import path from "path";
import { fileURLToPath } from "url";

import Logs from "../libs/logs.js";
import Cache from "../libs/cache.js";

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const LOCALES_FILE = path.join(__dirname, '../data/locales.json');

const LOCALES_DATA = {};

const isPlainObject = (obj) => {
  if (Object.prototype.toString.call(obj) !== '[object Object]') return false;

  const proto = Object.getPrototypeOf(obj);
  return proto === Object.prototype || proto === null;
}

const initLocales = () => {
  Cache.getData(LOCALES_FILE).then(data => {
    Logs.out('load locales data', data);
    Object.assign(LOCALES_DATA, data);
  }).catch(error => {
    Logs.out('not load locales data', error.message);
  });
}

const saveLocales = () => {
  Cache.setData(LOCALES_FILE, LOCALES_DATA).catch(error => {
    Logs.out('save cache failed', error);
  });
}

export const get = async (keys) => {
  return new Promise((resolve, reject) => {
    if (typeof(keys) === 'undefined') {
      resolve(LOCALES_DATA);
    }
    else if (typeof(keys) === 'string') {
      resolve(LOCALES_DATA[keys] ?? null);
    }
    else if (Array.isArray(keys) && keys.every(key => typeof(key) === 'string')) {
      const result = {};
      keys.forEach(key => {
        result[key] = LOCALES_DATA[key] ?? null;
      });
      resolve(result);
    }
    else {
      reject(new Error('invalid keys'));
    }
  });
}

export const set = async (key, value) => {
  return new Promise((resolve, reject) => {
    if (typeof(key) === 'string' && typeof(value) !== 'undefined') {
      LOCALES_DATA[key] = value;
      saveLocales();
      resolve();
    }
    else if (isPlainObject(key)
    && Object.keys(key).every(k => typeof(k) === 'string')
    && Object.values(key).every(v => typeof(v) === 'string')) {
      Object.assign(LOCALES_DATA, key);
      saveLocales();
      resolve();
    }
    else {
      reject(new Error('invalid key or value'));
    }
  });
}

export const remove = async (keys) => {
  return new Promise((resolve, reject) => {
    if (typeof(keys) === 'string') {
      delete LOCALES_DATA[keys];
      saveLocales();
      resolve();
    }
    else if (Array.isArray(keys) && keys.every(key => typeof(key) === 'string')) {
      keys.forEach(key => {
        delete LOCALES_DATA[key];
      });
      saveLocales();
      resolve();
    }
    else {
      reject(new Error('invalid keys'));
    }
  });
}

// 进程结束时保存数据
process.on('exit', saveLocales);
process.on('SIGINT', () => {
  process.exit(0);
});
process.on('SIGTERM', () => {
  process.exit(0);
});
process.on('SIGUSR2', () => {
  process.exit(0);
});

// 初始化缓存
initLocales();

export default { get, set, remove };