import React, { useEffect, useState, useRef, useCallback } from 'react';
import { classNames } from '~/utils/classNames';
import { Line } from 'react-chartjs-2';
import {
  Chart as ChartJS,
  CategoryScale,
  LinearScale,
  PointElement,
  LineElement,
  Title,
  Tooltip,
  Legend,
} from 'chart.js';
import { toast } from 'react-toastify'; // Import toast

// Register ChartJS components
ChartJS.register(CategoryScale, LinearScale, PointElement, LineElement, Title, Tooltip, Legend);

interface BatteryManager extends EventTarget {
  charging: boolean;
  chargingTime: number;
  dischargingTime: number;
  level: number;
}

interface ProcessInfo {
  name: string;
  type: 'API' | 'Animation' | 'Background' | 'Render' | 'Network' | 'Storage';
  cpuUsage: number;
  memoryUsage: number;
  status: 'active' | 'idle' | 'suspended';
  lastUpdate: string;
  impact: 'high' | 'medium' | 'low';
}

interface SystemMetrics {
  cpu: number;
  memory: {
    used: number;
    total: number;
    percentage: number;
  };
  activeProcesses: number;
  uptime: number;
  battery?: {
    level: number;
    charging: boolean;
    timeRemaining?: number;
  };
  network: {
    downlink: number;
    latency: number;
    type: string;
  };
}

interface MetricsHistory {
  timestamps: string[];
  cpu: number[];
  memory: number[];
  battery: number[];
  network: number[];
}

interface EnergySavings {
  updatesReduced: number;
  timeInSaverMode: number;
  estimatedEnergySaved: number; // in mWh (milliwatt-hours)
}

declare global {
  interface Navigator {
    getBattery(): Promise<BatteryManager>;
  }
  interface Performance {
    memory?: {
      jsHeapSizeLimit: number;
      totalJSHeapSize: number;
      usedJSHeapSize: number;
    };
  }
}

const MAX_HISTORY_POINTS = 60; // 1 minute of history at 1s intervals
const BATTERY_THRESHOLD = 20; // Enable energy saver when battery below 20%
const UPDATE_INTERVALS = {
  normal: {
    metrics: 1000, // 1s
    processes: 2000, // 2s
  },
  energySaver: {
    metrics: 5000, // 5s
    processes: 10000, // 10s
  },
};

// Energy consumption estimates (milliwatts)
const ENERGY_COSTS = {
  update: 2, // mW per update
  apiCall: 5, // mW per API call
  rendering: 1, // mW per render
};

export default function TaskManagerTab() {
  const [processes, setProcesses] = useState<ProcessInfo[]>([]);
  const [metrics, setMetrics] = useState<SystemMetrics>({
    cpu: 0,
    memory: { used: 0, total: 0, percentage: 0 },
    activeProcesses: 0,
    uptime: 0,
    network: { downlink: 0, latency: 0, type: 'unknown' },
  });
  const [metricsHistory, setMetricsHistory] = useState<MetricsHistory>({
    timestamps: [],
    cpu: [],
    memory: [],
    battery: [],
    network: [],
  });
  const [loading, setLoading] = useState({
    metrics: false,
    processes: false,
  });
  const [energySaverMode, setEnergySaverMode] = useState<boolean>(() => {
    // Initialize from localStorage, default to false
    const saved = localStorage.getItem('energySaverMode');
    return saved ? JSON.parse(saved) : false;
  });

  const [autoEnergySaver, setAutoEnergySaver] = useState<boolean>(() => {
    // Initialize from localStorage, default to false
    const saved = localStorage.getItem('autoEnergySaver');
    return saved ? JSON.parse(saved) : false;
  });

  const [energySavings, setEnergySavings] = useState<EnergySavings>({
    updatesReduced: 0,
    timeInSaverMode: 0,
    estimatedEnergySaved: 0,
  });

  const saverModeStartTime = useRef<number | null>(null);

  // Handle energy saver mode changes
  const handleEnergySaverChange = (checked: boolean) => {
    setEnergySaverMode(checked);
    localStorage.setItem('energySaverMode', JSON.stringify(checked));
    toast.success(checked ? 'Energy Saver mode enabled' : 'Energy Saver mode disabled');
  };

  // Handle auto energy saver changes
  const handleAutoEnergySaverChange = (checked: boolean) => {
    setAutoEnergySaver(checked);
    localStorage.setItem('autoEnergySaver', JSON.stringify(checked));
    toast.success(checked ? 'Auto Energy Saver enabled' : 'Auto Energy Saver disabled');

    if (!checked) {
      // When disabling auto mode, also disable energy saver mode
      setEnergySaverMode(false);
      localStorage.setItem('energySaverMode', 'false');
    }
  };

  // Calculate energy savings
  const updateEnergySavings = useCallback(() => {
    if (!energySaverMode) {
      saverModeStartTime.current = null;
      return;
    }

    if (!saverModeStartTime.current) {
      saverModeStartTime.current = Date.now();
    }

    const timeInSaverMode = (Date.now() - saverModeStartTime.current) / 1000; // in seconds
    const normalUpdatesPerMinute =
      60 / (UPDATE_INTERVALS.normal.metrics / 1000) + 60 / (UPDATE_INTERVALS.normal.processes / 1000);
    const saverUpdatesPerMinute =
      60 / (UPDATE_INTERVALS.energySaver.metrics / 1000) + 60 / (UPDATE_INTERVALS.energySaver.processes / 1000);
    const updatesReduced = Math.floor((normalUpdatesPerMinute - saverUpdatesPerMinute) * (timeInSaverMode / 60));

    // Calculate energy saved (mWh)
    const energySaved =
      (updatesReduced * ENERGY_COSTS.update + // Energy saved from reduced updates
        updatesReduced * ENERGY_COSTS.apiCall + // Energy saved from fewer API calls
        updatesReduced * ENERGY_COSTS.rendering) / // Energy saved from fewer renders
      3600; // Convert to watt-hours (divide by 3600 seconds)

    setEnergySavings({
      updatesReduced,
      timeInSaverMode,
      estimatedEnergySaved: energySaved,
    });
  }, [energySaverMode]);

  useEffect((): (() => void) | undefined => {
    if (!energySaverMode) {
      // Clear any existing intervals and reset savings when disabled
      setEnergySavings({
        updatesReduced: 0,
        timeInSaverMode: 0,
        estimatedEnergySaved: 0,
      });
      return undefined;
    }

    const savingsInterval = setInterval(updateEnergySavings, 1000);

    return () => clearInterval(savingsInterval);
  }, [energySaverMode, updateEnergySavings]);

  useEffect((): (() => void) | undefined => {
    if (!autoEnergySaver) {
      // If auto mode is disabled, clear any forced energy saver state
      setEnergySaverMode(false);
      return undefined;
    }

    const checkBatteryStatus = async () => {
      try {
        const battery = await navigator.getBattery();
        const shouldEnableSaver = !battery.charging && battery.level * 100 <= BATTERY_THRESHOLD;
        setEnergySaverMode(shouldEnableSaver);
      } catch {
        console.log('Battery API not available');
      }
    };

    checkBatteryStatus();

    const batteryCheckInterval = setInterval(checkBatteryStatus, 60000);

    return () => clearInterval(batteryCheckInterval);
  }, [autoEnergySaver]);

  const getUsageColor = (usage: number): string => {
    if (usage > 80) {
      return 'text-red-500';
    }

    if (usage > 50) {
      return 'text-yellow-500';
    }

    return 'text-gray-500';
  };

  const getImpactColor = (impact: 'high' | 'medium' | 'low'): string => {
    if (impact === 'high') {
      return 'text-red-500';
    }

    if (impact === 'medium') {
      return 'text-yellow-500';
    }

    return 'text-gray-500';
  };

  const renderUsageGraph = (data: number[], label: string, color: string) => {
    const chartData = {
      labels: metricsHistory.timestamps,
      datasets: [
        {
          label,
          data,
          borderColor: color,
          fill: false,
          tension: 0.4,
        },
      ],
    };

    const options = {
      responsive: true,
      maintainAspectRatio: false,
      scales: {
        y: {
          beginAtZero: true,
          max: 100,
          grid: {
            color: 'rgba(255, 255, 255, 0.1)',
          },
        },
        x: {
          grid: {
            display: false,
          },
        },
      },
      plugins: {
        legend: {
          display: false,
        },
      },
      animation: {
        duration: 0,
      } as const,
    };

    return (
      <div className="h-32">
        <Line data={chartData} options={options} />
      </div>
    );
  };

  const updateMetrics = async () => {
    try {
      setLoading((prev) => ({ ...prev, metrics: true }));

      // Get memory info
      const memory = performance.memory || {
        jsHeapSizeLimit: 0,
        totalJSHeapSize: 0,
        usedJSHeapSize: 0,
      };
      const totalMem = memory.totalJSHeapSize / (1024 * 1024);
      const usedMem = memory.usedJSHeapSize / (1024 * 1024);
      const memPercentage = (usedMem / totalMem) * 100;

      // Get battery info
      let batteryInfo: SystemMetrics['battery'] | undefined;

      try {
        const battery = await navigator.getBattery();
        batteryInfo = {
          level: battery.level * 100,
          charging: battery.charging,
          timeRemaining: battery.charging ? battery.chargingTime : battery.dischargingTime,
        };
      } catch {
        console.log('Battery API not available');
      }

      // Get network info
      const connection =
        (navigator as any).connection || (navigator as any).mozConnection || (navigator as any).webkitConnection;
      const networkInfo = {
        downlink: connection?.downlink || 0,
        latency: connection?.rtt || 0,
        type: connection?.type || 'unknown',
      };

      const newMetrics = {
        cpu: Math.random() * 100,
        memory: {
          used: Math.round(usedMem),
          total: Math.round(totalMem),
          percentage: Math.round(memPercentage),
        },
        activeProcesses: document.querySelectorAll('[data-process]').length,
        uptime: performance.now() / 1000,
        battery: batteryInfo,
        network: networkInfo,
      };

      setMetrics(newMetrics);

      // Update metrics history
      const now = new Date().toLocaleTimeString();
      setMetricsHistory((prev) => {
        const timestamps = [...prev.timestamps, now].slice(-MAX_HISTORY_POINTS);
        const cpu = [...prev.cpu, newMetrics.cpu].slice(-MAX_HISTORY_POINTS);
        const memory = [...prev.memory, newMetrics.memory.percentage].slice(-MAX_HISTORY_POINTS);
        const battery = [...prev.battery, batteryInfo?.level || 0].slice(-MAX_HISTORY_POINTS);
        const network = [...prev.network, networkInfo.downlink].slice(-MAX_HISTORY_POINTS);

        return { timestamps, cpu, memory, battery, network };
      });
    } catch (error: unknown) {
      console.error('Failed to update system metrics:', error);
    } finally {
      setLoading((prev) => ({ ...prev, metrics: false }));
    }
  };

  const updateProcesses = async () => {
    try {
      setLoading((prev) => ({ ...prev, processes: true }));

      // Enhanced process monitoring
      const mockProcesses: ProcessInfo[] = [
        {
          name: 'Ollama Model Updates',
          type: 'Network',
          cpuUsage: Math.random() * 5,
          memoryUsage: Math.random() * 50,
          status: 'idle',
          lastUpdate: new Date().toISOString(),
          impact: 'high',
        },
        {
          name: 'UI Animations',
          type: 'Animation',
          cpuUsage: Math.random() * 3,
          memoryUsage: Math.random() * 30,
          status: 'idle',
          lastUpdate: new Date().toISOString(),
          impact: 'medium',
        },
        {
          name: 'Background Sync',
          type: 'Background',
          cpuUsage: Math.random() * 2,
          memoryUsage: Math.random() * 20,
          status: 'idle',
          lastUpdate: new Date().toISOString(),
          impact: 'low',
        },
        {
          name: 'IndexedDB Operations',
          type: 'Storage',
          cpuUsage: Math.random() * 1,
          memoryUsage: Math.random() * 15,
          status: 'idle',
          lastUpdate: new Date().toISOString(),
          impact: 'low',
        },
        {
          name: 'WebSocket Connection',
          type: 'Network',
          cpuUsage: Math.random() * 2,
          memoryUsage: Math.random() * 10,
          status: 'idle',
          lastUpdate: new Date().toISOString(),
          impact: 'medium',
        },
      ];

      setProcesses(mockProcesses);
    } catch (error) {
      console.error('Failed to update process list:', error);
    } finally {
      setLoading((prev) => ({ ...prev, processes: false }));
    }
  };

  // Initial update effect
  useEffect((): (() => void) => {
    // Initial update
    updateMetrics();
    updateProcesses();

    // Set up intervals for live updates
    const metricsInterval = setInterval(
      updateMetrics,
      energySaverMode ? UPDATE_INTERVALS.energySaver.metrics : UPDATE_INTERVALS.normal.metrics,
    );
    const processesInterval = setInterval(
      updateProcesses,
      energySaverMode ? UPDATE_INTERVALS.energySaver.processes : UPDATE_INTERVALS.normal.processes,
    );

    // Cleanup on unmount
    return () => {
      clearInterval(metricsInterval);
      clearInterval(processesInterval);
    };
  }, [energySaverMode]); // Re-create intervals when energy saver mode changes

  return (
    <div className="space-y-6">
      {/* System Overview */}
      <div className="p-6 rounded-xl bg-white dark:bg-[#0A0A0A] border border-[#E5E5E5] dark:border-[#1A1A1A]">
        <div className="flex justify-between items-center mb-4">
          <h2 className="text-lg font-medium text-bolt-elements-textPrimary">System Overview</h2>
          <div className="flex items-center gap-4">
            <div className="flex items-center gap-2">
              <input
                type="checkbox"
                id="autoEnergySaver"
                checked={autoEnergySaver}
                onChange={(e) => handleAutoEnergySaverChange(e.target.checked)}
                className="form-checkbox h-4 w-4 text-purple-600 rounded border-gray-300 dark:border-gray-700"
              />
              <label htmlFor="autoEnergySaver" className="text-sm text-bolt-elements-textSecondary">
                Auto Energy Saver
              </label>
            </div>
            <div className="flex items-center gap-2">
              <input
                type="checkbox"
                id="energySaver"
                checked={energySaverMode}
                onChange={(e) => !autoEnergySaver && handleEnergySaverChange(e.target.checked)}
                disabled={autoEnergySaver}
                className="form-checkbox h-4 w-4 text-purple-600 rounded border-gray-300 dark:border-gray-700 disabled:opacity-50"
              />
              <label
                htmlFor="energySaver"
                className={classNames('text-sm text-bolt-elements-textSecondary', { 'opacity-50': autoEnergySaver })}
              >
                Energy Saver
                {energySaverMode && <span className="ml-2 text-xs text-bolt-elements-textSecondary">Active</span>}
              </label>
            </div>
          </div>
        </div>

        <div className="grid grid-cols-2 md:grid-cols-4 gap-4">
          <div className="p-4 rounded-lg bg-[#F8F8F8] dark:bg-[#141414]">
            <div className="flex items-center gap-2 mb-2">
              <div className="i-ph:cpu text-gray-500 dark:text-gray-400 w-4 h-4" />
              <span className="text-sm text-bolt-elements-textSecondary">CPU Usage</span>
            </div>
            <p className={classNames('text-lg font-medium', getUsageColor(metrics.cpu))}>{Math.round(metrics.cpu)}%</p>
            {renderUsageGraph(metricsHistory.cpu, 'CPU', '#9333ea')}
          </div>

          <div className="p-4 rounded-lg bg-[#F8F8F8] dark:bg-[#141414]">
            <div className="flex items-center gap-2 mb-2">
              <div className="i-ph:database text-gray-500 dark:text-gray-400 w-4 h-4" />
              <span className="text-sm text-bolt-elements-textSecondary">Memory Usage</span>
            </div>
            <p className={classNames('text-lg font-medium', getUsageColor(metrics.memory.percentage))}>
              {metrics.memory.used}MB / {metrics.memory.total}MB
            </p>
            {renderUsageGraph(metricsHistory.memory, 'Memory', '#2563eb')}
          </div>

          <div className="p-4 rounded-lg bg-[#F8F8F8] dark:bg-[#141414]">
            <div className="flex items-center gap-2 mb-2">
              <div className="i-ph:battery text-gray-500 dark:text-gray-400 w-4 h-4" />
              <span className="text-sm text-bolt-elements-textSecondary">Battery</span>
            </div>
            {metrics.battery ? (
              <div>
                <p className="text-lg font-medium text-bolt-elements-textPrimary">
                  {Math.round(metrics.battery.level)}%
                  {metrics.battery.charging && (
                    <span className="ml-2 text-bolt-elements-textSecondary">
                      <div className="i-ph:lightning-fill w-4 h-4 inline-block" />
                    </span>
                  )}
                </p>
                {metrics.battery.timeRemaining && metrics.battery.timeRemaining !== Infinity && (
                  <p className="text-xs text-bolt-elements-textSecondary mt-1">
                    {metrics.battery.charging ? 'Full in: ' : 'Remaining: '}
                    {Math.round(metrics.battery.timeRemaining / 60)}m
                  </p>
                )}
                {renderUsageGraph(metricsHistory.battery, 'Battery', '#22c55e')}
              </div>
            ) : (
              <p className="text-sm text-bolt-elements-textSecondary">Not available</p>
            )}
          </div>

          <div className="p-4 rounded-lg bg-[#F8F8F8] dark:bg-[#141414]">
            <div className="flex items-center gap-2 mb-2">
              <div className="i-ph:wifi text-gray-500 dark:text-gray-400 w-4 h-4" />
              <span className="text-sm text-bolt-elements-textSecondary">Network</span>
            </div>
            <p className="text-lg font-medium text-bolt-elements-textPrimary">{metrics.network.downlink} Mbps</p>
            <p className="text-xs text-bolt-elements-textSecondary mt-1">Latency: {metrics.network.latency}ms</p>
            {renderUsageGraph(metricsHistory.network, 'Network', '#f59e0b')}
          </div>
        </div>
      </div>

      {/* Process List */}
      <div className="p-6 rounded-xl bg-white dark:bg-[#0A0A0A] border border-[#E5E5E5] dark:border-[#1A1A1A]">
        <div className="flex items-center justify-between mb-4">
          <div className="flex items-center gap-3">
            <div className="i-ph:list-bullets text-purple-500 w-5 h-5" />
            <h3 className="text-base font-medium text-bolt-elements-textPrimary">Active Processes</h3>
          </div>
          <button
            onClick={updateProcesses}
            className={classNames(
              'flex items-center gap-2 px-3 py-2 rounded-lg text-sm',
              'bg-[#F5F5F5] dark:bg-[#1A1A1A] hover:bg-[#E5E5E5] dark:hover:bg-[#2A2A2A]',
              'text-bolt-elements-textPrimary dark:text-bolt-elements-textPrimary',
              'transition-colors duration-200',
              { 'opacity-50 cursor-not-allowed': loading.processes },
            )}
            disabled={loading.processes}
          >
            <div className={classNames('i-ph:arrows-clockwise w-4 h-4', loading.processes ? 'animate-spin' : '')} />
            Refresh
          </button>
        </div>

        <div className="overflow-x-auto">
          <table className="w-full">
            <thead>
              <tr className="border-b border-[#E5E5E5] dark:border-[#1A1A1A]">
                <th className="py-2 px-4 text-left text-sm font-medium text-bolt-elements-textSecondary">Process</th>
                <th className="py-2 px-4 text-left text-sm font-medium text-bolt-elements-textSecondary">Type</th>
                <th className="py-2 px-4 text-left text-sm font-medium text-bolt-elements-textSecondary">CPU</th>
                <th className="py-2 px-4 text-left text-sm font-medium text-bolt-elements-textSecondary">Memory</th>
                <th className="py-2 px-4 text-left text-sm font-medium text-bolt-elements-textSecondary">Status</th>
                <th className="py-2 px-4 text-left text-sm font-medium text-bolt-elements-textSecondary">Impact</th>
                <th className="py-2 px-4 text-left text-sm font-medium text-bolt-elements-textSecondary">
                  Last Update
                </th>
              </tr>
            </thead>
            <tbody>
              {processes.map((process, index) => (
                <tr
                  key={index}
                  data-process={process.name}
                  className="border-b border-[#E5E5E5] dark:border-[#1A1A1A] last:border-0"
                >
                  <td className="py-3 px-4">
                    <div className="flex items-center gap-2">
                      <div className="i-ph:cube text-gray-500 dark:text-gray-400 w-4 h-4" />
                      <span className="text-sm text-bolt-elements-textPrimary">{process.name}</span>
                    </div>
                  </td>
                  <td className="py-3 px-4">
                    <span className="text-sm text-bolt-elements-textSecondary">{process.type}</span>
                  </td>
                  <td className="py-3 px-4">
                    <span className={classNames('text-sm', getUsageColor(process.cpuUsage))}>
                      {process.cpuUsage.toFixed(1)}%
                    </span>
                  </td>
                  <td className="py-3 px-4">
                    <span className={classNames('text-sm', getUsageColor(process.memoryUsage))}>
                      {process.memoryUsage.toFixed(1)} MB
                    </span>
                  </td>
                  <td className="py-3 px-4">
                    <span className={classNames('text-sm text-bolt-elements-textSecondary capitalize')}>
                      {process.status}
                    </span>
                  </td>
                  <td className="py-3 px-4">
                    <span className={classNames('text-sm', getImpactColor(process.impact))}>{process.impact}</span>
                  </td>
                  <td className="py-3 px-4">
                    <span className="text-sm text-bolt-elements-textSecondary">
                      {new Date(process.lastUpdate).toLocaleTimeString()}
                    </span>
                  </td>
                </tr>
              ))}
            </tbody>
          </table>
        </div>
      </div>

      {/* Energy Savings */}
      <div className="p-6 rounded-xl bg-white dark:bg-[#0A0A0A] border border-[#E5E5E5] dark:border-[#1A1A1A]">
        <h3 className="text-base font-medium text-bolt-elements-textPrimary">Energy Savings</h3>
        <div className="grid grid-cols-2 md:grid-cols-4 gap-4 mt-4">
          <div className="p-4 rounded-lg bg-[#F8F8F8] dark:bg-[#141414]">
            <div className="flex items-center gap-2 mb-2">
              <div className="i-ph:clock text-gray-500 dark:text-gray-400 w-4 h-4" />
              <span className="text-sm text-bolt-elements-textSecondary">Time in Saver Mode</span>
            </div>
            <p className="text-lg font-medium text-bolt-elements-textPrimary">
              {Math.floor(energySavings.timeInSaverMode / 60)}m {Math.floor(energySavings.timeInSaverMode % 60)}s
            </p>
          </div>

          <div className="p-4 rounded-lg bg-[#F8F8F8] dark:bg-[#141414]">
            <div className="flex items-center gap-2 mb-2">
              <div className="i-ph:chart-line text-gray-500 dark:text-gray-400 w-4 h-4" />
              <span className="text-sm text-bolt-elements-textSecondary">Updates Reduced</span>
            </div>
            <p className="text-lg font-medium text-bolt-elements-textPrimary">{energySavings.updatesReduced}</p>
          </div>

          <div className="p-4 rounded-lg bg-[#F8F8F8] dark:bg-[#141414]">
            <div className="flex items-center gap-2 mb-2">
              <div className="i-ph:battery text-gray-500 dark:text-gray-400 w-4 h-4" />
              <span className="text-sm text-bolt-elements-textSecondary">Estimated Energy Saved</span>
            </div>
            <p className="text-lg font-medium text-bolt-elements-textPrimary">
              {energySavings.estimatedEnergySaved.toFixed(2)} mWh
            </p>
          </div>
        </div>
      </div>
    </div>
  );
}