/**
 * 通用拖拽状态 Hook。
 * 业务组件可以保留各自的文件处理逻辑，但拖拽边界统一使用同一套判断。
 */

import { useCallback, useState } from 'react'
import {
  hasDragLeftDropZone,
  prepareFileDrag,
  validateImageFiles,
} from '@/components/upload/drag-drop-utils'

export interface DragState {
  isDragging: boolean
  isPreviewDragging: boolean
  isDisplayImageDragging: boolean
  batchPreviewDragging: Record<string, boolean>
}

export interface UseDragHandlersOptions {
  isValidMainFile: (file: File) => boolean
  onMaterialFileDrop: (files: File[]) => void
  onPreviewImageDrop: (files: File[]) => void
  onDisplayImageDrop: (file: File) => void
  setError: (error: string) => void
  disabled?: boolean
}

export function useDragHandlers(options: UseDragHandlersOptions) {
  const {
    isValidMainFile,
    onMaterialFileDrop,
    onPreviewImageDrop,
    onDisplayImageDrop,
    setError,
    disabled = false,
  } = options

  const [isDragging, setIsDragging] = useState(false)
  const [isPreviewDragging, setIsPreviewDragging] = useState(false)
  const [isDisplayImageDragging, setIsDisplayImageDragging] = useState(false)
  const [batchPreviewDragging, setBatchPreviewDragging] = useState<Record<string, boolean>>({})

  const handleDragEnter = useCallback((event: React.DragEvent) => {
    prepareFileDrag(event, disabled)
    if (!disabled) setIsDragging(true)
  }, [disabled])

  const handleDragLeave = useCallback((event: React.DragEvent) => {
    event.preventDefault()
    event.stopPropagation()
    if (hasDragLeftDropZone(event)) setIsDragging(false)
  }, [])

  const handleDragOver = useCallback((event: React.DragEvent) => {
    prepareFileDrag(event, disabled)
  }, [disabled])

  const handleDrop = useCallback((event: React.DragEvent) => {
    prepareFileDrag(event, disabled)
    setIsDragging(false)
    if (disabled) {
      setError('文件正在上传，请等待完成后再添加')
      return
    }

    const files = Array.from(event.dataTransfer.files)
    if (files.length === 0) return

    const materialFiles = files.filter(isValidMainFile)
    if (materialFiles.length > 0) {
      const invalidNames = files
        .filter((file) => !isValidMainFile(file))
        .map((file) => file.name)
      setError(
        invalidNames.length > 0
          ? `以下文件不支持当前素材类型，已忽略：${invalidNames.join('、')}`
          : '',
      )
      onMaterialFileDrop(materialFiles)
    } else {
      setError('请拖拽素材文件到此区域，图片请拖拽到对应的图片上传区域')
    }
  }, [disabled, isValidMainFile, onMaterialFileDrop, setError])

  const handlePreviewDragEnter = useCallback((event: React.DragEvent) => {
    prepareFileDrag(event, disabled)
    if (!disabled) setIsPreviewDragging(true)
  }, [disabled])

  const handlePreviewDragLeave = useCallback((event: React.DragEvent) => {
    event.preventDefault()
    event.stopPropagation()
    if (hasDragLeftDropZone(event)) setIsPreviewDragging(false)
  }, [])

  const handlePreviewDragOver = useCallback((event: React.DragEvent) => {
    prepareFileDrag(event, disabled)
  }, [disabled])

  const handlePreviewDrop = useCallback((event: React.DragEvent) => {
    prepareFileDrag(event, disabled)
    setIsPreviewDragging(false)
    if (disabled) {
      setError('文件正在上传，请等待完成后再添加预览图')
      return
    }

    const files = Array.from(event.dataTransfer.files)
    if (files.length === 0) return

    const { acceptedFiles, errors } = validateImageFiles(files)
    if (acceptedFiles.length > 0) {
      setError(errors.join('；'))
      onPreviewImageDrop(acceptedFiles)
    } else {
      setError('请拖拽图片文件')
    }
  }, [disabled, onPreviewImageDrop, setError])

  const handleDisplayImageDragEnter = useCallback((event: React.DragEvent) => {
    prepareFileDrag(event, disabled)
    if (!disabled) setIsDisplayImageDragging(true)
  }, [disabled])

  const handleDisplayImageDragLeave = useCallback((event: React.DragEvent) => {
    event.preventDefault()
    event.stopPropagation()
    if (hasDragLeftDropZone(event)) setIsDisplayImageDragging(false)
  }, [])

  const handleDisplayImageDragOver = useCallback((event: React.DragEvent) => {
    prepareFileDrag(event, disabled)
  }, [disabled])

  const handleDisplayImageDrop = useCallback((event: React.DragEvent) => {
    prepareFileDrag(event, disabled)
    setIsDisplayImageDragging(false)
    if (disabled) {
      setError('文件正在上传，请等待完成后再更换展示图')
      return
    }

    const files = Array.from(event.dataTransfer.files)
    if (files.length === 0) return

    const { acceptedFiles, errors } = validateImageFiles(files, { maxCount: 1 })
    if (acceptedFiles[0]) {
      setError(errors.join('；'))
      onDisplayImageDrop(acceptedFiles[0])
    } else {
      setError('请拖拽图片文件')
    }
  }, [disabled, onDisplayImageDrop, setError])

  const handleBatchPreviewDragEnter = useCallback((itemId: string) => {
    if (disabled) return
    setBatchPreviewDragging((prev) => ({ ...prev, [itemId]: true }))
  }, [disabled])

  const handleBatchPreviewDragLeave = useCallback((itemId: string) => {
    setBatchPreviewDragging((prev) => ({ ...prev, [itemId]: false }))
  }, [])

  const resetBatchPreviewDragging = useCallback((itemId: string) => {
    setBatchPreviewDragging((prev) => ({ ...prev, [itemId]: false }))
  }, [])

  return {
    isDragging,
    isPreviewDragging,
    isDisplayImageDragging,
    batchPreviewDragging,
    handleDragEnter,
    handleDragLeave,
    handleDragOver,
    handleDrop,
    handlePreviewDragEnter,
    handlePreviewDragLeave,
    handlePreviewDragOver,
    handlePreviewDrop,
    handleDisplayImageDragEnter,
    handleDisplayImageDragLeave,
    handleDisplayImageDragOver,
    handleDisplayImageDrop,
    handleBatchPreviewDragEnter,
    handleBatchPreviewDragLeave,
    resetBatchPreviewDragging,
    setBatchPreviewDragging,
  }
}