[def.key] = def.default;
      continue;
    }
    bag[def.key] = coerceValue(def, value as PropertyValue);
  }
  return bag;
}

function asRecord(value: unknown): Record<string, unknown> {
  return value && typeof value === 'object' ? (value as Record<string, unknown>) : {};
}

/**
 * A value from an untyped slot (node params, instance edits): lists and structs at any depth, each
 * item as the kind it says it is. Only what is no value at all (`null`, a bad tag) is dropped.
 */
function asStoredValue(value: unknown): PropertyValue | undefined {
  if (isPrimitive(value)) return value;
  if (Array.isArray(value))
    return value.map(asStoredValue).filter((item): item is PropertyValue => item !== undefined);
  if (!value || typeof value !== 'object') return undefined;
  const tag = tagOf(value);
  if (tag !== undefined) return isTaggedKind(tag) ? makeItem(tag, value as PropertyValue) : undefined;
  const fields: Record<string, PropertyValue> = {};
  for (const [key, item] of Object.entries(value)) {
    const stored = asStoredValue(item);
    if (stored !== undefined) fields[key] = stored;
  }
  return fields;
}

const isPrimitive = (value: unknown): value is number | string | boolean =>
  typeof value === 'number' || typeof value === 'string' || typeof value === 'boolean';

function toNumber(value: unknown): number {
  const n = Number(value);
  return Number.isFinite(n) ? n : 0;
}