import cv2

CASCADE_PATH = "src/face.xml"

def run_camera(save_folder=None):
    cap = cv2.VideoCapture(0)
    if not cap.isOpened():
        print("Cannot open camera")
        return
    face_cascade = cv2.CascadeClassifier(CASCADE_PATH)
    print("Press 'q' to quit, 's' to save a snapshot of the detected faces")
    idx = 0
    while True:
        ret, frame = cap.read()
        if not ret:
            print("Can't receive frame (stream end?). Exiting...")
            break
        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
        faces = face_cascade.detectMultiScale(gray, scaleFactor=1.1, minNeighbors=5, minSize=(30,30))
        for (x,y,w,h) in faces:
            cv2.rectangle(frame, (x,y), (x+w, y+h), (0,255,0), 2)
        cv2.imshow('Camera - face.xml detection', frame)
        key = cv2.waitKey(1) & 0xFF
        if key == ord('q'):
            break
        if key == ord('s') and save_folder:
            path = f"{save_folder}/snapshot_{idx}.jpg"
            cv2.imwrite(path, frame)
            print("Saved", path)
            idx += 1
    cap.release()
    cv2.destroyAllWindows()

if __name__ == '__main__':
    import sys, os
    save_folder = None
    if len(sys.argv) > 1:
        save_folder = sys.argv[1]
        os.makedirs(save_folder, exist_ok=True)
    run_camera(save_folder)