'use strict';

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

// 获取当前语言设置
const getCurrentLanguage = () => {
  try {
    // 1. 优先从用户数据目录的缓存文件读取（由前端设置）
    const userDataPath = getElectronUserDataPath();
    const langCachePath = path.join(userDataPath, 'language.json');

    if (fs.existsSync(langCachePath)) {
      const data = JSON.parse(fs.readFileSync(langCachePath, 'utf-8'));
      if (data.language && ['zh', 'en', 'zh-CN'].includes(data.language)) {
        return data.language;
      }
    }

    // 2. 尝试从配置文件读取
    const configPath = path.join(__dirname, 'config.default.js');
    if (fs.existsSync(configPath)) {
      const config = require(configPath);
      return config.language || 'zh';
    }
  } catch (e) {
    console.log('Failed to read language config:', e.message);
  }
  return 'zh';
};

// 获取 Electron 用户数据目录
const getElectronUserDataPath = () => {
  try {
    const { app } = require('electron');
    return app.getPath('userData');
  } catch (e) {
    // 在非 Electron 环境（如测试）下返回默认路径
    return path.join(__dirname, '..', '..');
  }
};

// 加载翻译文件
const loadTranslations = () => {
  const language = getCurrentLanguage();

  // 标准化语言代码：en -> en, zh-CN/zh -> zh
  let i18nFile = 'en';
  if (language.startsWith('zh')) {
    i18nFile = 'zh';
  }

  const i18nPath = path.join(__dirname, 'i18n', `${i18nFile}.json`);

  try {
    if (fs.existsSync(i18nPath)) {
      return JSON.parse(fs.readFileSync(i18nPath, 'utf-8'));
    }
  } catch (e) {
    console.log('Failed to load i18n file:', e.message);
  }

  // 默认加载中文
  const defaultPath = path.join(__dirname, 'i18n', 'zh.json');
  try {
    return JSON.parse(fs.readFileSync(defaultPath, 'utf-8'));
  } catch (e) {
    console.error('Failed to load default i18n file:', e.message);
    return {};
  }
};

// 缓存翻译数据
let translations = null;

// 获取翻译
const t = (key, params = {}) => {
  if (!translations) {
    translations = loadTranslations();
  }

  // 支持嵌套 key 如 "camera.cameraNotConnected"
  const keys = key.split('.');
  let value = translations;

  for (const k of keys) {
    if (value && typeof value === 'object' && k in value) {
      value = value[k];
    } else {
      return key; // 未找到翻译，返回原始 key
    }
  }

  // 如果找到翻译，用参数替换占位符
  if (typeof value === 'string' && Object.keys(params).length > 0) {
    return value.replace(/\{(\w+)\}/g, (match, paramKey) => {
      return params[paramKey] !== undefined ? params[paramKey] : match;
    });
  }

  return value;
};

// 重新加载翻译（当语言改变时调用）
const reloadTranslations = () => {
  translations = loadTranslations();
  console.log('i18n translations reloaded');
};

module.exports = {
  t,
  getCurrentLanguage,
  loadTranslations,
  reloadTranslations,
};