Add canvas tool service boundary

src/app_core/canvas_tool_ui.h

@@ -59,6 +59,17 @@ struct CanvasToolButtonState {
     bool flood_fill_active = false;
 };
 
+class CanvasToolServices {
+public:
+    virtual ~CanvasToolServices() = default;
+
+    virtual void select_toolbar_button(CanvasToolMode mode) = 0;
+    virtual void set_transform_action(CanvasToolTransformAction action) = 0;
+    virtual void set_canvas_mode(CanvasToolMode mode) = 0;
+    virtual void toggle_picking() = 0;
+    virtual void toggle_touch_lock() = 0;
+};
+
 [[nodiscard]] inline constexpr CanvasToolTransformAction transform_action_for_mode(CanvasToolMode mode) noexcept
 {
     if (mode == CanvasToolMode::copy) {
@@ -123,4 +134,47 @@ struct CanvasToolButtonState {
     return state;
 }
 
+[[nodiscard]] inline pp::foundation::Status execute_canvas_tool_plan(
+    const CanvasToolPlan& plan,
+    CanvasToolServices& services)
+{
+    switch (plan.operation) {
+    case CanvasToolOperation::select_mode:
+        if (!plan.selects_toolbar_button || !plan.updates_canvas_mode) {
+            return pp::foundation::Status::invalid_argument("canvas tool select plan must select toolbar and update mode");
+        }
+        if (plan.transform_action != transform_action_for_mode(plan.mode)) {
+            return pp::foundation::Status::invalid_argument("canvas tool select plan has mismatched transform action");
+        }
+        services.select_toolbar_button(plan.mode);
+        if (plan.transform_action != CanvasToolTransformAction::none) {
+            services.set_transform_action(plan.transform_action);
+        }
+        services.set_canvas_mode(plan.mode);
+        return pp::foundation::Status::success();
+
+    case CanvasToolOperation::toggle_picking:
+        if (!plan.requires_draw_mode) {
+            return pp::foundation::Status::invalid_argument("canvas pick plan must require draw mode");
+        }
+        if (plan.no_op) {
+            return pp::foundation::Status::success();
+        }
+        if (!plan.toggles_picking) {
+            return pp::foundation::Status::invalid_argument("canvas pick plan must toggle picking or be a no-op");
+        }
+        services.toggle_picking();
+        return pp::foundation::Status::success();
+
+    case CanvasToolOperation::toggle_touch_lock:
+        if (!plan.toggles_touch_lock || plan.no_op) {
+            return pp::foundation::Status::invalid_argument("canvas touch-lock plan must toggle touch lock");
+        }
+        services.toggle_touch_lock();
+        return pp::foundation::Status::success();
+    }
+
+    return pp::foundation::Status::invalid_argument("unknown canvas tool operation");
+}
+
 } // namespace pp::app