import { NextRequest, NextResponse } from 'next/server'
import { pool, Lead } from '@/lib/db'

export async function GET(request: NextRequest) {
  try {
    const { searchParams } = new URL(request.url)
    const page = parseInt(searchParams.get('page') || '1')
    const limit = parseInt(searchParams.get('limit') || '50')
    const sortBy = searchParams.get('sortBy') || 'created_at'
    const sortOrder = searchParams.get('sortOrder') || 'DESC'
    const search = searchParams.get('search') || ''
    
    const offset = (page - 1) * limit
    
    let whereClause = ''
    let queryParams: any[] = [limit, offset]
    
    if (search) {
      whereClause = `WHERE (first_name ILIKE $3 OR last_name ILIKE $3 OR email ILIKE $3 OR company_name ILIKE $3)`
      queryParams.push(`%${search}%`)
    }
    
    const validSortColumns = ['created_at', 'first_name', 'last_name', 'email', 'company_name', 'lead_source']
    const sortColumn = validSortColumns.includes(sortBy) ? sortBy : 'created_at'
    const order = sortOrder.toUpperCase() === 'ASC' ? 'ASC' : 'DESC'
    
    const leadsQuery = `
      SELECT * FROM leads 
      ${whereClause}
      ORDER BY ${sortColumn} ${order}
      LIMIT $1 OFFSET $2
    `
    
    const countQuery = `SELECT COUNT(*) as total FROM leads ${whereClause}`
    
    const [leadsResult, countResult] = await Promise.all([
      pool.query(leadsQuery, queryParams),
      pool.query(countQuery, search ? [`%${search}%`] : [])
    ])
    
    const leads: Lead[] = leadsResult.rows
    const total = parseInt(countResult.rows[0].total)
    const totalPages = Math.ceil(total / limit)
    
    return NextResponse.json({
      leads,
      pagination: {
        page,
        limit,
        total,
        totalPages,
        hasNext: page < totalPages,
        hasPrev: page > 1
      }
    })
  } catch (error) {
    console.error('Error fetching leads:', error)
    return NextResponse.json(
      { error: 'Failed to fetch leads' },
      { status: 500 }
    )
  }
}