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

interface MahasiswaTotal extends RowDataPacket {
  total_mahasiswa: number;
  mahasiswa_aktif: number;
  total_lulus: number;
  pria_lulus: number;
  wanita_lulus: number;
  total_berprestasi: number;
  prestasi_akademik: number;
  prestasi_non_akademik: number;
  ipk_rata_rata_aktif: number;
  ipk_rata_rata_lulus: number;
  total_mahasiswa_aktif_lulus: number;
}

// Fungsi untuk menangani preflight request (OPTIONS)
export async function OPTIONS() {
  return new NextResponse(null, {
    status: 200,
    headers: {
      'Access-Control-Allow-Origin': '*',
      'Access-Control-Allow-Methods': 'GET, OPTIONS',
      'Access-Control-Allow-Headers': 'Content-Type, Authorization',
      'Access-Control-Max-Age': '86400', // 24 jam
    },
  });
}

export async function GET() {
  const connection = await pool.getConnection();
  
  try {
    // Query gabungan untuk semua data
    const [results] = await connection.query<MahasiswaTotal[]>(`
      SELECT 
        (SELECT COUNT(*) FROM mahasiswa) AS total_mahasiswa,
        (SELECT COUNT(*) FROM mahasiswa m
            JOIN status_mahasiswa s ON m.nim = s.nim
            WHERE s.status_kuliah = 'Aktif') AS mahasiswa_aktif,
        (SELECT COUNT(*) FROM mahasiswa m
            JOIN status_mahasiswa s ON m.nim = s.nim
            WHERE s.status_kuliah = 'Lulus') AS total_lulus,
        (SELECT COUNT(*) FROM mahasiswa m
            JOIN status_mahasiswa s ON m.nim = s.nim
            WHERE s.status_kuliah = 'Lulus' AND m.jk = 'Pria') AS pria_lulus,
        (SELECT COUNT(*) FROM mahasiswa m
            JOIN status_mahasiswa s ON m.nim = s.nim
            WHERE s.status_kuliah = 'Lulus' AND m.jk = 'Wanita') AS wanita_lulus,
        (SELECT COUNT(*) FROM prestasi_mahasiswa) AS total_berprestasi,
        (SELECT COUNT(*) FROM prestasi_mahasiswa WHERE jenis_prestasi = 'Akademik') AS prestasi_akademik,
        (SELECT COUNT(*) FROM prestasi_mahasiswa WHERE jenis_prestasi = 'Non-Akademik') AS prestasi_non_akademik,
        (SELECT COUNT(*) FROM mahasiswa m
            JOIN status_mahasiswa s ON m.nim = s.nim
            WHERE s.status_kuliah IN ('Aktif', 'Lulus')) AS total_mahasiswa_aktif_lulus,
        (SELECT ROUND(AVG(m.ipk), 2) FROM mahasiswa m
            JOIN status_mahasiswa s ON m.nim = s.nim
            WHERE s.status_kuliah = 'Aktif') AS ipk_rata_rata_aktif,
        (SELECT ROUND(AVG(m.ipk), 2) FROM mahasiswa m
            JOIN status_mahasiswa s ON m.nim = s.nim
            WHERE s.status_kuliah = 'Lulus') AS ipk_rata_rata_lulus
    `);

    // Menambahkan header cache dan CORS
    return NextResponse.json(results[0], {
      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 total mahasiswa:', error);
    return NextResponse.json(
      { error: 'Failed to fetch total mahasiswa' },
      { 
        status: 500,
        headers: {
          'Access-Control-Allow-Origin': '*',
          'Access-Control-Allow-Methods': 'GET, OPTIONS',
          'Access-Control-Allow-Headers': 'Content-Type, Authorization',
        },
      }
    );
  } finally {
    connection.release();
  }
}