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

interface KelompokKeahlianLulusTepat {
  nama_kelompok: string;
  jumlah_lulusan_tercepat: number;
}

export async function GET(request: Request) {
  try {
    // Get all lulus students with their kelompok keahlian
    const { data, error } = await supabase
      .from('mahasiswa')
      .select(`
        kelompok_keahlian!inner(
          nama_kelompok
        ),
        semester,
        status_kuliah
      `)
      .eq('status_kuliah', 'Lulus');

    if (error) {
      console.error('Error fetching kelompok keahlian lulus tepat:', error);
      return NextResponse.json(
        { error: 'Failed to fetch kelompok keahlian lulus tepat data' },
        {
          status: 500,
          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',
          },
        }
      );
    }

    // Process data to calculate percentages
    const groupedData = data.reduce((acc, item: any) => {
      const nama_kelompok = item.kelompok_keahlian?.nama_kelompok;
      if (!nama_kelompok) return acc;

      if (!acc[nama_kelompok]) {
        acc[nama_kelompok] = {
          total_lulus: 0,
          lulus_tepat: 0
        };
      }

      acc[nama_kelompok].total_lulus += 1;
      
      // Check if lulus tepat waktu (semester <= 8)
      if (item.semester <= 8) {
        acc[nama_kelompok].lulus_tepat += 1;
      }

      return acc;
    }, {} as Record<string, { total_lulus: number; lulus_tepat: number }>);

    // Convert to final format (without percentage) and sort by count DESC then name ASC
    const results: KelompokKeahlianLulusTepat[] = Object.entries(groupedData)
      .map(([nama_kelompok, counts]) => ({
        nama_kelompok,
        jumlah_lulusan_tercepat: counts.lulus_tepat,
      }))
      .sort((a, b) => {
        if (b.jumlah_lulusan_tercepat !== a.jumlah_lulusan_tercepat) {
          return b.jumlah_lulusan_tercepat - a.jumlah_lulusan_tercepat;
        }
        return a.nama_kelompok.localeCompare(b.nama_kelompok);
      });

    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 kelompok keahlian lulus tepat:', error);
    return NextResponse.json(
      { error: 'Failed to fetch kelompok keahlian lulus tepat data' },
      {
        status: 500,
        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',
        },
      }
    );
  }
}