simplified deserialisation

pyPhotoAlbum/commands.py

@@ -27,6 +27,34 @@ def _normalize_asset_path(image_path: str, asset_manager) -> str:
     return image_path
 
 
+def _deserialize_element(elem_data: Dict[str, Any]) -> BaseLayoutElement:
+    """
+    Deserialize element data into the appropriate element type.
+
+    Args:
+        elem_data: Dictionary containing serialized element data with 'type' key
+
+    Returns:
+        Deserialized element instance (ImageData, PlaceholderData, or TextBoxData)
+
+    Raises:
+        ValueError: If element type is unknown
+    """
+    elem_type = elem_data.get("type")
+
+    if elem_type == "image":
+        element = ImageData()
+    elif elem_type == "placeholder":
+        element = PlaceholderData()
+    elif elem_type == "textbox":
+        element = TextBoxData()
+    else:
+        raise ValueError(f"Unknown element type: {elem_type}")
+
+    element.deserialize(elem_data)
+    return element
+
+
 class Command(ABC):
     """Abstract base class for all commands"""
 
@@ -94,24 +122,8 @@ class AddElementCommand(Command):
     @staticmethod
     def deserialize(data: Dict[str, Any], project) -> "AddElementCommand":
         """Deserialize from dictionary"""
-        # Reconstruct element from serialized data
+        element = _deserialize_element(data["element"])
-        elem_data = data["element"]
+        # Note: page_layout will be handled by the CommandHistory deserializer
-        elem_type = elem_data.get("type")
-
-        element: BaseLayoutElement
-        if elem_type == "image":
-            element = ImageData()
-        elif elem_type == "placeholder":
-            element = PlaceholderData()
-        elif elem_type == "textbox":
-            element = TextBoxData()
-        else:
-            raise ValueError(f"Unknown element type: {elem_type}")
-
-        element.deserialize(elem_data)
-
-        # Note: We need to find the correct page_layout
-        # This will be handled by the CommandHistory deserializer
         cmd = AddElementCommand(None, element)
         cmd.executed = data.get("executed", False)
         return cmd
@@ -154,21 +166,7 @@ class DeleteElementCommand(Command):
     @staticmethod
     def deserialize(data: Dict[str, Any], project) -> "DeleteElementCommand":
         """Deserialize from dictionary"""
-        elem_data = data["element"]
+        element = _deserialize_element(data["element"])
-        elem_type = elem_data.get("type")
-
-        element: BaseLayoutElement
-        if elem_type == "image":
-            element = ImageData()
-        elif elem_type == "placeholder":
-            element = PlaceholderData()
-        elif elem_type == "textbox":
-            element = TextBoxData()
-        else:
-            raise ValueError(f"Unknown element type: {elem_type}")
-
-        element.deserialize(elem_data)
-
         cmd = DeleteElementCommand(None, element)
         cmd.executed = data.get("executed", False)
         return cmd
@@ -206,21 +204,7 @@ class MoveElementCommand(Command):
     @staticmethod
     def deserialize(data: Dict[str, Any], project) -> "MoveElementCommand":
         """Deserialize from dictionary"""
-        elem_data = data["element"]
+        element = _deserialize_element(data["element"])
-        elem_type = elem_data.get("type")
-
-        element: BaseLayoutElement
-        if elem_type == "image":
-            element = ImageData()
-        elif elem_type == "placeholder":
-            element = PlaceholderData()
-        elif elem_type == "textbox":
-            element = TextBoxData()
-        else:
-            raise ValueError(f"Unknown element type: {elem_type}")
-
-        element.deserialize(elem_data)
-
         return MoveElementCommand(element, tuple(data["old_position"]), tuple(data["new_position"]))
 
 
@@ -264,21 +248,7 @@ class ResizeElementCommand(Command):
     @staticmethod
     def deserialize(data: Dict[str, Any], project) -> "ResizeElementCommand":
         """Deserialize from dictionary"""
-        elem_data = data["element"]
+        element = _deserialize_element(data["element"])
-        elem_type = elem_data.get("type")
-
-        element: BaseLayoutElement
-        if elem_type == "image":
-            element = ImageData()
-        elif elem_type == "placeholder":
-            element = PlaceholderData()
-        elif elem_type == "textbox":
-            element = TextBoxData()
-        else:
-            raise ValueError(f"Unknown element type: {elem_type}")
-
-        element.deserialize(elem_data)
-
         return ResizeElementCommand(
             element,
             tuple(data["old_position"]),
@@ -389,21 +359,7 @@ class RotateElementCommand(Command):
     @staticmethod
     def deserialize(data: Dict[str, Any], project) -> "RotateElementCommand":
         """Deserialize from dictionary"""
-        elem_data = data["element"]
+        element = _deserialize_element(data["element"])
-        elem_type = elem_data.get("type")
-
-        element: BaseLayoutElement
-        if elem_type == "image":
-            element = ImageData()
-        elif elem_type == "placeholder":
-            element = PlaceholderData()
-        elif elem_type == "textbox":
-            element = TextBoxData()
-        else:
-            raise ValueError(f"Unknown element type: {elem_type}")
-
-        element.deserialize(elem_data)
-
         return RotateElementCommand(element, data["old_rotation"], data["new_rotation"])
 
 
@@ -487,23 +443,12 @@ class AlignElementsCommand(Command):
         """Deserialize from dictionary"""
         changes = []
         for change_data in data.get("changes", []):
-            elem_data = change_data["element"]
+            try:
-            elem_type = elem_data.get("type")
+                element = _deserialize_element(change_data["element"])
-
-            element: BaseLayoutElement
-            if elem_type == "image":
-                element = ImageData()
-            elif elem_type == "placeholder":
-                element = PlaceholderData()
-            elif elem_type == "textbox":
-                element = TextBoxData()
-            else:
-                continue
-
-            element.deserialize(elem_data)
                 old_position = tuple(change_data["old_position"])
                 changes.append((element, old_position))
-
+            except ValueError:
+                continue
         return AlignElementsCommand(changes)
 
 
@@ -549,24 +494,13 @@ class ResizeElementsCommand(Command):
         """Deserialize from dictionary"""
         changes = []
         for change_data in data.get("changes", []):
-            elem_data = change_data["element"]
+            try:
-            elem_type = elem_data.get("type")
+                element = _deserialize_element(change_data["element"])
-
-            element: BaseLayoutElement
-            if elem_type == "image":
-                element = ImageData()
-            elif elem_type == "placeholder":
-                element = PlaceholderData()
-            elif elem_type == "textbox":
-                element = TextBoxData()
-            else:
-                continue
-
-            element.deserialize(elem_data)
                 old_position = tuple(change_data["old_position"])
                 old_size = tuple(change_data["old_size"])
                 changes.append((element, old_position, old_size))
-
+            except ValueError:
+                continue
         return ResizeElementsCommand(changes)
 
 
@@ -609,21 +543,7 @@ class ChangeZOrderCommand(Command):
     @staticmethod
     def deserialize(data: Dict[str, Any], project) -> "ChangeZOrderCommand":
         """Deserialize from dictionary"""
-        elem_data = data["element"]
+        element = _deserialize_element(data["element"])
-        elem_type = elem_data.get("type")
-
-        element: BaseLayoutElement
-        if elem_type == "image":
-            element = ImageData()
-        elif elem_type == "placeholder":
-            element = PlaceholderData()
-        elif elem_type == "textbox":
-            element = TextBoxData()
-        else:
-            raise ValueError(f"Unknown element type: {elem_type}")
-
-        element.deserialize(elem_data)
-
         return ChangeZOrderCommand(
             None, element, data["old_index"], data["new_index"]  # page_layout will be set by CommandHistory
         )

tests/test_commands.py

@@ -734,6 +734,7 @@ class TestCommandHistory:
         """Test deserializing unknown command type returns None and continues"""
         history = CommandHistory()
         mock_project = Mock()
+        mock_project.pages = []
 
         data = {
             "undo_stack": [
@@ -797,6 +798,7 @@ class TestCommandHistory:
 
         # Deserialize
         mock_project = Mock()
+        mock_project.pages = []
         new_history = CommandHistory()
         new_history.deserialize(data, mock_project)