import { View, Text, Image } from '@tarojs/components'
import Taro from '@tarojs/taro'
import { useState, useEffect, useRef } from 'react'
import './index.scss'
import { getProductById } from '../../utils/productConfig'
import { getDesignList, setDesignList, updateDesign, type DesignItem, type StickerItem } from '../../utils/store'
import { createDesign, updateDesign as updateDesignApi, persistDesignMedia } from '../../utils/api'
import { useThemeContext } from '../../context/ThemeContext'
import { useSafeArea } from '../../hooks/useSafeArea'
import { useStatusBar } from '../../hooks/useStatusBar'
import ThemedPageMeta from '../../components/ThemedPageMeta'
import ScrollTopMask from '../../components/ScrollTopMask'
import BottomActionBar from '../../components/BottomActionBar'

export default function DIYPage() {
  const { theme, resolvedTheme } = useThemeContext()
  const safe = useSafeArea()
  useStatusBar(resolvedTheme)
  const [category, setCategory] = useState<any>(null)
  const [step, setStep] = useState(1)
  const [designId, setDesignId] = useState('')
  const [quantity, setQuantity] = useState(1)
  const [stickers, setStickers] = useState<StickerItem[]>([])
  const [activeStickerId, setActiveStickerId] = useState<string | null>(null)
  const [isDragging, setIsDragging] = useState(false)
  const [startPos, setStartPos] = useState({ x: 0, y: 0 })
  const [previewMode, setPreviewMode] = useState(false)
  const [hasOverlap, setHasOverlap] = useState(false)

  /** 进入 DIY 即创建清单条目，并推进到「设计中」（问题3 修正：进入工作台即 SUBMITTED），失败降级本地 */
  const createDesignEntry = (product: { id: string; name: string; price: number; icon: string }, count: number) => {
    createDesign({
      productId: product.id,
      productName: product.name,
      unitPrice: product.price,
      count
    })
      .then(item => {
        setDesignList([item, ...getDesignList()]) // 回写缓存，checkout 等页面仍读缓存
        setDesignId(item.id)
        return updateDesignApi(item.id, { status: 'designing' })
          .then(updated => {
            setDesignList(getDesignList().map(d => d.id === item.id ? { ...d, status: updated.status } : d))
          })
          .catch(() => {
            setDesignList(getDesignList().map(d => d.id === item.id ? { ...d, status: 'designing' as const } : d))
          })
      })
      .catch(() => {
        const newDesign: DesignItem = {
          id: 'DSG' + Date.now(),
          productId: product.id,
          productName: product.name,
          productIcon: product.icon,
          unitPrice: product.price,
          count,
          status: 'designing',
          createdAt: new Date().toISOString().slice(0, 10)
        }
        setDesignList([...getDesignList(), newDesign])
        setDesignId(newDesign.id)
      })
  }

  useEffect(() => {
    const router = Taro.getCurrentInstance().router
    const params = router ? router.params : undefined
    const source = params ? params.source : undefined
    const productId = (params && params.productId) || (params && params.category)

    if (source === 'product' && productId) {
      const product = getProductById(productId)
      if (product) {
        setCategory(product)
        const count = Number(params ? params.quantity : undefined) || 1
        setQuantity(count)
        createDesignEntry(product, count)
      }
      return
    }

    if (source === 'designList' && params && params.designId) {
      const dId = params.designId
      const list = getDesignList()
      const design = list.find(d => d.id === dId)
      if (design) {
        setDesignId(dId)
        setQuantity(design.count)
        const product = getProductById(design.productId)
        if (product) setCategory(product)
        const dd = design.designData
        const rawStickers = dd ? dd.stickers : undefined
        if (rawStickers) {
          // 问题1 留意点：旧数据 width/height 为图片原始像素语义，读取端按 mask 等比归一化
          //（契约实现注记，不做存量迁移）；新语义数据（≤mask 短边 60%）原样通过
          const mask = (dd && dd.category && dd.category.mask) || (product ? product.mask : undefined)
          const normalized: StickerItem[] = mask
            ? rawStickers.map(s => {
                if (s.width > mask.width || s.height > mask.height) {
                  const k = (Math.min(mask.width, mask.height) * 0.6) / Math.max(s.width, s.height)
                  return { ...s, width: Math.round(s.width * k), height: Math.round(s.height * k) }
                }
                return s
              })
            : rawStickers
          setStickers(normalized)
        } else if (dd ? dd.imageSrc : undefined) {
          // 兼容旧版数据
          const s: StickerItem = {
            id: 'legacy_' + Date.now(),
            src: dd.imageSrc,
            x: dd.imagePos ? dd.imagePos.x || 0 : 0,
            y: dd.imagePos ? dd.imagePos.y || 0 : 0,
            scale: dd.imagePos ? dd.imagePos.scale || 1 : 1,
            width: 200,
            height: 200,
            isOverlapping: false
          }
          setStickers([s])
        }

        // 问题3 修正：继续设计同样进入「设计中」状态（单向状态机，undesigned → designing）
        if (design.status === 'undesigned') {
          updateDesign(dId, { status: 'designing' })
          updateDesignApi(dId, { status: 'designing' }).catch(() => {})
        }
      }
      return
    }

    // 默认情况（从首页 old category 参数兼容）
    if (productId) {
      const found = getProductById(productId)
      if (found) {
        setCategory(found)
        createDesignEntry(found, 1)
      }
    }
  }, [])

  // ---------- 草稿持久化（修正工作流 问题2）----------
  // 贴纸变化防抖 800ms：本地缓存即时同步 + 服务端静默同步；不推状态（SUBMITTED 只由显式动作触发）
  const draftTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null)
  const latestRef = useRef({ designId: '', quantity: 1, category: null as any, stickers: [] as StickerItem[] })
  latestRef.current = { designId, quantity, category, stickers }

  const saveDraft = () => {
    const { designId: dId, quantity: qty, category: cat, stickers: st } = latestRef.current
    if (!dId || !cat) return
    // WCD 红线：基于缓存中服务端最新 designData 合并（保留 wordcloud 分组），只覆盖本页编辑字段
    const cached = getDesignList().find(d => d.id === dId)
    const designData = {
      ...(cached && cached.designData ? cached.designData : {}),
      version: 1 as const,
      category: { id: cat.id, mask: cat.mask, ...(cat.tone ? { tone: cat.tone } : {}) },
      stickers: st
    }
    updateDesign(dId, { designData }) // 本地缓存即时同步（问题4：贴纸编辑页从这里读取）
    updateDesignApi(dId, {
      item: { productId: cat.id, productName: cat.name, unitPrice: cat.price, count: qty, designData }
    }).catch(() => {}) // 草稿静默降级：失败仅落缓存
  }

  const flushDraft = () => {
    if (draftTimerRef.current) {
      clearTimeout(draftTimerRef.current)
      draftTimerRef.current = null
    }
    saveDraft()
  }

  // 隐藏页面（切后台/跳转）时强制落盘，防止防抖窗口内的改动丢失
  Taro.useDidHide(flushDraft)
  // 卸载时同样落盘
  useEffect(() => flushDraft, [])
  // eslint-disable-next-line react-hooks/exhaustive-deps

  const skipDraftRef = useRef(true)
  useEffect(() => {
    if (skipDraftRef.current) { skipDraftRef.current = false; return }
    if (draftTimerRef.current) clearTimeout(draftTimerRef.current)
    draftTimerRef.current = setTimeout(saveDraft, 800)
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [stickers])

  // 问题5 留意点：页面栈返回（贴纸编辑页保存后 navigateBack）不触发重新挂载，
  // 需在 onShow 从缓存同步最新贴纸（src/edits），否则工作台仍渲染旧 state。
  // 首次 onShow 跳过——mount 读取端已做过旧数据归一化，避免被未归一化的缓存覆盖。
  const skipShowRef = useRef(true)
  Taro.useDidShow(() => {
    if (skipShowRef.current) { skipShowRef.current = false; return }
    const dId = latestRef.current.designId
    if (!dId) return
    const cached = getDesignList().find(d => d.id === dId)
    const list = cached && cached.designData ? cached.designData.stickers : undefined
    if (list && list.length) {
      setStickers(checkOverlap(list))
    }
  })

  // 矩形碰撞检测
  const checkOverlap = (list: StickerItem[]) => {
    const newList = list.map(s => ({ ...s, isOverlapping: false }))
    for (let i = 0; i < newList.length; i++) {
      for (let j = i + 1; j < newList.length; j++) {
        const a = newList[i]
        const b = newList[j]
        const aw = a.width * a.scale
        const ah = a.height * a.scale
        const bw = b.width * b.scale
        const bh = b.height * b.scale
        if (
          a.x < b.x + bw &&
          a.x + aw > b.x &&
          a.y < b.y + bh &&
          a.y + ah > b.y
        ) {
          newList[i].isOverlapping = true
          newList[j].isOverlapping = true
        }
      }
    }
    const overlapAny = newList.some(s => s.isOverlapping)
    setHasOverlap(overlapAny)
    return newList
  }

  const addSticker = () => {
    Taro.chooseImage({
      count: 1,
      sizeType: ['compressed'],
      sourceType: ['album', 'camera'],
      success: (res) => {
        const src = res.tempFilePaths[0]
        // 获取图片尺寸用于碰撞检测
        Taro.getImageInfo({
          src,
          success: (info) => {
            // 问题1 修正：归一化到画布坐标空间（width/height = 画布显示像素，契约实现注记）
            const maskMin = Math.min(category.mask.width, category.mask.height)
            const k = (maskMin * 0.6) / Math.max(info.width, info.height)
            const newSticker: StickerItem = {
              id: 'stk_' + Date.now(),
              src,
              x: 0,
              y: 0,
              scale: 1,
              width: Math.round(info.width * k),
              height: Math.round(info.height * k),
              isOverlapping: false
            }
            const next = [...stickers, newSticker]
            const checked = checkOverlap(next)
            setStickers(checked)
            setActiveStickerId(newSticker.id)
          },
          fail: () => {
            // fallback 尺寸（同样按画布空间归一化）
            const maskMin = Math.min(category.mask.width, category.mask.height)
            const k = (maskMin * 0.6) / 200
            const newSticker: StickerItem = {
              id: 'stk_' + Date.now(),
              src,
              x: 0,
              y: 0,
              scale: 1,
              width: Math.round(200 * k),
              height: Math.round(200 * k),
              isOverlapping: false
            }
            const next = [...stickers, newSticker]
            const checked = checkOverlap(next)
            setStickers(checked)
            setActiveStickerId(newSticker.id)
          }
        })
      }
    })
  }

  const deleteSticker = (id: string) => {
    const next = stickers.filter(s => s.id !== id)
    const checked = checkOverlap(next)
    setStickers(checked)
    if (activeStickerId === id) setActiveStickerId(null)
  }

  const handleStickerTouchStart = (e: any, id: string) => {
    const touch = e.touches[0]
    const s = stickers.find(x => x.id === id)
    if (!s) return
    setActiveStickerId(id)
    setIsDragging(true)
    setStartPos({ x: touch.clientX - s.x, y: touch.clientY - s.y })
  }

  const handleStickerTouchMove = (e: any) => {
    if (!isDragging || !activeStickerId) return
    const touch = e.touches[0]
    // 需求决定（2026-09-12）：贴纸允许拖出画布外自由摆放，不做坐标钳制
    const next = stickers.map(s => {
      if (s.id !== activeStickerId) return s
      return { ...s, x: touch.clientX - startPos.x, y: touch.clientY - startPos.y }
    })
    const checked = checkOverlap(next)
    setStickers(checked)
  }

  const handleTouchEnd = () => setIsDragging(false)

  const handleEditSticker = () => {
    if (!activeStickerId || !designId) return
    flushDraft() // 问题4：跳编辑页前清掉防抖窗口，缓存里保证有最新贴纸
    Taro.navigateTo({
      url: `/pages/diy/stickerEdit/index?designId=${designId}&stickerId=${activeStickerId}`
    })
  }

  const handleScale = (id: string, delta: number) => {
    const next = stickers.map(s => {
      if (s.id !== id) return s
      return { ...s, scale: Math.max(0.3, Math.min(3, s.scale + delta)) }
    })
    const checked = checkOverlap(next)
    setStickers(checked)
  }

  // 问题5 修正：渲染端消费贴纸 edits（亮度/色相/对比度 → CSS filter），
  // 与贴纸编辑页同一呈现逻辑；checkout 预览消费 edits 记入 R3 待办
  const stickerFilter = (s: StickerItem) => {
    const ed = s.edits
    if (!ed) return undefined
    const b = ed.brightness || 0
    const h = ed.hue || 0
    const c = ed.contrast || 0
    if (b === 0 && h === 0 && c === 0) return undefined
    return `brightness(${100 + b}%) hue-rotate(${h}deg) contrast(${100 + c}%)`
  }

  const goBack = () => {
    Taro.navigateBack()
  }

  const getMaskStyle = () => {
    if (!category) return { width: 300, height: 420 }
    const base: any = { width: category.mask.width, height: category.mask.height }
    if (category.mask.shape === 'rect') {
      base.borderRadius = category.mask.borderRadius || 0
    }
    if (category.mask.shape === 'circle') {
      base.borderRadius = '50%'
    }
    return base
  }

  const handleComplete = async () => {
    if (hasOverlap) {
      Taro.showToast({ title: '贴纸不能重叠', icon: 'none' })
      return
    }
    if (designId && category) {
      // 贴纸/底图持久化（决策#4，R4 负责）：本地图 → COS 持久 URL，保证后端 WCD 打包可下载素材
      const data = await persistDesignMedia({ stickers, category, version: 1 })
      // category 裁剪为 {id, mask, tone}（阶段0 决策#2；契约约束#3：mask 必须保留）
      const trimmedCategory = {
        id: category.id,
        mask: category.mask,
        ...(category.tone ? { tone: category.tone } : {})
      }
      // WCD 红线：基于服务端已有 designData 合并（保留 R4 写入的 wordcloud 分组等），只覆盖本页编辑的字段
      const cached = getDesignList().find(d => d.id === designId)
      const designData = {
        ...(cached && cached.designData ? cached.designData : {}),
        version: 1 as const,
        category: trimmedCategory,
        stickers: data.stickers || stickers
      }
      // 本地缓存同步（checkout 仍读缓存）
      updateDesign(designId, { status: 'designing', designData })
      try {
        await updateDesignApi(designId, {
          status: 'designing',
          item: {
            productId: category.id,
            productName: category.name,
            unitPrice: category.price,
            count: quantity,
            designData
          }
        })
      } catch {
        Taro.showToast({ title: '网络不可用，已暂存到本地', icon: 'none' })
      }
    }
    setPreviewMode(false)
    Taro.navigateTo({ url: `/pages/checkout/index?designId=${designId}` })
  }

  const activeSticker = activeStickerId ? stickers.find(s => s.id === activeStickerId) : undefined
  const activeScale = activeSticker ? activeSticker.scale : 1

  if (!category) {
    return (
      <View className={`theme-${resolvedTheme}`}>
        <ThemedPageMeta />
      <ScrollTopMask title="设计工作台" targetSelector=".page-header.surface-card" showBack />
        <View className='diy-page'>
          <Text className='page-title'>加载中...</Text>
        </View>
      </View>
    )
  }

  return (
    <View className={`theme-${resolvedTheme}`}>
      <ThemedPageMeta />
      <ScrollTopMask title="设计工作台" targetSelector=".page-header.surface-card" showBack />
      <View className='diy-page'>

        <View className='page-header surface-card' style={{ paddingTop: `${safe.statusBarHeight + 12}px` }}>
          <View className='flex-between' style={{ width: '100%' }}>
            <Text className='back-btn' onTap={goBack}>←</Text>
            <Text className='page-title'>设计工作台</Text>
            <View className='header-spacer' />
          </View>
        </View>

        {/* 画布区域 — catchtouchmove 阻止事件冒泡导致页面滚动 */}
        <View className='canvas-wrapper surface-card mt-20' catchMove>
          <View className='canvas-area' style={getMaskStyle()}>
            {stickers.map(s => (
              <Image
                key={s.id}
                className={`canvas-image ${s.isOverlapping ? 'overlap' : ''} ${activeStickerId === s.id ? 'active' : ''}`}
                src={s.src}
                style={{
                  transform: `translate(${s.x}px, ${s.y}px) scale(${s.scale})`,
                  opacity: isDragging && activeStickerId === s.id ? 0.8 : 1,
                  zIndex: activeStickerId === s.id ? 10 : 5,
                  filter: stickerFilter(s),
                  width: s.width || 200,
                  height: s.height || 200
                }}
                onTouchStart={(e) => handleStickerTouchStart(e, s.id)}
                onTouchMove={handleStickerTouchMove}
                onTouchEnd={handleTouchEnd}
                onTap={() => setActiveStickerId(s.id)}
                mode='aspectFit'
              />
            ))}
            <View className='mask-border' style={getMaskStyle()} />
          </View>
        </View>

        {/* 贴纸列表与控制 */}
        <View className='sticker-panel surface-card mt-20'>
          <Text className='section-title'>贴纸</Text>
          <View className='sticker-list'>
            {stickers.map(s => (
              <View key={s.id} className={`sticker-thumb ${s.isOverlapping ? 'overlap' : ''} ${activeStickerId === s.id ? 'active' : ''}`}>
                <Image src={s.src} className='sticker-thumb-img' mode='aspectFit' onTap={() => setActiveStickerId(s.id)} />
                <View className='sticker-del' onTap={() => deleteSticker(s.id)}>
                  <Text className='del-icon'>×</Text>
                </View>
              </View>
            ))}
            <View className='sticker-add-btn' onTap={addSticker}>
              <Text className='add-icon'>+</Text>
              <Text className='add-label'>添加</Text>
            </View>
          </View>
          {hasOverlap && <Text className='overlap-hint'>有贴纸重叠，请调整位置</Text>}
        </View>

        {/* 控制工具栏 */}
        {activeStickerId && (
          <View className='toolbar surface-card mt-20'>
            <View className='tool-row'>
              <Text className='tool-label'>缩放</Text>
              <View className='flex-center' style={{ gap: '20px' }}>
                <View className='tool-btn' onTap={() => handleScale(activeStickerId, -0.1)}>－</View>
                <Text className='tool-value'>{Math.round(activeScale * 100)}%</Text>
                <View className='tool-btn' onTap={() => handleScale(activeStickerId, 0.1)}>＋</View>
              </View>
            </View>
            <View className='tool-row'>
              <Text className='tool-label'>提示</Text>
              <Text className='tool-hint'>拖动调整位置，贴纸不可重叠</Text>
            </View>
          </View>
        )}

        {/* 常驻编辑按钮 */}
        <View className='edit-btn-bar mt-20'>
          <View
            className={`edit-btn ${activeStickerId ? 'active' : 'disabled'}`}
            onTap={handleEditSticker}
          >
            <Text>编辑</Text>
          </View>
        </View>

        {/* 底部操作按钮 */}
        <BottomActionBar>
          <View className='btn-primary' onTap={() => setPreviewMode(true)}>
            <Text>预览效果</Text>
          </View>
          <View className='btn-secondary' onTap={addSticker}>
            <Text>添加贴纸</Text>
          </View>
        </BottomActionBar>

        {/* 预览弹层 */}
        {previewMode && (
          <View className='preview-overlay'>
            <View className='preview-card surface-card'>
              <Text className='preview-title'>确认效果</Text>
              <View className='preview-canvas' style={getMaskStyle()}>
                {stickers.map(s => (
                  <Image
                    key={s.id}
                    className={`preview-image ${s.isOverlapping ? 'overlap' : ''}`}
                    src={s.src}
                    style={{
                      transform: `translate(${s.x}px, ${s.y}px) scale(${s.scale})`,
                      filter: stickerFilter(s),
                      width: s.width || 200,
                      height: s.height || 200
                    }}
                    mode='aspectFit'
                  />
                ))}
              </View>
              <View className='product-info'>
                <Text className='product-name'>{category.name}</Text>
                <Text className='product-size'>画布尺寸: {category.mask.width} × {category.mask.height} px</Text>
                {hasOverlap && <Text className='overlap-hint'>贴纸有重叠，不可提交</Text>}
              </View>
              <View className='preview-actions'>
                <View className='btn-secondary' onTap={() => setPreviewMode(false)}>
                  <Text>返回修改</Text>
                </View>
                <View className={`btn-primary ${hasOverlap ? 'disabled' : ''}`} onTap={handleComplete}>
                  <Text>确认完成</Text>
                </View>
              </View>
            </View>
          </View>
        )}

        <View className='safe-bottom-placeholder' />
      </View>
    </View>
  )
}