'use client';

import { useEffect, useState, useMemo } 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";
import { Button } from "@/components/ui/button";
import { ExternalLink } from "lucide-react";
import Link from "next/link";

// Dynamically import ApexCharts to avoid SSR issues
const Chart = dynamic(() => import('react-apexcharts'), { ssr: false });

interface KategoriIPKData {
  tahun_angkatan: number;
  kategori_ipk: string;
  jumlah: number;
}

interface DistribusiIPKChartProps {
  selectedYear?: string;
  height?: string;
  showDetailButton?: boolean;
}

export default function DistribusiIPKChart({ 
  selectedYear = 'all',
  height = "h-[300px] sm:h-[300px] md:h-[300px]",
  showDetailButton = true 
}: DistribusiIPKChartProps) {
  const { theme } = useTheme();
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [data, setData] = useState<KategoriIPKData[]>([]);
  const [series, setSeries] = useState<ApexAxisChartSeries>([]);

  // Get unique tahun angkatan and sort them
  const tahunAngkatan = useMemo(() => {
    return [...new Set(data.map(item => item.tahun_angkatan))].sort((a, b) => a - b);
  }, [data]);

  const chartOptions: ApexOptions = useMemo(() => ({
    chart: {
      type: 'bar',
      stacked: true,
      toolbar: {
        show: true,
        tools: {
          download: true,
          selection: true,
          zoom: true,
          zoomin: true,
          zoomout: true,
          pan: true,
          reset: true
        },
      },
      background: theme === 'dark' ? '#0F172B' : '#fff',
    },
    plotOptions: {
      bar: {
        horizontal: true,
        barHeight: '70%',
      },
    },
    dataLabels: {
      enabled: true,
      formatter: function (val: number, opts: any) {
        const seriesIndex = opts.seriesIndex;
        const dataPointIndex = opts.dataPointIndex;
        
        // Hitung total untuk tahun angkatan ini
        const allSeries = opts.w.config.series;
        let totalForYear = 0;
        allSeries.forEach((series: any) => {
          totalForYear += series.data[dataPointIndex] || 0;
        });
        
        if (totalForYear === 0 || val === 0) return '0%';
        
        const percentage = ((val / totalForYear) * 100).toFixed(0);
        return percentage + '%';
      },
      style: {
        fontSize: '12px',
        colors: [theme === 'dark' ? '#fff' : '#000']
      }
    },
    stroke: {
      show: true,
      width: 2,
      colors: ['transparent'],
    },
    xaxis: {
      categories: tahunAngkatan,
      title: {
        text: 'Jumlah Mahasiswa',
        style: {
          fontSize: '14px',
          fontWeight: 'bold',
          color: theme === 'dark' ? '#fff' : '#000'
        }
      },
      labels: {
        style: {
          fontSize: '12px',
          colors: theme === 'dark' ? '#fff' : '#000'
        }
      },
      min: 0,
      tickAmount: 5
    },
    yaxis: {
      title: {
        text: 'Tahun Angkatan',
        style: {
          fontSize: '14px',
          fontWeight: 'bold',
          color: theme === 'dark' ? '#fff' : '#000'
        }
      },
      labels: {
        style: {
          fontSize: '12px',
          colors: theme === 'dark' ? '#fff' : '#000'
        }
      }
    },
    fill: {
      opacity: 1,
    },
    legend: {
      position: 'top',
      fontSize: '11px',
      markers: {
        size: 8,
      },
      itemMargin: {
        horizontal: 12,
        vertical: 8,
      },
      labels: {
        colors: theme === 'dark' ? '#fff' : '#000',
      },
      formatter: function(seriesName: string) {
        return seriesName;
      }
    },
    colors: ['#008FFB', '#00E396', '#FEB019', '#EF4444'], // Sangat Baik, Baik, Cukup, Kurang
    tooltip: {
      theme: theme === 'dark' ? 'dark' : 'light',
      shared: true,
      intersect: false,
      custom: function({ series, seriesIndex, dataPointIndex, w }: any) {
        const tahun = w.globals.labels[dataPointIndex];
        const isDark = theme === 'dark';
        
        // Hitung total untuk tahun ini
        let total = 0;
        series.forEach((seriesData: number[]) => {
          total += seriesData[dataPointIndex] || 0;
        });
        
        const kategoriLabels = [
          '4.00 - 3.00 Sangat Baik',
          '2.99 - 2.50 Baik',
          '2.49 - 2.00 Cukup',
          '< 2.00 Kurang'
        ];
        const kategoriColors = ['#008FFB', '#00E396', '#FEB019', '#EF4444'];
        
        let tooltipContent = `
          <div style="
            padding: 12px 16px; 
            background: ${isDark ? 'rgba(30, 41, 59, 0.95)' : 'rgba(255, 255, 255, 0.95)'}; 
            backdrop-filter: blur(10px);
            border: none; 
            border-radius: 12px; 
            box-shadow: 0 8px 32px ${isDark ? 'rgba(0, 0, 0, 0.3)' : 'rgba(0, 0, 0, 0.1)'};
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            min-width: 200px;
          ">
            <div style="
              font-size: 13px; 
              font-weight: 600; 
              color: ${isDark ? '#f1f5f9' : '#1f2937'}; 
              margin-bottom: 8px;
              text-align: center;
            ">Angkatan ${tahun}</div>`;
        
        // Tambahkan setiap kategori
        series.forEach((seriesData: number[], index: number) => {
          const value = seriesData[dataPointIndex] || 0;
          if (value > 0) {
            const percentage = total > 0 ? ((value / total) * 100).toFixed(1) : '0';
            tooltipContent += `
              <div style="display: flex; align-items: center; margin-bottom: 4px;">
                <div style="width: 8px; height: 8px; background: ${kategoriColors[index]}; border-radius: 50%; margin-right: 8px;"></div>
                <span style="font-size: 12px; color: ${isDark ? '#cbd5e1' : '#374151'};">${kategoriLabels[index]}</span>
                <span style="font-size: 12px; font-weight: 600; color: ${isDark ? '#f1f5f9' : '#1f2937'}; margin-left: auto;">${value} (${percentage}%)</span>
              </div>`;
          }
        });
        
        // Tambahkan total
        tooltipContent += `
            <div style="
              border-top: 1px solid ${isDark ? '#475569' : '#e5e7eb'}; 
              margin-top: 8px; 
              padding-top: 8px;
              display: flex; 
              align-items: center;
            ">
              <div style="width: 8px; height: 8px; background: #6366f1; border-radius: 50%; margin-right: 8px;"></div>
              <span style="font-size: 12px; font-weight: 600; color: ${isDark ? '#f1f5f9' : '#1f2937'};">Total</span>
              <span style="font-size: 13px; font-weight: 700; color: #6366f1; margin-left: auto;">${total}</span>
            </div>
          </div>
        `;
        
        return tooltipContent;
      }
    }
  }), [theme, tahunAngkatan]);

  useEffect(() => {
    const fetchData = async () => {
      try {
        setLoading(true);
        setError(null);
        
        const url = selectedYear === 'all'
          ? '/api/mahasiswa/kategoriipk'
          : `/api/mahasiswa/kategoriipk?tahun_angkatan=${selectedYear}`;
        
        const response = await fetch(url);
        
        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');
        }
        
        setData(result);

        // Process data to create series
        const tahunAngkatan = [...new Set(result.map(item => item.tahun_angkatan))].sort((a, b) => a - b);
        const kategori = ['Sangat Baik', 'Baik', 'Cukup', 'Kurang'];
        // Label lengkap dengan angka IPK untuk ditampilkan di legend
        const kategoriLabels = [
          '4.00 - 3.00 Sangat Baik',
          '2.99 - 2.50 Baik',
          '2.49 - 2.00 Cukup',
          '< 2.00 Kurang'
        ];
        
        // Buat series data dengan label lengkap (angka IPK + kategori)
        const seriesData = kategori.map((kat, index) => ({
          name: kategoriLabels[index], // Label ini akan ditampilkan di legend
          data: tahunAngkatan.map(tahun => {
            const item = result.find(d => d.tahun_angkatan === tahun && d.kategori_ipk === kat);
            return item ? item.jumlah : 0;
          }),
        }));

        setSeries(seriesData);
      } catch (err) {
        console.error('Error in fetchData:', err);
        setError(err instanceof Error ? err.message : 'An error occurred while fetching data');
      } finally {
        setLoading(false);
      }
    };

    fetchData();
  }, [selectedYear]);

  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 (data.length === 0) {
    return (
      <Card className="bg-white dark:bg-slate-900 shadow-lg">
        <CardHeader>
          <CardTitle className="text-xl font-bold dark:text-white">
            Distribusi IPK
            {selectedYear !== 'all' ? ` Angkatan ${selectedYear}` : ''}
          </CardTitle>
        </CardHeader>
        <CardContent>
          <p className="text-sm text-muted-foreground">
            Tidak ada data yang tersedia untuk periode ini.
          </p>
        </CardContent>
      </Card>
    );
  }

  return (
    <Card className="bg-white dark:bg-slate-900 shadow-lg">
      <CardHeader>
        <div className="flex justify-between items-center">
          <CardTitle className="text-xl font-bold dark:text-white">
            Persentase Distribusi IPK Berdasarkan Tahun Angkatan
            {selectedYear !== 'all' ? ` Angkatan ${selectedYear}` : ''}
          </CardTitle>
          {showDetailButton && (
            <Link href="/detail/kategori-ipk" target="_blank">
              <Button variant="outline" size="sm" className="flex items-center gap-1 dark:text-white">
                <ExternalLink className="size-3" />
                Detail
              </Button>
            </Link>
          )}
        </div>
      </CardHeader>
      <CardContent>
        <div className={`${height} w-full max-w-5xl mx-auto`}>
          {typeof window !== 'undefined' && (
            <Chart
              options={chartOptions}
              series={series}
              type="bar"
              height="100%"
              width="100%"
            />
          )}
        </div>
      </CardContent>
    </Card>
  );
}