Extract layer menu action planning

src/app_core/document_layer.h

@@ -32,6 +32,21 @@ enum class DocumentLayerOperation {
     set_highlight,
 };
 
+enum class DocumentLayerMenuCommand {
+    clear,
+    rename,
+    merge_down,
+};
+
+enum class DocumentLayerMenuAction {
+    clear_current_layer,
+    show_rename_dialog,
+    merge_with_lower_layer,
+    show_merge_animated_not_supported,
+    no_op_select_layer,
+    no_op_select_upper_layer,
+};
+
 struct DocumentLayerRenamePlan {
     std::string old_name;
     std::string new_name;
@@ -55,6 +70,14 @@ struct DocumentLayerOperationPlan {
     bool updates_title = false;
 };
 
+struct DocumentLayerMenuPlan {
+    DocumentLayerMenuCommand command = DocumentLayerMenuCommand::clear;
+    DocumentLayerMenuAction action = DocumentLayerMenuAction::clear_current_layer;
+    std::string label;
+    int from_index = 0;
+    int to_index = 0;
+};
+
 [[nodiscard]] inline pp::foundation::Status validate_layer_index(
     int layer_count,
     int index) noexcept
@@ -328,4 +351,63 @@ struct DocumentLayerOperationPlan {
     return pp::foundation::Result<DocumentLayerOperationPlan>::success(plan);
 }
 
+[[nodiscard]] inline pp::foundation::Result<DocumentLayerMenuPlan> plan_document_layer_menu(
+    DocumentLayerMenuCommand command,
+    bool has_current_layer,
+    int current_index,
+    int animation_duration,
+    std::string_view current_layer_name,
+    std::string_view lower_layer_name)
+{
+    if (current_index < 0) {
+        return pp::foundation::Result<DocumentLayerMenuPlan>::failure(
+            pp::foundation::Status::out_of_range("current layer index must not be negative"));
+    }
+    if (animation_duration < 0) {
+        return pp::foundation::Result<DocumentLayerMenuPlan>::failure(
+            pp::foundation::Status::out_of_range("animation duration must not be negative"));
+    }
+
+    DocumentLayerMenuPlan plan;
+    plan.command = command;
+    plan.from_index = current_index;
+    plan.to_index = current_index > 0 ? current_index - 1 : 0;
+
+    switch (command) {
+    case DocumentLayerMenuCommand::clear:
+        plan.action = has_current_layer
+            ? DocumentLayerMenuAction::clear_current_layer
+            : DocumentLayerMenuAction::no_op_select_layer;
+        plan.label = has_current_layer
+            ? "Clear Layer " + std::string(current_layer_name)
+            : "Clear Layer (Select a layer)";
+        break;
+    case DocumentLayerMenuCommand::rename:
+        plan.action = has_current_layer
+            ? DocumentLayerMenuAction::show_rename_dialog
+            : DocumentLayerMenuAction::no_op_select_layer;
+        plan.label = has_current_layer
+            ? "Rename Layer " + std::string(current_layer_name)
+            : "Rename Layer (Select a layer)";
+        break;
+    case DocumentLayerMenuCommand::merge_down:
+        if (!has_current_layer) {
+            plan.action = DocumentLayerMenuAction::no_op_select_layer;
+            plan.label = "Merge Layer (Select a layer)";
+        } else if (animation_duration > 1) {
+            plan.action = DocumentLayerMenuAction::show_merge_animated_not_supported;
+            plan.label = "Merge Layer (Animation not supported)";
+        } else if (current_index <= 0) {
+            plan.action = DocumentLayerMenuAction::no_op_select_upper_layer;
+            plan.label = "Merge Layer (Select upper layers)";
+        } else {
+            plan.action = DocumentLayerMenuAction::merge_with_lower_layer;
+            plan.label = "Merge with " + std::string(lower_layer_name);
+        }
+        break;
+    }
+
+    return pp::foundation::Result<DocumentLayerMenuPlan>::success(std::move(plan));
+}
+
 }

src/app_layout.cpp

@@ -190,6 +190,39 @@ void apply_file_menu_plan(App& app, pp::app::FileMenuCommand command)
     }
 }
 
+pp::app::DocumentLayerMenuPlan make_layer_menu_plan(
+    pp::app::DocumentLayerMenuCommand command,
+    App& app)
+{
+    const bool has_current_layer = app.layers && app.layers->m_current_layer;
+    const int current_index = app.canvas && app.canvas->m_canvas
+        ? app.canvas->m_canvas->m_current_layer_idx
+        : 0;
+    const int animation_duration = Canvas::I
+        ? Canvas::I->anim_duration()
+        : 0;
+    const std::string current_name = has_current_layer
+        ? app.layers->m_current_layer->m_label_text
+        : std::string {};
+    std::string lower_name;
+    if (app.canvas && app.canvas->m_canvas && current_index > 0
+        && current_index - 1 < static_cast<int>(app.canvas->m_canvas->m_layers.size()))
+    {
+        lower_name = app.canvas->m_canvas->m_layers[current_index - 1]->m_name;
+    }
+
+    const auto plan = pp::app::plan_document_layer_menu(
+        command,
+        has_current_layer,
+        current_index,
+        animation_duration,
+        current_name,
+        lower_name);
+    if (plan)
+        return plan.value();
+    return {};
+}
+
 } // namespace
 
 void App::title_update()
@@ -1513,67 +1546,52 @@ void App::init_menu_layer()
             layout[main_id]->add_child(popup);
 
             popup->find<NodeButtonCustom>("layer-clear")->on_click = [this, popup](Node*) {
-                canvas->m_canvas->clear();
+                const auto plan = make_layer_menu_plan(pp::app::DocumentLayerMenuCommand::clear, *this);
+                if (plan.action == pp::app::DocumentLayerMenuAction::clear_current_layer)
+                    canvas->m_canvas->clear();
                 popup->mouse_release();
                 popup->destroy();
             };
-            if (layers->m_current_layer)
+            {
+                const auto plan = make_layer_menu_plan(pp::app::DocumentLayerMenuCommand::clear, *this);
                 popup->find<NodeButtonCustom>("layer-clear")->
                     find<NodeText>("menu-label")->
-                    set_text(("Clear Layer " + layers->m_current_layer->m_label_text).c_str());
+                    set_text(plan.label.c_str());
+            }
 
             popup->find<NodeButtonCustom>("layer-rename")->on_click = [this, popup](Node*) {
-                dialog_layer_rename();
+                const auto plan = make_layer_menu_plan(pp::app::DocumentLayerMenuCommand::rename, *this);
+                if (plan.action == pp::app::DocumentLayerMenuAction::show_rename_dialog)
+                    dialog_layer_rename();
                 popup->mouse_release();
                 popup->destroy();
             };
-            if (layers->m_current_layer)
+            {
+                const auto plan = make_layer_menu_plan(pp::app::DocumentLayerMenuCommand::rename, *this);
                 popup->find<NodeButtonCustom>("layer-rename")->
                     find<NodeText>("menu-label")->
-                    set_text(("Rename Layer " + layers->m_current_layer->m_label_text).c_str());
-            else
-                popup->find<NodeButtonCustom>("layer-rename")->
-                    find<NodeText>("menu-label")->
-                    set_text("Rename Layer (Select a layer)");
+                    set_text(plan.label.c_str());
+            }
 
             popup->find<NodeButtonCustom>("layer-merge")->on_click = [this, popup](Node*) {
-                //layers->get_child_index(layers->)
-                if (Canvas::I->anim_duration() > 1)
+                const auto plan = make_layer_menu_plan(pp::app::DocumentLayerMenuCommand::merge_down, *this);
+                if (plan.action == pp::app::DocumentLayerMenuAction::show_merge_animated_not_supported)
                 {
                     message_box("Not supported", "Merging animated layers is not supported yet.");
                 }
-                else
+                else if (plan.action == pp::app::DocumentLayerMenuAction::merge_with_lower_layer)
                 {
-                    int current_idx_order = Canvas::I->m_current_layer_idx;
-                    if (current_idx_order > 0)
-                    {
-                        layers->merge(current_idx_order, current_idx_order - 1, true);
-                    }
+                    layers->merge(plan.from_index, plan.to_index, true);
                 }
                 popup->mouse_release();
                 popup->destroy();
             };
-            if (layers->m_current_layer)
             {
-                int current_idx_order = canvas->m_canvas->m_current_layer_idx;
-                if (current_idx_order > 0)
-                {
-                    int down_layer_idx = current_idx_order - 1;
-                    popup->find<NodeButtonCustom>("layer-merge")->
-                        find<NodeText>("menu-label")->
-                        set_text(("Merge with " + canvas->m_canvas->m_layers[down_layer_idx]->m_name).c_str());
-                }
-                else
-                {
-                    popup->find<NodeButtonCustom>("layer-merge")->
-                        find<NodeText>("menu-label")->
-                        set_text("Merge Layer (Select upper layers)");
-                }
-            }
-            else
+                const auto plan = make_layer_menu_plan(pp::app::DocumentLayerMenuCommand::merge_down, *this);
                 popup->find<NodeButtonCustom>("layer-merge")->
-                find<NodeText>("menu-label")->
-                set_text("Merge Layer (Select a layer)");
+                    find<NodeText>("menu-label")->
+                    set_text(plan.label.c_str());
+            }
 
         };
     }