from unittest.mock import MagicMock, patch

import numpy as np
import pytest

from bookmark.camera import CameraSource


def test_open_raises_when_capture_not_opened():
    with patch("bookmark.camera.cv2.VideoCapture") as mock_video_capture:
        mock_instance = MagicMock()
        mock_instance.isOpened.return_value = False
        mock_video_capture.return_value = mock_instance

        source = CameraSource(device_index=0)
        with pytest.raises(RuntimeError, match="Could not open camera"):
            source.open()

        # Verify that release() was called on the failed capture
        mock_instance.release.assert_called_once()


def test_read_frame_returns_frame_from_capture():
    with patch("bookmark.camera.cv2.VideoCapture") as mock_video_capture:
        mock_instance = MagicMock()
        mock_instance.isOpened.return_value = True
        fake_frame = np.zeros((10, 10, 3), dtype=np.uint8)
        mock_instance.read.return_value = (True, fake_frame)
        mock_video_capture.return_value = mock_instance

        source = CameraSource(device_index=0)
        source.open()
        frame = source.read_frame()

        assert frame.shape == (10, 10, 3)


def test_read_frame_raises_when_capture_fails():
    with patch("bookmark.camera.cv2.VideoCapture") as mock_video_capture:
        mock_instance = MagicMock()
        mock_instance.isOpened.return_value = True
        mock_instance.read.return_value = (False, None)
        mock_video_capture.return_value = mock_instance

        source = CameraSource(device_index=0)
        source.open()
        with pytest.raises(RuntimeError, match="Failed to read frame"):
            source.read_frame()


def test_read_frame_raises_if_not_opened():
    source = CameraSource(device_index=0)
    with pytest.raises(RuntimeError, match="not opened"):
        source.read_frame()


def test_open_twice_releases_first_capture():
    with patch("bookmark.camera.cv2.VideoCapture") as mock_video_capture:
        # Setup two distinct mock instances
        first_mock = MagicMock()
        first_mock.isOpened.return_value = True
        second_mock = MagicMock()
        second_mock.isOpened.return_value = True
        mock_video_capture.side_effect = [first_mock, second_mock]

        source = CameraSource(device_index=0)

        # First open
        source.open()
        assert source._capture is first_mock

        # Second open should release the first capture
        source.open()
        assert source._capture is second_mock

        # Verify the first mock's release() was called before the second was assigned
        first_mock.release.assert_called_once()