import cv2
import numpy as np

def region_of_interest(img, vertices):
    mask = np.zeros_like(img)
    cv2.fillPoly(mask, vertices, 255)
    masked_image = cv2.bitwise_and(img, mask)
    return masked_image

def draw_lines(img, lines):
    if lines is None:
        return
    img = np.copy(img)
    blank_image = np.zeros((img.shape[0], img.shape[1], 3), dtype=np.uint8)

    for line in lines:
        for x1, y1, x2, y2 in line:
            cv2.line(blank_image, (x1, y1), (x2, y2), (0, 255, 0), thickness=5)

    img = cv2.addWeighted(img, 0.8, blank_image, 1, 0.0)
    return img

def process(image):
    height = image.shape[0]
    width = image.shape[1]

    region_of_interest_vertices = [
        (0, height),
        (width // 2, height // 2),
        (width, height)
    ]

    gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
    canny_image = cv2.Canny(gray_image, 100, 200)
    cropped_image = region_of_interest(canny_image,
                                       np.array([region_of_interest_vertices], np.int32))

    lines = cv2.HoughLinesP(cropped_image,
                            rho=2,
                            theta=np.pi / 180,
                            threshold=50,
                            lines=np.array([]),
                            minLineLength=40,
                            maxLineGap=100)

    image_with_lines = draw_lines(image, lines)
    return image_with_lines

def main():
    cap = cv2.VideoCapture(0)

    while cap.isOpened():
        ret, frame = cap.read()
        if not ret:
            break

        frame = process(frame)

        cv2.imshow('frame', frame)

        if cv2.waitKey(1) & 0xFF == ord('q'):
            break

    cap.release()
    cv2.destroyAllWindows()

if __name__ == "__main__":
    main()