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

export async function GET() {
  const connection = await pool.getConnection();
  
  try {
    const currentYear = new Date().getFullYear();
    const [results] = await connection.query(`
      SELECT DISTINCT tahun_angkatan 
      FROM mahasiswa 
      WHERE tahun_angkatan >= ? 
      ORDER BY tahun_angkatan DESC
      LIMIT 7
    `, [currentYear - 6]);

    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 tahun angkatan:', error);
    return NextResponse.json(
      { error: 'Failed to fetch tahun angkatan data' },
      { 
        status: 500,
        headers: {
          'Access-Control-Allow-Origin': '*',
          'Access-Control-Allow-Methods': 'GET, OPTIONS',
          'Access-Control-Allow-Headers': 'Content-Type, Authorization',
        },
      }
    );
  } finally {
    connection.release();
  }
}