File size: 5,264 Bytes
00a912e
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
import { Skeleton } from '@/components/ui/skeleton'
import { cn } from '@/lib/utils'
import type { Track } from '@music-together/shared'
import { useVirtualizer } from '@tanstack/react-virtual'
import { Loader2, Music2 } from 'lucide-react'
import React, { forwardRef, useEffect, useImperativeHandle, useState } from 'react'
import { TrackListItem } from './TrackListItem'

/** Start loading more items when the last visible row is within this many rows of the end */
const LOAD_MORE_THRESHOLD = 5

export interface VirtualTrackListProps {
  tracks: Track[]
  loading: boolean
  hasMore: boolean
  loadingMore: boolean
  onLoadMore: () => void
  isTrackAdded: (track: Track) => boolean
  onAddTrack: (track: Track) => void
  onInsertAfterCurrent?: (track: Track) => void
  onArtistClick?: (artist: string) => void
  emptyIcon?: React.ReactNode
  emptyMessage?: string
  rowHeight?: number
  overscan?: number
  className?: string
}

export interface VirtualTrackListRef {
  scrollToTop: () => void
}

function TrackSkeleton() {
  return (
    <div className="flex items-center gap-3 px-3 py-2.5">
      <Skeleton className="h-4 w-6" />
      <Skeleton className="h-10 w-10 rounded" />
      <div className="min-w-0 flex-1 space-y-1.5">
        <Skeleton className="h-4 w-3/4" />
        <Skeleton className="h-3 w-1/2" />
      </div>
      <Skeleton className="h-8 w-8 rounded-md" />
    </div>
  )
}

export const VirtualTrackList = forwardRef<VirtualTrackListRef, VirtualTrackListProps>(function VirtualTrackList(
  {
    tracks,
    loading,
    hasMore,
    loadingMore,
    onLoadMore,
    isTrackAdded,
    onAddTrack,
    onInsertAfterCurrent,
    onArtistClick,
    emptyIcon,
    emptyMessage = '暂无内容',
    rowHeight = 52,
    overscan = 5,
    className,
  },
  ref,
) {
  const [scrollElement, setScrollElement] = useState<HTMLDivElement | null>(null)

  useImperativeHandle(ref, () => ({
    scrollToTop: () => scrollElement?.scrollTo({ top: 0 }),
  }))

  const rowCount = tracks.length + (hasMore ? 1 : 0)

  // TanStack Virtual manages mutable measurements internally and cannot be compiler-memoized.
  // eslint-disable-next-line react-hooks/incompatible-library
  const virtualizer = useVirtualizer({
    count: rowCount,
    getScrollElement: () => scrollElement,
    estimateSize: () => rowHeight,
    overscan,
  })

  // Infinite scroll: trigger onLoadMore when approaching the bottom
  const virtualItems = virtualizer.getVirtualItems()
  const lastItemIndex = virtualItems.at(-1)?.index

  useEffect(() => {
    if (lastItemIndex === undefined) return
    if (lastItemIndex >= tracks.length - LOAD_MORE_THRESHOLD && hasMore && !loadingMore) {
      onLoadMore()
    }
  }, [lastItemIndex, tracks.length, hasMore, loadingMore, onLoadMore])

  // Loading skeleton
  if (loading) {
    return (
      <div className={cn('min-h-0 flex-1 overflow-y-auto rounded-md border', className)}>
        <div className="divide-y">
          {Array.from({ length: 5 }).map((_, i) => (
            <TrackSkeleton key={i} />
          ))}
        </div>
      </div>
    )
  }

  // Empty state
  if (tracks.length === 0) {
    return (
      <div className={cn('min-h-0 flex-1 overflow-y-auto rounded-md border', className)}>
        <div className="flex h-48 flex-col items-center justify-center gap-2 text-muted-foreground">
          {emptyIcon ?? <Music2 className="h-8 w-8" />}
          <span className="text-sm">{emptyMessage}</span>
        </div>
      </div>
    )
  }

  return (
    <div
      ref={setScrollElement}
      className={cn('min-h-0 min-w-0 flex-1 overflow-x-hidden overflow-y-auto rounded-md border', className)}
    >
      <div
        style={{
          height: `${virtualizer.getTotalSize()}px`,
          width: '100%',
          position: 'relative',
        }}
      >
        {virtualItems.map((virtualRow) => {
          const isLoaderRow = virtualRow.index >= tracks.length

          if (isLoaderRow) {
            return (
              <div
                key="loader"
                style={{
                  position: 'absolute',
                  top: 0,
                  left: 0,
                  width: '100%',
                  height: `${virtualRow.size}px`,
                  transform: `translateY(${virtualRow.start}px)`,
                }}
                className="flex items-center justify-center"
              >
                <Loader2 className="h-4 w-4 animate-spin text-muted-foreground" />
              </div>
            )
          }

          const track = tracks[virtualRow.index]
          if (!track) return null

          return (
            <TrackListItem
              key={track.id}
              track={track}
              index={virtualRow.index}
              isAdded={isTrackAdded(track)}
              onAdd={onAddTrack}
              onInsertAfterCurrent={onInsertAfterCurrent}
              onArtistClick={onArtistClick}
              style={{
                position: 'absolute',
                top: 0,
                left: 0,
                width: '100%',
                height: `${virtualRow.size}px`,
                transform: `translateY(${virtualRow.start}px)`,
              }}
            />
          )
        })}
      </div>
    </div>
  )
})