const fs = require('fs');
const path = require('path');

const ROOT_DIR = path.join(__dirname, '..');
const APP_CONFIG_FILE = path.join(ROOT_DIR, 'config.json');
const DEFAULT_APP_CONFIG = {
  api: {
    music: 'https://api.chksz.top/api/163_music',
    lyric: 'https://api.chksz.top/api/163_lyric',
    search: 'https://api.chksz.top/api/163_search',
    playlist: 'https://api.chksz.top/api/163_playlist',
    neteaseBaseUrl: 'https://music.163.com',
  },
  paths: {
    downloadDir: 'downloads',
    historyFile: 'download_history.json',
    runtimeConfigFile: 'downloader_config.json',
    trashDir: '.trash',
    tempZipDir: '.tmp_zip',
  },
  defaults: {
    quality: 'jymaster',
    retries: 3,
    historyLimit: 500,
  },
};

function loadAppConfig() {
  try {
    if (!fs.existsSync(APP_CONFIG_FILE)) return DEFAULT_APP_CONFIG;
    const config = JSON.parse(fs.readFileSync(APP_CONFIG_FILE, 'utf-8'));
    return {
      api: { ...DEFAULT_APP_CONFIG.api, ...(config.api || {}) },
      paths: { ...DEFAULT_APP_CONFIG.paths, ...(config.paths || {}) },
      defaults: { ...DEFAULT_APP_CONFIG.defaults, ...(config.defaults || {}) },
    };
  } catch (e) {
    console.warn(`⚠️  配置文件读取失败，将使用默认配置: ${e.message}`);
    return DEFAULT_APP_CONFIG;
  }
}

function resolveConfigPath(configPath, fallback) {
  const value = typeof configPath === 'string' && configPath.trim() ? configPath.trim() : fallback;
  return path.isAbsolute(value) ? value : path.join(ROOT_DIR, value);
}

function getConfigString(value, fallback) {
  return typeof value === 'string' && value.trim() ? value.trim() : fallback;
}

const APP_CONFIG = loadAppConfig();
const API = {
  music: getConfigString(APP_CONFIG.api.music, DEFAULT_APP_CONFIG.api.music),
  lyric: getConfigString(APP_CONFIG.api.lyric, DEFAULT_APP_CONFIG.api.lyric),
  search: getConfigString(APP_CONFIG.api.search, DEFAULT_APP_CONFIG.api.search),
  playlist: getConfigString(APP_CONFIG.api.playlist, DEFAULT_APP_CONFIG.api.playlist),
  neteaseBaseUrl: getConfigString(APP_CONFIG.api.neteaseBaseUrl, DEFAULT_APP_CONFIG.api.neteaseBaseUrl),
};
const NETEASE_BASE_URL = API.neteaseBaseUrl.replace(/\/$/, '');
const DOWNLOAD_DIR = resolveConfigPath(APP_CONFIG.paths.downloadDir, DEFAULT_APP_CONFIG.paths.downloadDir);
const HISTORY_FILE = resolveConfigPath(APP_CONFIG.paths.historyFile, DEFAULT_APP_CONFIG.paths.historyFile);
const CONFIG_FILE = resolveConfigPath(APP_CONFIG.paths.runtimeConfigFile, DEFAULT_APP_CONFIG.paths.runtimeConfigFile);
const TRASH_DIR = resolveConfigPath(APP_CONFIG.paths.trashDir, DEFAULT_APP_CONFIG.paths.trashDir);
const TEMP_ZIP_DIR = resolveConfigPath(APP_CONFIG.paths.tempZipDir, DEFAULT_APP_CONFIG.paths.tempZipDir);
const QUALITY_LEVELS = ['standard', 'exhigh', 'lossless', 'hires', 'jymaster', 'sky', 'jyeffect'];
const QUALITY_LABELS = {
  standard: '标准',
  exhigh: '极高',
  lossless: '无损',
  hires: 'Hi-Res',
  jymaster: '超清母带',
  sky: '空间音频',
  jyeffect: '高清臻品',
};
const DEFAULT_LEVEL = QUALITY_LEVELS.includes(APP_CONFIG.defaults.quality)
  ? APP_CONFIG.defaults.quality
  : DEFAULT_APP_CONFIG.defaults.quality;
const DEFAULT_RETRIES = Number.isInteger(APP_CONFIG.defaults.retries) && APP_CONFIG.defaults.retries > 0
  ? APP_CONFIG.defaults.retries
  : DEFAULT_APP_CONFIG.defaults.retries;
const HISTORY_LIMIT = Number.isInteger(APP_CONFIG.defaults.historyLimit) && APP_CONFIG.defaults.historyLimit > 0
  ? APP_CONFIG.defaults.historyLimit
  : DEFAULT_APP_CONFIG.defaults.historyLimit;

function loadRuntimeConfig() {
  try {
    if (fs.existsSync(CONFIG_FILE)) return JSON.parse(fs.readFileSync(CONFIG_FILE, 'utf-8'));
  } catch {}
  return {};
}

function saveRuntimeConfig(config) {
  fs.mkdirSync(path.dirname(CONFIG_FILE), { recursive: true });
  fs.writeFileSync(CONFIG_FILE, JSON.stringify(config, null, 2), 'utf-8');
}

function getConfig(key, defaultVal) {
  const config = loadRuntimeConfig();
  return config[key] !== undefined ? config[key] : defaultVal;
}

function setConfig(key, val) {
  const config = loadRuntimeConfig();
  config[key] = val;
  saveRuntimeConfig(config);
}

if (!fs.existsSync(DOWNLOAD_DIR)) fs.mkdirSync(DOWNLOAD_DIR, { recursive: true });

module.exports = {
  API,
  NETEASE_BASE_URL,
  DOWNLOAD_DIR,
  HISTORY_FILE,
  CONFIG_FILE,
  TRASH_DIR,
  TEMP_ZIP_DIR,
  QUALITY_LEVELS,
  QUALITY_LABELS,
  DEFAULT_LEVEL,
  DEFAULT_RETRIES,
  HISTORY_LIMIT,
  getConfig,
  setConfig,
};