1 files changed, 86 insertions, 0 deletions
diff --git a/src/crepe/system/InputSystem.h b/src/crepe/system/InputSystem.h
new file mode 100644
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--- /dev/null
+++ b/src/crepe/system/InputSystem.h
@@ -0,0 +1,86 @@
+#pragma once
+
+#include "facade/SDLContext.h"
+#include "types.h"
+#include "util/OptionalRef.h"
+
+#include "System.h"
+
+namespace crepe {
+
+class Button;
+
+class Transform;
+/**
+ * \class InputSystem
+ * \brief Handles the processing of input events like mouse and keyboard interactions.
+ * 
+ * This system processes events such as mouse clicks, mouse movement, and keyboard
+ * actions. It is responsible for detecting interactions with UI buttons and
+ * passing the corresponding events to the registered listeners.
+ */
+class InputSystem : public System {
+public:
+	using System::System;
+
+	/**
+     * \brief Updates the system, processing all input events.
+     * This method processes all events and triggers corresponding actions.
+     */
+	void update() override;
+
+private:
+	//! Stores the last position of the mouse when the button was pressed.
+	std::pair<int, int> last_mouse_down_position{-1, -1};
+
+	//! Stores the last mouse button pressed.
+	MouseButton last_mouse_button = MouseButton::NONE;
+
+	//! The tolerance in game units for detecting a mouse click.
+	const int click_tolerance = 5;
+
+	/**
+     * \brief Handles the click event.
+     * \param eventData The event data containing information about the mouse click.
+     * 
+     * This method processes the mouse click event and triggers the corresponding button action.
+     */
+	void handle_click(const SDLContext::EventData & eventData);
+
+	/**
+     * \brief Handles the mouse movement event.
+     * \param eventData The event data containing information about the mouse movement.
+     * 
+     * This method processes the mouse movement event and updates the button hover state.
+     */
+	void handle_move(const SDLContext::EventData & eventData);
+
+	/**
+     * \brief Finds the transform component associated with a button.
+     * \param button The button to find the associated transform for.
+     * \param transforms A list of transforms to search through.
+     * \return A pointer to the transform of the button, or nullptr if not found.
+     */
+	OptionalRef<Transform> find_transform_for_button(Button & button,
+													 RefVector<Transform> & transforms);
+
+	/**
+     * \brief Checks if the mouse position is inside the bounds of the button.
+     * \param eventData The event data containing the mouse position.
+     * \param button The button to check.
+     * \param transform The transform component of the button.
+     * \return True if the mouse is inside the button, false otherwise.
+     */
+	bool is_mouse_inside_button(const SDLContext::EventData & eventData, const Button & button,
+								const Transform & transform);
+
+	/**
+     * \brief Handles the button press event, calling the on_click callback if necessary.
+     * \param button The button being pressed.
+     * 
+     * This method triggers the on_click action for the button when it is pressed.
+     */
+	void handle_button_press(Button & button);
+};
+
+} // namespace crepe