Let us start here, from square one. No, from Zero!

touch/handler.h

@@ -0,0 +1,60 @@
+#pragma once
+
+#include <string>
+#include <windows.h>
+
+#include "touch.h"
+
+// touch states
+extern std::mutex TOUCH_POINTS_M;
+extern std::mutex TOUCH_EVENTS_M;
+extern std::vector<TouchPoint> TOUCH_POINTS;
+
+enum msg_handler_action {
+    /*
+     * The message was unhandled by the touch handler. This is the default value set when
+     * the touch handler is called.
+     */
+    ACTION_PASS = 0,
+
+    /*
+     * The message was handled by the touch handler, but `DefWindowProc` should be called
+     * and its return value used instead of the stored one.
+     */
+    ACTION_RETURN_DEFAULT = 1,
+
+    /*
+     * The message was handled by the touch handler and the stored `return_value` should be
+     * used as the return value.
+     */
+    ACTION_RETURN_STORED = 2,
+};
+
+struct msg_handler_result {
+    msg_handler_action action;
+    LRESULT return_value;
+};
+
+class TouchHandler {
+public:
+
+    TouchHandler(std::string name);
+    virtual ~TouchHandler() = default;
+
+    static bool is_available() {
+        return false;
+    }
+
+    virtual bool window_register(HWND hWnd) {
+        return true;
+    }
+    virtual bool window_unregister(HWND hWnd) {
+        return true;
+    }
+
+    virtual void handle_message(msg_handler_result &result, HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) = 0;
+};
+
+void add_touch_event(TouchEvent *te);
+
+void update_card_button();