'use client';

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

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

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

interface Props {
  tahunAngkatan: string;
}

export default function StatistikPerAngkatanChart({ tahunAngkatan }: Props) {
  const { theme, systemTheme } = useTheme();
  const [statistikData, setStatistikData] = useState<GenderStatistik[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    const fetchData = async () => {
      try {
        setLoading(true);
        setError(null);
        
        const response = await fetch(`/api/mahasiswa/gender-per-angkatan?tahun=${tahunAngkatan}`);
        
        if (!response.ok) {
          throw new Error(`Failed to fetch data: ${response.status} ${response.statusText}`);
        }
        
        const result = await response.json();
        
        if (!Array.isArray(result)) {
          throw new Error('Invalid data format received from server');
        }
        
        setStatistikData(result);
      } catch (err) {
        console.error('Error in fetchData:', err);
        setError(err instanceof Error ? err.message : 'An error occurred while fetching data');
      } finally {
        setLoading(false);
      }
    };

    if (tahunAngkatan !== "all") {
      fetchData();
    }
  }, [tahunAngkatan]);

  const [chartOptions, setChartOptions] = useState({
    chart: {
      type: 'pie' as const,
      toolbar: {
        show: true,
        tools: {
          download: true,
          selection: true,
          zoom: true,
          zoomin: true,
          zoomout: true,
          pan: true,
          reset: true
        }
      },
      background: 'transparent',
    },
    labels: ['Laki-laki', 'Perempuan'],
    colors: ['#3B82F6', '#EC4899'],
    legend: {
      position: 'bottom' as const,
      fontSize: '14px',
      markers: {
        size: 12,
        strokeWidth: 0
      },
      itemMargin: {
        horizontal: 10
      },
      labels: {
        colors: '#000',
        style: {
          fontSize: '14px',
          fontFamily: 'Inter, sans-serif',
          fontWeight: '500'
        }
      }
    },
    dataLabels: {
      enabled: true,
                formatter: function (val: number, opts: any) {
        return val.toString();
      },
      style: {
        fontSize: '14px',
        fontFamily: 'Inter, sans-serif',
        fontWeight: '500'
      },
      offsetY: 0,
      dropShadow: {
        enabled: false
      },
      position: 'top'
    },
    tooltip: {
      theme: 'light',
      y: {
        formatter: function (val: number) {
          return val + " mahasiswa"
        }
      }
    }
  });
  
  // Update theme when it changes
  useEffect(() => {
    const currentTheme = theme === 'system' ? systemTheme : theme;
    const textColor = currentTheme === 'dark' ? '#fff' : '#000';
    const tooltipTheme = currentTheme === 'dark' ? 'dark' : 'light';
    
    setChartOptions(prev => ({
      ...prev,
      chart: {
        ...prev.chart,
        background: currentTheme === 'dark' ? '#0F172B' : '#fff',
      },
      legend: {
        ...prev.legend,
        labels: {
          ...prev.legend.labels,
          colors: textColor,
        }
      },
      dataLabels: {
        ...prev.dataLabels,
        style: {
          ...prev.dataLabels.style,
          color: textColor
        }
      },
      tooltip: {
        ...prev.tooltip,
        theme: tooltipTheme
      }
    }));
  }, [theme, systemTheme]);
  
  // Update dataLabels formatter when data changes
  useEffect(() => {
    if (statistikData.length > 0) {
      setChartOptions(prev => ({
        ...prev,
        dataLabels: {
          ...prev.dataLabels,
          formatter: function (val: number, opts: any) {
            const total = statistikData.reduce((sum, item) => sum + item.jumlah, 0);
            const percentage = ((statistikData[opts.seriesIndex]?.jumlah / total) * 100) || 0;
            return `${percentage.toFixed(0)}%`;
          }
        }
      }));
    }
  }, [statistikData]);

  const chartSeries = statistikData.map(item => item.jumlah);
  const totalMahasiswa = statistikData.reduce((sum, item) => sum + item.jumlah, 0);

  if (tahunAngkatan === "all") {
    return null;
  }

  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 dark:text-red-400">
            Error: {error}
          </CardTitle>
        </CardHeader>
      </Card>
    );
  }

  if (statistikData.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">
          Total Mahasiswa Angkatan {tahunAngkatan}
        </CardTitle>
        <div className="text-lg font-semibold text-gray-600 dark:text-gray-300">
          Total Mahasiswa: {totalMahasiswa}
        </div>
      </CardHeader>
      <CardContent>
        <div className="h-[350px] w-full max-w-5xl mx-auto">
          <Chart
            options={chartOptions}
            series={chartSeries}
            type="pie"
            height="100%"
            width="90%"
          />
        </div>
      </CardContent>
    </Card>
  );
}