import { useCallback, useRef, useMemo } from "react"
import type { MediaAsset } from "@/api/template-editor"

interface UseAssetSelectionOptions {
  filteredAssets: MediaAsset[]
  selectedIds: string[]
  onSelectionChange?: (ids: string[]) => void
}

interface UseAssetSelectionReturn {
  selectedSet: Set<string>
  toggleSelect: (asset: MediaAsset, idx: number, shiftKey: boolean) => void
  clearSelection: () => void
}

/**
 * 素材选择 Hook —— 单选/多选/Shift 连选
 */
const useAssetSelection = ({
  filteredAssets,
  selectedIds,
  onSelectionChange,
}: UseAssetSelectionOptions): UseAssetSelectionReturn => {
  const lastClickedIdx = useRef<number | null>(null)

  const selectedSet = useMemo(() => new Set(selectedIds), [selectedIds])

  const toggleSelect = useCallback(
    (asset: MediaAsset, idx: number, shiftKey: boolean) => {
      if (!onSelectionChange) return

      if (shiftKey && lastClickedIdx.current !== null) {
        // Shift 连选
        const start = Math.min(lastClickedIdx.current, idx)
        const end = Math.max(lastClickedIdx.current, idx)
        const rangeIds = filteredAssets.slice(start, end + 1).map((a) => a.id)
        const newSet = new Set(selectedIds)
        rangeIds.forEach((id) => newSet.add(id))
        onSelectionChange(Array.from(newSet))
      } else {
        const newSet = new Set(selectedIds)
        if (newSet.has(asset.id)) {
          newSet.delete(asset.id)
        } else {
          newSet.add(asset.id)
        }
        onSelectionChange(Array.from(newSet))
      }
      lastClickedIdx.current = idx
    },
    [onSelectionChange, selectedIds, filteredAssets],
  )

  const clearSelection = useCallback(() => {
    onSelectionChange?.([])
  }, [onSelectionChange])

  return {
    selectedSet,
    toggleSelect,
    clearSelection,
  }
}

export default useAssetSelection