class GdToolkitImageManipulationTestBase

abstract class GdToolkitImageManipulationTestBase extends KernelTestBase {
  
  /**
   * Colors that are used in testing.
   */
  protected const BLACK = [
    0,
    0,
    0,
    0,
  ];
  protected const RED = [
    255,
    0,
    0,
    0,
  ];
  protected const GREEN = [
    0,
    255,
    0,
    0,
  ];
  protected const BLUE = [
    0,
    0,
    255,
    0,
  ];
  protected const YELLOW = [
    255,
    255,
    0,
    0,
  ];
  protected const WHITE = [
    255,
    255,
    255,
    0,
  ];
  protected const TRANSPARENT = [
    0,
    0,
    0,
    127,
  ];
  protected const FUCHSIA = [
    255,
    0,
    255,
    0,
  ];
  protected const ROTATE_TRANSPARENT = [
    255,
    255,
    255,
    127,
  ];
  
  /**
   * The image factory service.
   */
  protected ImageFactory $imageFactory;
  
  /**
   * A directory where test image files can be saved to.
   */
  protected string $directory;
  
  /**
   * The file name of the image under test.
   */
  protected string $sourceTestImage;
  
  /**
   * {@inheritdoc}
   */
  protected static $modules = [
    'system',
  ];
  
  /**
   * {@inheritdoc}
   */
  protected function setUp() : void {
    parent::setUp();
    $this->installConfig([
      'system',
    ]);
    // Set the image factory service.
    $this->imageFactory = $this->container
      ->get('image.factory');
    $this->assertEquals('gd', $this->imageFactory
      ->getToolkitId(), 'The image factory is set to use the \'gd\' image toolkit.');
    // Prepare a directory for test file results.
    $this->directory = 'public://image_test';
    \Drupal::service('file_system')->prepareDirectory($this->directory, FileSystemInterface::CREATE_DIRECTORY);
  }
  
  /**
   * Assert two colors are equal by RGBA, net of full transparency.
   *
   * @param int[] $expected
   *   The expected RGBA array.
   * @param int[] $actual
   *   The actual RGBA array.
   * @param int $tolerance
   *   The acceptable difference between the colors.
   * @param string $message
   *   The assertion message.
   */
  protected function assertColorsAreEqual(array $expected, array $actual, int $tolerance, string $message = '') : void {
    // Fully transparent colors are equal, regardless of RGB.
    if ($actual[3] == 127 && $expected[3] == 127) {
      return;
    }
    $distance = pow($actual[0] - $expected[0], 2) + pow($actual[1] - $expected[1], 2) + pow($actual[2] - $expected[2], 2) + pow($actual[3] - $expected[3], 2);
    $this->assertLessThanOrEqual($tolerance, $distance, $message . " - Actual: {" . implode(',', $actual) . "}, Expected: {" . implode(',', $expected) . "}, Distance: " . $distance . ", Tolerance: " . $tolerance);
  }
  
  /**
   * Function for finding a pixel's RGBa values.
   */
  public function getPixelColor(ImageInterface $image, int $x, int $y) : array {
    $toolkit = $image->getToolkit();
    $color_index = imagecolorat($toolkit->getImage(), $x, $y);
    $transparent_index = imagecolortransparent($toolkit->getImage());
    if ($color_index == $transparent_index) {
      return [
        0,
        0,
        0,
        127,
      ];
    }
    return array_values(imagecolorsforindex($toolkit->getImage(), $color_index));
  }
  
  /**
   * Data provider for ::testManipulations().
   */
  public static function providerOperationTestCases() : array {
    // Typically the corner colors will be unchanged. These colors are in the
    // order of top-left, top-right, bottom-right, bottom-left.
    $default_corners = [
      static::RED,
      static::GREEN,
      static::BLUE,
      static::TRANSPARENT,
    ];
    // Setup a list of tests to perform on each type.
    $test_cases = [
      'resize' => [
        'operation' => 'resize',
        'arguments' => [
          'width' => 20,
          'height' => 10,
        ],
        'width' => 20,
        'height' => 10,
        'corners' => $default_corners,
      ],
      'scale_x' => [
        'operation' => 'scale',
        'arguments' => [
          'width' => 20,
        ],
        'width' => 20,
        'height' => 10,
        'corners' => $default_corners,
      ],
      'scale_y' => [
        'operation' => 'scale',
        'arguments' => [
          'height' => 10,
        ],
        'width' => 20,
        'height' => 10,
        'corners' => $default_corners,
      ],
      'upscale_x' => [
        'operation' => 'scale',
        'arguments' => [
          'width' => 80,
          'upscale' => TRUE,
        ],
        'width' => 80,
        'height' => 40,
        'corners' => $default_corners,
      ],
      'upscale_y' => [
        'operation' => 'scale',
        'arguments' => [
          'height' => 40,
          'upscale' => TRUE,
        ],
        'width' => 80,
        'height' => 40,
        'corners' => $default_corners,
      ],
      'crop' => [
        'operation' => 'crop',
        'arguments' => [
          'x' => 12,
          'y' => 4,
          'width' => 16,
          'height' => 12,
        ],
        'width' => 16,
        'height' => 12,
        'corners' => array_fill(0, 4, static::WHITE),
      ],
      'scale_and_crop' => [
        'operation' => 'scale_and_crop',
        'arguments' => [
          'width' => 10,
          'height' => 8,
        ],
        'width' => 10,
        'height' => 8,
        'corners' => array_fill(0, 4, static::BLACK),
      ],
      'convert_jpg' => [
        'operation' => 'convert',
        'width' => 40,
        'height' => 20,
        'arguments' => [
          'extension' => 'jpeg',
        ],
        'corners' => $default_corners,
      ],
      'convert_gif' => [
        'operation' => 'convert',
        'width' => 40,
        'height' => 20,
        'arguments' => [
          'extension' => 'gif',
        ],
        'corners' => $default_corners,
      ],
      'convert_png' => [
        'operation' => 'convert',
        'width' => 40,
        'height' => 20,
        'arguments' => [
          'extension' => 'png',
        ],
        'corners' => $default_corners,
      ],
      'convert_webp' => [
        'operation' => 'convert',
        'width' => 40,
        'height' => 20,
        'arguments' => [
          'extension' => 'webp',
        ],
        'corners' => $default_corners,
      ],
      'convert_avif' => [
        'operation' => 'convert',
        'width' => 40,
        'height' => 20,
        'arguments' => [
          'extension' => 'avif',
        ],
        'corners' => $default_corners,
      ],
    ];
    // Systems using non-bundled GD2 may miss imagerotate(). Test if available.
    if (function_exists('imagerotate')) {
      $test_cases += [
        'rotate_5' => [
          'operation' => 'rotate',
          // Fuchsia background.
'arguments' => [
            'degrees' => 5,
            'background' => '#FF00FF',
          ],
          'width' => 40,
          'height' => 23,
          'corners' => [
            [
              255,
              0,
              93,
              0,
            ],
            static::FUCHSIA,
            static::FUCHSIA,
            static::FUCHSIA,
          ],
        ],
        'rotate_transparent_5' => [
          'operation' => 'rotate',
          'arguments' => [
            'degrees' => 5,
          ],
          'width' => 40,
          'height' => 23,
          'corners' => [
            [
              255,
              93,
              93,
              46,
            ],
            static::ROTATE_TRANSPARENT,
            static::ROTATE_TRANSPARENT,
            static::ROTATE_TRANSPARENT,
          ],
        ],
        'rotate_90' => [
          'operation' => 'rotate',
          // Fuchsia background.
'arguments' => [
            'degrees' => 90,
            'background' => '#FF00FF',
          ],
          'width' => 20,
          'height' => 40,
          'corners' => [
            static::TRANSPARENT,
            static::RED,
            static::GREEN,
            static::BLUE,
          ],
        ],
        'rotate_transparent_90' => [
          'operation' => 'rotate',
          'arguments' => [
            'degrees' => 90,
          ],
          'width' => 20,
          'height' => 40,
          'corners' => [
            static::TRANSPARENT,
            static::RED,
            static::GREEN,
            static::BLUE,
          ],
        ],
      ];
    }
    // Systems using non-bundled GD2 may miss imagefilter(). Test if available.
    if (function_exists('imagefilter')) {
      $test_cases += [
        'desaturate' => [
          'operation' => 'desaturate',
          'arguments' => [],
          'height' => 20,
          'width' => 40,
          // Grayscale corners are a bit funky. Each of the corners are a shade
          // of gray. The values of these were determined simply by looking at
          // the final image to see what desaturated colors end up being.
'corners' => [
            array_fill(0, 3, 76) + [
              3 => 0,
            ],
            array_fill(0, 3, 149) + [
              3 => 0,
            ],
            array_fill(0, 3, 29) + [
              3 => 0,
            ],
            array_fill(0, 3, 225) + [
              3 => 127,
            ],
          ],
        ],
      ];
    }
    $ret = [];
    foreach ($test_cases as $test_case => $values) {
      $operation = $values['operation'];
      $arguments = $values['arguments'];
      unset($values['operation'], $values['arguments']);
      $ret[$test_case] = [
        $test_case,
        $operation,
        $arguments,
        $values,
      ];
    }
    return $ret;
  }
  
  /**
   * Tests height, width and color for the corners for the final images.
   *
   * Since PHP can't visually check that our images have been manipulated
   * properly, build a list of expected color values for each of the corners and
   * the expected height and widths for the final images.
   */
  public function testManipulations(string $test_case, string $operation, array $arguments, array $expected) : void {
    // Load up a fresh image.
    $image = $this->imageFactory
      ->get('core/tests/fixtures/files/' . $this->sourceTestImage);
    $toolkit = $image->getToolkit();
    $this->assertTrue($image->isValid());
    $image_original_type = $image->getToolkit()
      ->getType();
    $this->assertTrue(imageistruecolor($toolkit->getImage()), "Image '{$this->sourceTestImage}' after load should be a truecolor image, but it is not.");
    // Perform our operation.
    $image->apply($operation, $arguments);
    // Flush Image object to disk storage.
    $file_path = $this->directory . '/' . $test_case . image_type_to_extension($image->getToolkit()
      ->getType());
    $image->save($file_path);
    // Check that the both the GD object and the Image object have an accurate
    // record of the dimensions.
    if (isset($expected['height']) && isset($expected['width'])) {
      $this->assertSame($expected['height'], imagesy($toolkit->getImage()), "Image '{$this->sourceTestImage}' after '{$test_case}' should have a proper height.");
      $this->assertSame($expected['width'], imagesx($toolkit->getImage()), "Image '{$this->sourceTestImage}' after '{$test_case}' should have a proper width.");
      $this->assertSame($expected['height'], $image->getHeight(), "Image '{$this->sourceTestImage}' after '{$test_case}' should have a proper height.");
      $this->assertSame($expected['width'], $image->getWidth(), "Image '{$this->sourceTestImage}' after '{$test_case}' should have a proper width.");
    }
    // Now check each of the corners to ensure color correctness.
    foreach ($expected['corners'] as $key => $expected_color) {
      // Get the location of the corner.
      [$x, $y] = match ($key) {  0 => [
          0,
          0,
        ],
        1 => [
          $image->getWidth() - 1,
          0,
        ],
        2 => [
          $image->getWidth() - 1,
          $image->getHeight() - 1,
        ],
        3 => [
          0,
          $image->getHeight() - 1,
        ],
      
      };
      $actual_color = $this->getPixelColor($image, $x, $y);
      // If image cannot handle transparent colors, skip the pixel color test.
      if ($actual_color[3] === 0 && $expected_color[3] === 127) {
        continue;
      }
      // JPEG and AVIF have small differences in color after processing.
      $tolerance = match ($image_original_type) {  IMAGETYPE_JPEG, IMAGETYPE_AVIF => 3,
        default => 1,
      
      };
      $this->assertColorsAreEqual($expected_color, $actual_color, $tolerance, "Image '{$this->sourceTestImage}' object after '{$test_case}' action has the correct color placement at corner '{$key}'");
    }
    // Check that saved image reloads without raising PHP errors.
    $image_reloaded = $this->imageFactory
      ->get($file_path);
    $this->assertInstanceOf(\GdImage::class, $image_reloaded->getToolkit()
      ->getImage());
  }

}