/**
 * IndexedDB 封装 —— 持久化 FileSystemDirectoryHandle
 *
 * chrome.storage 存不了 FileSystemDirectoryHandle（它不是 JSON 可序列化类型），
 * 必须用 IndexedDB（structured clone 支持）。存一次后跨会话免重复授权。
 */

const DB_NAME = 'ozon-seller-kit';
const STORE = 'handles';
const ROOT_KEY = 'SH_ROOT_DIR';

function openDb(): Promise<IDBDatabase> {
  return new Promise((resolve, reject) => {
    const req = indexedDB.open(DB_NAME, 1);
    req.onupgradeneeded = () => {
      if (!req.result.objectStoreNames.contains(STORE)) {
        req.result.createObjectStore(STORE);
      }
    };
    req.onsuccess = () => resolve(req.result);
    req.onerror = () => reject(req.error);
  });
}

export async function idbSet(key: string, value: unknown): Promise<void> {
  const db = await openDb();
  return new Promise((resolve, reject) => {
    const tx = db.transaction(STORE, 'readwrite');
    tx.objectStore(STORE).put(value, key);
    tx.oncomplete = () => {
      db.close();
      resolve();
    };
    tx.onerror = () => {
      db.close();
      reject(tx.error);
    };
  });
}

export async function idbGet<T>(key: string): Promise<T | null> {
  const db = await openDb();
  return new Promise((resolve, reject) => {
    const tx = db.transaction(STORE, 'readonly');
    const req = tx.objectStore(STORE).get(key);
    req.onsuccess = () => {
      db.close();
      resolve((req.result as T) ?? null);
    };
    req.onerror = () => {
      db.close();
      reject(req.error);
    };
  });
}

export async function saveRootDir(handle: FileSystemDirectoryHandle): Promise<void> {
  await idbSet(ROOT_KEY, handle);
}

export async function loadRootDir(): Promise<FileSystemDirectoryHandle | null> {
  return idbGet<FileSystemDirectoryHandle>(ROOT_KEY);
}