import React, { useState, useEffect, useMemo } from 'react'
import { View, Text, Image, ScrollView } from '@tarojs/components'
import Taro from '@tarojs/taro'
import type { ShopGoods, ShopGoodsSku } from '@/api/shop/shopGoods/model'
import type { ShopGoodsSpec } from '@/api/shop/shopGoodsSpec/model'
import Price from '@/components/common/Price'

interface SkuSelectorProps {
  visible: boolean
  product: ShopGoods | null
  mode?: 'cart' | 'buy'
  onClose: () => void
  onConfirm: (sku: ShopGoodsSku, quantity: number) => void
}

// 将平铺的规格值列表转换为按规格ID分组的格式
interface SpecGroup {
  specId: number
  specName: string
  values: Array<{ specValueId: number; specValue: string }>
}

// 解析可能为JSON字符串的规格值
const parseSpecValue = (value: string | undefined): string => {
  if (!value) return ''
  const trimmed = value.trim()
  // 处理带引号的JSON字符串，如 "红色" -> 红色
  if (trimmed.startsWith('"') && trimmed.endsWith('"') && trimmed.length >= 2) {
    try {
      return JSON.parse(trimmed)
    } catch {
      return trimmed.slice(1, -1)
    }
  }
  return trimmed
}

const SkuSelector: React.FC<SkuSelectorProps> = ({
  visible,
  product,
  mode = 'cart',
  onClose,
  onConfirm,
}) => {
  const [selectedSpecs, setSelectedSpecs] = useState<Record<number, number>>({})
  const [selectedSku, setSelectedSku] = useState<ShopGoodsSku | null>(null)
  const [quantity, setQuantity] = useState(1)
  const [showOverlay, setShowOverlay] = useState(false)
  const [slideUp, setSlideUp] = useState(false)

  // 控制动画
  useEffect(() => {
    if (visible) {
      setShowOverlay(true)
      // 延迟一帧触发滑入动画
      setTimeout(() => setSlideUp(true), 10)
    } else {
      setSlideUp(false)
      setTimeout(() => setShowOverlay(false), 300)
    }
  }, [visible])

  // 将平铺的goodsSpecs转换为按规格分组的格式
  const specGroups = useMemo<SpecGroup[]>(() => {
    if (!product?.goodsSpecs?.length) return []
    
    const groupMap = new Map<number, SpecGroup>()
    
    product.goodsSpecs.forEach((spec: ShopGoodsSpec, idx: number) => {
      if (!groupMap.has(spec.specId!)) {
        groupMap.set(spec.specId!, {
          specId: spec.specId!,
          specName: spec.specName || `规格${groupMap.size + 1}`,
          values: []
        })
      }
      groupMap.get(spec.specId!)!.values.push({
        specValueId: spec.id || idx, // 优先使用规格值ID，否则用索引
        specValue: parseSpecValue(spec.specValue)
      })
    })
    
    return Array.from(groupMap.values())
  }, [product?.goodsSpecs])

  // 当弹窗重新打开时，重置状态
  useEffect(() => {
    if (visible) {
      setSelectedSpecs({})
      setSelectedSku(null)
      setQuantity(1)
    }
  }, [visible])

  // 根据已选规格查找匹配的 SKU
  useEffect(() => {
    if (!product?.goodsSkus?.length) {
      // 单规格商品，使用商品本身的价格
      setSelectedSku(null)
      return
    }

    const specValues = Object.values(selectedSpecs)
    const specCount = specGroups.length

    if (specValues.length < specCount) {
      setSelectedSku(null)
      return
    }

    // 根据选中的 specValueId 找到对应的中文值，拼接后排序匹配
    const selectedValues: string[] = []
    specGroups.forEach(group => {
      const valueId = selectedSpecs[group.specId]
      if (valueId !== undefined) {
        const value = group.values.find(v => v.specValueId === valueId)
        if (value) selectedValues.push(value.specValue)
      }
    })
    const selectedStr = selectedValues.sort().join('|')

    const matched = product.goodsSkus.find(sku => {
      const skuValue = sku.sku || ''
      const skuParts = skuValue.split('|').map(s => parseSpecValue(s.trim()))
      const skuStr = skuParts.sort().join('|')
      return skuStr === selectedStr
    })

    setSelectedSku(matched || null)
  }, [selectedSpecs, product, specGroups])

  const handleSpecClick = (specId: number, valueId: number) => {
    setSelectedSpecs(prev => {
      const next = { ...prev }
      if (next[specId] === valueId) {
        delete next[specId]
      } else {
        next[specId] = valueId
      }
      return next
    })
    setQuantity(1)
  }

  const handleClose = () => {
    setSlideUp(false)
    setTimeout(() => {
      setShowOverlay(false)
      onClose()
    }, 300)
  }

  const handleConfirm = () => {
    try {
      // 单规格商品（无SKU列表 或 SKU列表为空数组）
      if ((!product?.goodsSkus || product.goodsSkus.length === 0) && product) {
        const fakeSku: ShopGoodsSku = {
          id: 0,
          goodsId: product.goodsId!,
          price: product.price || product.salePrice,
          salePrice: product.salePrice || product.price,
          stock: product.stock,
          image: product.image,
        }
        handleClose()
        onConfirm(fakeSku, quantity)
        return
      }

      // 多规格商品 - 必须已选择 SKU
      if (selectedSku) {
        handleClose()
        onConfirm(selectedSku, quantity)
        return
      }

      // 有规格但未选择完整
      if (specGroups.length > 0) {
        Taro.showToast({ title: '请选择完整的规格', icon: 'none' })
        return
      }

      // 其他情况
      Taro.showToast({ title: '无法添加商品', icon: 'none' })
    } catch (err) {
      Taro.showToast({ title: '操作失败', icon: 'none' })
    }
  }

  // 价格优先级：SKU售价 > SKU原价 > 商品售价 > 商品原价 > 0
  // 注意：ShopGoods 模型中 price=商品价格(低), salePrice=销售/市场价(高)
  //       ShopGoodsSku 模型中 price=商品价格, salePrice=市场价格(高)
  // 统一以 price 为准，salePrice 仅作兜底展示
  const currentPrice = selectedSku?.price || selectedSku?.salePrice || product?.price || product?.salePrice || '0'
  const currentStock = selectedSku?.stock ?? product?.stock ?? 0
  const currentImage = selectedSku?.image || product?.image || (product?.files?.split(',')[0]) || ''

  // 单规格商品可以确认，或者多规格商品已选择了 SKU
  const canConfirm = (!product?.goodsSkus || product.goodsSkus.length === 0) || selectedSku !== null

  // 获取未选择完整的规格提示
  const getUnselectedSpec = () => {
    if (specGroups.length === 0) return null
    const unselected = specGroups.find(
      spec => !selectedSpecs[spec.specId]
    )
    return unselected?.specName
  }

  // 获取选中的规格文字描述
  const getSelectedText = () => {
    const selected: string[] = []
    specGroups.forEach(group => {
      const valueId = selectedSpecs[group.specId]
      if (valueId !== undefined) {
        const value = group.values.find(v => v.specValueId === valueId)
        if (value) selected.push(value.specValue)
      }
    })
    return selected.length > 0 ? selected.join(', ') : '默认'
  }

  // 如果不需要显示，直接返回null
  if (!showOverlay) return null

  return (
    <View className='sku-selector-overlay'>
      {/* 遮罩层 */}
      <View
        className={`absolute inset-0 bg-black/50 ${slideUp ? 'opacity-100' : 'opacity-0'}`}
        style={{ zIndex: 110 }}
        onClick={handleClose}
      />

      {/* 弹窗内容 */}
      <View
        className={`absolute bottom-0 left-0 right-0 bg-white rounded-t-2xl ${slideUp ? '' : 'hidden'}`}
        style={{ maxHeight: '70vh', zIndex: 110, paddingBottom: 'env(safe-area-inset-bottom)' }}
      >
        <View className='p-4'>
          {/* 关闭按钮 */}
          <View className='flex justify-end mb-2'>
            <View 
              className='w-6 h-6 rounded-full bg-gray-100 flex items-center justify-center'
              onClick={handleClose}
            >
              <Text className='text-gray-400 text-sm'>×</Text>
            </View>
          </View>

          {/* 商品信息 */}
          <View className='flex gap-3 pb-4 border-b border-gray-100'>
            <Image className='w-20 h-20 rounded-md bg-gray-100' src={currentImage} mode='aspectFill' />
            <View className='flex-1'>
              <Price price={currentPrice} size='large' />
              <Text className='text-xs text-gray-500 block' style={{ marginTop: '4px' }}>库存: {currentStock}</Text>
              <Text className='text-xs text-gray-400 block' style={{ marginTop: '2px' }}>
                已选: {getSelectedText()}
              </Text>
            </View>
          </View>

          {/* 规格选择 */}
          <ScrollView scrollY style={{ maxHeight: '40vh' }}>
            {specGroups.map((group) => (
              <View key={group.specId} className='py-3 border-b border-gray-50'>
                <Text className='text-sm font-medium text-gray-700 block' style={{ marginBottom: '8px' }}>
                  {group.specName}
                </Text>
                <View className='flex flex-wrap' style={{ gap: '8px' }}>
                  {group.values.map((value) => {
                    const isActive = selectedSpecs[group.specId] === value.specValueId
                    return (
                      <View
                        key={value.specValueId}
                        className={`px-3 py-1 rounded-full text-sm ${
                          isActive
                            ? 'bg-green-50 text-green-600 border border-green-500'
                            : 'bg-gray-50 text-gray-600 border border-gray-200'
                        }`}
                        onClick={() => handleSpecClick(group.specId, value.specValueId)}
                      >
                        <Text className={isActive ? 'text-green-600' : 'text-gray-600'}>{value.specValue}</Text>
                      </View>
                    )
                  })}
                </View>
              </View>
            ))}
            
            {/* 无规格时显示提示 */}
            {specGroups.length === 0 && product?.goodsSkus?.length === 0 && (
              <View className='py-4 text-center'>
                <Text className='text-sm text-gray-400'>单规格商品</Text>
              </View>
            )}
          </ScrollView>

          {/* 数量 */}
          <View className='py-3 flex items-center justify-between'>
            <Text className='text-sm text-gray-700'>数量</Text>
            <View className='flex items-center' style={{ gap: '12px' }}>
              <View
                className={`w-7 h-7 rounded-full border flex items-center justify-center ${
                  quantity <= 1 ? 'border-gray-200 text-gray-300' : 'border-gray-300 text-gray-500'
                }`}
                onClick={() => quantity > 1 && setQuantity(prev => prev - 1)}
              >
                <Text className={quantity <= 1 ? 'text-gray-300' : 'text-gray-500'}>-</Text>
              </View>
              <Text className='text-sm font-medium w-8 text-center'>{quantity}</Text>
              <View
                className={`w-7 h-7 rounded-full border flex items-center justify-center ${
                  quantity >= currentStock ? 'border-gray-200 text-gray-300' : 'border-gray-300 text-gray-500'
                }`}
                onClick={() => quantity < currentStock && setQuantity(prev => prev + 1)}
              >
                <Text className={quantity >= currentStock ? 'text-gray-300' : 'text-gray-500'}>+</Text>
              </View>
            </View>
          </View>

          {/* 确认按钮 */}
          <View className='pt-3'>
            <View
              className={`w-full py-3 rounded-full text-center text-sm font-medium ${
                canConfirm ? 'text-white' : 'text-white/60'
              }`}
              style={{ 
                backgroundColor: canConfirm ? '#0e932e' : '#ccc',
                opacity: canConfirm ? 1 : 0.7
              }}
              onClick={canConfirm ? handleConfirm : undefined}
            >
              <Text className={canConfirm ? 'text-white' : 'text-white/60'}>
                {getUnselectedSpec() ? `请选择${getUnselectedSpec()}` : (mode === 'cart' ? '加入购物车' : '立即购买')}
              </Text>
            </View>
          </View>
        </View>
      </View>
    </View>
  )
}

export default SkuSelector
