"""Unit tests for image validation logic."""

from unittest.mock import MagicMock

from PIL import Image
import pytest

from constants import errors
from constants import image_standards
from src import image_validation_logic
from src import image_validator


@pytest.fixture
def file_contents():
    """Return a mock file buffer."""
    return MagicMock()


@pytest.fixture
def pil_image():
    """Return a mock PIL image."""
    pil_image_mock = MagicMock(
        mode='Depeche',
        size=(3000, 3000),
    )

    return pil_image_mock


def test_validate_image_success(file_contents, monkeypatch, pil_image):
    """Test for a successful return when all validations pass."""
    monkeypatch.setattr(Image, 'open', MagicMock(return_value=pil_image))
    monkeypatch.setattr(
        image_validator, 'validate_mode', MagicMock(return_value=True)
    )
    monkeypatch.setattr(
        image_validator, 'validate_is_opaque', MagicMock(return_value=True)
    )
    monkeypatch.setattr(
        image_validator, 'validate_dimensions',
        MagicMock(return_value=image_standards.VALID_DIMENSIONS_CODE)
    )

    result = image_validation_logic.validate_image(
        file_contents=file_contents
    )

    image_validator.validate_mode.assert_called_with(pil_image.mode)
    image_validator.validate_dimensions.assert_called_with(
        width=pil_image.size[0],
        height=pil_image.size[1],
    )
    assert result is True


@pytest.mark.parametrize('error_code', [
    errors.IMAGE_TOO_SMALL_DIMENSIONS_CODE,
    errors.IMAGE_TOO_LARGE_DIMENSIONS_CODE,
    errors.IMAGE_WRONG_ASPECT_RATIO_CODE
])
def test_validate_image_wrong_dimensions(
        file_contents, monkeypatch, pil_image, error_code):
    """Test that validation fails if the dimensions are wrong."""
    monkeypatch.setattr(Image, 'open', MagicMock(return_value=pil_image))
    monkeypatch.setattr(
        image_validator, 'validate_mode', MagicMock(return_value=True)
    )
    monkeypatch.setattr(
        image_validator, 'validate_is_opaque', MagicMock(return_value=True)
    )
    monkeypatch.setattr(
        image_validator, 'validate_dimensions',
        MagicMock(return_value=error_code)
    )

    with pytest.raises(image_validation_logic.InvalidImageError) as e:
        image_validation_logic.validate_image(
            file_contents=file_contents
        )

    width, height = pil_image.size
    image_validator.validate_dimensions.assert_called_once_with(
        width=width,
        height=height,
    )
    assert str(e.value) == errors.ERROR_MESSAGES[error_code]
    assert e.value.code == error_code


def test_validate_image_bad_mode(file_contents, monkeypatch, pil_image):
    """Test that validation fails if the mode validation fails."""
    monkeypatch.setattr(Image, 'open', MagicMock(return_value=pil_image))
    monkeypatch.setattr(
        image_validator, 'validate_mode', MagicMock(return_value=False)
    )

    with pytest.raises(image_validation_logic.InvalidImageError) as e:
        image_validation_logic.validate_image(
            file_contents=file_contents
        )

    assert str(e.value) == errors.ERROR_MESSAGES[errors.IMAGE_INVALID_MODE_CODE].format(
        mode=pil_image.mode
    )
    assert e.value.code == errors.IMAGE_INVALID_MODE_CODE


def test_validate_image_not_opaque(file_contents, monkeypatch, pil_image):
    """Test that validation fails if the image is not opaque."""
    monkeypatch.setattr(Image, 'open', MagicMock(return_value=pil_image))
    monkeypatch.setattr(
        image_validator, 'validate_mode', MagicMock(return_value=True)
    )
    monkeypatch.setattr(
        image_validator, 'validate_is_opaque', MagicMock(return_value=False)
    )

    with pytest.raises(image_validation_logic.InvalidImageError) as e:
        image_validation_logic.validate_image(
            file_contents=file_contents
        )

    assert str(e.value) == errors.ERROR_MESSAGES[errors.IMAGE_NOT_OPAQUE_CODE]
    assert e.value.code == errors.IMAGE_NOT_OPAQUE_CODE