BYW-VoiceHub/app/components/Admin/PlaylistCardGenerator.vue

<template>
  <Transition name="fade">
    <div
      v-if="show"
      class="fixed inset-0 z-50 flex items-center justify-center bg-black/60 backdrop-blur-sm"
      @click="$emit('close')"
    >
      <Transition name="scale">
        <div
          v-if="show"
          class="bg-white border border-zinc-200 rounded-2xl shadow-2xl w-full max-w-sm overflow-hidden flex flex-col"
          @click.stop
        >
          <div class="flex items-center justify-between p-4 border-b border-zinc-200">
            <h3 class="text-sm font-black text-zinc-900 uppercase tracking-widest">生成歌单卡片</h3>
            <button
              class="text-zinc-500 hover:text-zinc-600 transition-colors"
              @click="$emit('close')"
            >
              <svg class="w-5 h-5" fill="none" stroke="currentColor" stroke-width="2" viewBox="0 0 24 24"><path d="M18 6L6 18M6 6l12 12"/></svg>
            </button>
          </div>

          <div class="p-6 flex flex-col items-center gap-4">
            <!-- 标题输入 -->
            <div class="w-full space-y-2">
              <label class="text-[11px] font-black uppercase text-zinc-600 tracking-wider">歌单标题</label>
              <input
                v-model="cardTitle"
                type="text"
                placeholder="例如: 2026-03-21 校园午间广播"
                class="w-full bg-white border border-zinc-200 rounded-lg px-3 py-2 text-sm text-zinc-600 focus:outline-none focus:border-blue-500/50 transition-colors"
                @input="drawCanvas"
              >
            </div>

            <!-- Canvas 预览 -->
            <div class="relative w-full aspect-[2/3] max-w-[280px] bg-white rounded-xl overflow-hidden border border-zinc-200 shadow-inner flex items-center justify-center">
              <canvas ref="canvasRef" width="400" :height="canvasHeight" class="w-full h-full object-contain bg-white"></canvas>
            </div>
            
            <p class="text-[10px] text-zinc-500 text-center">宽度 400 像素，高度自适应，适合在手机端查看和分享</p>
          </div>

          <div class="p-4 border-t border-zinc-200 bg-zinc-50/50 flex gap-3">
            <button
              class="flex-1 py-2.5 bg-zinc-100 hover:bg-zinc-200 text-zinc-600 text-xs font-bold rounded-xl transition-colors uppercase tracking-wider"
              @click="$emit('close')"
            >
              取消
            </button>
            <button
              class="flex-1 py-2.5 bg-blue-600 hover:bg-blue-500 text-white text-xs font-bold rounded-xl shadow-lg shadow-blue-900/20 transition-colors uppercase tracking-wider"
              @click="downloadCard"
            >
              下载图片
            </button>
          </div>
        </div>
      </Transition>
    </div>
  </Transition>
</template>

<script setup>
import { ref, onMounted, watch, nextTick, computed } from 'vue'

const props = defineProps({
  show: Boolean,
  songs: {
    type: Array,
    default: () => []
  },
  defaultTitle: {
    type: String,
    default: '校园广播歌单'
  }
})

const emit = defineEmits(['close'])

const canvasRef = ref(null)
const cardTitle = ref(props.defaultTitle)

const aiPrompt = ref('anime style school campus sunset beautiful sky highly detailed')
const isGeneratingAi = ref(false)
const bgImageObj = ref(null)

const maxDisplaySongs = 200
const songLeftX = 44
const songRightX = 360
const songAreaWidth = songRightX - songLeftX

const isBrowser = typeof document !== 'undefined'

let _sharedCtx = null
const getSharedCtx = () => {
  if (!isBrowser) return null
  if (_sharedCtx) return _sharedCtx
  try {
    const c = document.createElement('canvas')
    _sharedCtx = c.getContext('2d')
  } catch { _sharedCtx = null }
  return _sharedCtx
}

const fitText = (ctx, text, fontSize, maxWidth, lineHeight) => {
  const hasCtx = !!ctx
  const fontFamily = `"Inter", "system-ui", "PingFang SC", "Microsoft YaHei", sans-serif`
  const avgCharWidth = fontSize * 0.55
  const cjkCharWidth = fontSize * 1.05
  const splitLines = String(text || '').split(/\r?\n/)
  const lines = []
  for (const rawLine of splitLines) {
    if (hasCtx) {
      ctx.font = `${fontSize}px ${fontFamily}`
      const chars = Array.from(rawLine)
      let current = ''
      for (const ch of chars) {
        const tryStr = current + ch
        const w = ctx.measureText(tryStr).width
        if (w > maxWidth && current) {
          lines.push(current)
          current = ch
        } else {
          current = tryStr
        }
      }
      if (current) lines.push(current)
    } else {
      const chars = Array.from(rawLine)
      let current = ''
      let curW = 0
      for (const ch of chars) {
        const code = ch.codePointAt(0) || 0
        const isCJK = code > 0x2e80
        const w = isCJK ? cjkCharWidth : avgCharWidth
        if (curW + w > maxWidth && current) {
          lines.push(current)
          current = ch
          curW = w
        } else {
          current += ch
          curW += w
        }
      }
      if (current) lines.push(current)
    }
  }
  return { lines, lineHeight }
}

const canvasHeight = computed(() => {
  const count = Math.min(props.songs.length, maxDisplaySongs)
  if (!count) return 600
  const ctx = getSharedCtx()
  let totalH = 0
  const maxWidthTitle = songAreaWidth
  const maxWidthArtist = Math.max(100, songAreaWidth - 10)
  for (let i = 0; i < count; i++) {
    const s = props.songs[i]
    const song = s?.song || s || {}
    const title = song.title || '未知歌曲'
    const artist = song.artist || '未知歌手'
    const t1 = fitText(ctx, title, 16, maxWidthTitle, 22)
    const t2 = fitText(ctx, `- ${artist}`, 13, maxWidthArtist, 18)
    totalH += Math.max(28, (t1.lines.length * t1.lineHeight) + (t2.lines.length * t2.lineHeight) + 10)
  }
  return 240 + totalH
})



const drawCanvas = () => {
  if (!canvasRef.value) return
  const canvas = canvasRef.value
  const ctx = canvas.getContext('2d')
  if (!ctx) return
  
  const height = canvasHeight.value
  
  // 清空画布
  if (bgImageObj.value) {
    ctx.drawImage(bgImageObj.value, 0, 0, 400, height)
    // 增加一层半透明黑色遮罩，确保文字和列表框可见
    ctx.fillStyle = 'rgba(0, 0, 0, 0.15)'
    ctx.fillRect(0, 0, 400, height)
  } else {
    ctx.fillStyle = '#F8FAFC' // Background color
    ctx.fillRect(0, 0, 400, height)
  }

  // 绘制渐变头部
  const gradient = ctx.createLinearGradient(0, 0, 400, 0)
  if (bgImageObj.value) {
    gradient.addColorStop(0, 'rgba(0, 0, 0, 0.7)')
    gradient.addColorStop(1, 'rgba(0, 0, 0, 0.4)')
  } else {
    gradient.addColorStop(0, '#2563eb') // Primary Blue
    gradient.addColorStop(1, '#3b82f6')
  }
  ctx.fillStyle = gradient
  ctx.fillRect(0, 0, 400, 100)

  // 绘制标题
  ctx.fillStyle = '#FFFFFF'
  ctx.font = 'bold 24px "Inter", "system-ui", sans-serif'
  ctx.textAlign = 'center'
  ctx.fillText(cardTitle.value || '校园广播歌单', 200, 50)
  
  // 绘制副标题(日期)
  ctx.font = '14px "Inter", "system-ui", sans-serif'
  ctx.fillStyle = 'rgba(0, 0, 0, 0.75)'
  ctx.fillText(new Date().toLocaleDateString('zh-CN'), 200, 80)

  // 绘制列表背景
  if (bgImageObj.value) {
    ctx.fillStyle = 'rgba(255, 255, 255, 0.85)' // 半透明白色背景
  } else {
    ctx.fillStyle = '#FFFFFF'
  }
  ctx.shadowColor = 'rgba(0,0,0,0.05)'
  ctx.shadowBlur = 10
  ctx.shadowOffsetY = 4
  ctx.beginPath()
  ctx.roundRect(20, 120, 360, height - 180, 12)
  ctx.fill()
  ctx.shadowColor = 'transparent'

  // 绘制歌曲列表
  ctx.textAlign = 'left'
  ctx.textBaseline = 'top'
  let y = 160
  
  const displaySongs = props.songs.slice(0, maxDisplaySongs)
  displaySongs.forEach((schedule, index) => {
    const song = schedule.song || schedule
    
    // 序号
    ctx.fillStyle = '#2563eb'
    ctx.font = 'bold 16px "Inter", "system-ui", "PingFang SC", "Microsoft YaHei", sans-serif'
    ctx.textBaseline = 'top'
    ctx.fillText(`${index + 1}.`, 40, y)
    
    const maxWidthTitle = songAreaWidth
    const maxWidthArtist = Math.max(120, songAreaWidth - 10)
    const title = song.title || '未知歌曲'
    const artist = song.artist || '未知歌手'
    
    const t1 = fitText(ctx, title, 16, maxWidthTitle, 22)
    ctx.fillStyle = '#0F172A'
    ctx.font = `bold 16px "Inter", "system-ui", "PingFang SC", "Microsoft YaHei", sans-serif`
    let ty = y
    for (const line of t1.lines) {
      ctx.fillText(line, songLeftX, ty)
      ty += t1.lineHeight
    }
    
    const t2 = fitText(ctx, `- ${artist}`, 13, maxWidthArtist, 18)
    ctx.fillStyle = '#64748B'
    ctx.font = `13px "Inter", "system-ui", "PingFang SC", "Microsoft YaHei", sans-serif`
    let ay = ty + 4
    for (const line of t2.lines) {
      ctx.fillText(line, songLeftX, ay)
      ay += t2.lineHeight
    }
    
    const songBlockHeight = Math.max(28, (ty - y) + (ay - ty) + 4)
    y += songBlockHeight + 8
  })
  
  if (props.songs.length > maxDisplaySongs) {
    ctx.fillStyle = '#94A3B8'
    ctx.font = '14px "Inter", "system-ui", sans-serif'
    ctx.textAlign = 'center'
    ctx.fillText(`...及其他 ${props.songs.length - maxDisplaySongs} 首歌曲`, 200, y + 10)
  }

  // 绘制底部水印
  if (bgImageObj.value) {
    ctx.fillStyle = 'rgba(0, 0, 0, 0.55)'
  } else {
    ctx.fillStyle = '#CBD5E1'
  }
  ctx.font = '12px "Inter", "system-ui", sans-serif'
  ctx.textAlign = 'center'
  ctx.fillText('Generated by VoiceHub', 200, height - 20)
}

const downloadCard = () => {
  if (!canvasRef.value) return
  const dataUrl = canvasRef.value.toDataURL('image/png')
  const link = document.createElement('a')
  link.download = `歌单卡片_${new Date().toISOString().split('T')[0]}.png`
  link.href = dataUrl
  link.click()
  
  if (window.$showNotification) {
    window.$showNotification('图片导出成功', 'success')
  }
}

watch(() => props.show, (newVal) => {
  if (newVal) {
    cardTitle.value = props.defaultTitle
    nextTick(() => {
      drawCanvas()
    })
  }
})
</script>

<style scoped>
.fade-enter-active,
.fade-leave-active {
  transition: opacity 0.2s ease;
}
.fade-enter-from,
.fade-leave-to {
  opacity: 0;
}
.scale-enter-active,
.scale-leave-active {
  transition: transform 0.2s ease, opacity 0.2s ease;
}
.scale-enter-from,
.scale-leave-to {
  transform: scale(0.95);
  opacity: 0;
}
</style>