/**
 * 章节搜索API
 * 搜索章节标题和内容，不返回用户敏感信息
 */
import { NextResponse } from 'next/server'
import fs from 'fs'
import path from 'path'

export async function GET(request: Request) {
  try {
    const { searchParams } = new URL(request.url)
    const keyword = searchParams.get('q') || ''
    
    if (!keyword || keyword.trim().length < 1) {
      return NextResponse.json({
        success: true,
        results: [],
        total: 0,
        message: '请输入搜索关键词'
      })
    }
    
    const searchTerm = keyword.trim().toLowerCase()
    
    // 读取章节数据
    const dataPath = path.join(process.cwd(), 'public/book-chapters.json')
    const fileContent = fs.readFileSync(dataPath, 'utf-8')
    const chaptersData = JSON.parse(fileContent)
    
    // 读取书籍内容目录
    const bookDir = path.join(process.cwd(), 'book')
    
    const results: any[] = []
    
    // 遍历章节搜索
    for (const chapter of chaptersData) {
      const titleMatch = chapter.title?.toLowerCase().includes(searchTerm)
      const idMatch = chapter.id?.toLowerCase().includes(searchTerm)
      const partMatch = chapter.partTitle?.toLowerCase().includes(searchTerm)
      
      // 尝试读取章节内容进行搜索
      let contentMatch = false
      let matchedContent = ''
      
      // 兼容两种字段名: file 或 filePath
      const filePathField = chapter.filePath || chapter.file
      if (filePathField) {
        try {
          // 如果是绝对路径，直接使用；否则相对于项目根目录
          const filePath = filePathField.startsWith('/') ? filePathField : path.join(process.cwd(), filePathField)
          if (fs.existsSync(filePath)) {
            const content = fs.readFileSync(filePath, 'utf-8')
            // 移除敏感信息（手机号、微信号等）
            const cleanContent = content
              .replace(/1[3-9]\d{9}/g, '***')  // 手机号
              .replace(/微信[：:]\s*\S+/g, '微信：***')  // 微信号
              .replace(/QQ[：:]\s*\d+/g, 'QQ：***')  // QQ号
              .replace(/邮箱[：:]\s*\S+@\S+/g, '邮箱：***')  // 邮箱
            
            if (cleanContent.toLowerCase().includes(searchTerm)) {
              contentMatch = true
              // 提取匹配的上下文（前后50个字符）
              const lowerContent = cleanContent.toLowerCase()
              const matchIndex = lowerContent.indexOf(searchTerm)
              if (matchIndex !== -1) {
                const start = Math.max(0, matchIndex - 30)
                const end = Math.min(cleanContent.length, matchIndex + searchTerm.length + 50)
                matchedContent = (start > 0 ? '...' : '') + 
                  cleanContent.slice(start, end).replace(/\n/g, ' ') + 
                  (end < cleanContent.length ? '...' : '')
              }
            }
          }
        } catch (e) {
          // 文件读取失败，跳过内容搜索
        }
      }
      
      if (titleMatch || idMatch || partMatch || contentMatch) {
        // 从标题中提取章节号（如 "1.1 荷包：..." -> "1.1"）
        const sectionIdMatch = chapter.title?.match(/^(\d+\.\d+)\s/)
        const sectionId = sectionIdMatch ? sectionIdMatch[1] : chapter.id
        
        // 处理特殊ID
        let finalId = sectionId
        if (chapter.id === 'preface' || chapter.title?.includes('序言')) {
          finalId = 'preface'
        } else if (chapter.id === 'epilogue') {
          finalId = 'epilogue'
        } else if (chapter.id?.startsWith('appendix')) {
          finalId = chapter.id
        }
        
        // 判断是否免费章节
        const freeIds = ['preface', 'epilogue', '1.1', 'appendix-1', 'appendix-2', 'appendix-3']
        const isFree = freeIds.includes(finalId)
        
        results.push({
          id: finalId,  // 使用提取的章节号
          title: chapter.title,
          part: chapter.partTitle || chapter.part || '',
          chapter: chapter.chapterDir || chapter.chapter || '',
          isFree: isFree,
          matchType: titleMatch ? 'title' : (idMatch ? 'id' : (partMatch ? 'part' : 'content')),
          matchedContent: contentMatch ? matchedContent : '',
          // 格式化章节号
          chapterLabel: formatChapterLabel(finalId, chapter.index)
        })
      }
    }
    
    // 按匹配类型排序：标题匹配 > ID匹配 > 内容匹配
    results.sort((a, b) => {
      const order = { title: 0, id: 1, content: 2 }
      return (order[a.matchType as keyof typeof order] || 2) - (order[b.matchType as keyof typeof order] || 2)
    })
    
    return NextResponse.json({
      success: true,
      results: results.slice(0, 20), // 最多返回20条
      total: results.length,
      keyword: keyword
    })
    
  } catch (error) {
    console.error('Search error:', error)
    return NextResponse.json({
      success: false,
      error: '搜索失败',
      results: []
    }, { status: 500 })
  }
}

// 格式化章节标签
function formatChapterLabel(id: string, index?: number): string {
  if (!id) return ''
  if (id === 'preface') return '序言'
  if (id.startsWith('chapter-') && index) return `第${index}节`
  if (id.startsWith('appendix')) return '附录'
  if (id === 'epilogue') return '后记'
  
  // 处理 1.1, 3.2 这样的格式
  const match = id.match(/^(\d+)\.(\d+)$/)
  if (match) {
    return `${match[1]}.${match[2]}`
  }
  
  return id
}