import { useState, useCallback, useMemo } from "react"
import type { PipConfig, PipLayer, PipGridPosition } from "../../../types"
import { DEFAULT_PIP_LAYER, DEFAULT_PIP_CONFIG } from "../../../types"
import { GRID_POSITION_MAP, genLayerId } from "../constants"

const MIN_DIMENSION = 10
const MAX_DIMENSION = 80

interface UsePipConfigPanelOptions {
  config: PipConfig
  onChange: (config: PipConfig) => void
}

export const usePipConfigPanel = ({ config, onChange }: UsePipConfigPanelOptions) => {
  const [selectedId, setSelectedId] = useState<string>("")

  const selectedLayer = useMemo(
    () => config.layers.find((l) => l.id === selectedId) ?? null,
    [config.layers, selectedId],
  )

  /* ── 添加图层 ── */
  const handleAddLayer = useCallback(() => {
    const newLayer: PipLayer = {
      ...DEFAULT_PIP_LAYER,
      id: genLayerId(),
      name: `图层 ${config.layers.length + 1}`,
      z_index: config.layers.length + 1,
    }
    onChange({
      ...config,
      layers: [...config.layers, newLayer],
    })
    setSelectedId(newLayer.id)
  }, [config, onChange])

  /* ── 删除图层 ── */
  const handleDeleteLayer = useCallback(
    (id: string) => {
      const newLayers = config.layers.filter((l) => l.id !== id)
      onChange({ ...config, layers: newLayers })
      if (selectedId === id) {
        setSelectedId(newLayers.length > 0 ? newLayers[0].id : "")
      }
    },
    [config, onChange, selectedId],
  )

  /* ── 更新图层 ── */
  const updateLayer = useCallback(
    (id: string, partial: Partial<PipLayer>) => {
      onChange({
        ...config,
        layers: config.layers.map((l) => (l.id === id ? { ...l, ...partial } : l)),
      })
    },
    [config, onChange],
  )

  /* ── 切换启用 ── */
  const handleEnableToggle = useCallback(
    (checked: boolean) => {
      onChange({ ...config, enabled: checked })
    },
    [config, onChange],
  )

  /* ── 重置 ── */
  const handleReset = useCallback(() => {
    onChange({ ...DEFAULT_PIP_CONFIG })
    setSelectedId("")
  }, [onChange])

  /* ── 九宫格点击 ── */
  const handleGridClick = useCallback(
    (pos: PipGridPosition) => {
      if (!selectedLayer) return
      const coords = GRID_POSITION_MAP[pos]
      updateLayer(selectedLayer.id, {
        grid_position: pos,
        x: coords.x,
        y: coords.y,
      })
    },
    [selectedLayer, updateLayer],
  )

  /* ── 宽高变化 ── */
  const handleWidthChange = useCallback(
    (val: number) => {
      if (!selectedLayer) return
      const partial: Partial<PipLayer> = { width: val }
      if (selectedLayer.aspect_lock && selectedLayer.height > 0) {
        const ratio = selectedLayer.width / selectedLayer.height
        const newHeight = Math.round(val / ratio)
        partial.height = Math.max(MIN_DIMENSION, Math.min(MAX_DIMENSION, newHeight))
      }
      updateLayer(selectedLayer.id, partial)
    },
    [selectedLayer, updateLayer],
  )

  const handleHeightChange = useCallback(
    (val: number) => {
      if (!selectedLayer) return
      const partial: Partial<PipLayer> = { height: val }
      if (selectedLayer.aspect_lock && selectedLayer.width > 0 && selectedLayer.height > 0) {
        const ratio = selectedLayer.width / selectedLayer.height
        const newWidth = Math.round(val * ratio)
        partial.width = Math.max(MIN_DIMENSION, Math.min(MAX_DIMENSION, newWidth))
      }
      updateLayer(selectedLayer.id, partial)
    },
    [selectedLayer, updateLayer],
  )

  return {
    selectedId,
    setSelectedId,
    selectedLayer,
    handleAddLayer,
    handleDeleteLayer,
    updateLayer,
    handleEnableToggle,
    handleReset,
    handleGridClick,
    handleWidthChange,
    handleHeightChange,
  }
}