import React, { useRef, useEffect, useState } from 'react';
import { Line } from 'react-chartjs-2';
import ChartJS from 'chart.js/auto';
import zoomPlugin from 'chartjs-plugin-zoom';

ChartJS.register(zoomPlugin);

interface TimeSeriesEntry {
  time: string;
  value: number;
}

interface EnergyLineChartProps {
  consumption: TimeSeriesEntry[];
  generation: TimeSeriesEntry[];
}

const EnergyLineChart = ({ consumption, generation }: EnergyLineChartProps) => {
  const chartRef = useRef<any>(null);

  // Generate sorted unique time labels from both series
  const allTimes = Array.from(new Set([
    ...consumption.map(d => d.time),
    ...generation.map(d => d.time),
  ])).sort(); // e.g., ["00:00", "00:30", "01:00", ...]

  // Map times to values
  const consumptionMap = Object.fromEntries(consumption.map(d => [d.time, d.value]));
  const generationMap = Object.fromEntries(generation.map(d => [d.time, d.value]));

  const [startIndex, setStartIndex] = useState(0);
  const [endIndex, setEndIndex] = useState(allTimes.length - 1);

  useEffect(() => {
    if (typeof window !== 'undefined') {
      import('hammerjs');
    }
  }, []);

  const filteredLabels = allTimes.slice(startIndex, endIndex + 1);
  const filteredConsumption = filteredLabels.map(t => consumptionMap[t] ?? null);
  const filteredGeneration = filteredLabels.map(t => generationMap[t] ?? null);

  const allValues = [...filteredConsumption, ...filteredGeneration].filter(v => v !== null) as number[];
  const maxValue = allValues.length > 0 ? Math.max(...allValues) : 0;
  const yAxisSuggestedMax = maxValue * 1.15;

  const data = {
    labels: filteredLabels,
    datasets: [
      {
        label: 'Consumption',
        data: filteredConsumption,
        borderColor: '#8884d8',
        tension: 0.4,
        fill: false,
      },
      {
        label: 'Generation',
        data: filteredGeneration,
        borderColor: '#82ca9d',
        tension: 0.4,
        fill: false,
      },
    ],
  };

  const options = {
  responsive: true,
  maintainAspectRatio: false,
  plugins: {
    legend: { position: 'top' as const },
    zoom: {
      zoom: {
        wheel: { enabled: true },
        pinch: { enabled: true },
        mode: 'x' as const,
      },
      pan: { enabled: true, mode: 'x' as const },
    },
    tooltip: { enabled: true, mode: 'index' as const, intersect: false },
  },
  scales: {
    x: {
      title: {
        display: true,
        text: 'Time (HH:MM)',
        font: {
          weight: 'bold' as const, // ✅ FIX: cast as 'const'
        },
      },
    },
    y: {
      beginAtZero: true,
      suggestedMax: yAxisSuggestedMax,
      title: {
        display: true,
        text: 'Power (kW)',
        font: {
          weight: 'bold' as const, // ✅ FIX: cast as 'const'
        },
      },
    },
  },
} as const; // ✅ Ensures compatibility with chart.js types


  const handleResetZoom = () => {
    chartRef.current?.resetZoom();
  };

  return (
    <div className="bg-white p-4 rounded-lg shadow-md dark:bg-gray-800 dark:text-white-light">
      <div className="h-98 w-full">
        <div className="flex justify-between items-center mb-2">
          <h2 className="text-lg font-bold dark:text-white-light">Energy Consumption & Generation</h2>
          <button onClick={handleResetZoom} className="btn-primary px-8 py-2 text-sm">
            Reset
          </button>
        </div>

        {/* Time range selectors */}
        <div className="mb-4 flex gap-4 items-center">
          <label className='font-medium'>
            From:{' '}
            <select
              value={startIndex}
              onChange={(e) => {
                const val = Number(e.target.value);
                setStartIndex(val <= endIndex ? val : endIndex);
              }}
              className="border rounded p-1"
            >
              {allTimes.map((label, idx) => (
                <option key={idx} value={idx}>{label}</option>
              ))}
            </select>
          </label>
          <label className='font-medium'>
            To:{' '}
            <select
              value={endIndex}
              onChange={(e) => {
                const val = Number(e.target.value);
                setEndIndex(val >= startIndex ? val : startIndex);
              }}
              className="border rounded p-1"
            >
              {allTimes.map((label, idx) => (
                <option key={idx} value={idx}>{label}</option>
              ))}
            </select>
          </label>
        </div>

        <div className="h-96 w-full">
          <Line ref={chartRef} data={data} options={options} />
        </div>
      </div>
    </div>
  );
};

export default EnergyLineChart;