from datetime import datetime, date, time, timedelta
import os
import cv2

def five_minute_segment_from(the_time):
    return the_time.replace(minute=(the_time.minute // 1)*1, second=0, microsecond=0)

def path_to_video_at(time_stamp):
    return 'videos/' + str(time_stamp) + '.mkv'

#delay for long delay
long_delay = timedelta(hours=1)


queue = [(False, None)] * 100 #queue of recent frames
last_time_stamp = five_minute_segment_from(datetime.now()) 
  
# live webcam feed
camera = cv2.VideoCapture(0) 
if not camera.isOpened():
    print("Cannot open camera")
    exit()

# video writer
fourcc = cv2.VideoWriter_fourcc(*'H264')
out = cv2.VideoWriter(path_to_video_at(last_time_stamp), fourcc, camera.get(cv2.CAP_PROP_FPS), (int(camera.get(3)),int(camera.get(4))))

# video feed from previously captured video
old_time = cv2.VideoCapture(path_to_video_at(last_time_stamp))

cv2.namedWindow("mirror", cv2.WINDOW_NORMAL)
cv2.setWindowProperty("mirror", cv2.WND_PROP_FULLSCREEN, cv2.WINDOW_FULLSCREEN)

idx = 0 
offset = 0
longterm = False
while(True): 
    if last_time_stamp != five_minute_segment_from(datetime.now()):
        # find file older than our long delay
        old_file = path_to_video_at(five_minute_segment_from(datetime.now() - long_delay - timedelta(minutes=5)))
        print(f"deleting old file {old_file}")
        os.remove(old_file)

        out.release()
        out = cv2.VideoWriter(path_to_video_at(last_time_stamp), 
            fourcc, 
            camera.get(cv2.CAP_PROP_FPS), 
            (int(camera.get(3)), int(camera.get(4)))
            )
        if old_time.isOpened():
            old_time.release()

        new_file = path_to_video_at(five_minute_segment_from(datetime.now() - timedelta(minutes=10)))
        pint(f"opening the previously recorded file {new_file} to read from for long mirror")
        old_time = cv2.VideoCapture(new_file)

    last_time_stamp = five_minute_segment_from(datetime.now())

    ret, frame = camera.read() 
    frame = cv2.flip(frame, 1)

    # record the frame to the appropriate file, and also to the short term buffer
    out.write(frame)
    queue[idx] = ret, frame

    prev_frame_valid, prev_frame = queue[(idx - offset) % len(queue)]
    old_frame_valid, old_frame = old_time.read()
    if not longterm and prev_frame_valid:
        cv2.imshow('mirror', prev_frame)
    elif longterm and old_frame_valid:
        cv2.imshow('mirror', old_frame)

    key = cv2.waitKey(16) # listen for keyprress for some number of ms
    if key & 0xFF == ord('q') or key == 27: # q or esc 
        break
    if key & 0xFF == ord('a'):
        offset += 1
    if key & 0xFF == ord('d'):
        offset -= 1
    if key & 0xFF == ord('z'):
        longterm = not longterm

    idx = (idx + 1) % len(queue)
  
# After the loop release the cap object 
camera.release()
out.release()
# Destroy all the windows 
cv2.destroyAllWindows()