import { useState, useEffect, useRef } from 'react'
import { useParams, useNavigate } from 'react-router-dom'
import { Layout, Menu, Spin, FloatButton, Button, Tooltip, message, Anchor, Modal, Input, Switch, Space, Dropdown } from 'antd'
import { EditOutlined, VerticalAlignTopOutlined, ShareAltOutlined, MenuFoldOutlined, MenuUnfoldOutlined, FileTextOutlined, FolderOutlined, FilePdfOutlined, CopyOutlined, LockOutlined, CloudDownloadOutlined, CloudUploadOutlined, DownOutlined } from '@ant-design/icons'
import ReactMarkdown from 'react-markdown'
import remarkGfm from 'remark-gfm'
import rehypeRaw from 'rehype-raw'
import rehypeSlug from 'rehype-slug'
import rehypeHighlight from 'rehype-highlight'
import 'highlight.js/styles/github.css'
import { getProjectTree, getFileContent, getDocumentUrl } from '@/api/file'
import { gitPull, gitPush, getGitRepos } from '@/api/project'
import { getProjectShareInfo, updateShareSettings } from '@/api/share'
import VirtualPDFViewer from '@/components/PDFViewer/VirtualPDFViewer'
import Toast from '@/components/Toast/Toast'
import './DocumentPage.css'

const { Sider, Content } = Layout

function DocumentPage() {
  const { projectId } = useParams()
  const navigate = useNavigate()
  const [fileTree, setFileTree] = useState([])
  const [selectedFile, setSelectedFile] = useState('')
  const [markdownContent, setMarkdownContent] = useState('')
  const [loading, setLoading] = useState(false)
  const [openKeys, setOpenKeys] = useState([])
  const [tocCollapsed, setTocCollapsed] = useState(false)
  const [tocItems, setTocItems] = useState([])
  const [shareModalVisible, setShareModalVisible] = useState(false)
  const [shareInfo, setShareInfo] = useState(null)
  const [hasPassword, setHasPassword] = useState(false)
  const [password, setPassword] = useState('')
  const [userRole, setUserRole] = useState('viewer') // 用户角色：owner/admin/editor/viewer
  const [pdfViewerVisible, setPdfViewerVisible] = useState(false)
  const [pdfUrl, setPdfUrl] = useState('')
  const [pdfFilename, setPdfFilename] = useState('')
  const [viewMode, setViewMode] = useState('markdown') // 'markdown' or 'pdf'
  const [gitRepos, setGitRepos] = useState([])
  const contentRef = useRef(null)

  useEffect(() => {
    loadFileTree()
  }, [projectId])

  useEffect(() => {
    if (userRole && userRole !== 'viewer') {
      loadGitRepos()
    }
  }, [projectId, userRole])

  const loadGitRepos = async () => {
    try {
      const res = await getGitRepos(projectId)
      setGitRepos(res.data || [])
    } catch (error) {
      console.error('Load git repos error:', error)
    }
  }

  // 加载文件树
  const loadFileTree = async () => {
    try {
      const res = await getProjectTree(projectId)
      const data = res.data || {}
      const tree = data.tree || data || []  // 兼容新旧格式
      const role = data.user_role || 'viewer'

      setFileTree(tree)
      setUserRole(role)

      // 默认打开 README.md
      const readmeNode = findReadme(tree)
      if (readmeNode) {
        setSelectedFile(readmeNode.key)
        loadMarkdown(readmeNode.key)
      }
    } catch (error) {
      console.error('Load file tree error:', error)
    }
  }

  // 查找根目录的 README.md
  const findReadme = (nodes) => {
    // 只在根目录查找
    for (const node of nodes) {
      if (node.title === 'README.md' && node.isLeaf) {
        return node
      }
    }
    return null
  }

  // 转换文件树为菜单项
  const convertTreeToMenuItems = (nodes) => {
    return nodes.map((node) => {
      if (!node.isLeaf) {
        // 目录
        return {
          key: node.key,
          label: node.title,
          icon: <FolderOutlined />,
          children: node.children ? convertTreeToMenuItems(node.children) : [],
        }
      } else if (node.title && node.title.endsWith('.md')) {
        // Markdown 文件
        return {
          key: node.key,
          label: node.title.replace('.md', ''),
          icon: <FileTextOutlined />,
        }
      } else if (node.title && node.title.endsWith('.pdf')) {
        // PDF 文件
        return {
          key: node.key,
          label: node.title,
          icon: <FilePdfOutlined style={{ color: '#f5222d' }} />,
        }
      }
      return null
    }).filter(Boolean)
  }

  // 加载 markdown 文件
  const loadMarkdown = async (filePath) => {
    setLoading(true)
    setTocItems([]) // 清空旧的目录数据
    try {
      const res = await getFileContent(projectId, filePath)
      setMarkdownContent(res.data?.content || '')

      // 滚动到顶部
      if (contentRef.current) {
        contentRef.current.scrollTo({ top: 0, behavior: 'smooth' })
      }
    } catch (error) {
      console.error('Load markdown error:', error)
      setMarkdownContent('# 文档加载失败\n\n无法加载该文档，请稍后重试。')
    } finally {
      setLoading(false)
    }
  }

  // 提取 markdown 标题生成目录
  useEffect(() => {
    if (markdownContent) {
      const headings = []
      const lines = markdownContent.split('\n')

      lines.forEach((line) => {
        const match = line.match(/^(#{1,6})\s+(.+)$/)
        if (match) {
          const level = match[1].length
          const title = match[2]
          // 模拟 rehype-slug/github-slugger 的 ID 生成规则
          const key = title
            .toLowerCase()
            .trim()
            .replace(/\s+/g, '-')                // 空格转连字符
            .replace(/[^\w\-\u4e00-\u9fa5]+/g, '') // 移除非单词字符(保留中文、数字、字母、下划线、连字符)
            .replace(/\-\-+/g, '-')              // 合并重复连字符
            .replace(/^-+/, '')                  // 去除头部连字符
            .replace(/-+$/, '')                  // 去除尾部连字符

          headings.push({
            key: `#${key}`,
            href: `#${key}`,
            title,
            level,
          })
        }
      })

      setTocItems(headings)
    }
  }, [markdownContent])

  // 处理菜单点击
  const handleMenuClick = ({ key }) => {
    setSelectedFile(key)

    // 检查是否是PDF文件
    if (key.toLowerCase().endsWith('.pdf')) {
      // 显示PDF - 添加token到URL
      let url = getDocumentUrl(projectId, key)
      const token = localStorage.getItem('access_token')
      if (token) {
        url += `?token=${encodeURIComponent(token)}`
      }
      setPdfUrl(url)
      setPdfFilename(key.split('/').pop())
      setViewMode('pdf')
    } else {
      // 加载Markdown文件
      setViewMode('markdown')
      loadMarkdown(key)
    }
  }

  // 解析相对路径
  const resolveRelativePath = (currentPath, relativePath) => {
    // 获取当前文件所在目录
    const currentDir = currentPath.substring(0, currentPath.lastIndexOf('/'))

    // 分割相对路径
    const parts = relativePath.split('/')
    const dirParts = currentDir ? currentDir.split('/') : []

    // 处理 ../ 和 ./
    for (const part of parts) {
      if (part === '..') {
        dirParts.pop()
      } else if (part !== '.' && part !== '') {
        dirParts.push(part)
      }
    }

    return dirParts.join('/')
  }

  // 处理markdown内部链接点击
  const handleMarkdownLink = (e, href) => {
    // 检查是否是外部链接
    if (!href || href.startsWith('http://') || href.startsWith('https://') || href.startsWith('//')) {
      return // 外部链接，允许默认行为
    }

    // 检查是否是锚点链接
    if (href.startsWith('#')) {
      return // 锚点链接，允许默认行为
    }

    // 检查是否是文档文件（.md 或 .pdf）
    const isMd = href.endsWith('.md')
    const isPdf = href.toLowerCase().endsWith('.pdf')

    if (!isMd && !isPdf) {
      return // 不是文档文件，允许默认行为
    }

    // 阻止默认跳转
    e.preventDefault()

    // 先解码 href（因为 Markdown 中的链接可能已经是 URL 编码的）
    let decodedHref = href
    try {
      decodedHref = decodeURIComponent(href)
    } catch (e) {
      // 解码失败，使用原始值
    }

    // 解析相对路径
    const targetPath = resolveRelativePath(selectedFile, decodedHref)

    // 自动展开父目录
    const parentPath = targetPath.substring(0, targetPath.lastIndexOf('/'))
    if (parentPath && !openKeys.includes(parentPath)) {
      // 收集所有父路径
      const pathParts = parentPath.split('/')
      const allParentPaths = []
      let currentPath = ''
      for (const part of pathParts) {
        currentPath = currentPath ? `${currentPath}/${part}` : part
        allParentPaths.push(currentPath)
      }
      setOpenKeys([...new Set([...openKeys, ...allParentPaths])])
    }

    // 选中文件并加载
    setSelectedFile(targetPath)

    if (isPdf) {
      // PDF文件：切换到PDF模式
      let url = getDocumentUrl(projectId, targetPath)
      const token = localStorage.getItem('access_token')
      if (token) {
        url += `?token=${encodeURIComponent(token)}`
      }
      setPdfUrl(url)
      setPdfFilename(targetPath.split('/').pop())
      setViewMode('pdf')
    } else {
      // Markdown文件：加载内容
      setViewMode('markdown')
      loadMarkdown(targetPath)
    }
  }

  const handleGitPull = async (repoId = null, force = false) => {
    if (gitRepos.length === 0) {
      message.warning('未配置Git仓库')
      return
    }
    try {
      const res = await gitPull(projectId, repoId, force)
      message.success(res.message || 'Git Pull 成功')
      // Refresh tree
      loadFileTree()
      // Reload current file if open
      if (selectedFile) {
        loadMarkdown(selectedFile)
      }
    } catch (error) {
       console.error('Git Pull error:', error)
       const errorMsg = error.response?.data?.detail || 'Git Pull 失败'
       
       if (!force) {
         Modal.confirm({
           title: 'Git Pull 失败',
           content: (
             <div>
               <p>{errorMsg}</p>
               <p style={{ color: 'red', fontWeight: 'bold', marginTop: 8 }}>
                 是否强制重置到远程版本？
               </p>
               <p style={{ color: '#666', fontSize: 12 }}>
                 警告：这将丢失所有本地未提交的修改！
               </p>
             </div>
           ),
           okText: '强制重置',
           okType: 'danger',
           cancelText: '取消',
           onOk: () => handleGitPull(repoId, true)
         })
         return
       }
       
       message.error(errorMsg)
    }
  }

  const handleGitPush = async (repoId = null, force = false) => {
    if (gitRepos.length === 0) {
      message.warning('未配置Git仓库')
      return
    }
    try {
      const res = await gitPush(projectId, repoId, force)
      message.success(res.message || 'Git Push 成功')
    } catch (error) {
       console.error('Git Push error:', error)
       const errorMsg = error.response?.data?.detail || 'Git Push 失败'
       
       if (!force) {
         Modal.confirm({
           title: 'Git Push 失败',
           content: (
             <div>
               <p>{errorMsg}</p>
               <p style={{ color: 'red', fontWeight: 'bold', marginTop: 8 }}>
                 是否强制推送到远程？
               </p>
               <p style={{ color: '#666', fontSize: 12 }}>
                 警告：这将覆盖远程仓库的修改！
               </p>
             </div>
           ),
           okText: '强制推送',
           okType: 'danger',
           cancelText: '取消',
           onOk: () => handleGitPush(repoId, true)
         })
         return
       }
       
       message.error(errorMsg)
    }
  }

  const renderGitActions = () => {
    if (gitRepos.length <= 1) {
      // 0 或 1 个仓库，显示普通按钮
      return (
        <Space.Compact>
          <Tooltip title="Git Pull">
            <Button
              type="text"
              size="middle"
              icon={<CloudDownloadOutlined />}
              onClick={() => handleGitPull()}
            />
          </Tooltip>
          <Tooltip title="Git Push">
            <Button
              type="text"
              size="middle"
              icon={<CloudUploadOutlined />}
              onClick={() => handleGitPush()}
            />
          </Tooltip>
        </Space.Compact>
      )
    }

    // 多个仓库，显示下拉菜单
    const pullItems = gitRepos.map(repo => ({
      key: repo.id,
      label: repo.name + (repo.is_default ? ' (默认)' : ''),
      onClick: () => handleGitPull(repo.id),
    }))

    const pushItems = gitRepos.map(repo => ({
      key: repo.id,
      label: repo.name + (repo.is_default ? ' (默认)' : ''),
      onClick: () => handleGitPush(repo.id),
    }))

    return (
      <Space.Compact>
        <Dropdown menu={{ items: pullItems }}>
          <Tooltip title="Git Pull">
            <Button
              type="text"
              size="middle"
              icon={<CloudDownloadOutlined />}
            />
          </Tooltip>
        </Dropdown>
        <Dropdown menu={{ items: pushItems }}>
          <Tooltip title="Git Push">
            <Button
              type="text"
              size="middle"
              icon={<CloudUploadOutlined />}
            />
          </Tooltip>
        </Dropdown>
      </Space.Compact>
    )
  }

  // 进入编辑模式
  const handleEdit = () => {
    navigate(`/projects/${projectId}/editor`)
  }

  // 打开分享设置
  const handleShare = async () => {
    try {
      const res = await getProjectShareInfo(projectId)
      setShareInfo(res.data)
      setHasPassword(res.data.has_password)
      setPassword(res.data.access_pass || '')  // 显示已设置的密码
      setShareModalVisible(true)
    } catch (error) {
      console.error('Get share info error:', error)
      message.error('获取分享信息失败')
    }
  }

  // 复制分享链接
  const handleCopyLink = async () => {
    if (!shareInfo) return
    const fullUrl = `${window.location.origin}${shareInfo.share_url}`
    
    try {
      if (navigator.clipboard && window.isSecureContext) {
        await navigator.clipboard.writeText(fullUrl)
        Toast.success('复制成功', '分享链接已复制到剪贴板')
      } else {
        // Fallback for non-secure contexts or older browsers
        const textArea = document.createElement("textarea")
        textArea.value = fullUrl
        textArea.style.position = "fixed"
        textArea.style.left = "-9999px"
        textArea.style.top = "0"
        document.body.appendChild(textArea)
        textArea.focus()
        textArea.select()
        const successful = document.execCommand('copy')
        document.body.removeChild(textArea)
        if (successful) {
           Toast.success('复制成功', '分享链接已复制到剪贴板')
        } else {
           Toast.error('复制失败', '请手动复制链接')
        }
      }
    } catch (err) {
      console.error('Failed to copy:', err)
      Toast.error('复制失败', '无法访问剪贴板')
    }
  }

  // 切换密码保护
  const handlePasswordToggle = async (checked) => {
    if (!checked) {
      // 取消密码
      try {
        await updateShareSettings(projectId, { access_pass: null })
        setHasPassword(false)
        setPassword('')
        message.success('已取消访问密码')
        // 刷新分享信息
        const res = await getProjectShareInfo(projectId)
        setShareInfo(res.data)
      } catch (error) {
        console.error('Update settings error:', error)
        message.error('操作失败')
      }
    } else {
      setHasPassword(true)
    }
  }

  // 保存密码
  const handleSavePassword = async () => {
    if (!password.trim()) {
      message.warning('请输入访问密码')
      return
    }
    try {
      await updateShareSettings(projectId, { access_pass: password })
      message.success('访问密码已设置')
      // 刷新分享信息
      const res = await getProjectShareInfo(projectId)
      setShareInfo(res.data)
      setHasPassword(true)
    } catch (error) {
      console.error('Save password error:', error)
      message.error('设置密码失败')
    }
  }

  const menuItems = convertTreeToMenuItems(fileTree)

  return (
    <div className="project-docs-page">
      <Layout className="docs-layout">
        {/* 左侧目录 */}
        <Sider width={280} className="docs-sider" theme="light">
          <div className="docs-sider-header">
            <h2>项目文档</h2>
            <div className="docs-sider-actions">
              {/* 只有 owner/admin/editor 可以编辑和Git操作 */}
              {userRole !== 'viewer' && (
                <>
                  <Button
                    type="primary"
                    size="small"
                    className="mode-toggle-btn"
                    icon={<EditOutlined />}
                    onClick={handleEdit}
                  >
                    编辑模式
                  </Button>
                  {renderGitActions()}
                </>
              )}
              <Tooltip title="分享">
                <Button
                  type="text"
                  size="middle"
                  icon={<ShareAltOutlined />}
                  onClick={handleShare}
                />
              </Tooltip>
            </div>
          </div>

          <Menu
            mode="inline"
            selectedKeys={[selectedFile]}
            openKeys={openKeys}
            onOpenChange={setOpenKeys}
            items={menuItems}
            onClick={handleMenuClick}
            className="docs-menu"
          />
        </Sider>

        {/* 右侧内容区 */}
        <Layout className="docs-content-layout">
          <Content className="docs-content" ref={contentRef}>
            <div className={`docs-content-wrapper ${viewMode === 'pdf' ? 'pdf-mode' : ''}`}>
              {loading ? (
                <div className="docs-loading">
                  <Spin size="large">
                    <div style={{ marginTop: 16 }}>加载中...</div>
                  </Spin>
                </div>
              ) : viewMode === 'pdf' ? (
                <VirtualPDFViewer
                  url={pdfUrl}
                  filename={pdfFilename}
                />
              ) : (
                <div className="markdown-body">
                  <ReactMarkdown
                    remarkPlugins={[remarkGfm]}
                    rehypePlugins={[rehypeRaw, rehypeSlug, rehypeHighlight]}
                    components={{
                      a: ({ node, href, children, ...props }) => (
                        <a
                          href={href}
                          onClick={(e) => handleMarkdownLink(e, href)}
                          {...props}
                        >
                          {children}
                        </a>
                      ),
                    }}
                  >
                    {markdownContent}
                  </ReactMarkdown>
                </div>
              )}
            </div>

            {/* 返回顶部按钮 - 仅在markdown模式显示 */}
            {viewMode === 'markdown' && (
              <FloatButton
                icon={<VerticalAlignTopOutlined />}
                type="primary"
                style={{ right: tocCollapsed ? 24 : 280 }}
                onClick={() => {
                  if (contentRef.current) {
                    contentRef.current.scrollTo({ top: 0, behavior: 'smooth' })
                  }
                }}
              />
            )}
          </Content>

          {/* 右侧TOC面板 - 仅在markdown模式显示 */}
          {viewMode === 'markdown' && !tocCollapsed && (
            <Sider width={250} theme="light" className="docs-toc-sider">
              <div className="toc-header">
                <h3>文档索引</h3>
                <Button
                  type="text"
                  size="small"
                  icon={<MenuFoldOutlined />}
                  onClick={() => setTocCollapsed(true)}
                />
              </div>
              <div className="toc-content">
                {tocItems.length > 0 ? (
                  <Anchor
                    affix={false}
                    offsetTop={0}
                    getContainer={() => contentRef.current}
                    items={tocItems.map((item) => ({
                      key: item.key,
                      href: item.href,
                      title: (
                        <div style={{ paddingLeft: `${(item.level - 1) * 12}px`, display: 'flex', alignItems: 'center', gap: '4px' }}>
                          <FileTextOutlined style={{ fontSize: '12px', color: '#8c8c8c' }} />
                          {item.title}
                        </div>
                      ),
                    }))}
                  />
                ) : (
                  <div className="toc-empty">当前文档无标题</div>
                )}
              </div>
            </Sider>
          )}
        </Layout>

        {/* TOC展开按钮 */}
        {tocCollapsed && (
          <Button
            type="primary"
            icon={<MenuUnfoldOutlined />}
            className="toc-toggle-btn"
            onClick={() => setTocCollapsed(false)}
          >
            文档索引
          </Button>
        )}
      </Layout>

      {/* 分享模态框 */}
      <Modal
        title="分享项目"
        open={shareModalVisible}
        onCancel={() => setShareModalVisible(false)}
        footer={null}
        width={500}
      >
        {shareInfo && (
          <Space direction="vertical" style={{ width: '100%' }} size="large">
            <div>
              <label style={{ marginBottom: 8, display: 'block', fontWeight: 500 }}>分享链接</label>
              <Input
                value={`${window.location.origin}${shareInfo.share_url}`}
                readOnly
                addonAfter={
                  <CopyOutlined onClick={handleCopyLink} style={{ cursor: 'pointer' }} />
                }
              />
            </div>

            <div>
              <Space>
                <span style={{ fontWeight: 500 }}>访问密码保护</span>
                <Switch checked={hasPassword} onChange={handlePasswordToggle} />
              </Space>
            </div>

            {hasPassword && (
              <div>
                <Input.Password
                  placeholder="请输入访问密码"
                  value={password}
                  onChange={(e) => setPassword(e.target.value)}
                />
                <Button
                  type="primary"
                  onClick={handleSavePassword}
                  style={{ marginTop: 8 }}
                >
                  保存密码
                </Button>
              </div>
            )}
          </Space>
        )}
      </Modal>
    </div>
  )
}

export default DocumentPage