/**
 * 离线迁移脚本：把 dev Local Storage leveldb 里所有
 *   http://localhost:5173\x00\x01 前缀的 key
 * 替换成
 *   app://netcatty\x00\x01
 *
 * 运行时机：绿色便携版打包完、给用户之前执行一次。
 * 之后 Electron 启动时直接就能读正确 origin 的数据。
 *
 * 用法：node scripts/migratePortableLocalStorage.cjs <portableUserDataPath>
 *   例：node scripts/migratePortableLocalStorage.cjs release-green\win-unpacked\data
 *
 * 需要：level 包（npm i --no-save level）
 */

const fs = require("node:fs");
const path = require("node:path");
const { Level } = require("level");

const DEV_ORIGIN = "http://localhost:5173";
const PKG_ORIGIN = "app://netcatty";
const KEY_SEP = Buffer.from([0x00, 0x01]);
// Chromium Local Storage leveldb key 格式：
//   _<origin>\x00\x01<actualKey>
// 注意：origin 前有个下划线前缀！
const DEV_ORIGIN_FULL = "_" + DEV_ORIGIN;
const PKG_ORIGIN_FULL = "_" + PKG_ORIGIN;

function findSep(keyBuf, from) {
  for (let i = from; i < keyBuf.length - 1; i++) {
    if (keyBuf[i] === 0x00 && keyBuf[i + 1] === 0x01) return i;
  }
  return -1;
}

async function main() {
  const dataDir = process.argv[2];
  if (!dataDir) { console.error("usage: node migratePortableLocalStorage.cjs <portableUserDataPath>"); process.exit(2); }
  const lsDir = path.join(path.resolve(dataDir), "Local Storage", "leveldb");
  if (!fs.existsSync(lsDir)) { console.error("leveldb dir not found:", lsDir); process.exit(2); }

  // 先看看 origin 统计
  const db = new Level(lsDir, { keyEncoding: "buffer", valueEncoding: "buffer", createIfMissing: false });
  const counts = new Map(); // origin -> count
  const ops = [];
  let scanned = 0, migrated = 0;

  for await (const [keyBuf, valBuf] of db.iterator()) {
    scanned++;
    const sepIdx = findSep(keyBuf, 0);
    if (sepIdx < 0) continue;
    const origin = keyBuf.subarray(0, sepIdx).toString("utf-8");
    counts.set(origin, (counts.get(origin) || 0) + 1);

    if (origin === DEV_ORIGIN_FULL) {
      // 新 key：_app://netcatty + \x00\x01 + actualKey
      const newKey = Buffer.concat([Buffer.from(PKG_ORIGIN_FULL, "utf-8"), KEY_SEP, keyBuf.subarray(sepIdx + 2)]);
      ops.push({ type: "put", key: newKey, value: valBuf });
      ops.push({ type: "del", key: keyBuf });
      migrated++;
    }
  }
  await db.close();

  console.log(`扫描 ${scanned} 个 key，origin 分布：`);
  for (const [o, c] of counts) console.log(`  ${o || "(无 origin)"} → ${c}`);

  if (migrated === 0) {
    console.log("\n没有 http://localhost:5173 前缀的 key 需要迁移。跳过。");
    return;
  }

  // 备份当前 leveldb
  const bak = lsDir + ".bak_" + new Date().toISOString().replace(/[:.]/g, "-");
  fs.cpSync(lsDir, bak, { recursive: true });
  console.log(`\n已备份 leveldb → ${bak}`);

  // 执行迁移
  const db2 = new Level(lsDir, { keyEncoding: "buffer", valueEncoding: "buffer", createIfMissing: false });
  await db2.batch(ops);
  await db2.close();
  console.log(`迁移完成：${migrated} 个 key 从 ${DEV_ORIGIN} → ${PKG_ORIGIN}`);

  // 验证
  const db3 = new Level(lsDir, { keyEncoding: "buffer", valueEncoding: "buffer", createIfMissing: false });
  const after = new Map();
  for await (const [k] of db3.iterator()) {
    const sep = findSep(k, 0);
    if (sep >= 0) {
      const o = k.subarray(0, sep).toString("utf-8");
      after.set(o, (after.get(o) || 0) + 1);
    }
  }
  await db3.close();
  console.log("\n迁移后 origin 分布：");
  for (const [o, c] of after) console.log(`  ${o || "(无)"} → ${c}`);
}

main().catch(e => { console.error("FATAL:", e.message); process.exit(1); });