(function (root) {
  "use strict";
  const DB_NAME = "voiceofml-reader";
  const STORE_NAME = "entries";
  const BOOKMARK_STORE_NAME = "bookmarks";
  const MAX_ENTRIES = 200;
  const SCHEMA_VERSION = 1;
  const DB_VERSION = 3;
  let databasePromise = null;
  const subscribers = new Set();
  const storeChannel =
    typeof root.BroadcastChannel === "function"
      ? new root.BroadcastChannel("voiceofml-reader-store-v1")
      : null;
  let disposed = false;
  if (storeChannel)
    storeChannel.onmessage = (event) => {
      if (disposed) return;
      for (const listener of subscribers) listener({ ...event.data, remote: true });
    };
  function notify(change) {
    if (disposed) return;
    try {
      storeChannel?.postMessage(change);
    } catch (_) {}
    for (const listener of subscribers) listener({ ...change, remote: false });
  }
  function subscribe(listener) {
    if (typeof listener !== "function")
      throw new TypeError("Reader store subscriber must be a function");
    if (disposed) return () => {};
    subscribers.add(listener);
    return () => subscribers.delete(listener);
  }
  function dispose() {
    if (disposed) return;
    disposed = true;
    subscribers.clear();
    try {
      storeChannel?.close?.();
    } catch (_) {}
  }

  function openDatabase() {
    if (databasePromise) return databasePromise;
    const opening = new Promise((resolve, reject) => {
      const request = indexedDB.open(DB_NAME, DB_VERSION);
      request.onupgradeneeded = () => {
        const database = request.result;
        for (const name of Array.from(database.objectStoreNames)) database.deleteObjectStore(name);
        const store = database.createObjectStore(STORE_NAME, { keyPath: "url" });
        store.createIndex("lastReadAt", "lastReadAt");
        const bookmarks = database.createObjectStore(BOOKMARK_STORE_NAME, { keyPath: "id" });
        bookmarks.createIndex("url", "url");
        bookmarks.createIndex("createdAt", "createdAt");
      };
      request.onsuccess = () => {
        const database = request.result;
        database.onversionchange = () => {
          database.close();
          if (databasePromise === opening) databasePromise = null;
        };
        if (databasePromise !== opening) {
          database.close();
          return;
        }
        resolve(database);
      };
      request.onblocked = () => {
        if (databasePromise === opening) databasePromise = null;
        reject(new Error("Reader database upgrade was blocked by another tab"));
      };
      request.onerror = () => {
        if (databasePromise === opening) databasePromise = null;
        reject(request.error);
      };
    });
    databasePromise = opening;
    return databasePromise;
  }

  async function transaction(mode, callback) {
    const database = await openDatabase();
    return new Promise((resolve, reject) => {
      const tx = database.transaction(STORE_NAME, mode);
      const result = callback(tx.objectStore(STORE_NAME));
      tx.oncomplete = () => resolve(result);
      tx.onerror = () => reject(tx.error);
      tx.onabort = () => reject(tx.error);
    });
  }

  function normalizeHistoryEntry(entry) {
    if (!entry || typeof entry.url !== "string" || !entry.url)
      return null;
    return {
      ...entry,
      schemaVersion: SCHEMA_VERSION,
      title: String(entry.title || ""),
      extension: String(entry.extension || ""),
      lastReadAt: Number.isFinite(Number(entry.lastReadAt)) ? Number(entry.lastReadAt) : Date.now()
    };
  }
  function normalizeBookmarkEntry(entry) {
    if (
      !entry ||
      typeof entry.id !== "string" ||
      !entry.id ||
      typeof entry.url !== "string" ||
      !entry.url
    )
      return null;
    return {
      ...entry,
      schemaVersion: SCHEMA_VERSION,
      label: String(entry.label || "未命名书签"),
      createdAt: Number.isFinite(Number(entry.createdAt)) ? Number(entry.createdAt) : Date.now()
    };
  }
  async function get(url) {
    const database = await openDatabase();
    return new Promise((resolve, reject) => {
      const tx = database.transaction(STORE_NAME, "readwrite"),
        store = tx.objectStore(STORE_NAME);
      const request = store.get(url);
      request.onsuccess = () => {
        const raw = request.result || null,
          entry = raw?.schemaVersion === SCHEMA_VERSION ? normalizeHistoryEntry(raw) : null;
        if (raw && !entry) {
          store.delete(url);
          resolve(null);
        } else {
          resolve(entry);
        }
      };
      request.onerror = () => reject(request.error);
    });
  }

  async function put(entry) {
    entry = normalizeHistoryEntry(entry);
    if (!entry) throw new TypeError("Invalid reader history entry");
    const database = await openDatabase();
    await new Promise((resolve, reject) => {
      const tx = database.transaction(STORE_NAME, "readwrite");
      const store = tx.objectStore(STORE_NAME);
      const existing = store.get(entry.url);
      existing.onsuccess = () => {
        if (existing.result) {
          if (Number(existing.result.lastReadAt) > Number(entry.lastReadAt)) return;
          store.put(entry);
          return;
        }
        const count = store.count();
        count.onsuccess = () => {
          if (count.result < MAX_ENTRIES) {
            store.put(entry);
            return;
          }
          const oldest = store.index("lastReadAt").openCursor();
          oldest.onsuccess = () => {
            if (oldest.result) oldest.result.delete();
            store.put(entry);
          };
        };
      };
      tx.oncomplete = () => {
        notify({ type: "history", url: entry.url, lastReadAt: entry.lastReadAt });
        resolve();
      };
      tx.onerror = () => reject(tx.error);
      tx.onabort = () => reject(tx.error);
    });
  }

  async function listEntries(
    storeName,
    indexName,
    normalize,
    { query = null, direction = "next", limit = Infinity } = {}
  ) {
    const database = await openDatabase();
    return new Promise((resolve, reject) => {
      const entries = [];
      const tx = database.transaction(storeName, "readwrite"),
        store = tx.objectStore(storeName);
      const request = store.index(indexName).openCursor(query, direction);
      request.onsuccess = () => {
        const cursor = request.result;
        if (!cursor || entries.length >= limit) return resolve(entries);
        const entry = cursor.value.schemaVersion === SCHEMA_VERSION ? normalize(cursor.value) : null;
        if (entry) {
          entries.push(entry);
        } else cursor.delete();
        cursor.continue();
      };
      request.onerror = () => reject(request.error);
    });
  }

  function list(limit = MAX_ENTRIES) {
    return listEntries(STORE_NAME, "lastReadAt", normalizeHistoryEntry, {
      direction: "prev",
      limit
    });
  }

  async function remove(url) {
    await transaction("readwrite", (store) => store.delete(url));
    notify({ type: "history-remove", url });
  }
  async function clearHistory() {
    await transaction("readwrite", (store) => store.clear());
    notify({ type: "history-clear" });
  }
  async function putBookmark(entry) {
    entry = normalizeBookmarkEntry(entry);
    if (!entry) throw new TypeError("Invalid reader bookmark entry");
    const database = await openDatabase();
    await new Promise((resolve, reject) => {
      const tx = database.transaction(BOOKMARK_STORE_NAME, "readwrite");
      tx.objectStore(BOOKMARK_STORE_NAME).put(entry);
      tx.oncomplete = () => {
        notify({ type: "bookmark", url: entry.url, id: entry.id });
        resolve();
      };
      tx.onerror = () => reject(tx.error);
      tx.onabort = () => reject(tx.error);
    });
  }
  async function listBookmarks(url) {
    const entries = await listEntries(BOOKMARK_STORE_NAME, "url", normalizeBookmarkEntry, {
      query: IDBKeyRange.only(url)
    });
    return entries.sort((a, b) => b.createdAt - a.createdAt);
  }
  function listAllBookmarks() {
    return listEntries(BOOKMARK_STORE_NAME, "createdAt", normalizeBookmarkEntry, {
      direction: "prev"
    });
  }
  async function removeBookmark(id) {
    const database = await openDatabase();
    await new Promise((resolve, reject) => {
      const tx = database.transaction(BOOKMARK_STORE_NAME, "readwrite");
      tx.objectStore(BOOKMARK_STORE_NAME).delete(id);
      tx.oncomplete = () => {
        notify({ type: "bookmark-remove", id });
        resolve();
      };
      tx.onerror = () => reject(tx.error);
      tx.onabort = () => reject(tx.error);
    });
  }
  root.VoiceOfMLReaderStore = Object.freeze({
    DB_NAME,
    DB_VERSION,
    MAX_ENTRIES,
    SCHEMA_VERSION,
    get,
    put,
    list,
    remove,
    clearHistory,
    putBookmark,
    listBookmarks,
    listAllBookmarks,
    removeBookmark,
    subscribe,
    dispose
  });
})(typeof self !== "undefined" ? self : window);