Covered Theme module with tests

- Extracted `ColorReplacementGenerator`;
- Extracted `ColorConverterImpl`;
- Added documentation to some classes;
- `hex_to_rgba` now supports shorthand hex colors (#fff).

scripts/utils/color_converter/color_converter.py

@@ -0,0 +1,26 @@
+from abc import ABC, abstractmethod
+
+
+class ColorConverter(ABC):
+    @staticmethod
+    @abstractmethod
+    def hex_to_rgba(hex_color):
+        """
+        Converts a HEX color code to RGBA format.
+        :param hex_color: HEX color code (e.g., '#ff5733' or 'ff5733').
+        :return: Tuple of RGBA values (red, green, blue, alpha).
+        :raises ValueError: If the HEX color code is invalid.
+        """
+        pass
+
+    @staticmethod
+    @abstractmethod
+    def hsl_to_rgb(hue, saturation, lightness):
+        """
+        Converts HSL color values to RGB format.
+        :param hue: Hue value (0-360).
+        :param saturation: Saturation value (0-1).
+        :param lightness: Lightness value (0-1).
+        :return: Tuple of RGB values (red, green, blue) in range(0-255).
+        """
+        pass

scripts/utils/color_converter/color_converter_impl.py

@@ -0,0 +1,43 @@
+import colorsys
+
+from scripts.utils.color_converter.color_converter import ColorConverter
+
+
+class ColorConverterImpl(ColorConverter):
+    @staticmethod
+    def hex_to_rgba(hex_color):
+        try:
+            hex_color = hex_color.lstrip('#')
+
+            # Handle shorthand hex colors (e.g., #fff)
+            if len(hex_color) == 3:
+                hex_color = ''.join([char * 2 for char in hex_color])
+
+            # Add alpha channel if missing
+            if len(hex_color) == 6:
+                hex_color += "ff"
+
+            # Validate the hex color
+            int(hex_color, 16)
+
+        except ValueError:
+            raise ValueError(f'Error: Invalid HEX color code: #{hex_color}')
+
+        else:
+            return int(hex_color[0:2], 16), \
+                int(hex_color[2:4], 16), \
+                int(hex_color[4:6], 16), \
+                int(hex_color[6:8], 16) / 255
+
+    @staticmethod
+    def hsl_to_rgb(hue, saturation, lightness):
+        if hue > 360 or hue < 0:
+            raise ValueError(f'Hue must be between 0 and 360, not {hue}')
+        if saturation > 1 or saturation < 0:
+            raise ValueError(f'Saturation must be between 0 and 1, not {saturation}')
+        if lightness > 1 or lightness < 0:
+            raise ValueError(f'Lightness must be between 0 and 1, not {lightness}')
+
+        h = hue / 360
+        red, green, blue = [round(item * 255) for item in colorsys.hls_to_rgb(h, lightness, saturation)]
+        return red, green, blue