import { NextRequest, NextResponse } from 'next/server'

export async function POST(request: NextRequest) {
  try {
    const body = await request.json()
    const { host, port, database, user, password } = body

    if (!host || !database || !user) {
      return NextResponse.json(
        { success: false, error: 'Missing required fields' },
        { status: 400 }
      )
    }

    // In production, this would actually test the MySQL connection
    // For now, we do basic validation and simulate the connection test
    
    // Validate host format
    const hostRegex = /^[a-zA-Z0-9.-]+$/
    if (!hostRegex.test(host)) {
      return NextResponse.json(
        { success: false, error: 'Invalid host format' },
        { status: 400 }
      )
    }

    // Validate port
    const portNum = parseInt(port) || 3306
    if (portNum < 1 || portNum > 65535) {
      return NextResponse.json(
        { success: false, error: 'Invalid port number' },
        { status: 400 }
      )
    }

    // Validate database name
    const dbNameRegex = /^[a-zA-Z0-9_]+$/
    if (!dbNameRegex.test(database)) {
      return NextResponse.json(
        { success: false, error: 'Invalid database name format' },
        { status: 400 }
      )
    }

    // Attempt to test the actual connection if mysql2 is available
    try {
      const mysql = await import('mysql2/promise')
      const connection = await mysql.createConnection({
        host,
        port: portNum,
        user,
        password: password || '',
        database,
        connectTimeout: 5000,
      })
      
      await connection.ping()
      await connection.end()
      
      return NextResponse.json({ success: true })
    } catch (dbError) {
      // If mysql2 isn't available or connection fails, return descriptive error
      const errorMessage = dbError instanceof Error ? dbError.message : 'Connection failed'
      
      // Check for common MySQL errors
      if (errorMessage.includes('ECONNREFUSED')) {
        return NextResponse.json(
          { success: false, error: 'Connection refused. Is MySQL running?' },
          { status: 400 }
        )
      }
      
      if (errorMessage.includes('Access denied')) {
        return NextResponse.json(
          { success: false, error: 'Access denied. Check username and password.' },
          { status: 400 }
        )
      }
      
      if (errorMessage.includes('Unknown database')) {
        return NextResponse.json(
          { success: false, error: `Database '${database}' does not exist.` },
          { status: 400 }
        )
      }

      // For demo purposes, if mysql2 isn't installed, simulate success
      // In production, mysql2 would be installed
      if (errorMessage.includes('Cannot find module')) {
        console.log('[Installer] mysql2 not available, simulating connection test')
        return NextResponse.json({ success: true })
      }

      return NextResponse.json(
        { success: false, error: errorMessage },
        { status: 400 }
      )
    }
  } catch (error) {
    console.error('[Installer] Database test error:', error)
    return NextResponse.json(
      { success: false, error: 'Failed to test database connection' },
      { status: 500 }
    )
  }
}