<template>
  <div class="course-detail-container">
    <!-- 课程头部 -->
    <div class="course-header card">
      <div class="header-content">
        <div class="breadcrumb">
          <el-breadcrumb separator="/">
            <el-breadcrumb-item :to="{ path: '/trainee/course-center' }">
              课程中心
            </el-breadcrumb-item>
            <el-breadcrumb-item>{{ courseInfo.title }}</el-breadcrumb-item>
          </el-breadcrumb>
        </div>
        
        <h1 class="course-title">{{ courseInfo.title }}</h1>
        <p class="course-desc">{{ courseInfo.description }}</p>
        
        <div class="course-meta">
          <span class="meta-item">
            <el-icon><Clock /></el-icon>
            时长：{{ courseInfo.duration }}
          </span>
          <span class="meta-item">
            <el-icon><Document /></el-icon>
            资料：{{ materials.length }} 个
          </span>
          <span class="meta-item">
            <el-icon><View /></el-icon>
            学习人数：{{ courseInfo.students }}
          </span>
        </div>

        <div class="progress-section">
          <div class="progress-info">
            <span>学习进度</span>
            <span class="progress-value">{{ courseInfo.progress }}%</span>
          </div>
          <el-progress :percentage="courseInfo.progress" :stroke-width="10" />
        </div>
      </div>
    </div>

    <!-- 课程内容 -->
    <div class="course-content">
      <!-- 侧边栏：资料列表 -->
      <div class="content-sidebar card">
        <div class="sidebar-header">
          <h3 class="sidebar-title">学习资料</h3>
          <el-input
            v-model="searchKeyword"
            placeholder="搜索资料"
            size="small"
            clearable
            style="width: 180px"
          >
            <template #prefix>
              <el-icon><Search /></el-icon>
            </template>
          </el-input>
        </div>
        
        <!-- 文件类型筛选 -->
        <div class="file-type-filter">
          <el-radio-group v-model="fileTypeFilter" size="small">
            <el-radio-button label="">全部</el-radio-button>
            <el-radio-button label="document">文档</el-radio-button>
            <el-radio-button label="video">视频</el-radio-button>
            <el-radio-button label="audio">音频</el-radio-button>
            <el-radio-button label="image">图片</el-radio-button>
          </el-radio-group>
            </div>
            
        <div class="material-list" v-loading="loadingMaterials">
          <div 
            class="material-item"
            :class="{ active: currentMaterial?.id === material.id }"
            v-for="material in filteredMaterials"
            :key="material.id"
            @click="selectMaterial(material)"
          >
            <el-icon class="material-icon" :size="20">
              <component :is="getMaterialIcon(material.name)" />
                  </el-icon>
            <div class="material-info">
              <div class="material-name" :title="material.name">{{ material.name }}</div>
              <div class="material-meta">
                <span>{{ formatFileSize(material.file_size) }}</span>
                <span>{{ getFileType(material.name) }}</span>
              </div>
            </div>
          </div>
          
          <el-empty 
            v-if="filteredMaterials.length === 0 && !loadingMaterials" 
            description="暂无资料"
            :image-size="80"
          />
        </div>
      </div>

      <!-- 主内容区：预览区域 -->
      <div class="content-main card">
        <div v-if="!currentMaterial" class="empty-state">
          <el-icon :size="64" color="#909399"><Document /></el-icon>
          <p>请从左侧选择学习资料</p>
        </div>
        
        <div v-else class="preview-container" v-loading="loadingPreview" ref="previewContainerRef" :class="{ 'is-fullscreen': isFullscreen }">
          <!-- 工具栏 -->
          <div class="preview-toolbar">
            <div class="toolbar-left">
              <h2 class="preview-title">{{ currentMaterial.name }}</h2>
          </div>
            <div class="toolbar-right">
              <el-button v-if="courseInfo.allow_download" @click="downloadCurrent" :icon="Download">
                下载
              </el-button>
              <el-button @click="toggleFullscreen" v-if="canFullscreen" :icon="isFullscreen ? Close : FullScreen">
                {{ isFullscreen ? '退出全屏' : '全屏' }}
              </el-button>
            </div>
          </div>
          
          <!-- 预览内容 -->
          <div class="preview-content" ref="previewContentRef">
            <!-- PDF预览 -->
            <div v-if="previewInfo?.preview_type === 'pdf'" class="pdf-viewer-container">
              <div class="pdf-toolbar">
                <div class="page-controls">
                  <el-button :icon="ArrowLeft" size="small" :disabled="pdfPage <= 1" @click="pdfPage--" />
                  <span class="page-info" v-if="pdfPages > 0">{{ pdfPage }} / {{ pdfPages }}</span>
                  <el-button :icon="ArrowRight" size="small" :disabled="pdfPage >= pdfPages" @click="pdfPage++" />
                </div>
                <div class="zoom-controls">
                  <el-button :icon="ZoomOut" size="small" @click="pdfScale = Math.max(0.5, pdfScale - 0.25)" />
                  <span class="zoom-info">{{ Math.round(pdfScale * 100) }}%</span>
                  <el-button :icon="ZoomIn" size="small" @click="pdfScale = Math.min(3.0, pdfScale + 0.25)" />
                </div>
              </div>
              <div class="pdf-wrapper" ref="pdfWrapperRef">
                <div class="pdf-scale-wrapper" :style="pdfScaleStyle">
                  <vue-pdf-embed
                    :source="getPreviewUrl(previewInfo.preview_url)"
                    :page="pdfPage"
                    :width="pdfDisplayWidth"
                    @loaded="handlePdfLoad"
                    @loading-failed="handlePdfError"
                  />
                </div>
              </div>
            </div>
            
            <!-- 视频预览 -->
            <div v-else-if="previewInfo?.preview_type === 'video'" class="video-viewer">
              <video 
                controls 
                width="100%" 
                :src="getPreviewUrl(previewInfo.preview_url)"
              >
                您的浏览器不支持视频播放
              </video>
            </div>
            
            <!-- 音频预览 -->
            <div v-else-if="previewInfo?.preview_type === 'audio'" class="audio-viewer">
              <div class="audio-wrapper">
                <el-icon :size="80" color="#409eff"><Headset /></el-icon>
                <h3>{{ currentMaterial.name }}</h3>
                <audio 
                  controls 
                  :src="getPreviewUrl(previewInfo.preview_url)"
                  style="width: 100%; max-width: 600px; margin-top: 20px;"
                >
                  您的浏览器不支持音频播放
                </audio>
              </div>
            </div>
            
            <!-- 图片预览 -->
            <div v-else-if="previewInfo?.preview_type === 'image'" class="image-viewer">
              <el-image 
                :src="getPreviewUrl(previewInfo.preview_url)" 
                :preview-src-list="[getPreviewUrl(previewInfo.preview_url)]"
                fit="contain"
                style="width: 100%; height: 100%;"
              />
          </div>
          
            <!-- Markdown 预览 -->
            <div v-else-if="previewInfo?.preview_type === 'text' && isMarkdownFile(currentMaterial?.name)" class="markdown-viewer">
              <div class="markdown-content" v-html="renderedMarkdown"></div>
            </div>
            
            <!-- 文本预览 -->
            <div v-else-if="previewInfo?.preview_type === 'text'" class="text-viewer">
              <div class="text-content">
                <pre>{{ previewInfo.content }}</pre>
              </div>
            </div>
            
            <!-- HTML预览（Excel等） -->
            <div v-else-if="previewInfo?.preview_type === 'html' && previewInfo?.is_converted" class="html-viewer">
              <iframe 
                :src="getPreviewUrl(previewInfo.preview_url)"
                frameborder="0"
                allowfullscreen
                class="html-iframe"
              />
            </div>
            
            <!-- 下载模式 -->
            <div v-else-if="previewInfo?.preview_type === 'download'" class="download-viewer">
              <div class="download-wrapper">
                <el-icon :size="80" color="#909399"><Download /></el-icon>
                <h3>{{ currentMaterial.name }}</h3>
                <p>此文件暂不支持在线预览</p>
                <el-button v-if="courseInfo.allow_download" type="primary" size="large" @click="downloadCurrent" :icon="Download">
                  下载文件
                </el-button>
                <el-tag v-else type="info" size="large">该课程不允许下载资料</el-tag>
                <div class="file-info">
                  <span>文件大小：{{ formatFileSize(currentMaterial.file_size) }}</span>
                  <span>文件类型：{{ getFileType(currentMaterial.name) }}</span>
                </div>
              </div>
          </div>

            <!-- 转换中提示 -->
            <div v-if="isConverting" class="converting-hint">
              <el-icon class="is-loading" :size="24"><Loading /></el-icon>
              <span>正在转换文档，请稍候...</span>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</template>

<script setup lang="ts">
import { ref, computed, onMounted, onUnmounted } from 'vue'
import { useRoute, useRouter } from 'vue-router'
import { ElMessage } from 'element-plus'
import { 
  Clock, Document, View, Search, Download, 
  Headset, Loading, VideoCamera, Picture,
  ArrowLeft, ArrowRight, ZoomIn, ZoomOut, Close, FullScreen
} from '@element-plus/icons-vue'
import VuePdfEmbed from 'vue-pdf-embed'
import * as pdfjsLib from 'pdfjs-dist'

// 使用 Vite 的 ?url 导入方式获取 worker 文件的 URL
import pdfWorker from 'pdfjs-dist/build/pdf.worker?url'
import { getCourseDetail } from '@/api/trainee'
import { getMaterials, getPreview, downloadFile } from '@/api/material'
import type { Material, PreviewInfo } from '@/types/material'
import { formatFileSize, getFileCategory, getFileExtension } from '@/types/material'
import MarkdownIt from 'markdown-it'
import DOMPurify from 'dompurify'

// 配置 PDF.js worker
pdfjsLib.GlobalWorkerOptions.workerSrc = pdfWorker

// 解决 pdfjs 字体加载导致的 OTS parsing error
// 使用本地化资源（/public/pdfjs/），避免依赖国外 CDN
const CMAP_URL = '/pdfjs/cmaps/'
const STANDARD_FONT_DATA_URL = '/pdfjs/standard_fonts/'

pdfjsLib.GlobalWorkerOptions.cMapUrl = CMAP_URL
pdfjsLib.GlobalWorkerOptions.cMapPacked = true
pdfjsLib.GlobalWorkerOptions.standardFontDataUrl = STANDARD_FONT_DATA_URL

const route = useRoute()
const router = useRouter()
const courseId = computed(() => route.query.id as string)

// 状态定义
const courseInfo = ref<any>({})
const materials = ref<Material[]>([])
const currentMaterial = ref<Material | null>(null)
const previewInfo = ref<PreviewInfo | null>(null)
const loadingMaterials = ref(false)
const loadingPreview = ref(false)
const searchKeyword = ref('')
const fileTypeFilter = ref('')
const isConverting = ref(false)
const isFullscreen = ref(false)

// PDF 相关状态
const pdfPage = ref(1)
const pdfPages = ref(0)
const pdfScale = ref(1.0)
const pdfLoading = ref(true)
const pdfContainerWidth = ref(0)
const pdfWrapperRef = ref<HTMLElement>()

// 预览容器引用
const previewContentRef = ref<HTMLElement>()
const previewContainerRef = ref<HTMLElement>()

// 设备像素比（用于高清屏幕渲染）
const devicePixelRatio = ref(typeof window !== 'undefined' ? window.devicePixelRatio || 1 : 1)

// PDF 渲染缩放比（用于高清渲染）
const pdfRenderScale = computed(() => {
  // 使用设备像素比，最小1.5倍，最大3倍（避免内存问题）
  return Math.min(Math.max(devicePixelRatio.value, 1.5), 3)
})

// PDF 显示宽度（考虑设备像素比以解决手机端模糊问题）
const pdfDisplayWidth = computed(() => {
  if (!pdfContainerWidth.value) return undefined
  // 基础宽度 = 容器宽度 - 内边距
  const baseWidth = (pdfContainerWidth.value - 40) * pdfScale.value
  // 乘以渲染缩放比，提高渲染分辨率
  return baseWidth * pdfRenderScale.value
})

// PDF 缩放样式（将高分辨率渲染缩放回正常显示尺寸）
const pdfScaleStyle = computed(() => {
  const scale = 1 / pdfRenderScale.value
  return {
    transform: `scale(${scale})`,
    transformOrigin: 'top center'
  }
})

// Markdown 渲染
const md = new MarkdownIt({
  html: true,
  linkify: true,
  typographer: true
})

const renderedMarkdown = computed(() => {
  if (previewInfo.value?.preview_type === 'text' && isMarkdownFile(currentMaterial.value?.name)) {
    return DOMPurify.sanitize(md.render(previewInfo.value.content || ''))
  }
  return ''
})

// 过滤后的资料列表
const filteredMaterials = computed(() => {
  let result = materials.value
  
  if (searchKeyword.value) {
    const keyword = searchKeyword.value.toLowerCase()
    result = result.filter(m => m.name.toLowerCase().includes(keyword))
  }
  
  if (fileTypeFilter.value) {
    result = result.filter(m => getFileCategory(m.name) === fileTypeFilter.value)
  }
  
  return result
})

// 全屏相关 - 支持所有预览类型（除了下载模式）
const canFullscreen = computed(() => {
  return previewInfo.value && previewInfo.value.preview_type !== 'download'
})

// 图标映射
const getMaterialIcon = (fileName: string) => {
  const type = getFileCategory(fileName)
  switch (type) {
    case 'document': return Document
    case 'video': return VideoCamera
    case 'audio': return Headset
    case 'image': return Picture
    default: return Document
  }
}

// 获取文件类型显示名称
const getFileType = (fileName: string) => {
  const ext = getFileExtension(fileName).toUpperCase()
  return ext || '未知'
}

// 是否为 Markdown 文件
const isMarkdownFile = (fileName?: string) => {
  if (!fileName) return false
  const ext = getFileExtension(fileName).toLowerCase()
  return ['md', 'markdown'].includes(ext)
}

// 获取预览 URL
const getPreviewUrl = (url?: string) => {
  if (!url) return ''
  return url
}

// 加载课程信息
const loadCourseInfo = async () => {
  try {
    const res: any = await getCourseDetail(courseId.value)
    if (res.code === 200) {
      courseInfo.value = res.data
    }
  } catch (error) {
    console.error('获取课程详情失败:', error)
    ElMessage.error('获取课程详情失败')
  }
}

// 加载资料列表
const loadMaterials = async () => {
  loadingMaterials.value = true
  try {
    const res: any = await getMaterials(courseId.value)
    if (res.code === 200) {
      materials.value = res.data
      // 如果有资料，默认选中第一个
      if (materials.value.length > 0) {
        selectMaterial(materials.value[0])
      }
    }
  } catch (error) {
    console.error('获取资料列表失败:', error)
    ElMessage.error('获取资料列表失败')
  } finally {
    loadingMaterials.value = false
  }
}

// 选择资料
const selectMaterial = async (material: Material) => {
  if (currentMaterial.value?.id === material.id) return
  
  currentMaterial.value = material
  loadingPreview.value = true
  pdfScale.value = 1.0
  pdfPage.value = 1
  
  try {
    const res: any = await getPreview(material.id)
    if (res.code === 200) {
      previewInfo.value = res.data
      // 如果是 PDF，等待 DOM 更新后计算宽度
      if (previewInfo.value?.preview_type === 'pdf') {
        setTimeout(debouncedUpdatePdfContainerWidth, 100)
      }
    } else if (res.code === 202) {
      isConverting.value = true
      // 轮询检查转换状态
      checkConversionStatus(material.id)
    }
  } catch (error) {
    console.error('获取预览信息失败:', error)
    ElMessage.error('获取预览信息失败')
  } finally {
    loadingPreview.value = false
  }
}

// 检查转换状态（简单模拟）
const checkConversionStatus = (materialId: string) => {
  const timer = setInterval(async () => {
    if (currentMaterial.value?.id !== materialId) {
      clearInterval(timer)
      return
    }
    
    try {
      const res: any = await getPreview(materialId)
      if (res.code === 200) {
        clearInterval(timer)
        isConverting.value = false
        previewInfo.value = res.data
      }
    } catch (e) {
      clearInterval(timer)
    }
  }, 3000)
}

// 下载文件
const downloadCurrent = () => {
  if (!currentMaterial.value) return
  downloadFile(currentMaterial.value.id, currentMaterial.value.name)
}

// 全屏切换
const toggleFullscreen = () => {
  if (isFullscreen.value) {
    exitFullscreen()
  } else {
    enterFullscreen()
  }
}

// 进入全屏
const enterFullscreen = () => {
  const el = previewContainerRef.value as any
  if (!el) return

  // 尝试原生全屏
  if (el.requestFullscreen) {
    el.requestFullscreen()
  } else if (el.webkitRequestFullscreen) { /* Safari */
    el.webkitRequestFullscreen()
  } else if (el.msRequestFullscreen) { /* IE11 */
    el.msRequestFullscreen()
  } else {
    // 降级方案：CSS全屏
    isFullscreen.value = true
    // PDF需要在布局变化后重新计算宽度
    setTimeout(debouncedUpdatePdfContainerWidth, 100)
  }
}

// 退出全屏
const exitFullscreen = () => {
  // 尝试退出原生全屏
  if (document.fullscreenElement || (document as any).webkitFullscreenElement || (document as any).msFullscreenElement) {
    if (document.exitFullscreen) {
      document.exitFullscreen()
    } else if ((document as any).webkitExitFullscreen) {
      (document as any).webkitExitFullscreen()
    } else if ((document as any).msExitFullscreen) {
      (document as any).msExitFullscreen()
    }
  } else {
    // 退出CSS全屏
    isFullscreen.value = false
    // PDF需要在布局变化后重新计算宽度
    setTimeout(debouncedUpdatePdfContainerWidth, 100)
  }
}

// 监听原生全屏变化
const handleFullscreenChange = () => {
  const isNativeFullscreen = !!(document.fullscreenElement || (document as any).webkitFullscreenElement || (document as any).msFullscreenElement)
  isFullscreen.value = isNativeFullscreen
  // 状态变化时更新PDF宽度
  setTimeout(debouncedUpdatePdfContainerWidth, 100)
}

// PDF 相关方法
const updatePdfContainerWidth = () => {
  if (pdfWrapperRef.value) {
    pdfContainerWidth.value = pdfWrapperRef.value.clientWidth
  }
}

// 防抖函数
const debounce = (func: Function, delay: number) => {
  let timeout: ReturnType<typeof setTimeout>
  return function(this: any, ...args: any[]) {
    const context = this
    clearTimeout(timeout)
    timeout = setTimeout(() => func.apply(context, args), delay)
  }
}

const debouncedUpdatePdfContainerWidth = debounce(updatePdfContainerWidth, 200)

const handlePdfLoad = (pdfDoc: any) => {
  pdfLoading.value = false
  pdfPages.value = pdfDoc.numPages
}

const handlePdfError = (error: any) => {
  console.error('PDF加载失败:', error)
  ElMessage.error('PDF加载失败，请尝试下载查看')
  pdfLoading.value = false
}

onMounted(() => {
  if (!courseId.value) {
    ElMessage.error('课程ID无效')
    router.push('/trainee/course-center')
    return
  }
  
  loadCourseInfo()
  loadMaterials()
  
  // 添加resize监听
  window.addEventListener('resize', debouncedUpdatePdfContainerWidth)
  
  // 添加全屏监听
  document.addEventListener('fullscreenchange', handleFullscreenChange)
  document.addEventListener('webkitfullscreenchange', handleFullscreenChange)
  document.addEventListener('mozfullscreenchange', handleFullscreenChange)
  document.addEventListener('MSFullscreenChange', handleFullscreenChange)

  setTimeout(debouncedUpdatePdfContainerWidth, 500) // 增加延时确保DOM就绪
})

onUnmounted(() => {
  window.removeEventListener('resize', debouncedUpdatePdfContainerWidth)
  document.removeEventListener('fullscreenchange', handleFullscreenChange)
  document.removeEventListener('webkitfullscreenchange', handleFullscreenChange)
  document.removeEventListener('mozfullscreenchange', handleFullscreenChange)
  document.removeEventListener('MSFullscreenChange', handleFullscreenChange)
})
</script>

<style lang="scss" scoped>
.course-detail-container {
  max-width: 1600px;
  margin: 0 auto;
  padding: 20px;
  min-height: calc(100vh - 60px);
  display: flex;
  flex-direction: column;
  
  .card {
    background: white;
    border-radius: 12px;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
  }

  .course-header {
    padding: 24px;
    margin-bottom: 20px;

    .header-content {
      .breadcrumb {
        margin-bottom: 16px;
      }

      .course-title {
        font-size: 28px;
        font-weight: 600;
        color: #1a1a1a;
        margin: 0 0 12px 0;
      }

      .course-desc {
        color: #606266;
        font-size: 14px;
        line-height: 1.6;
        margin-bottom: 20px;
      }

      .course-meta {
        display: flex;
        gap: 24px;
        margin-bottom: 24px;

        .meta-item {
          display: flex;
          align-items: center;
          gap: 6px;
          color: #606266;
          font-size: 14px;

          .el-icon {
            color: #409eff;
          }
        }
      }

      .progress-section {
        .progress-info {
          display: flex;
          justify-content: space-between;
          margin-bottom: 8px;
          font-size: 14px;
          color: #606266;

          .progress-value {
            font-weight: 600;
            color: #409eff;
          }
        }
      }
    }
  }

  .course-content {
    display: flex;
    gap: 20px;
    flex: 1;
    min-height: 600px;

    .content-sidebar {
      width: 320px;
      flex-shrink: 0;
      padding: 20px;
      display: flex;
      flex-direction: column;
      max-height: calc(100vh - 280px);
      
      .sidebar-header {
        display: flex;
        justify-content: space-between;
        align-items: center;
        margin-bottom: 16px;

      .sidebar-title {
        font-size: 18px;
        font-weight: 600;
        color: #333;
          margin: 0;
        }
      }
      
      .file-type-filter {
        margin-bottom: 16px;
        
        :deep(.el-radio-group) {
          display: flex;
          flex-wrap: wrap;
          gap: 8px;
          
          .el-radio-button {
            margin: 0;
          }
          
          .el-radio-button__inner {
            padding: 6px 12px;
            font-size: 12px;
            border-radius: 6px;
          }
        }
      }
      
      .material-list {
        flex: 1;
        overflow-y: auto;
        
        .material-item {
            display: flex;
            align-items: center;
          gap: 12px;
          padding: 12px;
          border-radius: 8px;
            cursor: pointer;
          transition: all 0.3s;
          margin-bottom: 8px;

            &:hover {
            background: #f5f7fa;
          }
          
          &.active {
            background: rgba(64, 158, 255, 0.1);
            border-left: 3px solid #409eff;
          }
          
          .material-icon {
            color: #409eff;
            flex-shrink: 0;
          }
          
          .material-info {
              flex: 1;
            min-width: 0;
            
            .material-name {
              font-size: 14px;
              font-weight: 500;
              color: #333;
              overflow: hidden;
              text-overflow: ellipsis;
              white-space: nowrap;
              margin-bottom: 4px;
            }

            .material-meta {
              display: flex;
              gap: 12px;
              font-size: 12px;
              color: #909399;
            }
          }
        }
      }
    }

    .content-main {
      flex: 1;
      padding: 20px;
      min-width: 0;
      display: flex;
      flex-direction: column;
      min-height: calc(100vh - 280px);

      .empty-state {
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        height: 500px;
        color: #909399;

        p {
          margin-top: 16px;
          font-size: 16px;
        }
      }
      
      .preview-container {
        display: flex;
        flex-direction: column;
        flex: 1;
        height: 100%;
        min-height: 600px;

        // CSS全屏模式样式
        &.is-fullscreen {
          position: fixed;
          top: 0;
          left: 0;
          width: 100vw;
          height: 100vh;
          z-index: 2000;
          background: white;
          margin: 0;
          padding: 16px;
          box-sizing: border-box;
          border-radius: 0;
          
          .preview-toolbar {
            padding-bottom: 12px;
            margin-bottom: 12px;
          }
          
          .preview-content {
            min-height: 0;
            height: auto;
            flex: 1;
            overflow: auto;
            
            .pdf-viewer-container {
              height: 100%;
              
              .pdf-wrapper {
                height: calc(100% - 50px);
              }
            }
            
            .video-viewer,
            .image-viewer,
            .html-viewer {
              height: 100%;
              
              video,
              iframe,
              .html-iframe {
                height: 100%;
                min-height: auto;
              }
            }
            
            .markdown-viewer,
            .text-viewer {
              height: 100%;
              
              .markdown-content,
              .text-content {
                height: 100%;
              }
            }
          }
        }
        
        .preview-toolbar {
          display: flex;
          justify-content: space-between;
          align-items: center;
          padding-bottom: 16px;
          border-bottom: 1px solid #e4e7ed;
          margin-bottom: 20px;
          
          .toolbar-left {
            flex: 1;
            min-width: 0;
            
            .preview-title {
              font-size: 20px;
          font-weight: 600;
          color: #333;
              margin: 0;
              overflow: hidden;
              text-overflow: ellipsis;
              white-space: nowrap;
            }
          }
          
          .toolbar-right {
            display: flex;
            gap: 12px;
          }
        }
        
        .preview-content {
          flex: 1;
          position: relative;
          min-height: 500px;
          display: flex;
          flex-direction: column;
          
          .pdf-viewer-container {
            display: flex;
            flex-direction: column;
            flex: 1;
            background: #f5f7fa;
            border-radius: 8px;
            overflow: hidden;

            .pdf-toolbar {
              display: flex;
              justify-content: space-between;
              align-items: center;
              padding: 10px 20px;
              background: #fff;
              border-bottom: 1px solid #e4e7ed;
              flex-shrink: 0;
              
              .page-controls,
              .zoom-controls {
                display: flex;
                align-items: center;
                gap: 12px;
                
                span {
                  font-size: 14px;
                  color: #606266;
                  min-width: 60px;
                  text-align: center;
                }
              }
            }

            .pdf-wrapper {
              flex: 1;
              overflow: auto;
              padding: 20px;
              display: flex;
              justify-content: center;
              align-items: flex-start;
              
              // 高清渲染缩放容器
              .pdf-scale-wrapper {
                display: flex;
                justify-content: center;
                
                :deep(.vue-pdf-embed) {
                  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
                  background: white;
                  // 确保canvas渲染清晰
                  image-rendering: -webkit-optimize-contrast;
                  image-rendering: crisp-edges;
                }
              }
            }
          }
          
          .video-viewer,
          .image-viewer {
            width: 100%;
            flex: 1;
            display: flex;
            flex-direction: column;
            min-height: 500px;
            
            iframe,
            video {
              border-radius: 8px;
              flex: 1;
            }
          }
          
          .html-viewer {
            width: 100%;
            flex: 1;
            display: flex;
            flex-direction: column;
            min-height: 600px;
            
            .html-iframe {
              width: 100%;
              flex: 1;
              // 使用视口高度计算，确保 iframe 有足够高度显示内容
              // 减去：导航栏(60px) + 课程头部(约180px) + 工具栏(约80px) + padding(40px)
              height: calc(100vh - 360px);
              min-height: 600px;
              border-radius: 8px;
              background: white;
            }
          }
          
          .audio-viewer,
          .download-viewer {
            display: flex;
            align-items: center;
            justify-content: center;
            flex: 1;
            
            .audio-wrapper,
            .download-wrapper {
              text-align: center;
              padding: 40px;
              
              h3 {
                margin: 20px 0;
                color: #333;
                font-size: 18px;
              }
              
              p {
                color: #909399;
                margin-bottom: 24px;
              }
              
              .file-info {
                margin-top: 20px;
            display: flex;
                gap: 24px;
            justify-content: center;
                color: #909399;
                font-size: 14px;
              }
            }
          }
          
          .markdown-viewer {
            width: 100%;
            flex: 1;
            display: flex;
            flex-direction: column;
            
            .markdown-content {
              background: white;
              border-radius: 8px;
              padding: 30px;
              flex: 1;
              overflow: auto;
              
              // Markdown 基础样式
              :deep(h1), :deep(h2), :deep(h3), :deep(h4), :deep(h5), :deep(h6) {
                margin-top: 24px;
                margin-bottom: 16px;
                font-weight: 600;
                line-height: 1.25;
                color: #1a1a1a;
              }
              
              :deep(h1) {
                font-size: 2em;
                padding-bottom: 0.3em;
                border-bottom: 1px solid #eaecef;
              }
              
              :deep(h2) {
                font-size: 1.5em;
                padding-bottom: 0.3em;
                border-bottom: 1px solid #eaecef;
              }
              
              :deep(h3) { font-size: 1.25em; }
              :deep(h4) { font-size: 1em; }
              :deep(h5) { font-size: 0.875em; }
              :deep(h6) { font-size: 0.85em; color: #6a737d; }
              
              :deep(p) {
                margin-top: 0;
                margin-bottom: 16px;
                line-height: 1.6;
                color: #333;
              }
              
              :deep(a) {
                color: #409eff;
                text-decoration: none;
                
                &:hover {
                  text-decoration: underline;
                }
              }
              
              :deep(ul), :deep(ol) {
                margin-top: 0;
                margin-bottom: 16px;
                padding-left: 2em;
              }
              
              :deep(li) {
                margin-top: 0.25em;
                line-height: 1.6;
              }
              
              :deep(blockquote) {
                margin: 16px 0;
                padding: 0 1em;
                color: #6a737d;
                border-left: 4px solid #dfe2e5;
                
                p {
                  margin-bottom: 0;
                }
              }
              
              :deep(code) {
                padding: 0.2em 0.4em;
                margin: 0;
                font-size: 85%;
                background-color: rgba(27, 31, 35, 0.05);
                border-radius: 3px;
                font-family: 'Courier New', monospace;
              }
              
              :deep(pre) {
                padding: 16px;
                overflow: auto;
                font-size: 85%;
                line-height: 1.45;
                background-color: #f6f8fa;
                border-radius: 6px;
                margin-bottom: 16px;
                
                code {
                  padding: 0;
                  background-color: transparent;
                }
              }
              
              :deep(table) {
                border-spacing: 0;
                border-collapse: collapse;
                margin-bottom: 16px;
                width: 100%;
                overflow: auto;
                
                th, td {
                  padding: 6px 13px;
                  border: 1px solid #dfe2e5;
                }
                
                th {
                  font-weight: 600;
                  background-color: #f6f8fa;
                }
                
                tr {
                  background-color: white;
                  border-top: 1px solid #c6cbd1;
                  
                  &:nth-child(2n) {
                    background-color: #f6f8fa;
                  }
                }
              }
              
              :deep(hr) {
                height: 0.25em;
                padding: 0;
                margin: 24px 0;
                background-color: #e1e4e8;
                border: 0;
              }
              
              :deep(img) {
                max-width: 100%;
                box-sizing: content-box;
                background-color: white;
              }
              
              :deep(strong) {
                font-weight: 600;
              }
              
              :deep(em) {
                font-style: italic;
              }
            }
          }
          
          .text-viewer {
            width: 100%;
            flex: 1;
            display: flex;
            flex-direction: column;
            
            .text-content {
              background: #f5f7fa;
              border-radius: 8px;
              padding: 20px;
              flex: 1;
              overflow: auto;
              
              pre {
                margin: 0;
                white-space: pre-wrap;
                word-wrap: break-word;
                font-family: 'Courier New', monospace;
                font-size: 14px;
                line-height: 1.6;
                color: #333;
              }
            }
          }
          
          .converting-hint {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 20px 30px;
            background: rgba(255, 255, 255, 0.95);
            border-radius: 8px;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
            font-size: 16px;
            color: #409eff;
            font-weight: 500;
          }
        }
      }
    }
  }
}

  // 响应式设计
  @media (max-width: 1200px) {
    .course-detail-container {
      .course-content {
        flex-direction: column;

        .content-sidebar {
          width: 100%;
          max-height: 300px;
        }
      }
    }
  }

  @media (max-width: 768px) {
    .course-detail-container {
      padding: 10px;

      .course-header {
        padding: 16px;
        margin-bottom: 12px;

        .header-content {
          .course-title {
            font-size: 20px;
          }
          
          .course-meta {
            flex-wrap: wrap;
            gap: 12px;
          }
        }
      }

      .course-content {
        gap: 12px;

        .content-sidebar {
          padding: 12px;
          
          .sidebar-header {
            margin-bottom: 12px;
          }
        }

        .content-main {
          padding: 12px;

          .preview-container {
            min-height: 400px;

            .preview-toolbar {
              flex-direction: column;
              align-items: flex-start;
              gap: 12px;
              margin-bottom: 12px;
              
              .toolbar-left {
                width: 100%;
              }
              
              .toolbar-right {
                width: 100%;
                justify-content: flex-end;
              }
            }

            .preview-content {
              .pdf-viewer-container {
                .pdf-wrapper {
                  padding: 10px;
                }
              }
            }
          }
        }
      }
    }
  }
</style>
