import type { NextApiRequest, NextApiResponse } from "next"
import sqlite3 from "sqlite3"
import path from "path"

export default async function handler(req: NextApiRequest, res: NextApiResponse) {
  if (req.method !== "GET") return res.status(405).json({ error: "Method not allowed" })
  
  const { format = 'json', type = 'sources' } = req.query
  
  const dbPath = path.join(process.cwd(), "database", "antihoax.db")
  const db = new sqlite3.Database(dbPath)
  
  try {
    let query = ""
    let filename = ""
    
    if (type === 'sources') {
      query = `
        SELECT s.domain, s.risk_level, s.status, s.created_at,
               GROUP_CONCAT(c.name) as categories
        FROM sources s 
        LEFT JOIN source_categories sc ON s.id = sc.source_id 
        LEFT JOIN categories c ON sc.category_id = c.id 
        WHERE s.status = 'verified'
        GROUP BY s.id
        ORDER BY s.risk_level DESC
      `
      filename = `sources_export_${Date.now()}.${format}`
    } else if (type === 'reports') {
      query = `
        SELECT source_url, status, categories, description, created_at
        FROM reports 
        WHERE status != 'spam'
        ORDER BY created_at DESC
      `
      filename = `reports_export_${Date.now()}.${format}`
    }
    
    const data = await new Promise<any[]>((resolve, reject) => {
      db.all(query, (err, rows) => {
        if (err) reject(err)
        else resolve(rows)
      })
    })
    
    if (format === 'csv') {
      // Convert to CSV
      if (data.length === 0) {
        return res.status(200).send('')
      }
      
      const headers = Object.keys(data[0]).join(',')
      const csvRows = data.map(row => 
        Object.values(row).map(value => 
          typeof value === 'string' && value.includes(',') 
            ? `"${value.replace(/"/g, '""')}"` 
            : value
        ).join(',')
      )
      
      const csvContent = [headers, ...csvRows].join('\n')
      
      res.setHeader('Content-Type', 'text/csv')
      res.setHeader('Content-Disposition', `attachment; filename="${filename}"`)
      res.send(csvContent)
      
    } else {
      // JSON format
      res.setHeader('Content-Type', 'application/json')
      res.setHeader('Content-Disposition', `attachment; filename="${filename}"`)
      res.json({
        exported_at: new Date().toISOString(),
        count: data.length,
        data
      })
    }
    
  } catch (error) {
    console.error('Export error:', error)
    res.status(500).json({ error: "Export failed" })
  } finally {
    db.close()
  }
}