import cv2
import imutils
import numpy as np
import argparse

HOGCV = cv2.HOGDescriptor()
HOGCV.setSVMDetector(cv2.HOGDescriptor_getDefaultPeopleDetector())

def detect(frame):
    bounding_box_cordinates, weights =  HOGCV.detectMultiScale(frame, winStride = (4, 4), padding = (8, 8), scale = 1.03)
    
    person = 1
    for x,y,w,h in bounding_box_cordinates:
        cv2.rectangle(frame, (x,y), (x+w,y+h), (0,255,0), 2)
        cv2.putText(frame, f'person {person}', (x,y), cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0,0,255), 1)
        person += 1
    
    cv2.putText(frame, 'Status : Detecting ', (40,40), cv2.FONT_HERSHEY_DUPLEX, 0.8, (255,0,0), 2)
    cv2.putText(frame, f'Total Persons : {person-1}', (40,70), cv2.FONT_HERSHEY_DUPLEX, 0.8, (255,0,0), 2)

    if str(args["preview"]) == 'true':
        cv2.imshow('output', frame)
    return frame

def humanDetector(args):
    image_path = args["image"]
    image_url_path = args["imageUrl"]
    video_path = args['video']
    if str(args["camera"]) == 'true' : camera = True 
    else : camera = False
    writer = None
    if args['output'] is not None and image_path is None:
        writer = cv2.VideoWriter(args['output'],cv2.VideoWriter_fourcc(*'MJPG'), 10, (600,600))
    if camera:
        print('[INFO] Opening Web Cam.')
        detectByCamera(ouput_path,writer)
    elif video_path is not None:
        print('[INFO] Opening Video from path.')
        detectByPathVideo(video_path, writer)
    elif image_path is not None:
        print('[INFO] Opening Image from path.')
        detectByPathImage(image_path, args['output'])
    elif image_url_path is not None:
        print('[INFO] Opening Image from URL path.')
        detectByPathUrlImage(image_url_path, args['output'])

def detectByCamera(writer):   
    video = cv2.VideoCapture(0)
    print('Detecting people...')
    while True:
        check, frame = video.read()
        frame = detect(frame)
        if writer is not None:
            writer.write(frame)
        key = cv2.waitKey(1)
        if key == ord('q'):
            break
    video.release()
    cv2.destroyAllWindows()

def detectByPathVideo(path, writer):
    video = cv2.VideoCapture(path)
    check, frame = video.read()
    if check == False:
        print('Video Not Found. Please Enter a Valid Path (Full path of Video Should be Provided).')
        return
    print('Detecting people...')
    while video.isOpened():
        #check is True if reading was successful 
        check, frame =  video.read()
        if check:
            frame = imutils.resize(frame , width=min(800,frame.shape[1]))
            frame = detect(frame)
            
            if writer is not None:
                writer.write(frame)
            
            key = cv2.waitKey(1)
            if key== ord('q'):
                break
        else:
            break
    video.release()
    cv2.destroyAllWindows()
def detectByCamera(writer):   
    video = cv2.VideoCapture(0)
    print('Detecting people...')
    while True:
        check, frame = video.read()
        frame = detect(frame)
        if writer is not None:
            writer.write(frame)
        key = cv2.waitKey(1)
        if key == ord('q'):
                break
    video.release()
    cv2.destroyAllWindows()

def detectByPathImage(path, output_path):
    image = cv2.imread(path)
    image = imutils.resize(image, width = min(800, image.shape[1])) 
    result_image = detect(image)
    if output_path is not None:
        cv2.imwrite(output_path, result_image)
    cv2.waitKey(0)
    cv2.destroyAllWindows()

def detectByPathUrlImage(pathUrl, output_path):
    image = imutils.url_to_image(pathUrl)
    image = imutils.resize(image, width = min(800, image.shape[1])) 
    result_image = detect(image)
    if output_path is not None:
        cv2.imwrite(output_path, result_image)
    cv2.waitKey(0)
    cv2.destroyAllWindows()

def argsParser():
    arg_parse = argparse.ArgumentParser()
    arg_parse.add_argument("-v", "--video", default=None, help="path to Video File ")
    arg_parse.add_argument("-i", "--image", default=None, help="path to Image File ")
    arg_parse.add_argument("-iu", "--imageUrl", default=None, help="Url to Image File ")
    arg_parse.add_argument("-c", "--camera", default=False, help="Set true if you want to use the camera.")
    arg_parse.add_argument("-p", "--preview", default=True, help="Set true if you want to open preview")
    arg_parse.add_argument("-o", "--output", type=str, help="path to optional output video file")
    args = vars(arg_parse.parse_args())
    return args

if __name__ == "__main__":
    HOGCV = cv2.HOGDescriptor()
    HOGCV.setSVMDetector(cv2.HOGDescriptor_getDefaultPeopleDetector())
    args = argsParser()
    humanDetector(args)