3 files changed, 115 insertions, 29 deletions

diff --git a/src/crepe/api/LoopManager.h b/src/crepe/api/LoopManager.h
index 6a212eb..7097ee1 100644
--- a/src/crepe/api/LoopManager.h
+++ b/src/crepe/api/LoopManager.h
@@ -61,7 +61,7 @@ private:
 	 *
 	 * Updates the game state based on the elapsed time since the last frame.
 	 */
-	void update();
+	virtual void update();
 
 	/**
 	 * \brief Late update which is called after update().
@@ -75,7 +75,7 @@ private:
 	 *
 	 * This function updates physics and game logic based on LoopTimer's fixed_delta_time.
 	 */
-	void fixed_update();
+	virtual void fixed_update();
 	/**
 	 * \brief Function for executing render-related systems.
 	 *
diff --git a/src/crepe/system/InputSystem.h b/src/crepe/system/InputSystem.h
new file mode 100644
index 0000000..0c42bd6
--- /dev/null
+++ b/src/crepe/system/InputSystem.h
@@ -0,0 +1,84 @@
+#pragma once
+
+#include "../facade/SDLContext.h"
+#include "../types.h"
+#include "../util/OptionalRef.h"
+
+#include "System.h"
+
+namespace crepe {
+
+class Camera;
+class Button;
+class Transform;
+
+/**
+ * \brief Handles the processing of input events created by SDLContext
+ *
+ * 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.
+	ivec2 last_mouse_down_position;
+
+	//! Stores the last mouse button pressed.
+	MouseButton last_mouse_button = MouseButton::NONE;
+
+	//! The maximum allowable distance between mouse down and mouse up to register as a click.
+	const int click_tolerance = 5;
+
+	/**
+	* \brief Handles the mouse click event.
+	* \param mouse_button The mouse button involved in the click.
+	* \param world_mouse_x The X coordinate of the mouse in world space.
+	* \param world_mouse_y The Y coordinate of the mouse in world space.
+	*
+	* This method processes the mouse click event and triggers the corresponding button action.
+	*/
+	void handle_click(const MouseButton & mouse_button, const int world_mouse_x,
+					  const int world_mouse_y);
+
+	/**
+	* \brief Handles the mouse movement event.
+	* \param event_data The event data containing information about the mouse movement.
+	* \param world_mouse_x The X coordinate of the mouse in world space.
+	* \param world_mouse_y The Y coordinate of the mouse in world space.
+	*
+	* This method processes the mouse movement event and updates the button hover state.
+	*/
+	void handle_move(const SDLContext::EventData & event_data, const int world_mouse_x,
+					 const int world_mouse_y);
+
+	/**
+	* \brief Checks if the mouse position is inside the bounds of the button.
+	* \param world_mouse_x The X coordinate of the mouse in world space.
+	* \param world_mouse_y The Y coordinate of the mouse in world space.
+	* \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 int world_mouse_x, const int world_mouse_y,
+								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
diff --git a/src/test/LoopManagerTest.cpp b/src/test/LoopManagerTest.cpp
index 5897906..f2ca8db 100644
--- a/src/test/LoopManagerTest.cpp
+++ b/src/test/LoopManagerTest.cpp
@@ -1,6 +1,8 @@
 #include <chrono>
 #include <gtest/gtest.h>
+#include <gmock/gmock.h>
 #include <thread>
+
 #define private public
 #define protected public
 #include "api/LoopManager.h"
@@ -11,35 +13,35 @@ using namespace crepe;
 
 class LoopManagerTest : public ::testing::Test {
 protected:
-	LoopManager loop_manager;
+    class TestGameLoop : public crepe::LoopManager {
+    public:
+        MOCK_METHOD(void, fixed_update, (), (override));
+        MOCK_METHOD(void, update, (), (override));
+    };
+
+    TestGameLoop test_loop;
 
-	void SetUp() override {
-		// Setting up loop manager and start the loop
-		loop_manager.loop_timer->set_target_fps(60);
-	}
+    void SetUp() override {
+        test_loop.loop_timer->set_target_fps(60); // Example target FPS
+    }
 };
 
-//Test to check if exactly 5 fixed updates are done every second (50Hz)
+// Test to check if exactly 50 fixed updates occur in 1 second (50Hz)
 TEST_F(LoopManagerTest, FixedUpdate) {
-	loop_manager.loop_timer->fixed_delta_time = std::chrono::milliseconds(20);
-	loop_manager.loop_timer->set_target_fps(50);
-	int fixed_update_count = 0;
-	loop_manager.loop_timer->start();
-	// We want to simulate the game loop for about 1 second
-	auto start_time = steady_clock::now();
-
-	// Simulate the game loop for 1 second
-	while (duration_cast<milliseconds>(steady_clock::now() - start_time)
-		   < std::chrono::milliseconds(1000)) {
-		loop_manager.loop_timer->update();
-		// Simulate processing fixed updates while there's lag to advance
-		while (loop_manager.loop_timer->get_lag()
-			   >= loop_manager.loop_timer->get_fixed_delta_time()) {
-			fixed_update_count++;
-			loop_manager.loop_timer->advance_fixed_update();
-		}
-
-		loop_manager.loop_timer->enforce_frame_rate();
-	}
-	ASSERT_EQ(fixed_update_count, 50);
+    // Arrange
+    using ::testing::AtLeast;
+    using ::testing::Exactly;
+
+    test_loop.loop_timer->fixed_delta_time = std::chrono::milliseconds(20);
+	test_loop.start();
+    // Expect the `fixed_update` method to be called exactly 50 times
+    EXPECT_CALL(test_loop, fixed_update()).Times(Exactly(50));
+
+    auto start_time = steady_clock::now();
+
+    // Act: Simulate the game loop for 1 second
+    while (duration_cast<milliseconds>(steady_clock::now() - start_time) < std::chrono::milliseconds(1000)) {
+
+    }
+	test_loop.game_running = false;
 }