<script setup>
import {ref, computed, watch} from 'vue';
import pinyin from 'pinyin';
import countryCode from './data/index.js';
import { useI18n } from 'vue-i18n'
import { useRouter } from 'vue-router'
definePageMeta({
  title: '国家地区',
  i18n: 'countryRegion.title',
})
const router = useRouter()
const { t, locale } = useI18n()
const value = ref('');
const alphabet = [
  '#',
  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
  'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
];

// 常用国家的代码列表
const frequentCountryCodes = ['CN', 'TW', 'JP', 'US'];

function groupByPinyinInitial(data) {
  const grouped = {};
  
  // 先处理常用国家
  grouped['#'] = [];
  data.forEach(country => {
    if (frequentCountryCodes.includes(country.code)) {
      const countryName = locale.value === 'zh-CN' ? country.cn : 
                         locale.value === 'zh-TW' ? country.tw : 
                         locale.value === 'ja-JP' ? country.ja :
                         country.en;
      grouped['#'].push({
        ...country,
        displayName: countryName
      });
    }
  });

  // 处理其他国家
  data.forEach(country => {
    if (!frequentCountryCodes.includes(country.code)) {
      const countryName = locale.value === 'zh-CN' ? country.cn : 
                         locale.value === 'zh-TW' ? country.tw : 
                         locale.value === 'ja-JP' ? country.ja :
                         country.en;
                         
      const initial = locale.value === 'ja-JP' ? '' : 
                     locale.value === 'zh-CN' || locale.value === 'zh-TW' ? 
                     pinyin(countryName, {style: pinyin.STYLE_FIRST_LETTER})[0][0].toUpperCase() :
                     countryName.charAt(0).toUpperCase();
                     
      if (!grouped[initial]) {
        grouped[initial] = [];
      }
      grouped[initial].push({
        ...country,
        displayName: countryName
      });
    }
  });

  if (locale.value === 'ja-JP') {
    // 日文环境下按照片假名排序
    grouped[''] = grouped[''].sort((a, b) => a.displayName.localeCompare(b.displayName, 'ja-JP'));
  }

  return grouped;
}

const groupedCountries = ref([])
const initData = () => {
  groupedCountries.value = groupByPinyinInitial(countryCode);
}

const searchCountry = computed(() => {
  if (!value.value) {
    return groupedCountries.value;
  }
  return Object.keys(groupedCountries.value).reduce((filtered, initial) => {
    const countries = groupedCountries.value[initial].filter(country =>
        country.displayName.toLowerCase().includes(value.value.toLowerCase())
    );
    if (countries.length > 0) {
      filtered[initial] = countries;
    }
    return filtered;
  }, {});
});

const showIndexBar = computed(() => locale.value !== 'ja-JP')

const handleCountrySelect = (country) => {
  router.push({
    path: '/login',
    query: {
      zone: country.zone,
      countryName: country.displayName
    }
  })
}

initData()

// 监听语言变化，重新初始化数据
watch(locale, () => {
  initData()
})
</script>

<template>
  <div>
    <van-sticky>
      <van-search v-model="value" :placeholder="t('countryRegion.searchPlaceholder')"/>
    </van-sticky>
    <van-index-bar 
      v-if="showIndexBar"
      sticky 
      :sticky-offset-top="55"  
      :index-list="alphabet"
    >
      <!-- 常用国家分类 -->
      <van-index-anchor index="#">{{ t('countryRegion.frequentCountry') }}</van-index-anchor>
      <van-cell 
        v-for="country in searchCountry['#']" 
        :key="country.code" 
        :title="country.displayName"
        @click="handleCountrySelect(country)"
        clickable
      >
        <div class="pr-[25px]"> +{{ country.zone }}</div>
      </van-cell>

      <!-- 其他国家按字母分类 -->
      <template v-for="(countries, index) in searchCountry" :key="index">
        <template v-if="index !== '#'">
          <van-index-anchor
              :index="index"
          ></van-index-anchor>
          <van-cell 
            v-for="country in countries" 
            :key="country.code" 
            :title="country.displayName"
            @click="handleCountrySelect(country)"
            clickable
          >
            <div class="pr-[25px]"> +{{ country.zone }}</div>
          </van-cell>
        </template>
      </template>
    </van-index-bar>

    <div v-else>
      <div class="mb-4">
        <div class="px-4 py-2 text-gray-600">{{ t('countryRegion.frequentCountry') }}</div>
        <van-cell 
          v-for="country in searchCountry['#']" 
          :key="country.code" 
          :title="country.displayName"
          @click="handleCountrySelect(country)"
          clickable
        >
          <div class="pr-[25px]"> +{{ country.zone }}</div>
        </van-cell>
      </div>

      <van-cell 
        v-for="country in Object.values(searchCountry).flat().filter(c => !frequentCountryCodes.includes(c.code))" 
        :key="country.code" 
        :title="country.displayName"
        @click="handleCountrySelect(country)"
        clickable
      >
        <div class="pr-[25px]"> +{{ country.zone }}</div>
      </van-cell>
    </div>

    <van-back-top v-if="showIndexBar" right="15vw" bottom="10vh"/>
  </div>
</template>

<style scoped>

</style>