Add history command service boundary

src/app_core/history_ui.h

@@ -23,6 +23,15 @@ struct HistoryUiPlan {
     bool no_op = false;
 };
 
+class HistoryUiServices {
+public:
+    virtual ~HistoryUiServices() = default;
+
+    virtual void invoke_undo() = 0;
+    virtual void invoke_redo() = 0;
+    virtual void clear_history() = 0;
+};
+
 [[nodiscard]] inline pp::foundation::Status validate_history_metric(int value, const char* message) noexcept
 {
     if (value < 0) {
@@ -107,4 +116,46 @@ struct HistoryUiPlan {
     return pp::foundation::Result<HistoryUiPlan>::success(plan);
 }
 
+[[nodiscard]] inline pp::foundation::Status execute_history_ui_plan(
+    const HistoryUiPlan& plan,
+    HistoryUiServices& services)
+{
+    const auto undo_status = validate_history_metric(plan.undo_count, "undo action count must not be negative");
+    if (!undo_status.ok()) {
+        return undo_status;
+    }
+    const auto redo_status = validate_history_metric(plan.redo_count, "redo action count must not be negative");
+    if (!redo_status.ok()) {
+        return redo_status;
+    }
+    const auto memory_status = validate_history_metric(plan.memory_bytes, "history memory bytes must not be negative");
+    if (!memory_status.ok()) {
+        return memory_status;
+    }
+
+    if (plan.no_op) {
+        return pp::foundation::Status::success();
+    }
+
+    switch (plan.operation) {
+    case HistoryUiOperation::undo:
+        if (plan.invokes_undo) {
+            services.invoke_undo();
+        }
+        return pp::foundation::Status::success();
+    case HistoryUiOperation::redo:
+        if (plan.invokes_redo) {
+            services.invoke_redo();
+        }
+        return pp::foundation::Status::success();
+    case HistoryUiOperation::clear:
+        if (plan.clears_history) {
+            services.clear_history();
+        }
+        return pp::foundation::Status::success();
+    }
+
+    return pp::foundation::Status::invalid_argument("unknown history operation");
+}
+
 } // namespace pp::app