import { NextResponse } from 'next/server'
import { getPrismaClient } from '@/lib/database/trades'

/**
 * Health check endpoint for DNS failover monitoring
 * Returns 200 OK only if server AND database are healthy
 * 
 * CRITICAL: If database is down, this returns 503
 * This triggers DNS failover to backup server
 */
export async function GET() {
  const startTime = Date.now()
  
  try {
    // Check database connectivity with 5-second timeout
    const prisma = getPrismaClient()
    const dbCheck = await Promise.race([
      prisma.$queryRaw`SELECT 1 as health_check`,
      new Promise((_, reject) => 
        setTimeout(() => reject(new Error('Database timeout')), 5000)
      )
    ])
    
    const responseTime = Date.now() - startTime
    
    return NextResponse.json(
      { 
        status: 'healthy',
        timestamp: new Date().toISOString(),
        uptime: process.uptime(),
        database: 'connected',
        responseTime: `${responseTime}ms`
      },
      { status: 200 }
    )
  } catch (error: any) {
    // Database failure - return 503 to trigger failover
    console.error('❌ Health check failed - Database unavailable:', error.message)
    
    return NextResponse.json(
      { 
        status: 'unhealthy',
        timestamp: new Date().toISOString(),
        uptime: process.uptime(),
        database: 'disconnected',
        error: error.message,
        responseTime: `${Date.now() - startTime}ms`
      },
      { status: 503 } // Service Unavailable - triggers DNS failover
    )
  }
}