/**
 * 搜索API
 * 支持从数据库搜索标题和内容
 * 同时支持搜索匹配的人和事情（隐藏功能）
 */

import { NextRequest, NextResponse } from 'next/server'
import { query } from '@/lib/db'
import { bookData } from '@/lib/book-data'
import fs from 'fs'
import path from 'path'

/**
 * 从文件系统搜索章节
 */
function searchFromFiles(keyword: string): any[] {
  const results: any[] = []
  const lowerKeyword = keyword.toLowerCase()
  
  for (const part of bookData) {
    for (const chapter of part.chapters) {
      for (const section of chapter.sections) {
        // 搜索标题
        if (section.title.toLowerCase().includes(lowerKeyword)) {
          results.push({
            id: section.id,
            title: section.title,
            partTitle: part.title,
            chapterTitle: chapter.title,
            price: section.price,
            isFree: section.isFree,
            matchType: 'title',
            score: 10 // 标题匹配得分更高
          })
          continue
        }
        
        // 搜索内容
        const filePath = path.join(process.cwd(), section.filePath)
        if (fs.existsSync(filePath)) {
          try {
            const content = fs.readFileSync(filePath, 'utf-8')
            if (content.toLowerCase().includes(lowerKeyword)) {
              // 提取匹配的上下文
              const lowerContent = content.toLowerCase()
              const matchIndex = lowerContent.indexOf(lowerKeyword)
              const start = Math.max(0, matchIndex - 50)
              const end = Math.min(content.length, matchIndex + keyword.length + 50)
              const snippet = content.substring(start, end)
              
              results.push({
                id: section.id,
                title: section.title,
                partTitle: part.title,
                chapterTitle: chapter.title,
                price: section.price,
                isFree: section.isFree,
                matchType: 'content',
                snippet: (start > 0 ? '...' : '') + snippet + (end < content.length ? '...' : ''),
                score: 5 // 内容匹配得分较低
              })
            }
          } catch (e) {
            // 忽略读取错误
          }
        }
      }
    }
  }
  
  // 按得分排序
  return results.sort((a, b) => b.score - a.score)
}

/**
 * 从数据库搜索章节
 */
async function searchFromDB(keyword: string): Promise<any[]> {
  try {
    const results = await query(`
      SELECT 
        id, 
        section_title as title, 
        part_title as partTitle, 
        chapter_title as chapterTitle, 
        price, 
        is_free as isFree,
        CASE 
          WHEN section_title LIKE ? THEN 'title'
          ELSE 'content'
        END as matchType,
        CASE 
          WHEN section_title LIKE ? THEN 10
          ELSE 5
        END as score,
        SUBSTRING(content, 
          GREATEST(1, LOCATE(?, content) - 50), 
          150
        ) as snippet
      FROM chapters 
      WHERE section_title LIKE ? 
         OR content LIKE ?
      ORDER BY score DESC, id ASC
      LIMIT 50
    `, [
      `%${keyword}%`,
      `%${keyword}%`,
      keyword,
      `%${keyword}%`,
      `%${keyword}%`
    ]) as any[]
    
    return results
  } catch (e) {
    console.error('[Search API] 数据库搜索失败:', e)
    return []
  }
}

/**
 * 提取文章中的人物信息（隐藏功能）
 * 用于"找伙伴"功能的智能匹配
 */
function extractPeopleFromContent(content: string): string[] {
  const people: string[] = []
  
  // 匹配常见人名模式
  // 中文名：2-4个汉字
  const chineseNames = content.match(/[\u4e00-\u9fa5]{2,4}(?=：|:|说|的|告诉|表示)/g) || []
  // 英文名/昵称：带@或引号的名称
  const nicknames = content.match(/["'@]([^"'@\s]+)["']?/g) || []
  // 职位+名字模式
  const titleNames = content.match(/(?:老板|总|经理|创始人|合伙人|店长)[\u4e00-\u9fa5]{2,3}/g) || []
  
  people.push(...chineseNames.slice(0, 10))
  people.push(...nicknames.map(n => n.replace(/["'@]/g, '')).slice(0, 5))
  people.push(...titleNames.slice(0, 5))
  
  // 去重
  return [...new Set(people)]
}

/**
 * 提取文章中的关键事件/标签
 */
function extractKeywords(content: string): string[] {
  const keywords: string[] = []
  
  // 行业关键词
  const industries = ['电商', '私域', '社群', '抖音', '直播', '餐饮', '美业', '健康', 'AI', '供应链', '金融', '拍卖', '游戏', '电竞']
  // 模式关键词
  const patterns = ['轻资产', '复购', '被动收入', '杠杆', '信息差', '流量', '分销', '代理', '加盟']
  // 金额模式
  const amounts = content.match(/(\d+)万/g) || []
  
  for (const ind of industries) {
    if (content.includes(ind)) keywords.push(ind)
  }
  for (const pat of patterns) {
    if (content.includes(pat)) keywords.push(pat)
  }
  keywords.push(...amounts.slice(0, 5))
  
  return [...new Set(keywords)]
}

/**
 * GET - 搜索
 * 参数:
 * - q: 搜索关键词
 * - type: 'all' | 'title' | 'content' | 'people' | 'keywords'
 * - source: 'db' | 'file' | 'auto' (默认auto)
 */
export async function GET(request: NextRequest) {
  const { searchParams } = new URL(request.url)
  const keyword = searchParams.get('q') || searchParams.get('keyword') || ''
  const type = searchParams.get('type') || 'all'
  const source = searchParams.get('source') || 'auto'
  
  if (!keyword || keyword.length < 1) {
    return NextResponse.json({
      success: false,
      error: '请输入搜索关键词'
    }, { status: 400 })
  }
  
  try {
    let results: any[] = []
    
    // 根据source选择搜索方式
    if (source === 'db') {
      results = await searchFromDB(keyword)
    } else if (source === 'file') {
      results = searchFromFiles(keyword)
    } else {
      // auto: 先尝试数据库，失败则使用文件
      results = await searchFromDB(keyword)
      if (results.length === 0) {
        results = searchFromFiles(keyword)
      }
    }
    
    // 根据type过滤
    if (type === 'title') {
      results = results.filter(r => r.matchType === 'title')
    } else if (type === 'content') {
      results = results.filter(r => r.matchType === 'content')
    }
    
    // 如果搜索人物或关键词（隐藏功能）
    let people: string[] = []
    let keywords: string[] = []
    
    if (type === 'people' || type === 'all') {
      // 从搜索结果的内容中提取人物
      for (const result of results.slice(0, 5)) {
        const filePath = path.join(process.cwd(), 'book')
        // 从bookData找到对应文件
        for (const part of bookData) {
          for (const chapter of part.chapters) {
            const section = chapter.sections.find(s => s.id === result.id)
            if (section) {
              const fullPath = path.join(process.cwd(), section.filePath)
              if (fs.existsSync(fullPath)) {
                const content = fs.readFileSync(fullPath, 'utf-8')
                people.push(...extractPeopleFromContent(content))
              }
            }
          }
        }
      }
      people = [...new Set(people)].slice(0, 20)
    }
    
    if (type === 'keywords' || type === 'all') {
      // 从搜索结果的内容中提取关键词
      for (const result of results.slice(0, 5)) {
        for (const part of bookData) {
          for (const chapter of part.chapters) {
            const section = chapter.sections.find(s => s.id === result.id)
            if (section) {
              const fullPath = path.join(process.cwd(), section.filePath)
              if (fs.existsSync(fullPath)) {
                const content = fs.readFileSync(fullPath, 'utf-8')
                keywords.push(...extractKeywords(content))
              }
            }
          }
        }
      }
      keywords = [...new Set(keywords)].slice(0, 20)
    }
    
    return NextResponse.json({
      success: true,
      data: {
        keyword,
        total: results.length,
        results: results.slice(0, 20), // 限制返回数量
        // 隐藏功能数据
        people: type === 'people' || type === 'all' ? people : undefined,
        keywords: type === 'keywords' || type === 'all' ? keywords : undefined
      }
    })
    
  } catch (error) {
    console.error('[Search API] 搜索失败:', error)
    return NextResponse.json({
      success: false,
      error: '搜索失败: ' + (error as Error).message
    }, { status: 500 })
  }
}