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

interface GenderData {
  tahun_angkatan: number;
  jk: string;
  jumlah: number;
}

export async function GET(request: Request) {
  const { searchParams } = new URL(request.url);
  const tahun = searchParams.get('tahun');

  if (!tahun) {
    return NextResponse.json(
      { error: 'Tahun angkatan is required' },
      { status: 400 }
    );
  }

  try {
    const { data, error } = await supabase
      .from('mahasiswa')
      .select('tahun_angkatan, jk')
      .eq('tahun_angkatan', parseInt(tahun));

    if (error) {
      console.error('Error fetching gender per angkatan:', error);
      return NextResponse.json(
        { error: 'Failed to fetch gender per angkatan data' },
        { 
          status: 500,
          headers: {
            'Access-Control-Allow-Origin': '*',
            'Access-Control-Allow-Methods': 'GET, OPTIONS',
            'Access-Control-Allow-Headers': 'Content-Type, Authorization',
          },
        }
      );
    }

    // Group by jk and count
    const groupedData = data.reduce((acc, item) => {
      acc[item.jk] = (acc[item.jk] || 0) + 1;
      return acc;
    }, {} as Record<string, number>);

    // Convert to final format
    const results: GenderData[] = Object.entries(groupedData).map(([jk, jumlah]) => ({
      tahun_angkatan: parseInt(tahun),
      jk,
      jumlah
    }));

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