import signal
import time
from pathlib import Path

import cv2
import numpy as np
from mss import mss


OUTPUT_FILE = Path("screen_recording.avi")
FPS = 20
MONITOR_NUMBER = 1

recording = True


def stop_recording(signum=None, frame=None):
    global recording
    recording = False
    print("\nStopping recording safely...")


signal.signal(signal.SIGINT, stop_recording)
signal.signal(signal.SIGTERM, stop_recording)


def main():
    global recording

    with mss() as sct:
        monitor = sct.monitors[MONITOR_NUMBER]

        width = monitor["width"]
        height = monitor["height"]

        # Video codecs generally prefer even dimensions.
        width -= width % 2
        height -= height % 2

        # MJPG inside AVI is more resistant to corruption than MP4.
        fourcc = cv2.VideoWriter_fourcc(*"MJPG")

        writer = cv2.VideoWriter(
            str(OUTPUT_FILE),
            fourcc,
            FPS,
            (width, height),
        )

        if not writer.isOpened():
            raise RuntimeError("Could not open VideoWriter")

        print(f"Recording {width}x{height} at {FPS} FPS")
        print("Press Ctrl+C once to stop safely.")

        frame_interval = 1.0 / FPS
        next_frame_time = time.perf_counter()

        try:
            while recording:
                screenshot = sct.grab(
                    {
                        "left": monitor["left"],
                        "top": monitor["top"],
                        "width": width,
                        "height": height,
                    }
                )

                frame = np.asarray(screenshot)
                frame = cv2.cvtColor(frame, cv2.COLOR_BGRA2BGR)

                writer.write(frame)

                next_frame_time += frame_interval
                sleep_time = next_frame_time - time.perf_counter()

                if sleep_time > 0:
                    time.sleep(sleep_time)
                else:
                    next_frame_time = time.perf_counter()

        finally:
            writer.release()
            cv2.destroyAllWindows()

            print(f"Recording saved safely: {OUTPUT_FILE.resolve()}")


if __name__ == "__main__":
    main()