import React, { useState, useEffect } from 'react'
import { View, Text, Image, ScrollView, Swiper, SwiperItem, RichText } from '@tarojs/components'
import { Tag } from '@nutui/nutui-react-taro'
import Taro, { useRouter, useShareAppMessage } from '@tarojs/taro'
import { getShopGoods } from '@/api/shop/shopGoods'
import {
  addShopGoodsFavorite,
  removeShopGoodsFavorite,
  getShopGoodsFavoriteStatus
} from '@/api/shop/shopGoodsFavorite'
import type { ShopGoods, ShopGoodsSku } from '@/api/shop/shopGoods/model'
import Price from '@/components/common/Price'
import SkuSelector from '@/components/business/SkuSelector'
import { useCartContext } from '@/contexts/CartContext'
import { useUserContext } from '@/contexts/UserContext'
import { useScrollHeight } from '@/hooks/useScrollHeight'
import { isGuest } from '@/utils/auth'
import { requireLogin } from '@/utils/login-guard'
import { isVipMember } from '@/utils/vip'

definePageConfig({
  navigationBarTitleText: '商品详情',
})

const ProductDetailPage: React.FC = () => {
  const router = useRouter()
  const id = Number(router.params.id || router.params.goodsId)
  const [product, setProduct] = useState<ShopGoods | null>(null)
  const [swiperHeight, setSwiperHeight] = useState(375)
  const [skuVisible, setSkuVisible] = useState(false)
  const [skuMode, setSkuMode] = useState<'cart' | 'buy'>('cart')
  const [isFavorite, setIsFavorite] = useState(false)
  const { addItem } = useCartContext()
  const { isLoggedIn } = useUserContext()
  // 底部操作栏高度约 90px（含按钮 + 安全区），动态计算 ScrollView 可用高度
  const scrollHeight = useScrollHeight(44)

  // 微信分享配置
  useShareAppMessage(() => {
    return {
      title: product?.name || product?.goodsName || '优质商品推荐',
      path: `/pages/shop/product-detail?id=${id}`,
      imageUrl: product?.image || ''
    }
  })

  useEffect(() => {
    if (id) {
      loadProduct()
      if (isLoggedIn) {
        checkFavoriteStatus()
      }
    }
  }, [id, isLoggedIn])

  // 监听 product 变化后再添加到历史记录
  useEffect(() => {
    if (product) {
      addToHistory()
    }
  }, [product])

  const loadProduct = async () => {
    try {
      const data = await getShopGoods(id)
      setProduct(data)
    } catch { /* ignore */ }
  }

  // VIP 会员显示 dealerPrice，普通用户显示 price
  const getDisplayPrice = (): string => {
    if (isVipMember() && product?.dealerPrice) {
      return product.dealerPrice
    }
    return product?.price || '0'
  }

  const checkFavoriteStatus = async () => {
    try {
      const status = await getShopGoodsFavoriteStatus({ goodsId: id })
      setIsFavorite(status)
    } catch { /* ignore */ }
  }

  const toggleFavorite = async () => {
    if (!requireLogin({ action: 'favorite', redirect: `/pages/shop/product-detail?id=${id}` })) return
    try {
      if (isFavorite) {
        await removeShopGoodsFavorite({ goodsId: id })
        setIsFavorite(false)
        Taro.showToast({ title: '已取消收藏', icon: 'success' })
      } else {
        await addShopGoodsFavorite({ goodsId: id })
        setIsFavorite(true)
        Taro.showToast({ title: '收藏成功', icon: 'success' })
      }
    } catch (e: any) {
      Taro.showToast({ title: e?.message || '操作失败', icon: 'none' })
    }
  }

  const addToHistory = () => {
    try {
      const history = Taro.getStorageSync('browse_history') || []
      const newItem = {
        goodsId: id,
        name: product?.name || product?.goodsName,
        image: product?.image,
        price: product?.price,
        timestamp: Date.now()
      }
      // 去重 + LRU 淘汰（最多50条，单条约200B，总计 < 10MB 安全范围）
      const MAX_HISTORY = 50
      const filtered = history.filter((item: { goodsId: number }) => item.goodsId !== id)
      filtered.unshift(newItem)
      const limited = filtered.slice(0, MAX_HISTORY)

      // 安全写入（捕获存储溢出）
      try {
        Taro.setStorageSync('browse_history', limited)
      } catch (storageErr) {
        // 存储空间不足时，缩减到一半再试
        const reduced = limited.slice(0, Math.floor(MAX_HISTORY / 2))
        Taro.setStorageSync('browse_history', reduced)
      }
    } catch { /* ignore */ }
  }

  const handleAddCart = () => {
    if (!requireLogin({ action: 'addToCart', redirect: `/pages/shop/product-detail?id=${id}` })) return
    setSkuMode('cart')
    setSkuVisible(true)
  }

  const handleBuyNow = () => {
    if (!requireLogin({ action: 'buyNow', redirect: `/pages/shop/product-detail?id=${id}` })) return
    setSkuMode('buy')
    setSkuVisible(true)
  }

  const handleSkuConfirm = async (sku: ShopGoodsSku | null, quantity: number) => {
    if (!product) {
      Taro.showToast({ title: '商品信息异常', icon: 'none' })
      return
    }

    if (skuMode === 'cart') {
      try {
        await addItem(product, sku, quantity)
      } catch (err) {
        console.error('[ProductDetail] 加入购物车失败:', err)
      }
    } else {
      // VIP 会员使用 dealerPrice 作为结算价
      const vipPrice = isVipMember() && product.dealerPrice ? product.dealerPrice : undefined
      const buyNowData = [{
        goodsId: product.goodsId!,
        skuId: sku?.id || 0,
        quantity: quantity,
        num: quantity,
        product: product,
        sku: sku,
        skuPrice: vipPrice,
        checked: true,
      }]

      Taro.setStorageSync('buy_now', JSON.stringify(buyNowData))
      Taro.navigateTo({ url: '/pages/shop/checkout?from=buyNow' })
    }
  }

  const handleGoCart = () => {
    Taro.navigateTo({ url: '/pages/shop/cart' })
  }

  const handleContactService = () => {
    Taro.navigateTo({ url: '/pages/user/customer-service/index' })
  }

  if (!product) {
    return (
      <View className='min-h-screen bg-white flex items-center justify-center'>
        <Text className='text-gray-400 text-sm'>加载中...</Text>
      </View>
    )
  }

  let images: string[] = []
  try {
    if (product.files) {
      const parsed = JSON.parse(product.files)
      if (Array.isArray(parsed)) {
        images = parsed.map((f: any) => f.url || f).filter(Boolean)
      }
    }
  } catch { /* ignore */ }
  if (images.length === 0 && product.image) {
    images = [product.image]
  }

  // 解析服务保障标签
  const ensureTags = product.ensureTag ? product.ensureTag.split(/[，,、]/).filter(Boolean) : []

  // 配送方式文案
  const deliveryText = product.deliveryMode === 1 ? '限自提' : '送上门'

  /**
   * 将商品详情内容中的 Markdown 图片语法转换为 RichText 可识别的 HTML
   * 支持格式：![alt](url) 和 ![alt](url?params)
   */
  const parseContent = (content: string): string => {
    if (!content) return ''
    let html = content
    // 将 ![...](url) 转换为 <img src="url" style="max-width:100%"/>
    html = html.replace(
      /!\[([^\]]*)\]\(([^)]+)\)/g,
      '<img src="$2" mode="widthFix" style="max-width:100%;display:block;" />'
    )
    // 兜底：如果内容里直接包含 http(s) 图片链接（非 img 标签包裹的），也尝试转成图片
    if (html.includes('http') && !html.includes('<img')) {
      html = html.replace(
        /(https?:\/\/[^\s\)]+\.(jpg|jpeg|png|gif|webp)(\?[^\s\)]*)?)/gi,
        '<img src="$1" mode="widthFix" style="max-width:100%;display:block;" />'
      )
    }
    return html
  }

  return (
    <View className='flex flex-col bg-gray-50' style={{ height: '100vh' }}>
      <ScrollView scrollY style={{ height: scrollHeight }}>

        {/* 图片轮播 */}
          <Swiper
              className='w-full'
              style={{ height: `${swiperHeight}px` }}
              indicatorDots
              indicatorColor='#e5e7eb'
              indicatorActiveColor='#0e932e'
              autoplay
              circular
          >
              {images.map((img, idx) => (
                  <SwiperItem key={idx}>
                      <Image
                          className='w-full'
                          style={{ display: 'block' }}
                          src={img}
                          mode='widthFix'
                          onLoad={(e: any) => {
                              // 根据第一张图片的实际宽高比动态设置 Swiper 高度
                              if (idx === 0) {
                                  const { width, height } = e.detail
                                  if (width > 0) {
                                      const screenWidth = Taro.getSystemInfoSync().windowWidth
                                      setSwiperHeight(Math.round((height / width) * screenWidth))
                                  }
                              }
                          }}
                          onClick={() => Taro.previewImage({ current: img, urls: images })}
                      />
                  </SwiperItem>
              ))}
              {images.length === 0 && (
                  <SwiperItem>
                      <View className='w-full h-full bg-gray-100 flex items-center justify-center'>
                          <Text className='text-gray-300 text-sm'>暂无图片</Text>
                      </View>
                  </SwiperItem>
              )}
          </Swiper>

        {/* 价格区域 */}
        <View className='bg-white p-4'>
          <View className='flex items-baseline gap-2'>
            <Price price={getDisplayPrice()} size='large' color='#ee0a24' loginMask />
              <Tag>到手价</Tag>
            {/* VIP 会员价 */}
            {!isGuest() && isVipMember() && Number(product.dealerPrice) > 0 ? (
              <View className='ml-auto inline-flex items-center gap-1 bg-amber-50 rounded px-2 py-1'>
                <Text className='text-xs text-amber-600 font-medium'>VIP专享</Text>
                <Text className='text-sm text-amber-700 font-bold'>¥{product.dealerPrice}</Text>
              </View>
            ) : (
              !isGuest() && Number(product.salePrice) > 0 && product.salePrice !== product.price && (
                <Text className='text-xs text-gray-400 ml-2 line-through'>¥{product.salePrice}</Text>
              )
            )}
          </View>
          {/* 会员价 */}
          {!isGuest() && !isVipMember() && Number(product.memberStorePrice) > 0 && product.memberStorePrice !== product.price && (
            <View className='mt-2 inline-block bg-orange-50 rounded px-2 py-1'>
              <Text className='text-xs text-orange-500'>会员价: ¥{product.memberStorePrice}</Text>
            </View>
          )}
          {/* 赚取积分 */}
          {product.gainIntegral && Number(product.gainIntegral) > 0 && (
            <View className='mt-1'>
              <Text className='text-xs text-orange-500'>购买可得 {product.gainIntegral} 积分</Text>
            </View>
          )}
          <View className='flex gap-2 mt-2'>
            <Text className='text-xs text-gray-400'>销量: {product.sales || 0}</Text>
            <Text className='text-xs text-gray-400'>库存: {product.stock || 0}</Text>
            {product.unitName && (
              <Text className='text-xs text-gray-400'>单位: {product.unitName}</Text>
            )}
          </View>
        </View>

        {/* 商品名称 */}
        <View className='bg-white px-4 pb-3'>
          <Text className='text-base font-medium text-gray-800 block leading-6'>
            {product.name || product.goodsName}
          </Text>
        </View>

        {/* 分类面包屑 */}
        {(product.categoryParent || product.categoryName) && (
          <View className='bg-white px-4 pb-3'>
            <Text className='text-xs text-gray-400'>
              {product.categoryParent ? `${product.categoryParent}` : ''}
              {product.categoryParent && product.categoryName ? ' > ' : ''}
              {product.categoryName ? `${product.categoryName}` : ''}
            </Text>
          </View>
        )}

        {/* SKU 已选提示（多规格商品） */}
        {product.specs === 1 && (
          <View
            className='bg-white mt-2 px-4 py-3 flex items-center justify-between'
            onClick={() => {
              setSkuMode('cart')
              setSkuVisible(true)
            }}
          >
            <View className='flex items-center'>
              <Text className='text-xs text-gray-500 mr-2'>已选</Text>
              <Text className='text-sm text-gray-700'>{product.specName || '请选择规格'}</Text>
            </View>
            <Text className='text-gray-300 text-sm'>&#10095;</Text>
          </View>
        )}

        {/* 配送信息 */}
        <View className='bg-white mt-2 px-4 py-3 flex items-center justify-between'>
          <View className='flex items-center'>
            <Text className='text-xs text-gray-500 mr-2'>配送</Text>
            <Text className='text-sm text-gray-700'>{deliveryText}</Text>
            {product.goodsWeight && Number(product.goodsWeight) > 0 && (
              <Text className='text-xs text-gray-400 ml-2'>重量: {product.goodsWeight}kg</Text>
            )}
          </View>
          <Text className='text-gray-300 text-sm'>&#10095;</Text>
        </View>

        {/* 服务保障 */}
        {ensureTags.length > 0 && (
          <View className='bg-white mt-2 px-4 py-3'>
            <View className='flex items-center'>
              <Text className='text-xs text-gray-500 mr-2'>服务</Text>
              <View className='flex flex-wrap gap-2'>
                {ensureTags.map((tag, idx) => (
                  <View key={idx} className='flex items-center'>
                    <Text className='text-xs text-gray-600'>{tag}</Text>
                    {idx < ensureTags.length - 1 && (
                      <Text className='text-xs text-gray-300 ml-2'>|</Text>
                    )}
                  </View>
                ))}
              </View>
            </View>
          </View>
        )}

        {/* 商品详情 */}
        <View className='bg-white mt-2 p-4'>
          <Text className='text-base font-medium text-gray-800 mb-3 block'>商品详情</Text>
          <View className='text-sm text-gray-600 leading-6'>
            {product.content ? (
              <RichText nodes={parseContent(product.content)} />
            ) : (
              <Text className='text-gray-400'>暂无详情</Text>
            )}
          </View>
        </View>

        {/* 底部留白（与固定栏同高 + 安全区，确保内容不被遮挡） */}
        <View style={{ height: '100px' }} />
      </ScrollView>

      {/* 底部操作栏 - 固定吸底 */}
      <View
        className='bg-white border-t border-gray-100 flex items-center'
        style={{
          position: 'fixed',
          left: 0,
          right: 0,
          bottom: 0,
          paddingBottom: 'env(safe-area-inset-bottom)',
          zIndex: 100,
        }}
      >
        {/* 图标入口 */}
        <View className='flex items-center px-2 py-2' style={{ minWidth: '120px' }}>
          <View className='flex-1 flex flex-col items-center' onClick={handleGoCart}>
            <Text className='text-lg'>🛒</Text>
            <Text className='text-xs text-gray-500 mt-1 whitespace-nowrap'>购物车</Text>
          </View>
          <View className='flex-1 flex flex-col items-center' onClick={handleContactService}>
            <Text className='text-lg'>💬</Text>
            <Text className='text-xs text-gray-500 mt-1'>客服</Text>
          </View>
          <View className='flex-1 flex flex-col items-center' onClick={toggleFavorite}>
            <Text className='text-lg'>{isFavorite ? '❤️' : '🤍'}</Text>
            <Text className='text-xs text-gray-500 mt-1'>收藏</Text>
          </View>
        </View>
        {/* 操作按钮 */}
        <View className='flex-1 flex gap-2 pr-3 py-2'>
          <View
            className='flex-1 py-2 rounded-full text-center'
            style={{ backgroundColor: '#ff9800' }}
            onClick={handleAddCart}
          >
            <Text className='text-white text-sm font-medium'>加入购物车</Text>
          </View>
          <View
            className='flex-1 py-2 rounded-full text-center'
            style={{ backgroundColor: '#ee0a24' }}
            onClick={handleBuyNow}
          >
            <Text className='text-white text-sm font-medium'>立即购买</Text>
          </View>
        </View>
      </View>

      {/* SKU 选择器 */}
      <SkuSelector
        visible={skuVisible}
        product={product}
        mode={skuMode}
        onClose={() => setSkuVisible(false)}
        onConfirm={handleSkuConfirm}
      />
    </View>
  )
}

export default ProductDetailPage
