hooks/useHandDetection.js

import { useState, useEffect, useRef } from 'react';
import { HandLandmarker, FilesetResolver } from '@mediapipe/tasks-vision';
import { drawLandmarks, analyzeHandGesture } from '../utils/handUtils';

const useHandDetection = (videoRef, canvasRef, isMobile) => {
  const [handLandmarker, setHandLandmarker] = useState(null);
  const [handDetected, setHandDetected] = useState(false);
  const [isMouthOpen, setIsMouthOpen] = useState(false);
  const [isLeftHand, setIsLeftHand] = useState(true);
  const [thumbPosition, setThumbPosition] = useState({ x: 0, y: 0 });
  const [isFirstLoad, setIsFirstLoad] = useState(true);
  
  const requestRef = useRef(null);
  const lastDetectionTimeRef = useRef(0);
  const isComponentMounted = useRef(true);
  
  // Initialize the HandLandmarker
  useEffect(() => {
    isComponentMounted.current = true;
    
    const initializeHandLandmarker = async () => {
      try {
        const vision = await FilesetResolver.forVisionTasks(
          "https://cdn.jsdelivr.net/npm/@mediapipe/tasks-vision@latest/wasm"
        );
        
        if (!isComponentMounted.current) return;
        
        const landmarker = await HandLandmarker.createFromOptions(vision, {
          baseOptions: {
            modelAssetPath: "https://storage.googleapis.com/mediapipe-models/hand_landmarker/hand_landmarker/float16/latest/hand_landmarker.task",
            delegate: "GPU"
          },
          runningMode: "VIDEO",
          numHands: 1,
          minHandDetectionConfidence: 0.5,
          minHandPresenceConfidence: 0.5,
          minTrackingConfidence: 0.5
        });
        
        if (!isComponentMounted.current) return;
        
        setHandLandmarker(landmarker);
        console.log("Hand landmarker initialized successfully");
        
        // Set first load to false after initialization
        setTimeout(() => {
          if (isComponentMounted.current) {
            setIsFirstLoad(false);
          }
        }, 3000);
      } catch (error) {
        console.error("Error initializing hand landmarker:", error);
      }
    };

    initializeHandLandmarker();

    return () => {
      isComponentMounted.current = false;
      if (requestRef.current) {
        cancelAnimationFrame(requestRef.current);
        requestRef.current = null;
      }
    };
  }, []);

  // Process video frames and detect hand gestures
  useEffect(() => {
    if (!handLandmarker || !videoRef.current || !canvasRef.current) return;

    const video = videoRef.current;
    const canvas = canvasRef.current;
    const ctx = canvas.getContext('2d');

    const detectHands = async (now) => {
      if (!isComponentMounted.current) return;
      
      if (video.readyState < 2) {
        requestRef.current = requestAnimationFrame(detectHands);
        return;
      }

      // Only run detection every 100ms for performance
      if (now - lastDetectionTimeRef.current > 100) {
        lastDetectionTimeRef.current = now;
        
        // Process the frame with HandLandmarker
        const results = handLandmarker.detectForVideo(video, now);
        
        // Clear the canvas
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        
        // Draw the video frame on the canvas, maintaining aspect ratio
        const videoWidth = video.videoWidth;
        const videoHeight = video.videoHeight;
        
        // Calculate dimensions to maintain aspect ratio
        let drawWidth = canvas.width;
        let drawHeight = canvas.height;
        let offsetX = 0;
        let offsetY = 0;
        
        // Center the video in the canvas
        ctx.drawImage(video, offsetX, offsetY, drawWidth, drawHeight);
        
        // Check if hands are detected
        if (results.landmarks && results.landmarks.length > 0) {
          const landmarks = results.landmarks[0];
          setHandDetected(true);
          
          // Draw hand landmarks
          drawLandmarks(ctx, landmarks, canvas, isMobile);
          
          // Analyze hand gesture
          const { isOpen, isLeftHand: isLeft, thumbPosition: thumbPos } = analyzeHandGesture(landmarks);
          
          // Update state with hand information
          setIsLeftHand(isLeft);
          setThumbPosition({
            x: thumbPos.x * canvas.width,
            y: thumbPos.y * canvas.height
          });
          
          // Update UI based on hand state
          if (isOpen !== isMouthOpen) {
            setIsMouthOpen(isOpen);
          }
        } else {
          // No hands detected
          setHandDetected(false);
          if (isMouthOpen) {
            setIsMouthOpen(false);
          }
        }
      }
      
      requestRef.current = requestAnimationFrame(detectHands);
    };

    requestRef.current = requestAnimationFrame(detectHands);

    return () => {
      if (requestRef.current) {
        cancelAnimationFrame(requestRef.current);
        requestRef.current = null;
      }
    };
  }, [handLandmarker, isMouthOpen, isMobile, videoRef, canvasRef]);

  return {
    handDetected,
    isMouthOpen,
    isLeftHand,
    thumbPosition,
    isFirstLoad,
    isComponentMounted
  };
};

export default useHandDetection;