/**
 * 国际化 Hook
 * 提供语言切换和文本翻译功能
 */

import { ref, watch } from 'vue'
import { useI18n as useVueI18n } from 'vue-i18n'
import { useAppStore } from '../stores'

// 支持的语言列表
export const SUPPORTED_LOCALES = [
  {
    code: 'zh-CN',
    name: '中文',
    nativeName: '中文',
    flag: '🇨🇳'
  },
  {
    code: 'en-US',
    name: 'English',
    nativeName: 'English',
    flag: '🇺🇸'
  }
]

// 检测浏览器语言
function detectBrowserLocale() {
  const browserLang = navigator.language || navigator.languages?.[0]
  
  if (browserLang?.startsWith('zh')) {
    return 'zh-CN'
  } else if (browserLang?.startsWith('en')) {
    return 'en-US'
  }
  
  return 'en-US' // 默认语言
}

// 格式化日期
export function formatDate(date, options = {}) {
  const defaultOptions = {
    year: 'numeric',
    month: 'long',
    day: 'numeric'
  }
  
  const { locale } = useI18n()
  return new Intl.DateTimeFormat(locale.value, { ...defaultOptions, ...options }).format(new Date(date))
}

// 格式化数字
export function formatNumber(number, options = {}) {
  const defaultOptions = {
    minimumFractionDigits: 0,
    maximumFractionDigits: 2
  }
  
  const { locale } = useI18n()
  return new Intl.NumberFormat(locale.value, { ...defaultOptions, ...options }).format(number)
}

// 格式化货币
export function formatCurrency(amount, currency = 'USD') {
  const { locale } = useI18n()
  return new Intl.NumberFormat(locale.value, {
    style: 'currency',
    currency
  }).format(amount)
}

// 格式化相对时间
export function formatRelativeTime(date) {
  const now = new Date()
  const targetDate = new Date(date)
  const diffInSeconds = Math.floor((now - targetDate) / 1000)
  
  const rtf = new Intl.RelativeTimeFormat(useI18n().locale.value, { numeric: 'auto' })
  
  const units = [
    { unit: 'year', seconds: 31536000 },
    { unit: 'month', seconds: 2592000 },
    { unit: 'week', seconds: 604800 },
    { unit: 'day', seconds: 86400 },
    { unit: 'hour', seconds: 3600 },
    { unit: 'minute', seconds: 60 },
    { unit: 'second', seconds: 1 }
  ]
  
  for (const { unit, seconds } of units) {
    const interval = Math.floor(diffInSeconds / seconds)
    if (interval >= 1) {
      return rtf.format(-interval, unit)
    }
  }
  
  return rtf.format(0, 'second')
}

export function useI18nExt() {
  const { locale: i18nLocale, messages, t, d } = useVueI18n()
  const appStore = useAppStore()
  
  // 当前语言
  const currentLocale = ref(i18nLocale.value)
  
  // 设置语言
  const setLocale = (localeCode, saveToStorage = true) => {
    // 验证语言有效性
    const isValidLocale = SUPPORTED_LOCALES.some(lang => lang.code === localeCode)
    if (!isValidLocale) {
      console.warn(`Invalid locale: ${localeCode}, falling back to 'en-US'`)
      localeCode = 'en-US'
    }
    
    // 更新 i18n 语言
    i18nLocale.value = localeCode
    
    // 更新当前语言状态
    currentLocale.value = localeCode
    
    // 只保存到 localStorage，store 由 App.vue 统一管理
    if (saveToStorage) {
      localStorage.setItem('app-locale', localeCode)
    }
    
    // 更新 HTML lang 属性
    document.documentElement.lang = localeCode
    
    // 不直接调用store，避免循环
    
    // 更新日期格式
    document.documentElement.dir = getTextDirection(localeCode)
  }
  
  // 获取文本方向
  const getTextDirection = (localeCode) => {
    // 大多数语言从左到右，少数语言从右到左
    const rtlLocales = ['ar', 'he', 'fa', 'ur']
    return rtlLocales.some(lang => localeCode.startsWith(lang)) ? 'rtl' : 'ltr'
  }
  
  // 获取语言显示名称
  const getLocaleName = (localeCode) => {
    const locale = SUPPORTED_LOCALES.find(lang => lang.code === localeCode)
    return locale ? `${locale.flag} ${locale.nativeName}` : localeCode
  }
  
  // 获取所有支持的语言
  const getSupportedLocales = () => {
    return SUPPORTED_LOCALES
  }
  
  // 检查是否为 RTL 语言
  const isRTL = () => {
    return getTextDirection(currentLocale.value) === 'rtl'
  }
  
  // 切换到下一个语言
  const toggleLocale = () => {
    const currentIndex = SUPPORTED_LOCALES.findIndex(lang => lang.code === currentLocale.value)
    const nextIndex = (currentIndex + 1) % SUPPORTED_LOCALES.length
    const nextLocale = SUPPORTED_LOCALES[nextIndex]
    
    setLocale(nextLocale.code)
  }
  
  // 动态加载语言包
  const loadLocaleMessages = async (localeCode) => {
    try {
      // 这里可以动态加载语言包文件
      // const messages = await import(`../locales/lang/${localeCode}.js`)
      // i18n.global.setLocaleMessage(localeCode, messages.default)
      
      console.log(`Loading messages for locale: ${localeCode}`)
    } catch (error) {
      console.error(`Failed to load messages for locale: ${localeCode}`, error)
    }
  }
  
  // 翻译函数扩展
  const translate = (key, params = {}) => {
    let translation = t(key)
    
    // 处理参数替换
    if (typeof params === 'object' && Object.keys(params).length > 0) {
      Object.keys(params).forEach(param => {
        translation = translation.replace(`{${param}}`, params[param])
      })
    }
    
    return translation
  }
  
  // 复数化处理
  const pluralize = (key, count) => {
    if (count === 0) {
      return t(`${key}.zero`)
    } else if (count === 1) {
      return t(`${key}.one`)
    } else if (count > 1 && count <= 10) {
      return t(`${key}.few`)
    } else {
      return t(`${key}.other`)
    }
  }
  
  // 初始化语言设置
  const initLocale = () => {
    // 从 localStorage 读取保存的语言设置
    const savedLocale = localStorage.getItem('app-locale')
    
    // 从 store 获取语言设置
    const storeLocale = appStore.locale
    
    // 优先级：store > localStorage > 浏览器检测
    const initialLocale = storeLocale || savedLocale || detectBrowserLocale()
    
    // 设置初始语言
    setLocale(initialLocale, false)
    
    // 移除所有监听器，避免循环调用
    // store 和 i18n 独立工作，避免相互干扰
  }
  
  return {
    locale: currentLocale,
    setLocale,
    getLocaleName,
    getSupportedLocales,
    isRTL,
    toggleLocale,
    loadLocaleMessages,
    translate,
    pluralize,
    formatDate,
    formatNumber,
    formatCurrency,
    formatRelativeTime,
    initLocale
  }
}

// 简化的导出供页面组件使用
export function useI18n() {
  const { locale: i18nLocale, t } = useVueI18n()
  const appStore = useAppStore()
  
  // 当前语言
  const currentLocale = ref(i18nLocale.value)
  
  // 设置语言
  const setLocale = (localeCode, saveToStorage = true) => {
    // 验证语言有效性
    const isValidLocale = SUPPORTED_LOCALES.some(lang => lang.code === localeCode)
    if (!isValidLocale) {
      console.warn(`Invalid locale: ${localeCode}, falling back to 'en-US'`)
      localeCode = 'en-US'
    }
    
    // 更新 i18n 语言
    i18nLocale.value = localeCode
    
    // 更新当前语言状态
    currentLocale.value = localeCode
    
    // 只保存到 localStorage，store 由 App.vue 统一管理
    if (saveToStorage) {
      localStorage.setItem('app-locale', localeCode)
    }
    
    // 更新 HTML lang 属性
    document.documentElement.lang = localeCode
  }
  
  return {
    currentLocale,
    locales: SUPPORTED_LOCALES,
    t,
    setLocale
  }
}