import { useState, useEffect, useCallback } from 'react';
import { useNavigate } from 'react-router-dom';
import {
  Eye,
  RefreshCw,
  Download,
  Maximize2,
  X,
  Activity,
  Thermometer,
  Waves,
  Grid3X3,
  Box,
  AlertCircle,
  CheckCircle,
  Clock,
  FileText
} from 'lucide-react';
import { useStudy } from '../context/StudyContext';
import { Card } from '../components/common/Card';
import Plot from 'react-plotly.js';

interface InsightInfo {
  type: string;
  name: string;
  description: string;
  applicable_to: string[];
}

interface GeneratedFile {
  filename: string;
  insight_type: string;
  timestamp: string | null;
  size_kb: number;
  modified: number;
}

interface InsightResult {
  success: boolean;
  insight_type: string;
  plotly_figure: any;
  summary: Record<string, any>;
  html_path: string | null;
}

const INSIGHT_ICONS: Record<string, React.ElementType> = {
  zernike_wfe: Waves,
  stress_field: Activity,
  modal: Box,
  thermal: Thermometer,
  design_space: Grid3X3
};

const INSIGHT_COLORS: Record<string, string> = {
  zernike_wfe: 'text-blue-400 bg-blue-500/10 border-blue-500/30',
  stress_field: 'text-red-400 bg-red-500/10 border-red-500/30',
  modal: 'text-purple-400 bg-purple-500/10 border-purple-500/30',
  thermal: 'text-orange-400 bg-orange-500/10 border-orange-500/30',
  design_space: 'text-green-400 bg-green-500/10 border-green-500/30'
};

export default function Insights() {
  const navigate = useNavigate();
  const { selectedStudy, isInitialized } = useStudy();

  const [availableInsights, setAvailableInsights] = useState<InsightInfo[]>([]);
  const [generatedFiles, setGeneratedFiles] = useState<GeneratedFile[]>([]);
  const [loading, setLoading] = useState(true);
  const [generating, setGenerating] = useState<string | null>(null);
  const [error, setError] = useState<string | null>(null);

  // Active insight for display
  const [activeInsight, setActiveInsight] = useState<InsightResult | null>(null);
  const [fullscreen, setFullscreen] = useState(false);

  // Redirect if no study
  useEffect(() => {
    if (isInitialized && !selectedStudy) {
      navigate('/');
    }
  }, [selectedStudy, navigate, isInitialized]);

  // Load available insights and generated files
  const loadInsights = useCallback(async () => {
    if (!selectedStudy) return;

    setLoading(true);
    setError(null);

    try {
      // Load available insights
      const availRes = await fetch(`/api/insights/studies/${selectedStudy.id}/insights/available`);
      const availData = await availRes.json();
      setAvailableInsights(availData.insights || []);

      // Load previously generated files
      const genRes = await fetch(`/api/insights/studies/${selectedStudy.id}/insights/generated`);
      const genData = await genRes.json();
      setGeneratedFiles(genData.files || []);

    } catch (err) {
      console.error('Failed to load insights:', err);
      setError('Failed to load insights data');
    } finally {
      setLoading(false);
    }
  }, [selectedStudy]);

  useEffect(() => {
    loadInsights();
  }, [loadInsights]);

  // Generate an insight
  const handleGenerate = async (insightType: string) => {
    if (!selectedStudy || generating) return;

    setGenerating(insightType);
    setError(null);

    try {
      const res = await fetch(
        `/api/insights/studies/${selectedStudy.id}/insights/generate/${insightType}`,
        { method: 'POST' }
      );

      if (!res.ok) {
        const errData = await res.json();
        throw new Error(errData.detail || 'Generation failed');
      }

      const result: InsightResult = await res.json();
      setActiveInsight(result);

      // Refresh file list
      loadInsights();

    } catch (err: any) {
      setError(err.message || 'Failed to generate insight');
    } finally {
      setGenerating(null);
    }
  };

  // View existing insight
  const handleViewExisting = async (file: GeneratedFile) => {
    if (!selectedStudy) return;

    setGenerating(file.insight_type);

    try {
      const res = await fetch(
        `/api/insights/studies/${selectedStudy.id}/insights/generate/${file.insight_type}`,
        { method: 'POST' }
      );

      if (!res.ok) {
        throw new Error('Failed to load insight');
      }

      const result: InsightResult = await res.json();
      setActiveInsight(result);

    } catch (err: any) {
      setError(err.message || 'Failed to load insight');
    } finally {
      setGenerating(null);
    }
  };

  // Open HTML in new tab
  const handleOpenHtml = (file: GeneratedFile) => {
    if (!selectedStudy) return;
    window.open(`/api/insights/studies/${selectedStudy.id}/insights/view/${file.insight_type}`, '_blank');
  };

  const getIcon = (type: string) => {
    const Icon = INSIGHT_ICONS[type] || Eye;
    return Icon;
  };

  const getColorClass = (type: string) => {
    return INSIGHT_COLORS[type] || 'text-gray-400 bg-gray-500/10 border-gray-500/30';
  };

  if (!isInitialized || !selectedStudy) {
    return (
      <div className="flex items-center justify-center min-h-screen">
        <div className="text-center">
          <RefreshCw className="w-8 h-8 animate-spin text-dark-400 mx-auto mb-4" />
          <p className="text-dark-400">Loading...</p>
        </div>
      </div>
    );
  }

  return (
    <div className="w-full">
      {/* Header */}
      <header className="mb-6 flex items-center justify-between border-b border-dark-600 pb-4">
        <div>
          <h1 className="text-2xl font-bold text-primary-400">Insights</h1>
          <p className="text-dark-400 text-sm">
            Physics visualizations for {selectedStudy.name || selectedStudy.id}
          </p>
        </div>
        <div className="flex items-center gap-2">
          <button
            onClick={loadInsights}
            disabled={loading}
            className="flex items-center gap-2 px-4 py-2 bg-dark-700 hover:bg-dark-600 text-white rounded-lg transition-colors disabled:opacity-50"
          >
            <RefreshCw className={`w-4 h-4 ${loading ? 'animate-spin' : ''}`} />
            Refresh
          </button>
        </div>
      </header>

      {/* Error Banner */}
      {error && (
        <div className="mb-6 p-4 bg-red-500/10 border border-red-500/30 rounded-lg flex items-center gap-3">
          <AlertCircle className="w-5 h-5 text-red-400 flex-shrink-0" />
          <p className="text-red-400">{error}</p>
          <button onClick={() => setError(null)} className="ml-auto text-red-400 hover:text-red-300">
            <X className="w-4 h-4" />
          </button>
        </div>
      )}

      <div className="grid grid-cols-1 lg:grid-cols-3 gap-6">
        {/* Left Panel: Available Insights */}
        <div className="lg:col-span-1 space-y-4">
          <Card title="Available Insights" className="p-0">
            {loading ? (
              <div className="p-6 text-center text-dark-400">
                <RefreshCw className="w-6 h-6 animate-spin mx-auto mb-2" />
                Loading...
              </div>
            ) : availableInsights.length === 0 ? (
              <div className="p-6 text-center text-dark-400">
                <Eye className="w-8 h-8 mx-auto mb-2 opacity-50" />
                <p>No insights available for this study.</p>
                <p className="text-xs mt-1">Run some trials first.</p>
              </div>
            ) : (
              <div className="divide-y divide-dark-600">
                {availableInsights.map((insight) => {
                  const Icon = getIcon(insight.type);
                  const colorClass = getColorClass(insight.type);
                  const isGenerating = generating === insight.type;

                  return (
                    <div key={insight.type} className="p-4 hover:bg-dark-750 transition-colors">
                      <div className="flex items-start gap-3">
                        <div className={`p-2 rounded-lg border ${colorClass}`}>
                          <Icon className="w-5 h-5" />
                        </div>
                        <div className="flex-1 min-w-0">
                          <h3 className="font-medium text-white">{insight.name}</h3>
                          <p className="text-xs text-dark-400 mt-0.5">{insight.description}</p>
                        </div>
                      </div>
                      <button
                        onClick={() => handleGenerate(insight.type)}
                        disabled={isGenerating}
                        className={`mt-3 w-full flex items-center justify-center gap-2 px-3 py-2 rounded-lg text-sm font-medium transition-colors ${
                          isGenerating
                            ? 'bg-dark-600 text-dark-400 cursor-wait'
                            : 'bg-primary-600 hover:bg-primary-500 text-white'
                        }`}
                      >
                        {isGenerating ? (
                          <>
                            <RefreshCw className="w-4 h-4 animate-spin" />
                            Generating...
                          </>
                        ) : (
                          <>
                            <Eye className="w-4 h-4" />
                            Generate
                          </>
                        )}
                      </button>
                    </div>
                  );
                })}
              </div>
            )}
          </Card>

          {/* Previously Generated */}
          {generatedFiles.length > 0 && (
            <Card title="Generated Files" className="p-0">
              <div className="divide-y divide-dark-600 max-h-64 overflow-y-auto">
                {generatedFiles.map((file) => {
                  const Icon = getIcon(file.insight_type);

                  return (
                    <div
                      key={file.filename}
                      className="p-3 hover:bg-dark-750 transition-colors flex items-center gap-3"
                    >
                      <Icon className="w-4 h-4 text-dark-400" />
                      <div className="flex-1 min-w-0">
                        <p className="text-sm text-white truncate">{file.insight_type}</p>
                        <p className="text-xs text-dark-500">{file.size_kb} KB</p>
                      </div>
                      <div className="flex gap-1">
                        <button
                          onClick={() => handleViewExisting(file)}
                          className="p-1.5 text-dark-400 hover:text-white hover:bg-dark-600 rounded transition-colors"
                          title="View in dashboard"
                        >
                          <Eye className="w-4 h-4" />
                        </button>
                        <button
                          onClick={() => handleOpenHtml(file)}
                          className="p-1.5 text-dark-400 hover:text-white hover:bg-dark-600 rounded transition-colors"
                          title="Open in new tab"
                        >
                          <Maximize2 className="w-4 h-4" />
                        </button>
                      </div>
                    </div>
                  );
                })}
              </div>
            </Card>
          )}
        </div>

        {/* Right Panel: Visualization */}
        <div className="lg:col-span-2">
          {activeInsight ? (
            <Card
              title={
                <div className="flex items-center justify-between">
                  <span>{activeInsight.insight_type.replace('_', ' ').toUpperCase()}</span>
                  <div className="flex gap-2">
                    <button
                      onClick={() => setFullscreen(true)}
                      className="p-1.5 text-dark-400 hover:text-white hover:bg-dark-600 rounded transition-colors"
                      title="Fullscreen"
                    >
                      <Maximize2 className="w-4 h-4" />
                    </button>
                    <button
                      onClick={() => setActiveInsight(null)}
                      className="p-1.5 text-dark-400 hover:text-white hover:bg-dark-600 rounded transition-colors"
                      title="Close"
                    >
                      <X className="w-4 h-4" />
                    </button>
                  </div>
                </div>
              }
              className="h-full"
            >
              {/* Summary Stats */}
              {activeInsight.summary && Object.keys(activeInsight.summary).length > 0 && (
                <div className="mb-4 grid grid-cols-2 md:grid-cols-4 gap-3">
                  {Object.entries(activeInsight.summary).slice(0, 8).map(([key, value]) => (
                    <div key={key} className="bg-dark-750 rounded-lg p-3">
                      <div className="text-xs text-dark-400 uppercase truncate">{key.replace(/_/g, ' ')}</div>
                      <div className="text-lg font-mono text-white truncate">
                        {typeof value === 'number'
                          ? value.toExponential ? value.toExponential(3) : value
                          : String(value)
                        }
                      </div>
                    </div>
                  ))}
                </div>
              )}

              {/* Plotly Figure */}
              {activeInsight.plotly_figure ? (
                <div className="bg-dark-900 rounded-lg overflow-hidden" style={{ height: '500px' }}>
                  <Plot
                    data={activeInsight.plotly_figure.data}
                    layout={{
                      ...activeInsight.plotly_figure.layout,
                      autosize: true,
                      margin: { l: 50, r: 50, t: 50, b: 50 },
                      paper_bgcolor: '#111827',
                      plot_bgcolor: '#1f2937',
                      font: { color: 'white' }
                    }}
                    config={{
                      responsive: true,
                      displayModeBar: true,
                      displaylogo: false
                    }}
                    style={{ width: '100%', height: '100%' }}
                  />
                </div>
              ) : (
                <div className="flex items-center justify-center h-64 text-dark-400">
                  <p>No visualization data available</p>
                </div>
              )}
            </Card>
          ) : (
            <Card className="h-full flex items-center justify-center min-h-[400px]">
              <div className="text-center text-dark-400">
                <Eye className="w-12 h-12 mx-auto mb-4 opacity-30" />
                <h3 className="text-lg font-medium text-dark-300 mb-2">No Insight Selected</h3>
                <p className="text-sm">
                  Select an insight type from the left panel to generate a visualization.
                </p>
              </div>
            </Card>
          )}
        </div>
      </div>

      {/* Fullscreen Modal */}
      {fullscreen && activeInsight?.plotly_figure && (
        <div className="fixed inset-0 z-50 bg-dark-900 flex flex-col">
          <div className="flex items-center justify-between p-4 border-b border-dark-600">
            <h2 className="text-xl font-bold text-white">
              {activeInsight.insight_type.replace('_', ' ').toUpperCase()}
            </h2>
            <button
              onClick={() => setFullscreen(false)}
              className="p-2 text-dark-400 hover:text-white hover:bg-dark-700 rounded-lg transition-colors"
            >
              <X className="w-6 h-6" />
            </button>
          </div>
          <div className="flex-1 p-4">
            <Plot
              data={activeInsight.plotly_figure.data}
              layout={{
                ...activeInsight.plotly_figure.layout,
                autosize: true,
                paper_bgcolor: '#111827',
                plot_bgcolor: '#1f2937',
                font: { color: 'white' }
              }}
              config={{
                responsive: true,
                displayModeBar: true,
                displaylogo: false
              }}
              style={{ width: '100%', height: '100%' }}
            />
          </div>
        </div>
      )}
    </div>
  );
}