// Importing the graph package index is what registers the built-in nodes.
import {
  createEmptyGraph,
  DECLARED_PORT_KINDS,
  type DeclaredPort,
  type DeclaredPortKind,
  type Graph,
  type GraphEdge,
  type GraphNode,
  isValidPortName,
  nodeDef,
} from '../graph';
import type { Asset, TextureFrame } from '../model/Asset';
import { isAssetType } from '../model/AssetTypes';
import { emptyEdit, type InstanceEdit, isEmptyEdit } from '../model/instance';
import type { FieldValue, PropertyBag, PropertyValue } from '../model/Properties';
import { PROJECT_FORMAT_VERSION, type Project } from '../model/Project';
import type { SceneObject } from '../model/SceneObject';
import { isTextureFile, normalizeFrameRect } from '../model/texture';
import { hasParentCycle } from '../model/walk';
import {
  coerceValue,
  COMMON_PROPS,
  isCommonProp,
  LIST_ITEM_KINDS,
  type ListItemKind,
  type PropertyDef,
  type PropertySchema,
  schemaFor,
  type StructFieldDef,
  VARIABLE_KINDS,
  variableDef,
  type VariableKind,
} from '../properties/PropertySchema';

/**
 * 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[]>();
  for (const a of rawAssets) {
    if (typeof a.id !== 'string' || !a.id || !isAssetType(a.type)) continue;
    if (a.type === 'behavior') {
      const vars = normalizeVariables(a.variables);
      variables.set(a.id, vars);
      schemas.set(a.id, [...COMMON_PROPS, ...vars]);
    } else {
      schemas.set(a.id, schemaFor(a.type));
    }
  }

  // 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 = schemas.get(id);
    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') {
      assets.push({ id, type, name, props, objects: normalizeObjects(a.objects, schemas) });
    } else if (type === 'behavior') {
      assets.push({
        id,
        type,
        name,
        props,
        variables: variables.get(id) ?? [],
        graph: normalizeGraph(a.graph),
      });
    } else if (type === 'texture') {
      assets.push({ id, type, name, props, ...normalizeTexture(a, takenIds) });
    } 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 : '';
  }

  return {
    formatVersion: PROJECT_FORMAT_VERSION,
    id: typeof r.id === 'string' && r.id ? r.id : fallbackId,
    name: typeof r.name === 'string' ? r.name : 'Untitled',
    assets,
    activeSceneId,
  };
}

/** Plain JSON-ready copy of the project (deep clone, stable key order for readable diffs). */
export function serializeProject(project: Project): unknown {
  return JSON.parse(JSON.stringify(project));
}

function normalizeObjects(raw: unknown, schemas: Map<string, PropertySchema>): 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 = schemas.get(o.assetId);
    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),
      // `ownerId` is the pre-hierarchy name of the same link.
      parentId: typeof o.parentId === 'string' ? o.parentId : typeof o.ownerId === 'string' ? o.ownerId : '',
      instanceEdits: normalizeInstanceEdits(o.instanceEdits),
    });
  }
  // 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;
}

/**
 * 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 (!/^[A-Za-z_][A-Za-z0-9_]*$/.test(key) || seen.has(key) || isCommonProp(key)) continue;
    seen.add(key);
    const items = (LIST_ITEM_KINDS as readonly string[]).includes(String(v.items))
      ? (v.items as ListItemKind)
      : undefined;
    const def = variableDef(key, kind, undefined, items, normalizeStructFields(v.fields));
    def.default = coerceValue(def, (v.default ?? def.default) as PropertyValue);
    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 (!/^[A-Za-z_][A-Za-z0-9_]*$/.test(key) || seen.has(key)) continue;
    if (!(LIST_ITEM_KINDS as readonly string[]).includes(String(f.kind))) continue;
    seen.add(key);
    fields.push({ key, kind: f.kind as ListItemKind });
  }
  return fields;
}

function normalizePorts(raw: unknown): DeclaredPort[] {
  const ports: DeclaredPort[] = [];
  const seen = new Set<string>();
  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({ key, kind });
  }
  return ports;
}

function normalizeGraph(raw: unknown): 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 : '';
    if (!id || nodeIds.has(id) || !nodeDef(type)) 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);
    if (ports.length > 0) node.ports = ports;
    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;
    graph.edges.push(edge);
  }
  return graph;
}

/**
 * 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,
    );
    frames.push({ id, name: typeof f.name === 'string' ? f.name : '', ...rect });
  }
  return { file, width, height, frames };
}

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) {
      if (!sparse) 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 are kept but
 * flattened one level, so nothing deeper than the model allows can enter behind the type's back.
 */
function asStoredValue(value: unknown): PropertyValue | undefined {
  const field = asFieldValue(value);
  if (field !== undefined) return field;
  if (!value || typeof value !== 'object') return undefined;
  const fields: Record<string, FieldValue> = {};
  for (const [key, item] of Object.entries(value)) {
    const stored = asFieldValue(item);
    if (stored !== undefined) fields[key] = stored;
  }
  return fields;
}

function asFieldValue(value: unknown): FieldValue | undefined {
  if (typeof value === 'number' || typeof value === 'string' || typeof value === 'boolean') return value;
  if (Array.isArray(value))
    return value.filter(
      (item): item is number | string | boolean =>
        typeof item === 'number' || typeof item === 'string' || typeof item === 'boolean',
    );
  return undefined;
}

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