const Utils = require('r3-utils');

/**

 OPTIONS_START
 OPTIONS_END

 **/

class Event {

  //CONSTRUCTOR_TEMPLATE_START
  constructor(options) {

    Event.Emit(Event.OBJECT_CREATED, this);

    //OPTIONS_INIT_START
    if (typeof options === 'undefined') {
        options = {};
    }
		//OPTIONS_INIT_END

    //CUSTOM_OPTIONS_INIT_START
    //CUSTOM_OPTIONS_INIT_END

    Object.assign(this, options);

    //CUSTOM_BEFORE_INIT_START
    //CUSTOM_BEFORE_INIT_END

    Event.Emit(Event.OBJECT_INITIALIZED, this);
  }
	//CONSTRUCTOR_TEMPLATE_END

  //CUSTOM_IMPLEMENTATION_START

	/**
	 * Some nice Events handling
	 * @type {{}}
	 */
	static Subscriptions = {};

	static Subscribe(
		eventName,
		fn
	) {
		/**
		 * Todo - maybe eventually store a boolean which indicates if the function has been executed
		 */
		let subscriptionId = Utils.RandomId(10);

		if (Event.Subscriptions.hasOwnProperty(eventName)) {

			if (Event.Subscriptions[eventName][subscriptionId]) {
				throw new Error('A component can only subscribe to a particular event ID once');
			}

			Event.Subscriptions[eventName][subscriptionId] = fn;
		} else {
			Event.Subscriptions[eventName] = {};
			Event.Subscriptions[eventName][subscriptionId] = fn;
		}

		/**
		 * Return a handle to the caller to allow us to unsubscribe to this event
		 */
		return {
			fn: fn,
			remove: function (eventId, subscriptionId) {

				return function () {

					/**
					 * Stop listening for this event from this component
					 */
					delete Event.Subscriptions[eventId][subscriptionId];

					/**
					 * If the length of listeners is 0, stop referencing this event
					 * @type {string[]}
					 */
					let listeners = Object.keys(Event.Subscriptions[eventId]);
					if (listeners.length === 0) {
						delete Event.Subscriptions[eventId];
					}
				}

			}(eventName, subscriptionId),
			subscriptionId : subscriptionId
		};
	};

	/**
	 * Subscribe to some events
	 * @param eventName
	 * @param callback
	 */
	subscribe(
		eventName,
		callback
	) {
		return Event.Subscribe(eventName, callback.bind(this));
	};

	/**
	 * Static Synchronous Event - Calls clientCallback directly after the event result is obtained
	 * @param eventId
	 * @param data
	 * @param clientCallback is executed ideally when the event completed
	 * @param clientErrorCallback
	 * @returns {number} of callbacks executed
	 * @constructor
	 */
	static Emit(
		eventId,
		data,
		clientCallback,
		clientErrorCallback
	) {
		if (Event.Subscriptions.hasOwnProperty(eventId)) {

			let subscriptionIds = Object.keys(Event.Subscriptions[eventId]);

			subscriptionIds.map(
				function(subscriptionId) {
					try {
						let result = Event.Subscriptions[eventId][subscriptionId](data);

						if (clientCallback) {
							clientCallback(result);
						}
					} catch (error) {
						if (clientErrorCallback) {
							clientErrorCallback(error);
						} else {
							console.error(error);
							throw error;
						}
					}
				}
			)
		}
	}

	emit(
		eventName,
		data,
		clientCallback,
		clientErrorCallback
	) {
		return Event.Emit(
			eventName,
			data,
			clientCallback,
			clientErrorCallback
		);
	}

	/**
	 * Execute the functions which subscribe to this event, but don't process the client callback - the subscription function
	 * should execute the client callback
	 * @param eventId
	 * @param data
	 * @param clientCallback
	 * @param clientErrorCallback
	 * @returns {number}
	 * @constructor
	 */
	static Async(
		eventId,
		data,
		clientCallback,
		clientErrorCallback
	) {
		if (Event.Subscriptions.hasOwnProperty(eventId)) {

			let subscriptionIds = Object.keys(Event.Subscriptions[eventId]);

			subscriptionIds.map(
				function(subscriptionId) {
					try {
						Event.Subscriptions[eventId][subscriptionId](data, clientCallback, clientErrorCallback);
					} catch (error) {
						if (clientErrorCallback) {
							clientErrorCallback(error);
						} else {
							console.error(error);
							throw error;
						}
					}
				}
			)
		}
	};
  //CUSTOM_IMPLEMENTATION_END

}

//CUSTOM_OUT_OF_CLASS_IMPLEMENTATION_START

//EVENT_GENERATED_START
Event.COMPONENT_INITIALIZED = 0x1;
Event.CREATE_INSTANCE_BEFORE = 0x2;
Event.DISPOSE_INSTANCE = 0x3;
Event.DISPOSE_OBJECT = 0x4;
Event.GET_RUNTIME = 0x5;
Event.GET_WINDOW_SIZE = 0x6;
Event.INSTANCE_CREATED = 0x7;
Event.INSTANCE_DISPOSED = 0x8;
Event.OBJECT_CREATED = 0x9;
Event.OBJECT_INITIALIZED = 0xa;
Event.PAUSE = 0xb;
Event.RESTART = 0xc;
Event.START = 0xd;
Event.UPDATE_FROM_INSTANCE_AFTER = 0xe;
Event.UPDATE_FROM_INSTANCE_BEFORE = 0xf;
Event.UPDATE_INSTANCE_AFTER = 0x10;
Event.UPDATE_INSTANCE_BEFORE = 0x11;
Event.MAX_EVENTS = 0x12;

Event.GetEventName = function(eventId) {

	switch(eventId) {
		case 0x1 : return 'component_initialized';
		case 0x2 : return 'create_instance_before';
		case 0x3 : return 'dispose_instance';
		case 0x4 : return 'dispose_object';
		case 0x5 : return 'get_runtime';
		case 0x6 : return 'get_window_size';
		case 0x7 : return 'instance_created';
		case 0x8 : return 'instance_disposed';
		case 0x9 : return 'object_created';
		case 0xa : return 'object_initialized';
		case 0xb : return 'pause';
		case 0xc : return 'restart';
		case 0xd : return 'start';
		case 0xe : return 'update_from_instance_after';
		case 0xf : return 'update_from_instance_before';
		case 0x10 : return 'update_instance_after';
		case 0x11 : return 'update_instance_before';
		default :
			throw new Error('Event type not defined : ' + eventId);
	}

};
//EVENT_GENERATED_END

//CUSTOM_OUT_OF_CLASS_IMPLEMENTATION_END

module.exports = Event;