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+#pragma once
+
+#include <memory>
+#include <typeindex>
+#include <unordered_map>
+#include <vector>
+
+#include "Event.h"
+#include "EventHandler.h"
+
+namespace crepe {
+
+//! Event listener unique ID
+typedef size_t subscription_t;
+
+/**
+ * \brief Event channel
+ *
+ * Events can be sent to a specific channel, which prevents listeners on other channels from
+ * being called. The default channel is EventManager::CHANNEL_ALL, which calls all listeners.
+ */
+typedef size_t event_channel_t;
+
+/**
+ * \class EventManager
+ * \brief Manages event subscriptions, triggers, and queues, enabling decoupled event handling.
+ *
+ * The `EventManager` acts as a centralized event system. It allows for registering callbacks
+ * for specific event types, triggering events synchronously, queueing events for later
+ * processing, and managing subscriptions via unique identifiers.
+ */
+class EventManager {
+public:
+ static constexpr const event_channel_t CHANNEL_ALL = -1;
+
+ /**
+ * \brief Get the singleton instance of the EventManager.
+ *
+ * This method returns the unique instance of the EventManager, creating it if it
+ * doesn't already exist. Ensures only one instance is active in the program.
+ *
+ * \return Reference to the singleton instance of the EventManager.
+ */
+ static EventManager & get_instance();
+
+ /**
+ * \brief Subscribe to a specific event type.
+ *
+ * Registers a callback for a given event type and optional channel. Each callback
+ * is assigned a unique subscription ID that can be used for later unsubscription.
+ *
+ * \tparam EventType The type of the event to subscribe to.
+ * \param callback The callback function to be invoked when the event is triggered.
+ * \param channel The channel number to subscribe to (default is CHANNEL_ALL, which listens to all channels).
+ * \return A unique subscription ID associated with the registered callback.
+ */
+ template <typename EventType>
+ subscription_t subscribe(const EventHandler<EventType> & callback,
+ event_channel_t channel = CHANNEL_ALL);
+
+ /**
+ * \brief Unsubscribe a previously registered callback.
+ *
+ * Removes a callback from the subscription list based on its unique subscription ID.
+ *
+ * \param event_id The unique subscription ID of the callback to remove.
+ */
+ void unsubscribe(subscription_t event_id);
+
+ /**
+ * \brief Trigger an event immediately.
+ *
+ * Synchronously invokes all registered callbacks for the given event type on the specified channel.
+ *
+ * \tparam EventType The type of the event to trigger.
+ * \param event The event instance to pass to the callbacks.
+ * \param channel The channel to trigger the event on (default is CHANNEL_ALL, which triggers on all channels).
+ */
+ template <typename EventType>
+ void trigger_event(const EventType & event, event_channel_t channel = CHANNEL_ALL);
+
+ /**
+ * \brief Queue an event for later processing.
+ *
+ * Adds an event to the event queue to be processed during the next call to `dispatch_events`.
+ *
+ * \tparam EventType The type of the event to queue.
+ * \param event The event instance to queue.
+ * \param channel The channel to associate with the event (default is CHANNEL_ALL).
+ */
+ template <typename EventType>
+ void queue_event(const EventType & event, event_channel_t channel = CHANNEL_ALL);
+
+ /**
+ * \brief Process all queued events.
+ *
+ * Iterates through the event queue and triggers callbacks for each queued event.
+ * Events are removed from the queue once processed.
+ */
+ void dispatch_events();
+
+ /**
+ * \brief Clear all subscriptions.
+ *
+ * Removes all registered event handlers and clears the subscription list.
+ */
+ void clear();
+
+private:
+ /**
+ * \brief Default constructor for the EventManager.
+ *
+ * Constructor is private to enforce the singleton pattern.
+ */
+ EventManager() = default;
+
+ /**
+ * \struct QueueEntry
+ * \brief Represents an entry in the event queue.
+ */
+ struct QueueEntry {
+ std::unique_ptr<Event> event; ///< The event instance.
+ event_channel_t channel = CHANNEL_ALL; ///< The channel associated with the event.
+ std::type_index type; ///< The type of the event.
+ };
+
+ /**
+ * \brief Internal event handler
+ *
+ * This function processes a single event, and is used to process events both during
+ * EventManager::dispatch_events and inside EventManager::trigger_event
+ *
+ * \param type \c typeid of concrete Event class
+ * \param channel Event channel
+ * \param data Event data
+ */
+ void handle_event(std::type_index type, event_channel_t channel, const Event & data);
+
+ /**
+ * \struct CallbackEntry
+ * \brief Represents a registered event handler callback.
+ */
+ struct CallbackEntry {
+ std::unique_ptr<IEventHandlerWrapper> callback; ///< The callback function wrapper.
+ event_channel_t channel = CHANNEL_ALL; ///< The channel this callback listens to.
+ subscription_t id = -1; ///< Unique subscription ID.
+ };
+
+ //! The queue of events to be processed during dispatch.
+ std::vector<QueueEntry> events_queue;
+
+ //! A map of event type to registered callbacks.
+ std::unordered_map<std::type_index, std::vector<CallbackEntry>> subscribers;
+
+ //! Counter to generate unique subscription IDs.
+ subscription_t subscription_counter = 0;
+};
+
+} // namespace crepe
+
+#include "EventManager.hpp"