import cv2
import threading
import numpy as np
from typing import Callable, Optional


class Camera:
    def __init__(self, index: int = 0):
        self.index = index
        self.cap: Optional[cv2.VideoCapture] = None
        self.thread: Optional[threading.Thread] = None
        self.stop_event = threading.Event()

    def open(self):
        if self.cap is None:
            self.cap = cv2.VideoCapture(self.index)
            if not self.cap.isOpened():
                self.cap = None
                raise RuntimeError("Could not open camera")

    def close(self):
        if self.cap is not None:
            self.cap.release()
            self.cap = None

    def take_photo(self) -> np.ndarray:
        self.open()
        try:
            ret, frame = self.cap.read()
            if not ret:
                raise RuntimeError("Failed to capture image")
            return frame
        finally:
            self.close()

    def start_capture(self, callback: Callable[[np.ndarray], None]):
        if self.thread and self.thread.is_alive():
            return

        self.open()
        self.stop_event.clear()

        def loop():
            while not self.stop_event.is_set():
                ret, frame = self.cap.read()
                if not ret:
                    break
                callback(frame)

        self.thread = threading.Thread(target=loop, daemon=True)
        self.thread.start()

    def stop_capture(self):
        self.stop_event.set()

        self.close()

        if self.thread:
            self.thread.join(timeout=2)
            self.thread = None