/**
 * 水平轨道时间线 — 支持裁剪手柄、分割、右键菜单
 * 时间标尺(20px) + 水平片段卡片轨道(100x100) + HTML5拖拽排序
 * "+" 卡片 → 类型+时长选择器
 *
 * 裁剪交互：
 * - 鼠标悬停片段两端显示拖拽手柄，拖动调整入点/出点
 * - 拖动时实时显示裁剪预览（入点/出点/时长）
 * - 右键片段弹出菜单：分割 / 恢复原始长度 / 删除
 */
import React, { useState, useRef, useCallback, useEffect, useLayoutEffect, useMemo } from "react"
import type { ClipData, ClipType, TrimConfig } from "../types"
import {
  DEFAULT_PIXELS_PER_SECOND,
  MIN_PIXELS_PER_SECOND,
  MAX_PIXELS_PER_SECOND,
  ZOOM_STEP,
  MIN_TRIM_DURATION,
  DEFAULT_ADD_DURATION,
  MIN_ADD_DURATION,
  MAX_ADD_DURATION,
  TRACK_GAP,
  ADD_PICKER_WIDTH,
} from "../constants/timeline"
import { formatTime } from "../utils/timeline"
import { ClipCard } from "./timeline/ClipCard"
import { TimeRuler } from "./timeline/TimeRuler"
import { AddClipPicker } from "./timeline/AddClipPicker"
import { TrimPreview } from "./timeline/TrimPreview"
import { ContextMenu } from "./timeline/ContextMenu"

interface TimelinePanelProps {
  clips: ClipData[]
  selectedClipId: string | null
  currentMode: string
  onClipSelect: (clipId: string) => void
  onClipReorder: (fromIdx: number, toIdx: number) => void
  onClipRemove: (clipId: string) => void
  onAddClip: (type: ClipType, duration: number) => void
  /** 裁剪更新：调整片段的 trim_config 和 duration */
  onClipTrim?: (clipId: string, trimConfig: TrimConfig, newDuration: number) => void
  /** 在指定位置分割片段 */
  onClipSplit?: (clipId: string, splitRatio: number) => void
  /** 恢复片段原始长度 */
  onClipResetTrim?: (clipId: string) => void
  /** 当前播放时间（秒） */
  currentTime?: number
  /** 缩放：每秒像素数 */
  pixelsPerSecond?: number
  /** 缩放变更回调 */
  onZoomChange?: (pps: number) => void
  /** 播放头跳转回调 */
  onSeek?: (time: number) => void
  /** 总时长（秒），可选（默认由 clips 计算） */
  totalDuration?: number
}

/** 裁剪拖拽方向 */
type TrimDirection = "left" | "right"

/** 裁剪拖拽状态 */
interface TrimDragState {
  clipId: string
  direction: TrimDirection
  startX: number
  originalTrim: TrimConfig
  originalDuration: number
}

/** 右键菜单状态 */
interface ContextMenuState {
  x: number
  y: number
  clipId: string
}

const TimelinePanel: React.FC<TimelinePanelProps> = ({
  clips,
  selectedClipId,
  currentMode,
  onClipSelect,
  onClipReorder,
  onClipRemove,
  onAddClip,
  onClipTrim,
  onClipSplit,
  onClipResetTrim,
  currentTime = 0,
  pixelsPerSecond = 40,
  onZoomChange,
  onSeek,
  totalDuration: totalDurationProp,
}) => {
  const [dragIdx, setDragIdx] = useState<number | null>(null)
  const [dragOverIdx, setDragOverIdx] = useState<number | null>(null)
  const dragRef = useRef<number | null>(null)
  const [showAddPicker, setShowAddPicker] = useState(false)
  const pickerRef = useRef<HTMLDivElement>(null)
  const addCardRef = useRef<HTMLDivElement>(null)
  const [pickerPos, setPickerPos] = useState<{ top: number; right: number }>({
    top: 0,
    right: 0,
  })

  /* ── 裁剪拖拽状态 ── */
  const [trimDrag, setTrimDrag] = useState<TrimDragState | null>(null)
  const [trimPreview, setTrimPreview] = useState<{
    clipId: string
    startTime: number
    endTime: number
    duration: number
    x: number
    y: number
  } | null>(null)

  /* ── 右键菜单 ── */
  const [contextMenu, setContextMenu] = useState<ContextMenuState | null>(null)
  const contextMenuRef = useRef<HTMLDivElement>(null)

  /* ── 悬停的片段 ID（显示裁剪手柄） ── */
  const [hoveredClipId, setHoveredClipId] = useState<string | null>(null)

  /* ── 播放头拖拽状态 ── */
  const [playheadDragging, setPlayheadDragging] = useState(false)
  const trackRef = useRef<HTMLDivElement>(null)

  /* ── 根据模式决定可选类型 ── */
  const availableTypes: ClipType[] = useMemo(
    () =>
      currentMode === "voice_over" ? ["voice"] : currentMode === "pip" ? ["pip"] : ["voice", "pip"], // voice_pip / one_take / 默认
    [currentMode],
  )

  /* ── 默认添加类型：跟随模式 ── */
  const defaultAddType: ClipType = useMemo(() => {
    if (currentMode === "voice_over") return "voice"
    if (currentMode === "pip") return "pip"
    return "voice"
  }, [currentMode])

  /* ── "+" 卡片：类型+时长选择状态 ── */
  const [addType, setAddType] = useState<ClipType>(defaultAddType)
  const [addDuration, setAddDuration] = useState<number>(DEFAULT_ADD_DURATION)

  /* ── 模式切换时自动同步默认添加类型 ── */
  useEffect(() => {
    if (!availableTypes.includes(addType)) {
      setAddType(defaultAddType)
    }
  }, [currentMode, addType, availableTypes, defaultAddType])

  /* ── 计算 picker 初始位置 ── */
  const updatePickerPosition = useCallback(() => {
    if (!addCardRef.current) return
    const rect = addCardRef.current.getBoundingClientRect()
    const vw = window.innerWidth
    const roughHeight = 180
    let top = rect.top - TRACK_GAP - roughHeight
    if (top < 8) top = 8
    let right = vw - rect.right
    if (rect.right - ADD_PICKER_WIDTH < 8) {
      right = vw - ADD_PICKER_WIDTH - 8
    }
    setPickerPos({ top, right })
  }, [])

  const handleTogglePicker = () => {
    if (!showAddPicker) {
      const defaultType =
        currentMode === "pip" ? "pip" : currentMode === "voice_over" ? "voice" : "voice"
      setAddType(defaultType)
      updatePickerPosition()
    }
    setShowAddPicker((v) => !v)
  }

  /* ── 渲染后精确边界校正 ── */
  useLayoutEffect(() => {
    if (!showAddPicker || !pickerRef.current || !addCardRef.current) return
    const pickerEl = pickerRef.current
    const addRect = addCardRef.current.getBoundingClientRect()
    const pickerH = pickerEl.offsetHeight
    const vh = window.innerHeight
    const vw = window.innerWidth
    let top = addRect.top - TRACK_GAP - pickerH
    if (top < 8) {
      top = addRect.bottom + TRACK_GAP
      if (top + pickerH > vh - 8) {
        top = vh - 8 - pickerH
        if (top < 8) top = 8
      }
    }
    let right = vw - addRect.right
    const pickerRect = pickerEl.getBoundingClientRect()
    if (pickerRect.left < 8) {
      right = vw - ADD_PICKER_WIDTH - 8
    }
    setPickerPos({ top, right })
  }, [showAddPicker])

  /* ── 点击外部关闭添加面板 ── */
  useEffect(() => {
    const handleClickOutside = (e: MouseEvent) => {
      if (pickerRef.current && !pickerRef.current.contains(e.target as Node)) {
        setShowAddPicker(false)
      }
    }
    if (showAddPicker) {
      document.addEventListener("mousedown", handleClickOutside)
    }
    return () => document.removeEventListener("mousedown", handleClickOutside)
  }, [showAddPicker])

  /* ── 点击外部关闭右键菜单 ── */
  useEffect(() => {
    const handleClickOutside = (e: MouseEvent) => {
      if (contextMenuRef.current && !contextMenuRef.current.contains(e.target as Node)) {
        setContextMenu(null)
      }
    }
    if (contextMenu) {
      document.addEventListener("mousedown", handleClickOutside)
    }
    return () => document.removeEventListener("mousedown", handleClickOutside)
  }, [contextMenu])

  /* ── 缩放 & 时长 ── */
  const pps = pixelsPerSecond ?? DEFAULT_PIXELS_PER_SECOND
  const totalDuration = totalDurationProp ?? clips.reduce((s, c) => s + c.duration, 0)

  /* ── 播放头拖拽全局 mousemove/mouseup ── */
  useEffect(() => {
    if (!playheadDragging) return

    const handleMouseMove = (e: MouseEvent) => {
      const trackEl = trackRef.current
      if (!trackEl) return
      const rect = trackEl.getBoundingClientRect()
      const x = e.clientX - rect.left + trackEl.scrollLeft
      const time = Math.max(0, Math.min(x / pps, totalDuration))
      onSeek?.(Math.round(time * 10) / 10)
    }

    const handleMouseUp = () => {
      setPlayheadDragging(false)
    }

    document.addEventListener("mousemove", handleMouseMove)
    document.addEventListener("mouseup", handleMouseUp)
    return () => {
      document.removeEventListener("mousemove", handleMouseMove)
      document.removeEventListener("mouseup", handleMouseUp)
    }
  }, [playheadDragging, pps, totalDuration, onSeek])

  /* ── 标尺点击跳转播放头 ── */
  const handleRulerClick = useCallback(
    (e: React.MouseEvent<HTMLDivElement>) => {
      const rect = e.currentTarget.getBoundingClientRect()
      const x = e.clientX - rect.left
      const time = Math.max(0, Math.min(x / pps, totalDuration))
      onSeek?.(Math.round(time * 10) / 10)
    },
    [pps, totalDuration, onSeek],
  )

  /* ── 播放头拖拽开始 ── */
  const handlePlayheadMouseDown = useCallback((e: React.MouseEvent) => {
    e.preventDefault()
    e.stopPropagation()
    setPlayheadDragging(true)
  }, [])

  /* ── 确认添加片段 ── */
  const handleConfirmAdd = () => {
    onAddClip(addType, addDuration)
    setShowAddPicker(false)
  }

  /* ── 片段拖拽排序 ── */
  const handleDragStart = (e: React.DragEvent, idx: number) => {
    // 如果正在裁剪拖拽，不允许排序拖拽
    if (trimDrag) return
    dragRef.current = idx
    setDragIdx(idx)
    e.dataTransfer.setData("application/x-clip-drag", String(idx))
    e.dataTransfer.effectAllowed = "move"
  }

  const handleDragOver = (e: React.DragEvent, idx: number) => {
    e.preventDefault()
    e.dataTransfer.dropEffect = "move"
    setDragOverIdx(idx)
  }

  const handleDragEnd = () => {
    dragRef.current = null
    setDragIdx(null)
    setDragOverIdx(null)
  }

  const handleDrop = (e: React.DragEvent, toIdx: number) => {
    e.preventDefault()
    setDragOverIdx(null)
    const fromStr = e.dataTransfer.getData("application/x-clip-drag")
    if (fromStr !== "") {
      const fromIdx = Number(fromStr)
      if (fromIdx !== toIdx) {
        onClipReorder(fromIdx, toIdx)
      }
    }
  }

  /* ── 空轨道区域不接受素材拖入 ── */
  const handleEmptyDragOver = (e: React.DragEvent) => {
    e.preventDefault()
  }

  /* ── 裁剪手柄拖拽 ── */
  const handleTrimHandleMouseDown = useCallback(
    (e: React.MouseEvent, clipId: string, direction: TrimDirection) => {
      e.preventDefault()
      e.stopPropagation()
      const clip = clips.find((c) => c.id === clipId)
      if (!clip) return

      const trim: TrimConfig = clip.trim_config ?? {
        start_time: 0,
        end_time: clip.duration,
        original_duration: clip.duration,
      }

      setTrimDrag({
        clipId,
        direction,
        startX: e.clientX,
        originalTrim: { ...trim },
        originalDuration: clip.duration,
      })
    },
    [clips],
  )

  /* ── 裁剪拖拽全局 mousemove/mouseup ── */
  useEffect(() => {
    if (!trimDrag) return

    const handleMouseMove = (e: MouseEvent) => {
      const dx = e.clientX - trimDrag.startX
      const dtSec = dx / pps
      const clip = clips.find((c) => c.id === trimDrag.clipId)
      if (!clip) return

      const origTrim = trimDrag.originalTrim
      const origDur = origTrim.original_duration ?? trimDrag.originalDuration
      let newStart = origTrim.start_time
      let newEnd = origTrim.end_time

      if (trimDrag.direction === "left") {
        // 左手柄：调整入点
        newStart = Math.max(0, Math.min(origTrim.start_time + dtSec, newEnd - MIN_TRIM_DURATION))
      } else {
        // 右手柄：调整出点
        newEnd = Math.max(
          origTrim.start_time + MIN_TRIM_DURATION,
          Math.min(origTrim.end_time + dtSec, origDur),
        )
      }

      const newDuration = Math.round((newEnd - newStart) * 10) / 10

      setTrimPreview({
        clipId: trimDrag.clipId,
        startTime: Math.round(newStart * 10) / 10,
        endTime: Math.round(newEnd * 10) / 10,
        duration: newDuration,
        x: e.clientX,
        y: e.clientY,
      })
    }

    const handleMouseUp = () => {
      if (trimPreview && trimPreview.clipId === trimDrag.clipId && onClipTrim) {
        const newTrim: TrimConfig = {
          start_time: trimPreview.startTime,
          end_time: trimPreview.endTime,
          original_duration: trimDrag.originalTrim.original_duration ?? trimDrag.originalDuration,
        }
        onClipTrim(trimDrag.clipId, newTrim, trimPreview.duration)
      }
      setTrimDrag(null)
      setTrimPreview(null)
    }

    document.addEventListener("mousemove", handleMouseMove)
    document.addEventListener("mouseup", handleMouseUp)
    return () => {
      document.removeEventListener("mousemove", handleMouseMove)
      document.removeEventListener("mouseup", handleMouseUp)
    }
  }, [trimDrag, trimPreview, clips, onClipTrim, pps])

  /* ── 右键菜单 ── */
  const handleContextMenu = useCallback((e: React.MouseEvent, clipId: string) => {
    e.preventDefault()
    e.stopPropagation()
    setContextMenu({ x: e.clientX, y: e.clientY, clipId })
  }, [])

  /* ── 右键菜单操作 ── */
  const handleContextSplit = useCallback(() => {
    if (!contextMenu) return
    if (onClipSplit) {
      onClipSplit(contextMenu.clipId, 0.5) // 在中间分割
    }
    setContextMenu(null)
  }, [contextMenu, onClipSplit])

  const handleContextResetTrim = useCallback(() => {
    if (!contextMenu) return
    if (onClipResetTrim) {
      onClipResetTrim(contextMenu.clipId)
    }
    setContextMenu(null)
  }, [contextMenu, onClipResetTrim])

  const handleContextDelete = useCallback(() => {
    if (!contextMenu) return
    onClipRemove(contextMenu.clipId)
    setContextMenu(null)
  }, [contextMenu, onClipRemove])

  return (
    <div className="ep-timeline-area">
      {/* 时间线头部 */}
      <div className="ep-timeline-header">
        <div className="ep-timeline-title">
          <span>🎬 时间线</span>
          <span className="ep-timeline-duration">总时长: {formatTime(totalDuration)}</span>
        </div>
        <div className="ep-timeline-actions">
          {/* 缩放控件 */}
          <div className="ep-timeline-zoom">
            <button
              className="ep-zoom-btn"
              onClick={() => onZoomChange?.(Math.max(MIN_PIXELS_PER_SECOND, pps - ZOOM_STEP))}
              title="缩小"
            >
              −
            </button>
            <input
              type="range"
              className="ep-zoom-slider"
              min={MIN_PIXELS_PER_SECOND}
              max={MAX_PIXELS_PER_SECOND}
              step={5}
              value={pps}
              onChange={(e) => onZoomChange?.(Number(e.target.value))}
            />
            <button
              className="ep-zoom-btn"
              onClick={() => onZoomChange?.(Math.min(MAX_PIXELS_PER_SECOND, pps + ZOOM_STEP))}
              title="放大"
            >
              +
            </button>
            <span className="ep-zoom-label">{pps}px/s</span>
          </div>
          <button
            className="ep-timeline-action-btn"
            onClick={() => {
              if (clips.length > 1) {
                const last = clips[clips.length - 1]
                onClipRemove(last.id)
              }
            }}
            title="删除最后一个片段"
          >
            ↩
          </button>
          <button className="ep-timeline-action-btn" title="重做">
            ↪
          </button>
        </div>
      </div>

      {/* 一镜到底提示 */}
      {currentMode === "one_take" && <div className="ep-one-take-hint">🎥 一镜到底模式无片段</div>}

      {/* 时间标尺 */}
      {currentMode !== "one_take" && (
        <TimeRuler totalDuration={totalDuration} pps={pps} onClick={handleRulerClick} />
      )}

      {/* 水平片段轨道 */}
      {currentMode !== "one_take" && (
        <div className="ep-clip-track" ref={trackRef} onDragOver={handleEmptyDragOver}>
          {/* 播放头 */}
          {currentMode !== "one_take" && totalDuration > 0 && (
            <div
              className="ep-playhead"
              style={{ left: currentTime * pps }}
              onMouseDown={handlePlayheadMouseDown}
            >
              <div className="ep-playhead-handle" />
            </div>
          )}
          {clips.length === 0 ? (
            <div className="ep-track-empty">
              <div className="ep-track-empty-icon">🎬</div>
              <div className="ep-track-empty-text">点击右侧 + 添加片段</div>
            </div>
          ) : (
            clips.map((clip, idx) => (
              <ClipCard
                key={clip.id}
                clip={clip}
                idx={idx}
                isSelected={selectedClipId === clip.id}
                isDragging={dragIdx === idx}
                isDragOver={dragOverIdx === idx}
                isHovered={hoveredClipId === clip.id}
                pps={pps}
                trimDragActive={!!trimDrag}
                showTrimHandles={!!onClipTrim}
                onDragStart={handleDragStart}
                onDragOver={handleDragOver}
                onDragEnd={handleDragEnd}
                onDrop={handleDrop}
                onSelect={onClipSelect}
                onContextMenu={handleContextMenu}
                onMouseEnter={() => setHoveredClipId(clip.id)}
                onMouseLeave={() => setHoveredClipId(null)}
                onTrimHandleMouseDown={handleTrimHandleMouseDown}
                onRemove={onClipRemove}
              />
            ))
          )}

          {/* ── 轨道末尾 "+" 添加卡片 ── */}
          <div className="ep-track-add-card-wrapper">
            <div
              ref={addCardRef}
              className="ep-track-add-card"
              onClick={handleTogglePicker}
              title="添加片段"
            >
              +
            </div>
          </div>
        </div>
      )}

      {/* 裁剪预览 tooltip */}
      {trimPreview && (
        <TrimPreview
          startTime={trimPreview.startTime}
          endTime={trimPreview.endTime}
          duration={trimPreview.duration}
          x={trimPreview.x}
          y={trimPreview.y}
        />
      )}

      {/* 右键菜单 */}
      {contextMenu && (
        <ContextMenu
          x={contextMenu.x}
          y={contextMenu.y}
          menuRef={contextMenuRef}
          hasTrim={!!clips.find((c) => c.id === contextMenu.clipId)?.trim_config}
          onSplit={handleContextSplit}
          onResetTrim={handleContextResetTrim}
          onDelete={handleContextDelete}
        />
      )}

      {/* 类型+时长选择面板 */}
      {showAddPicker && (
        <AddClipPicker
          pickerRef={pickerRef}
          position={pickerPos}
          availableTypes={availableTypes}
          addType={addType}
          addDuration={addDuration}
          minDuration={MIN_ADD_DURATION}
          maxDuration={MAX_ADD_DURATION}
          onTypeChange={setAddType}
          onDurationChange={setAddDuration}
          onConfirm={handleConfirmAdd}
        />
      )}
    </div>
  )
}

export default TimelinePanel