'use client';

import { useEffect, useState } from 'react';
import dynamic from 'next/dynamic';
import { ApexOptions } from 'apexcharts';
import { useTheme } from 'next-themes';
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";

const Chart = dynamic(() => import('react-apexcharts'), { ssr: false });

interface KelompokKeahlianPerAngkatanData {
  nama_kelompok: string;
  jumlah_mahasiswa: number;
}

interface Props {
  selectedYear: string;
}

export default function KelompokKeahlianPieChartPerAngkatan({ selectedYear }: Props) {
  const { theme } = useTheme();
  const [data, setData] = useState<KelompokKeahlianPerAngkatanData[]>([]);
  const [chartColors, setChartColors] = useState<string[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    const fetchData = async () => {
      try {
        setLoading(true);

        // Fetch year-filtered data and global data in parallel
        const [response, allResponse] = await Promise.all([
          fetch(`/api/mahasiswa/kk-dashboard?tahun_angkatan=${selectedYear}`),
          fetch('/api/mahasiswa/kk-dashboard'),
        ]);
        if (!response.ok) {
          throw new Error('Failed to fetch data');
        }
        const result = await response.json();
        const allResult = allResponse.ok ? await allResponse.json() : result;

        // Build global alphabetical list of kelompok (same order as bar chart)
        const colorPalette = ['#008FFB', '#00E396', '#FEB019', '#FF4560', '#775DD0', '#8B5CF6', '#EC4899', '#06B6D4', '#F97316'];
        const allKelompok: string[] = [...new Set((allResult as any[]).map((item: any) => item.nama_kelompok as string))]
          .sort((a, b) => a.localeCompare(b));

        // Group by nama_kelompok and sum jumlah_mahasiswa
        const groupedData = result.reduce((acc: { [key: string]: number }, item: any) => {
          const namaKelompok = item.nama_kelompok || 'Tidak Diketahui';
          acc[namaKelompok] = (acc[namaKelompok] || 0) + item.jumlah_mahasiswa;
          return acc;
        }, {});

        // Convert to array format and sort by jumlah_mahasiswa descending (display order)
        const chartData = Object.entries(groupedData).map(([nama_kelompok, jumlah_mahasiswa]) => ({
          nama_kelompok,
          jumlah_mahasiswa: jumlah_mahasiswa as number
        }));
        const sortedData = chartData.sort((a, b) => (b.jumlah_mahasiswa as number) - (a.jumlah_mahasiswa as number));

        // Assign colors based on global alphabetical position to match bar chart
        const computedColors = sortedData.map(item => {
          const idx = allKelompok.indexOf(item.nama_kelompok);
          return idx >= 0 ? colorPalette[idx % colorPalette.length] : '#999999';
        });

        setChartColors(computedColors);
        setData(sortedData);
      } catch (err) {
        setError(err instanceof Error ? err.message : 'An error occurred');
      } finally {
        setLoading(false);
      }
    };
    fetchData();
  }, [selectedYear]);

  // Prepare data for pie chart
  const series = data.map(item => item.jumlah_mahasiswa);
  const labels = data.map(item => item.nama_kelompok);

  const chartOptions: ApexOptions = {
    chart: {
      type: 'pie',
      toolbar: {
        show: true,
      },
      background: theme === 'dark' ? '#0F172B' : '#fff',
    },
    labels: labels,
    dataLabels: {
      enabled: true,
      formatter: function (val: number) {
        return `${val.toFixed(0)}%`;
      },
      style: {
        fontSize: '14px',
        fontFamily: 'Inter, sans-serif',
        fontWeight: '500'
      }
    },
    legend: {
      position: 'bottom',
      fontSize: '12px',
      markers: {
        size: 12,
      },
      itemMargin: {
        horizontal: 10,
        vertical: 5,
      },
      labels: {
        colors: theme === 'dark' ? '#fff' : '#000'
      }
    },
    colors: chartColors,
    tooltip: {
      theme: theme === 'dark' ? 'dark' : 'light',
      y: {
        formatter: function (val: number) {
          return val + ' mahasiswa';
        }
      }
    },
    plotOptions: {
      pie: {
        donut: {
          size: '0%',
        },
        offsetY: 0,
      },
    },
    states: {
      hover: {
        filter: {
          type: 'darken',
        },
      },
    },
  };

  if (loading) {
    return (
      <Card className="bg-white dark:bg-slate-900 shadow-lg">
        <CardHeader>
          <CardTitle className="text-xl font-bold dark:text-white">
            Loading...
          </CardTitle>
        </CardHeader>
      </Card>
    );
  }

  if (error) {
    return (
      <Card className="bg-white dark:bg-slate-900 shadow-lg">
        <CardHeader>
          <CardTitle className="text-xl font-bold text-red-500">
            Error: {error}
          </CardTitle>
        </CardHeader>
      </Card>
    );
  }

  if (data.length === 0) {
    return (
      <Card className="bg-white dark:bg-slate-900 shadow-lg">
        <CardHeader>
          <CardTitle className="text-xl font-bold dark:text-white">
            Tidak ada data yang tersedia
          </CardTitle>
        </CardHeader>
      </Card>
    );
  }

  return (
    <Card className="bg-white dark:bg-slate-900 shadow-lg">
      <CardHeader>
        <CardTitle className="text-xl font-bold dark:text-white">
          Persentase Jumlah Mahasiswa Berdasarkan Kelompok Keahlian
          {selectedYear !== 'all' ? ` Angkatan ${selectedYear}` : ''}
        </CardTitle>
      </CardHeader>
      <CardContent>
        <div className="h-[300px] sm:h-[300px] md:h-[300px] w-full max-w-5xl mx-auto">
          {typeof window !== 'undefined' && (
            <Chart
              options={chartOptions}
              series={series}
              type="pie"
              height="100%"
              width="100%"
            />
          )}
        </div>
      </CardContent>
    </Card>
  );
}