import Dexie, { type Table } from "dexie";
import type {
  AISession,
  Board,
  Book,
  Chapter,
  DocumentRef,
  Entity,
  NewProject,
  PlotBeat,
  Project,
  ProjectMeta,
} from "./types.js";
import type { StorageAdapter } from "./storage.js";
import { createUlid } from "./ids.js";
import { nowIso } from "./time.js";
import { fuzzySort } from "./fuzzy.js";

interface EntityRec {
  key: string;
  projectId: string;
  kind: string;
  data: Entity;
}

class PubScriptDB extends Dexie {
  projects!: Table<Project, string>;
  books!: Table<Book, string>;
  chapters!: Table<Chapter, string>;
  entities!: Table<EntityRec, string>;
  boards!: Table<Board, string>;
  plotBeats!: Table<PlotBeat, string>;
  aiSessions!: Table<AISession, string>;

  constructor() {
    super("pubscript");
    this.version(1).stores({
      projects: "id, projectId",
      books: "id, projectId",
      chapters: "id, bookId, projectId",
      entities: "key, projectId, kind",
      boards: "id, projectId",
      // Plot beats — atomic units of story structure (CHUNK #5).
      plotBeats: "id, [projectId+act], projectId, chapterId",
      aiSessions: "id, projectId",
    });
  }
}

const db = new PubScriptDB();

const entityKey = (projectId: string, kind: string, id: string): string =>
  `${projectId}|${kind}|${id}`;
const kindOf = (e: Entity): string =>
  "fields" in e ? "world" : "body" in e ? "note" : "character";

/**
 * Concatenate every human-readable field of an entity into a single searchable
 * string (name + field values). Used by the fuzzy search index.
 */
function entitySearchText(e: Entity): string {
  if ("fields" in e) {
    // WorldItem
    const parts = [e.name, e.kind];
    for (const v of Object.values(e.fields)) if (typeof v === "string") parts.push(v);
    return parts.join(" ");
  }
  if ("body" in e) {
    // Note
    return [e.body, ...e.tags].join(" ");
  }
  // Character
  return [
    e.name,
    e.role,
    e.bio,
    e.appearance,
    e.voice,
    e.relationships,
    e.arc,
    e.status,
    ...e.tags,
  ].join(" ");
}

/**
 * The local (offline-first) `StorageAdapter`, backed by IndexedDB via Dexie.
 * Implements the exact `StorageAdapter` contract so the app can run fully
 * offline and sync later. `onEvent` is a no-op offline (no remote peers).
 */
export const storageLocal: StorageAdapter = {
  async listProjects(): Promise<ProjectMeta[]> {
    const rows = await db.projects.toArray();
    return rows.map(
      ({ id, projectId, title, ownerId, sharedWith, settings, cover, createdAt, updatedAt }) => ({
        id, projectId, title, ownerId, sharedWith, settings, cover, createdAt, updatedAt,
        perm: "edit" as const, owned: true,
      }),
    );
  },

  async createProject(p: NewProject): Promise<Project> {
    const id = createUlid();
    const t = nowIso();
    const project: Project = {
      id,
      projectId: id,
      title: p.title,
      ownerId: "local",
      sharedWith: [],
      settings: { language: p.language ?? "en" },
      cover: { color: p.cover?.color ?? "#8b5cf6", ...(p.cover?.image ? { image: p.cover.image } : {}) },
      createdAt: t,
      updatedAt: t,
    };
    await db.projects.put(project);
    return project;
  },

  async getProject(id: string): Promise<Project> {
    const p = await db.projects.get(id);
    if (!p) throw new Error(`project ${id} not found`);
    return p;
  },

  async deleteProject(id: string): Promise<void> {
    await db.projects.delete(id);
    await db.books.where("projectId").equals(id).delete();
    await db.chapters.where("projectId").equals(id).delete();
    await db.entities.where("projectId").equals(id).delete();
    await db.boards.where("projectId").equals(id).delete();
    await db.plotBeats.where("projectId").equals(id).delete();
    await db.aiSessions.where("projectId").equals(id).delete();
  },

  async createBook(b: { projectId: string; title: string }): Promise<Book> {
    const id = createUlid();
    const book: Book = { id, projectId: b.projectId, title: b.title, order: 0, chapters: [] };
    await db.books.put(book);
    return book;
  },

  async listBooks(projectId: string): Promise<Book[]> {
    const rows = await db.books.where("projectId").equals(projectId).toArray();
    return rows.sort((a, b) => a.order - b.order);
  },

  async listChapters(bookId: string): Promise<Chapter[]> {
    const rows = await db.chapters.where("bookId").equals(bookId).toArray();
    return rows.sort((a, b) => a.order - b.order);
  },

  async deleteChapter(id: string): Promise<void> {
    await db.chapters.delete(id);
  },

  async saveDocument(doc: DocumentRef): Promise<void> {
    const existing = await db.chapters.get(doc.id);
    const existingCount =
      !existing && doc.bookId
        ? await db.chapters.where("bookId").equals(doc.bookId).count()
        : 0;
    const base: Chapter = existing ?? {
      id: doc.id,
      bookId: doc.bookId ?? "",
      projectId: doc.projectId,
      title: doc.title,
      doc: doc.doc,
      rev: 0,
      order: existingCount,
      meta: { wordCount: 0, scenes: [], updatedAt: nowIso() },
    };
    await db.chapters.put({
      ...base,
      title: doc.title,
      doc: doc.doc,
      rev: doc.rev + 1,
      meta: { ...base.meta, updatedAt: nowIso() },
    });
  },

  async getChapter(id: string): Promise<Chapter | null> {
    return (await db.chapters.get(id)) ?? null;
  },

  async saveEntity(e: Entity): Promise<void> {
    const kind = kindOf(e);
    await db.entities.put({ key: entityKey(e.projectId, kind, e.id), projectId: e.projectId, kind, data: e });
  },

  async listEntities(projectId: string, kind?: string): Promise<Entity[]> {
    const rows = await db.entities
      .where("projectId")
      .equals(projectId)
      .toArray();
    const filtered = kind ? rows.filter((r) => r.kind === kind) : rows;
    return filtered.map((r) => r.data);
  },

  async getEntity(projectId: string, kind: string, id: string): Promise<Entity | null> {
    const row = await db.entities.get(entityKey(projectId, kind, id));
    return row ? row.data : null;
  },

  async deleteEntity(projectId: string, kind: string, id: string): Promise<void> {
    await db.entities.delete(entityKey(projectId, kind, id));
  },

  async searchEntities(projectId: string, q: string): Promise<Entity[]> {
    const all = await this.listEntities(projectId);
    if (!q) return all;
    return fuzzySort(all, q, entitySearchText);
  },

  async saveBoard(b: Board): Promise<void> {
    await db.boards.put(b);
  },

  async getBoard(projectId: string): Promise<Board | null> {
    const rows = await db.boards
      .where("projectId")
      .equals(projectId)
      .toArray();
    return rows[0] ?? null;
  },

  async listPlotBeats(projectId: string): Promise<PlotBeat[]> {
    const rows = await db.plotBeats
      .where("projectId")
      .equals(projectId)
      .toArray();
    // Stable order: by act, then order within act.
    return rows.sort((a, b) => a.act - b.act || a.order - b.order);
  },

  async savePlotBeat(b: PlotBeat): Promise<void> {
    await db.plotBeats.put(b);
  },

  async deletePlotBeat(projectId: string, id: string): Promise<void> {
    const existing = await db.plotBeats.get(id);
    if (!existing || existing.projectId !== projectId) {
      throw new Error(`No plot beat ${id} in project ${projectId}.`);
    }
    await db.plotBeats.delete(id);
  },

  async saveAISession(s: AISession): Promise<void> {
    await db.aiSessions.put(s);
  },

  onEvent(): () => void {
    // Offline: no remote live events to relay.
    return () => {};
  },
};

export type StorageLocal = typeof storageLocal;