import { NextResponse } from 'next/server';
import pool from '@/lib/db';
import { RowDataPacket } from 'mysql2';

export async function GET(request: Request) {
  const { searchParams } = new URL(request.url);
  const tahunAngkatan = searchParams.get('tahun_angkatan');
  
  if (!tahunAngkatan) {
    return NextResponse.json(
      { error: 'Tahun angkatan diperlukan' },
      { status: 400 }
    );
  }

  const connection = await pool.getConnection();
  
  try {
    const query = `
      SELECT 
        jk,
        ROUND(AVG(ipk), 2) as rata_rata_ipk
      FROM mahasiswa
      WHERE tahun_angkatan = ?
      GROUP BY jk
      ORDER BY jk ASC
    `;

    const [results] = await connection.query<RowDataPacket[]>(query, [tahunAngkatan]);

    return NextResponse.json(results, {
      headers: {
        'Cache-Control': 'public, max-age=60, stale-while-revalidate=30',
        'Access-Control-Allow-Origin': '*',
        'Access-Control-Allow-Methods': 'GET, OPTIONS',
        'Access-Control-Allow-Headers': 'Content-Type, Authorization',
      },
    });
  } catch (error) {
    console.error('Error fetching IPK data:', error);
    return NextResponse.json(
      { error: 'Failed to fetch IPK data' },
      { 
        status: 500,
        headers: {
          'Access-Control-Allow-Origin': '*',
          'Access-Control-Allow-Methods': 'GET, OPTIONS',
          'Access-Control-Allow-Headers': 'Content-Type, Authorization',
        },
      }
    );
  } finally {
    connection.release();
  }
}