import type { NextApiRequest, NextApiResponse } from "next"
import { db, schema } from '../../../lib/db/connection'
import { eq, desc } from 'drizzle-orm'

export default async function handler(req: NextApiRequest, res: NextApiResponse) {
  if (req.method === "GET") {
    const { format = 'json', type = 'sources' } = req.query
    
    try {
      let data: any[] = []
      let filename = ""
      
      if (type === 'sources') {
        data = await db.select({
          domain: schema.sources.domain,
          risk_level: schema.sources.riskLevel,
          status: schema.sources.status,
          created_at: schema.sources.createdAt
        })
        .from(schema.sources)
        .where(eq(schema.sources.status, 'verified'))
        .orderBy(desc(schema.sources.riskLevel))
        
        filename = `sources_export_${Date.now()}.${format}`
      } else if (type === 'reports') {
        data = await db.select({
          source_url: schema.reports.sourceUrl,
          status: schema.reports.status,
          description: schema.reports.description,
          created_at: schema.reports.createdAt
        })
        .from(schema.reports)
        .orderBy(desc(schema.reports.createdAt))
        
        filename = `reports_export_${Date.now()}.${format}`
      }
      
      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" })
    }
    
  } else if (req.method === "POST") {
    // Handle export job creation
    const { type, format, dateRange, filters } = req.body
    
    // Create mock export job
    const job = {
      id: Date.now().toString(),
      name: `Export ${type} as ${format}`,
      type,
      format,
      status: 'completed',
      created_at: new Date().toISOString(),
      download_url: `/api/admin/export?type=${type}&format=${format}`,
      file_size: '2.4 MB',
      records_count: 150
    }
    
    res.json(job)
    
  } else {
    res.status(405).json({ error: "Method not allowed" })
  }
}