import React, { useState, useRef, useEffect } from 'react';
import { Upload, Brain, CheckCircle, AlertCircle, Download, FileText, Activity, TrendingUp } from 'lucide-react';
import { Button, Card, Badge } from '../../../ui';
import { OnboardingStepProps } from '../OnboardingWizard';
import { useModal } from '../../../../hooks/ui/useModal';
import { useToast } from '../../../../hooks/ui/useToast';
import { useOnboarding } from '../../../../hooks/business/onboarding';
import { useAuthUser, useAuthLoading } from '../../../../stores/auth.store';
import { useCurrentTenant, useTenantLoading } from '../../../../stores';

type ProcessingStage = 'upload' | 'validating' | 'analyzing' | 'completed' | 'error';

interface ProcessingResult {
  // Validation data
  is_valid: boolean;
  total_records: number;
  unique_products: number;
  product_list: string[];
  validation_errors: string[];
  validation_warnings: string[];
  summary: {
    date_range: string;
    total_sales: number;
    average_daily_sales: number;
  };
  // Analysis data
  productsIdentified: number;
  categoriesDetected: number;
  businessModel: string;
  confidenceScore: number;
  recommendations: string[];
}

// This function has been replaced by the onboarding hooks

export const DataProcessingStep: React.FC<OnboardingStepProps> = ({
  data,
  onDataChange,
  onNext,
  onPrevious,
  isFirstStep,
  isLastStep
}) => {
  const user = useAuthUser();
  const authLoading = useAuthLoading();
  const currentTenant = useCurrentTenant();
  const tenantLoading = useTenantLoading();
  
  // Use the new onboarding hooks
  const {
    processSalesFile,
    generateInventorySuggestions,
    salesProcessing: {
      stage: onboardingStage,
      progress: onboardingProgress,
      currentMessage: onboardingMessage,
      validationResults,
      suggestions
    },
    tenantCreation,
    isLoading,
    error,
    clearError
  } = useOnboarding();
  
  const errorModal = useModal();
  const toast = useToast();
  
  // Check if we're still loading user or tenant data
  const isLoadingUserData = authLoading || tenantLoading;
  
  // Get tenant ID from multiple sources with fallback
  const getTenantId = (): string | null => {
    // Also check the onboarding data for tenant creation success
    const onboardingTenantId = data.bakery?.tenant_id;
    const tenantId = currentTenant?.id || user?.tenant_id || onboardingTenantId || null;
    console.log('DataProcessingStep - getTenantId:', {
      currentTenant: currentTenant?.id,
      userTenantId: user?.tenant_id,
      onboardingTenantId: onboardingTenantId,
      finalTenantId: tenantId,
      isLoadingUserData,
      authLoading,
      tenantLoading,
      user: user ? { id: user.id, email: user.email } : null,
      tenantCreationSuccess: data.tenantCreation?.isSuccess
    });
    return tenantId;
  };
  
  // Check if tenant data is available (not loading and has ID, OR tenant was created successfully)
  const isTenantAvailable = (): boolean => {
    const hasAuth = !authLoading && user;
    const hasTenantId = getTenantId() !== null;
    const tenantCreatedSuccessfully = tenantCreation.isSuccess;
    const tenantCreatedInOnboarding = data.bakery?.tenantCreated === true;
    
    const isAvailable = hasAuth && (hasTenantId || tenantCreatedSuccessfully || tenantCreatedInOnboarding);
    console.log('DataProcessingStep - isTenantAvailable:', {
      hasAuth,
      hasTenantId,
      tenantCreatedSuccessfully,
      tenantCreatedInOnboarding,
      isAvailable,
      authLoading,
      tenantLoading,
      tenantCreationFromHook: tenantCreation,
      bakeryData: data.bakery
    });
    
    return isAvailable;
  };
  // Use onboarding hook state when available, fallback to local state
  const [localStage, setLocalStage] = useState<ProcessingStage>(data.processingStage || 'upload');
  const [uploadedFile, setUploadedFile] = useState<File | null>(data.files?.salesData || null);
  const [localResults, setLocalResults] = useState<ProcessingResult | null>(data.processingResults || null);
  
  // Derive current state from onboarding hooks or local state
  // Priority: if local is 'completed' or 'error', use local; otherwise use onboarding state
  const stage = (localStage === 'completed' || localStage === 'error') 
    ? localStage 
    : (onboardingStage || localStage);
  const progress = onboardingProgress || 0;
  const currentMessage = onboardingMessage || '';
  const results = (validationResults && suggestions) ? {
    ...validationResults,
    aiSuggestions: suggestions,
    // Add calculated fields from backend response
    productsIdentified: validationResults.unique_products || validationResults.product_list?.length || 0,
    categoriesDetected: suggestions ? new Set(suggestions.map((s: any) => s.category)).size : 0,
    businessModel: 'production',
    confidenceScore: 85,
    recommendations: validationResults.summary?.suggestions || [],
    // Backend response details
    totalRecords: validationResults.total_records || 0,
    validRecords: validationResults.valid_records || 0,
    invalidRecords: validationResults.invalid_records || 0,
    fileFormat: validationResults.summary?.file_format || 'csv',
    fileSizeMb: validationResults.summary?.file_size_mb || 0,
    estimatedProcessingTime: validationResults.summary?.estimated_processing_time_seconds || 0,
    detectedColumns: validationResults.summary?.detected_columns || [],
    validationMessage: validationResults.message || 'Validación completada'
  } : localResults;

  // Debug logging for state changes
  console.log('DataProcessingStep - State debug:', {
    localStage,
    onboardingStage,
    finalStage: stage,
    hasValidationResults: !!validationResults,
    hasSuggestions: !!suggestions,
    hasResults: !!results,
    localResults: !!localResults
  });
  const [dragActive, setDragActive] = useState(false);
  
  const fileInputRef = useRef<HTMLInputElement>(null);
  const lastStateRef = useRef({ stage, progress, currentMessage, results, suggestions, uploadedFile });

  useEffect(() => {
    // Only update if state actually changed
    const currentState = { stage, progress, currentMessage, results, suggestions, uploadedFile };
    if (JSON.stringify(currentState) !== JSON.stringify(lastStateRef.current)) {
      lastStateRef.current = currentState;
      
      // Update parent data when state changes
      onDataChange({
        processingStage: stage,
        processingProgress: progress,
        currentMessage: currentMessage,
        processingResults: results,
        suggestions: suggestions,
        files: {
          ...data.files,
          salesData: uploadedFile
        }
      });
    }
  }, [stage, progress, currentMessage, results, suggestions, uploadedFile, onDataChange, data.files]);

  const handleDragOver = (e: React.DragEvent) => {
    e.preventDefault();
    setDragActive(true);
  };

  const handleDragLeave = (e: React.DragEvent) => {
    e.preventDefault();
    setDragActive(false);
  };

  const handleDrop = (e: React.DragEvent) => {
    e.preventDefault();
    setDragActive(false);
    
    const files = Array.from(e.dataTransfer.files);
    if (files.length > 0) {
      handleFileUpload(files[0]);
    }
  };

  const handleFileSelect = (e: React.ChangeEvent<HTMLInputElement>) => {
    if (e.target.files && e.target.files.length > 0) {
      handleFileUpload(e.target.files[0]);
    }
  };

  const handleFileUpload = async (file: File) => {
    // Validate file type
    const validExtensions = ['.csv', '.xlsx', '.xls', '.json'];
    const fileExtension = file.name.toLowerCase().substring(file.name.lastIndexOf('.'));
    
    if (!validExtensions.includes(fileExtension)) {
      toast.addToast('Formato de archivo no válido. Usa CSV, JSON o Excel (.xlsx, .xls)', {
        title: 'Formato inválido',
        type: 'error'
      });
      return;
    }

    // Check file size (max 10MB)
    if (file.size > 10 * 1024 * 1024) {
      toast.addToast('El archivo es demasiado grande. Máximo 10MB permitido.', {
        title: 'Archivo muy grande',
        type: 'error'
      });
      return;
    }

    setUploadedFile(file);
    setLocalStage('validating');

    try {
      // Wait for user data to load if still loading
      if (!isTenantAvailable()) {
        console.log('Tenant not available, waiting...');
        setUploadedFile(null);
        setLocalStage('upload');
        toast.addToast('Por favor espere mientras cargamos su información...', {
          title: 'Esperando datos de usuario',
          type: 'info'
        });
        return;
      }
      
      console.log('DataProcessingStep - Starting file processing', {
        fileName: file.name,
        fileSize: file.size,
        fileType: file.type,
        lastModified: file.lastModified
      });

      // Use the onboarding hook for file processing
      const success = await processSalesFile(file, (progress, stage, message) => {
        console.log(`Processing: ${progress}% - ${stage} - ${message}`);
      });
      
      if (success) {
        setLocalStage('completed');
        
        // If we have results from the onboarding hook, store them locally too
        if (validationResults && suggestions) {
          const processedResults = {
            ...validationResults,
            aiSuggestions: suggestions,
            productsIdentified: validationResults.product_list?.length || 0,
            categoriesDetected: suggestions ? new Set(suggestions.map((s: any) => s.category)).size : 0,
            businessModel: 'production',
            confidenceScore: 85,
            recommendations: []
          };
          setLocalResults(processedResults);
        }
        
        toast.addToast('El archivo se procesó correctamente', {
          title: 'Procesamiento completado',
          type: 'success'
        });
      } else {
        throw new Error('Error procesando el archivo');
      }
      
    } catch (error) {
      console.error('DataProcessingStep - Processing error:', error);
      console.error('DataProcessingStep - Error details:', {
        error,
        errorMessage: error instanceof Error ? error.message : 'Unknown error',
        errorStack: error instanceof Error ? error.stack : undefined,
        uploadedFile: file?.name,
        fileSize: file?.size,
        fileType: file?.type,
        localUploadedFile: uploadedFile?.name
      });
      
      setLocalStage('error');
      const errorMessage = error instanceof Error ? error.message : 'Error en el procesamiento de datos';
      
      toast.addToast(errorMessage, {
        title: 'Error en el procesamiento',
        type: 'error'
      });
    }
  };

  const downloadTemplate = () => {
    // Provide a static CSV template
    const csvContent = `fecha,producto,cantidad,precio_unitario,precio_total,cliente,canal_venta
2024-01-15,Pan Integral,5,2.50,12.50,Cliente A,Tienda
2024-01-15,Croissant,3,1.80,5.40,Cliente B,Online
2024-01-15,Baguette,2,3.00,6.00,Cliente C,Tienda
2024-01-16,Pan de Centeno,4,2.80,11.20,Cliente A,Tienda
2024-01-16,Empanadas,6,4.50,27.00,Cliente D,Delivery`;

    const blob = new Blob([csvContent], { type: 'text/csv;charset=utf-8;' });
    const link = document.createElement('a');
    const url = URL.createObjectURL(blob);
    
    link.setAttribute('href', url);
    link.setAttribute('download', 'plantilla_ventas.csv');
    link.style.visibility = 'hidden';
    
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    
    toast.addToast('La plantilla se descargó correctamente.', {
      title: 'Plantilla descargada',
      type: 'success'
    });
  };

  const resetProcess = () => {
    setLocalStage('upload');
    setUploadedFile(null);
    setLocalResults(null);
    if (fileInputRef.current) {
      fileInputRef.current.value = '';
    }
    if (error) {
      clearError();
    }
  };

  return (
    <div className="space-y-8">
      {/* Loading state when tenant data is not available */}
      {!isTenantAvailable() && (
        <Card className="p-8 text-center">
          <div className="w-16 h-16 bg-[var(--color-info)]/10 rounded-full flex items-center justify-center mx-auto mb-6">
            <Activity className="w-8 h-8 text-[var(--color-info)] animate-pulse" />
          </div>
          <h3 className="text-xl font-semibold text-[var(--text-primary)] mb-3">
            Cargando datos de usuario...
          </h3>
          <p className="text-[var(--text-secondary)]">
            Por favor espere mientras cargamos su información de tenant
          </p>
        </Card>
      )}

      {/* Improved Upload Stage */}
      {(stage === 'idle' || localStage === 'upload') && isTenantAvailable() && (
        <>
          <div
            className={`
              border-2 border-dashed rounded-2xl p-16 text-center transition-all duration-300 cursor-pointer group
              ${
                dragActive
                  ? 'border-[var(--color-primary)] bg-[var(--color-primary)]/10 scale-[1.02] shadow-lg'
                  : uploadedFile
                    ? 'border-[var(--color-success)] bg-[var(--color-success)]/10 shadow-md'
                    : 'border-[var(--border-secondary)] hover:border-[var(--color-primary)] hover:bg-[var(--bg-secondary)]/30 hover:shadow-lg'
              }
            `}
            onDragOver={handleDragOver}
            onDragLeave={handleDragLeave}
            onDrop={handleDrop}
            onClick={() => fileInputRef.current?.click()}
          >
            <input
              ref={fileInputRef}
              type="file"
              accept=".csv,.xlsx,.xls"
              onChange={handleFileSelect}
              className="hidden"
            />
            
            <div className="space-y-8">
              {uploadedFile ? (
                <>
                  <div className="w-20 h-20 bg-[var(--color-success)]/10 rounded-full flex items-center justify-center mx-auto">
                    <CheckCircle className="w-10 h-10 text-[var(--color-success)]" />
                  </div>
                  <div>
                    <h3 className="text-3xl font-bold text-[var(--color-success)] mb-3">
                      ¡Perfecto! Archivo listo
                    </h3>
                    <div className="bg-[var(--bg-secondary)] rounded-lg p-4 inline-block">
                      <p className="text-[var(--text-primary)] font-medium text-lg">
                        📄 {uploadedFile.name}
                      </p>
                      <p className="text-[var(--text-secondary)] text-sm mt-1">
                        {(uploadedFile.size / 1024 / 1024).toFixed(2)} MB • Listo para procesar
                      </p>
                    </div>
                  </div>
                </>
              ) : (
                <>
                  <div className="w-20 h-20 bg-[var(--color-primary)]/10 rounded-full flex items-center justify-center mx-auto group-hover:scale-110 transition-transform duration-300">
                    <Upload className="w-10 h-10 text-[var(--color-primary)]" />
                  </div>
                  <div>
                    <h3 className="text-3xl font-bold text-[var(--text-primary)] mb-4">
                      Sube tu historial de ventas
                    </h3>
                    <p className="text-[var(--text-secondary)] text-xl leading-relaxed max-w-md mx-auto">
                      Arrastra y suelta tu archivo aquí, o <span className="text-[var(--color-primary)] font-semibold">haz clic para seleccionar</span>
                    </p>
                  </div>
                  
                  {/* Visual indicators */}
                  <div className="flex justify-center space-x-8 mt-8">
                    <div className="text-center">
                      <div className="w-12 h-12 bg-green-100 rounded-lg flex items-center justify-center mx-auto mb-2">
                        <span className="text-2xl">📊</span>
                      </div>
                      <span className="text-sm text-[var(--text-secondary)]">CSV</span>
                    </div>
                    <div className="text-center">
                      <div className="w-12 h-12 bg-green-100 rounded-lg flex items-center justify-center mx-auto mb-2">
                        <span className="text-2xl">📈</span>
                      </div>
                      <span className="text-sm text-[var(--text-secondary)]">Excel</span>
                    </div>
                    <div className="text-center">
                      <div className="w-12 h-12 bg-blue-100 rounded-lg flex items-center justify-center mx-auto mb-2">
                        <span className="text-2xl">⚡</span>
                      </div>
                      <span className="text-sm text-[var(--text-secondary)]">Hasta 10MB</span>
                    </div>
                  </div>
                </>
              )}
            </div>

            <div className="mt-10 px-4 py-2 bg-[var(--bg-secondary)]/50 rounded-lg text-sm text-[var(--text-tertiary)] inline-block">
              💡 Formatos aceptados: CSV, Excel (XLSX, XLS) • Tamaño máximo: 10MB
            </div>
          </div>

          {/* Improved Template Download Section */}
          <div className="bg-gradient-to-r from-[var(--color-info)]/5 to-[var(--color-primary)]/5 rounded-xl p-6 border border-[var(--color-info)]/20">
            <div className="flex flex-col md:flex-row items-center space-y-4 md:space-y-0 md:space-x-6">
              <div className="w-16 h-16 rounded-full bg-[var(--color-info)]/10 flex items-center justify-center flex-shrink-0">
                <Download className="w-8 h-8 text-[var(--color-info)]" />
              </div>
              <div className="flex-1 text-center md:text-left">
                <h4 className="text-lg font-semibold text-[var(--text-primary)] mb-2">
                  ¿Necesitas ayuda con el formato?
                </h4>
                <p className="text-[var(--text-secondary)] mb-4">
                  Descarga nuestra plantilla Excel con ejemplos y formato correcto para tus datos de ventas
                </p>
                <Button
                  onClick={downloadTemplate}
                  className="bg-[var(--color-info)] hover:bg-[var(--color-info)]/90 text-white shadow-lg"
                >
                  <Download className="w-4 h-4 mr-2" />
                  Descargar Plantilla Gratuita
                </Button>
              </div>
            </div>
          </div>
        </>
      )}

      {/* Processing Stages */}
      {(stage === 'validating' || stage === 'analyzing') && (
        <Card className="p-8">
          <div className="text-center">
            <div className="relative mb-8">
              <div className={`w-20 h-20 rounded-full flex items-center justify-center mx-auto mb-6 ${
                stage === 'validating' 
                  ? 'bg-[var(--color-info)]/10 animate-pulse' 
                  : 'bg-[var(--color-primary)]/10 animate-pulse'
              }`}>
                {stage === 'validating' ? (
                  <FileText className={`w-8 h-8 ${stage === 'validating' ? 'text-[var(--color-info)]' : 'text-[var(--color-primary)]'}`} />
                ) : (
                  <Brain className="w-8 h-8 text-[var(--color-primary)]" />
                )}
              </div>
              
              <h3 className="text-2xl font-semibold text-[var(--text-primary)] mb-2">
                {stage === 'validating' ? 'Validando datos...' : 'Analizando con IA...'}
              </h3>
              <p className="text-[var(--text-secondary)] mb-8">
                {currentMessage}
              </p>
            </div>

            {/* Progress Bar */}
            <div className="mb-8">
              <div className="flex justify-between items-center mb-3">
                <span className="text-sm font-medium text-[var(--text-primary)]">
                  Progreso
                </span>
                <span className="text-sm text-[var(--text-secondary)]">{progress}%</span>
              </div>
              <div className="w-full bg-[var(--bg-secondary)] rounded-full h-3">
                <div
                  className="bg-gradient-to-r from-[var(--color-info)] to-[var(--color-primary)] h-3 rounded-full transition-all duration-500 ease-out"
                  style={{ width: `${progress}%` }}
                />
              </div>
            </div>

            {/* Processing Steps */}
            <div className="grid grid-cols-3 gap-4">
              <div className={`p-4 rounded-lg text-center ${
                progress >= 40 ? 'bg-[var(--color-success)]/10 text-[var(--color-success)]' : 'bg-[var(--bg-secondary)]'
              }`}>
                <FileText className="w-6 h-6 mx-auto mb-2" />
                <span className="text-sm font-medium">Validación</span>
              </div>
              <div className={`p-4 rounded-lg text-center ${
                progress >= 70 ? 'bg-[var(--color-success)]/10 text-[var(--color-success)]' : 'bg-[var(--bg-secondary)]'
              }`}>
                <Brain className="w-6 h-6 mx-auto mb-2" />
                <span className="text-sm font-medium">Análisis IA</span>
              </div>
              <div className={`p-4 rounded-lg text-center ${
                progress >= 100 ? 'bg-[var(--color-success)]/10 text-[var(--color-success)]' : 'bg-[var(--bg-secondary)]'
              }`}>
                <CheckCircle className="w-6 h-6 mx-auto mb-2" />
                <span className="text-sm font-medium">Completo</span>
              </div>
            </div>
          </div>
        </Card>
      )}

      {/* Simplified Results Stage */}
      {stage === 'completed' && results && (
        <div className="space-y-8">
          {/* Success Header */}
          <div className="text-center">
            <div className="w-16 h-16 bg-[var(--color-success)] rounded-full flex items-center justify-center mx-auto mb-6">
              <CheckCircle className="w-8 h-8 text-white" />
            </div>
            <h3 className="text-2xl font-semibold text-[var(--color-success)] mb-3">
              ¡Procesamiento Completado!
            </h3>
            <p className="text-[var(--text-secondary)] max-w-2xl mx-auto">
              {results.validationMessage || 'Tus datos han sido procesados exitosamente'}
            </p>
            {results.fileSizeMb && (
              <div className="text-xs text-[var(--text-tertiary)] mt-2">
                Archivo {results.fileFormat?.toUpperCase()} • {results.fileSizeMb.toFixed(2)} MB 
                {results.estimatedProcessingTime && ` • ${results.estimatedProcessingTime}s procesamiento`}
              </div>
            )}
          </div>

          {/* Enhanced Stats Cards */}
          <div className="grid grid-cols-2 md:grid-cols-4 gap-4">
            <div className="text-center p-4 bg-[var(--color-info)]/10 rounded-lg">
              <p className="text-2xl font-bold text-[var(--color-info)]">{results.totalRecords || results.total_records}</p>
              <p className="text-sm text-[var(--text-secondary)]">Total Registros</p>
            </div>
            <div className="text-center p-4 bg-[var(--color-success)]/10 rounded-lg">
              <p className="text-2xl font-bold text-[var(--color-success)]">{results.validRecords || results.valid_records}</p>
              <p className="text-sm text-[var(--text-secondary)]">Válidos</p>
            </div>
            <div className="text-center p-4 bg-[var(--color-error)]/10 rounded-lg">
              <p className="text-2xl font-bold text-[var(--color-error)]">{results.invalidRecords || results.invalid_records || 0}</p>
              <p className="text-sm text-[var(--text-secondary)]">Inválidos</p>
            </div>
            
            <div className="text-center p-4 bg-[var(--color-primary)]/10 rounded-lg">
              <p className="text-2xl font-bold text-[var(--color-primary)]">{results.productsIdentified}</p>
              <p className="text-sm text-[var(--text-secondary)]">Productos</p>
            </div>
            
            <div className="text-center p-4 bg-[var(--color-success)]/10 rounded-lg">
              <p className="text-2xl font-bold text-[var(--color-success)]">{results.confidenceScore}%</p>
              <p className="text-sm text-[var(--text-secondary)]">Confianza</p>
            </div>
            
            <div className="text-center p-4 bg-[var(--bg-secondary)] rounded-lg">
              <p className="text-lg font-bold text-[var(--text-primary)]">
                {results.businessModel === 'artisan' ? 'Artesanal' : 
                 results.businessModel === 'retail' ? 'Retail' : 'Híbrido'}
              </p>
              <p className="text-sm text-[var(--text-secondary)]">Modelo</p>
            </div>
          </div>

          {/* Additional Details from Backend */}
          {(results.detectedColumns?.length > 0 || results.recommendations?.length > 0) && (
            <div className="grid md:grid-cols-2 gap-6">
              {/* Detected Columns */}
              {results.detectedColumns?.length > 0 && (
                <Card className="p-4">
                  <h4 className="font-semibold text-[var(--text-primary)] mb-3">Columnas Detectadas</h4>
                  <div className="flex flex-wrap gap-2">
                    {results.detectedColumns.map((column, index) => (
                      <span key={index} 
                            className="px-2 py-1 bg-[var(--color-primary)]/10 text-[var(--color-primary)] text-xs rounded-full border border-[var(--color-primary)]/20">
                        {column}
                      </span>
                    ))}
                  </div>
                </Card>
              )}

              {/* Backend Recommendations */}
              {results.recommendations?.length > 0 && (
                <Card className="p-4">
                  <h4 className="font-semibold text-[var(--text-primary)] mb-3">Recomendaciones</h4>
                  <ul className="space-y-2">
                    {results.recommendations.slice(0, 3).map((rec, index) => (
                      <li key={index} className="text-sm text-[var(--text-secondary)] flex items-start">
                        <span className="text-[var(--color-success)] mr-2">•</span>
                        {rec}
                      </li>
                    ))}
                  </ul>
                </Card>
              )}
            </div>
          )}
        </div>
      )}

      {/* Error State */}
      {stage === 'error' && (
        <Card className="p-8 text-center">
          <div className="w-16 h-16 bg-[var(--color-error)] rounded-full flex items-center justify-center mx-auto mb-6">
            <AlertCircle className="w-8 h-8 text-white" />
          </div>
          <h3 className="text-xl font-semibold text-[var(--color-error)] mb-3">
            Error en el procesamiento
          </h3>
          <p className="text-[var(--text-secondary)] mb-6">
            {currentMessage}
          </p>
          <Button onClick={resetProcess} variant="outline">
            Intentar nuevamente
          </Button>
        </Card>
      )}
    </div>
  );
};