import type { DetectionConfig, DetectionResult, DetectionMetrics, DetectionMode } from './types';
import { DetectionWorkerManager } from './detection-worker-manager';
import { detectDeviceCapabilities, getRecommendedConfig } from './device-capabilities';
import { skuIdentificationService } from '../sku-identification';

// Extend window interface for TensorFlow.js
declare global {
  interface Window {
    tf: unknown;
  }
}

/**
 * Main detection engine that coordinates continuous and trigger detection
 */
export class DetectionEngine {
  private workerManager: DetectionWorkerManager;
  private config: DetectionConfig;
  private model: unknown = null; // TensorFlow.js model instance
  
  // Detection state
  private isRunning = false;
  private detectionMode: DetectionMode = 'hybrid';
  private frameSkipCounter = 0;
  private detectionCount = 0;
  
  // Temporal filtering
  private detectionHistory: DetectionResult[] = [];
  private lastValidDetection: DetectionResult | null = null;
  
  // Performance tracking
  private metrics: DetectionMetrics = {
    fps: 0,
    inferenceTime: 0,
    memoryUsage: 0
  };
  
  // Event callbacks
  private onDetectionCallback?: (detection: DetectionResult | null) => void;
  private onMetricsCallback?: (metrics: DetectionMetrics) => void;
  private lastDetectionCallbackTime?: number;
  
  constructor() {
    console.log('🏗️ DetectionEngine constructor called');
    this.workerManager = new DetectionWorkerManager();
    
    
    // Get device-optimized configuration
    const capabilities = detectDeviceCapabilities();
    this.config = getRecommendedConfig(capabilities);
    
    console.log('✅ Detection engine initialized', { capabilities, config: this.config });
  }

  /**
   * Initialize the detection engine with a specific model
   */
  async initialize(modelVariant?: 'quantized' | 'standard' | 'full', onProgress?: (progress: number) => void): Promise<void> {
    const variant = modelVariant || this.config.modelVariant;
    
    console.log(`🔧 Initializing detection engine with ${variant} model...`);
    
    try {
      // Load the model into the worker
      console.log('📥 Loading model into worker...');
      await this.workerManager.loadModel(variant, onProgress);
      
      // Configure the worker with current settings
      console.log('⚙️ Configuring worker...');
      await this.workerManager.configure(this.config);
      
      console.log(`✅ Detection engine initialized with ${variant} model`);
      
    } catch (error) {
      console.error('❌ Failed to initialize detection engine:', error);
      throw error;
    }
  }

  /**
   * Start continuous detection
   */
  startContinuousDetection(videoElement: HTMLVideoElement): void {
    console.log('🚀 startContinuousDetection called:', { 
      isRunning: this.isRunning, 
      enableContinuous: this.config.enableContinuous,
      videoElement: !!videoElement 
    });
    
    if (this.isRunning) {
      console.warn('Detection already running');
      return;
    }
    
    this.isRunning = true;
    this.detectionMode = this.config.enableContinuous ? 'continuous' : 'trigger';
    
    if (this.config.enableContinuous) {
      console.log('🔄 Starting continuous detection loop...');
      this.runContinuousLoop(videoElement);
    }
    
    console.log(`✅ Started detection in ${this.detectionMode} mode`);
  }

  /**
   * Stop continuous detection
   */
  stopContinuousDetection(): void {
    this.isRunning = false;
    this.frameSkipCounter = 0;
    this.detectionHistory = [];
    console.log('Stopped continuous detection');
  }

  /**
   * Perform single trigger detection - higher quality/confidence than continuous
   */
  async triggerDetection(videoElement: HTMLVideoElement): Promise<DetectionResult | null> {
    const startTime = performance.now();
    
    try {
      console.log('🎯 Starting trigger detection (high quality)');
      
      // Capture image data for trigger detection (high quality)
      const imageData = this.captureVideoFrame(videoElement, true);
      
      // Use worker manager for detection
      const detections = await this.workerManager.detect(imageData);
      const detection = detections.length > 0 ? detections[0] : null;
      
      // Update metrics
      this.metrics.inferenceTime = performance.now() - startTime;
      
      console.log('✅ Trigger detection completed:', detection);
      
      // Trigger callbacks for immediate display
      if (this.onDetectionCallback && detection) {
        this.onDetectionCallback(detection);
      }
      
      return detection;
      
    } catch (error) {
      console.error('❌ Trigger detection failed:', error);
      throw error;
    }
  }

  /**
   * Identify product SKU from detected shoe
   * @param videoElement - Video element to capture image from
   * @returns Promise<string | null> - Product SKU if identified successfully
   */
  async identifyProductSKU(videoElement: HTMLVideoElement): Promise<string | null> {
    try {
      console.log('🔍 Starting product SKU identification...');
      
      // Capture high-quality image for SKU identification
      const imageData = this.captureVideoFrame(videoElement, true);
      
      // Call SKU identification service
      const sku = await skuIdentificationService.identifySKU(imageData);
      
      if (sku) {
        console.log('✅ Product SKU identified:', sku);
      } else {
        console.log('❌ No valid SKU found');
      }
      
      return sku;
      
    } catch (error) {
      console.error('❌ SKU identification failed:', error);
      return null;
    }
  }

  /**
   * Continuous detection loop
   */
  private async runContinuousLoop(videoElement: HTMLVideoElement): Promise<void> {
    if (!this.isRunning) return;
    
    // Frame skipping logic
    this.frameSkipCounter++;
    if (this.frameSkipCounter < this.config.frameSkip) {
      // Skip this frame, schedule next iteration
      requestAnimationFrame(() => this.runContinuousLoop(videoElement));
      return;
    }
    
    this.frameSkipCounter = 0;
    // Only log every 10th detection to reduce noise
    if (this.detectionCount % 10 === 0) {
      console.log(`🔄 Continuous detection running... (${this.detectionCount} inferences)`);
    }
    
    try {
      const startTime = performance.now();
      
      // Capture image data for continuous detection (lower quality)
      const imageData = this.captureVideoFrame(videoElement, false);
      
      // Use worker manager for detection
      const detections = await this.workerManager.detect(imageData);
      const detection = detections.length > 0 ? detections[0] : null;
      
      const inferenceTime = performance.now() - startTime;
      console.log('⚡ Continuous detection completed:', { time: inferenceTime, detection });
      
      // Apply temporal filtering
      const validDetection = this.applyTemporalFiltering(detection);
      
      // Update metrics
      this.updateMetrics(inferenceTime);
      
      // Trigger callbacks (only if we have a valid detection)
      // Use a debounced approach to avoid too frequent updates
      if (this.onDetectionCallback) {
        // Only update if it's been at least 100ms since last detection callback for continuous
        const now = Date.now();
        if (!this.lastDetectionCallbackTime || now - this.lastDetectionCallbackTime > 100) {
          this.onDetectionCallback(validDetection);
          this.lastDetectionCallbackTime = now;
        }
      }
      
    } catch (error) {
      console.error('Continuous detection error:', error);
    }
    
    // Schedule next iteration
    if (this.isRunning) {
      requestAnimationFrame(() => this.runContinuousLoop(videoElement));
    }
  }

  /**
   * Capture frame from video element
   */
  private captureVideoFrame(videoElement: HTMLVideoElement, highQuality: boolean): ImageData {
    const canvas = document.createElement('canvas');
    const ctx = canvas.getContext('2d')!;
    
    // Use different resolutions based on detection mode
    const [targetWidth, targetHeight] = highQuality 
      ? [640, 480]  // High quality for trigger detection
      : [320, 240]; // Lower quality for continuous detection
    
    canvas.width = targetWidth;
    canvas.height = targetHeight;
    
    // Draw video frame to canvas
    ctx.drawImage(videoElement, 0, 0, targetWidth, targetHeight);
    
    // Extract image data
    const imageData = ctx.getImageData(0, 0, targetWidth, targetHeight);
    
    // Cleanup
    canvas.remove();
    
    return imageData;
  }

  /**
   * Apply temporal consistency filtering to reduce false positives
   */
  private applyTemporalFiltering(detection: DetectionResult | null): DetectionResult | null {
    if (!detection) {
      // No detection - decay previous detections
      this.detectionHistory = this.detectionHistory.filter(d => 
        Date.now() - d.timestamp < 1000 // Keep detections from last second
      );
      
      // If we have recent consistent detections, continue showing them
      if (this.detectionHistory.length >= 2) {
        return this.lastValidDetection;
      }
      
      return null;
    }
    
    // Add current detection to history
    this.detectionHistory.push(detection);
    
    // Keep only recent detections (last 3 seconds)
    this.detectionHistory = this.detectionHistory.filter(d => 
      Date.now() - d.timestamp < 3000
    );
    
    // Check temporal consistency
    const recentDetections = this.detectionHistory.filter(d => 
      Date.now() - d.timestamp < 500 // Last 500ms
    );
    
    if (recentDetections.length >= 2) {
      // We have consistent detections - this is likely valid
      this.lastValidDetection = detection;
      return detection;
    }
    
    // Not enough temporal consistency yet
    return this.lastValidDetection;
  }

  /**
   * Update performance metrics
   */
  private updateMetrics(inferenceTime: number): void {
    this.detectionCount++;
    this.metrics = {
      fps: 0, // Placeholder, as PerformanceMonitor is removed
      inferenceTime: inferenceTime,
      memoryUsage: this.getMemoryUsage()
    };

    if (this.onMetricsCallback) {
      this.onMetricsCallback(this.metrics);
    }
  }

  

  /**
   * Get current memory usage (rough estimate)
   */
  private getMemoryUsage(): number {
    const memInfo = (performance as Performance & { memory?: { usedJSHeapSize: number } }).memory;
    if (memInfo && memInfo.usedJSHeapSize) {
      return memInfo.usedJSHeapSize / (1024 * 1024); // MB
    }
    return 0;
  }


  /**
   * Set detection callback
   */
  onDetection(callback: (detection: DetectionResult | null) => void): void {
    this.onDetectionCallback = callback;
  }

  /**
   * Set metrics callback
   */
  onMetrics(callback: (metrics: DetectionMetrics) => void): void {
    this.onMetricsCallback = callback;
  }

  /**
   * Update configuration
   */
  async updateConfig(newConfig: Partial<DetectionConfig>): Promise<void> {
    this.config = { ...this.config, ...newConfig };
    await this.workerManager.configure(this.config);
    console.log('Configuration updated:', this.config);
  }

  /**
   * Get current configuration
   */
  getConfig(): DetectionConfig {
    return { ...this.config };
  }

  /**
   * Get current metrics
   */
  getMetrics(): DetectionMetrics {
    return { ...this.metrics };
  }

  /**
   * Check if detection is running
   */
  isDetectionRunning(): boolean {
    return this.isRunning;
  }

  /**
   * Destroy the detection engine
   */
  destroy(): void {
    this.stopContinuousDetection();
    this.workerManager.destroy();
  }
}