// codex_data_dir.js —— 会话相关功能使用的 Codex 数据目录，可由用户覆盖默认 ~/.codex。
const { app } = require("electron");
const fs = require("fs");
const os = require("os");
const path = require("path");

const DEFAULT_DIR = path.join(os.homedir(), ".codex");
let loaded = false;
let configuredDir = null;

function configFile() {
  return path.join(app.getPath("userData"), "codex-data-dir.json");
}

function normalize(dir) {
  if (typeof dir !== "string" || !dir.trim() || !path.isAbsolute(dir.trim())) return null;
  return path.resolve(dir.trim());
}

function load() {
  if (loaded) return;
  loaded = true;
  try {
    configuredDir = normalize(JSON.parse(fs.readFileSync(configFile(), "utf-8")).path);
  } catch {}
}

function get() {
  load();
  return configuredDir || DEFAULT_DIR;
}

function isCodexDataDir(dir) {
  try {
    const names = fs.readdirSync(dir);
    return names.includes("sessions") || names.includes("archived_sessions") || names.includes("config.toml") ||
      names.includes("auth.json") || names.some((name) => /^state_.*\.sqlite(?:-(?:wal|shm))?$/.test(name));
  } catch {
    return false;
  }
}

function isDirectory(dir) {
  try {
    return fs.statSync(dir).isDirectory();
  } catch {
    return false;
  }
}

function writeAtomic(file, text) {
  fs.mkdirSync(path.dirname(file), { recursive: true });
  const tmp = file + ".tmp-" + process.pid + "-" + Date.now();
  const fd = fs.openSync(tmp, "w", 0o600);
  try {
    fs.writeFileSync(fd, text, "utf-8");
    fs.fsyncSync(fd);
  } finally {
    fs.closeSync(fd);
  }
  try {
    fs.renameSync(tmp, file);
  } finally {
    try { fs.rmSync(tmp, { force: true }); } catch {}
  }
}

function set(dir) {
  const next = normalize(dir);
  if (!next || !isDirectory(next)) {
    throw new Error("请选择存在的 Codex 数据目录");
  }
  if (!isCodexDataDir(next)) {
    throw new Error("所选目录未找到 Codex 数据（sessions、config.toml 或 state_*.sqlite）");
  }
  configuredDir = next === DEFAULT_DIR ? null : next;
  loaded = true;
  writeAtomic(configFile(), JSON.stringify({ path: configuredDir || "", updatedAt: new Date().toISOString() }, null, 2));
  return info();
}

function reset() {
  configuredDir = null;
  loaded = true;
  writeAtomic(configFile(), JSON.stringify({ path: "", updatedAt: new Date().toISOString() }, null, 2));
  return info();
}

function info() {
  const dir = get();
  return { path: dir, isDefault: dir === DEFAULT_DIR, exists: isDirectory(dir) };
}

module.exports = { get, set, reset, info, isCodexDataDir };