// Copyright (c) 2022 Dominic Masters
// 
// This software is released under the MIT License.
// https://opensource.org/licenses/MIT

#pragma once
#include "../libs.h"
#include "../assert/assert.h"
#include "../util/array.h"

#define EVENT_LISTENER_COUNT_MAX 128

typedef uint8_t event_t;

typedef bool eventcallback_t(
  void *user, event_t event, void *args[], int32_t argc
);

typedef struct {
  void *user;
  event_t event;
  eventcallback_t *callback;
} eventlistener_t;

typedef struct {
  eventlistener_t listeners[EVENT_LISTENER_COUNT_MAX];
} eventmanager_t;

/**
 * Initialize the event manager.
 * 
 * @param manager Event manager to initialize.
 */
void eventManagerInit(eventmanager_t *manager);

/**
 * Subscribe to an event on a given event manager.
 * 
 * @param man Event manager to subscribe to.
 * @param event Event to subscribe to.
 * @param user Any custom user data to provide to the event callback.
 * @param callback Callback to fire when the event is triggered.
 * @return The event listener that was subscribed to.
 */
eventlistener_t * eventManagerSubscribe(
  eventmanager_t *man, event_t event, void *user, eventcallback_t *callback
);

/**
 * Unsubscribe an event listener that was previously subscribed.
 * 
 * @param listener Listener to unsubscribe.
 */
void eventManagerUnsubscribe(eventmanager_t *man, eventlistener_t *listener);

/**
 * Trigger a specific event on the event manager.
 * 
 * @param manager Manager to trigger the event on.
 * @param event Event to trigger
 * @param args Array of pointers for event arguments.
 * @param argc Count of event arguments.
 * @return True if no events are subscribed, otherwise only returns true if all
 *         event listeners also return true.
 */
bool eventManagerTrigger(
  eventmanager_t *manager, event_t event, void *args[], int32_t argc
);