import EventCallbackReg from './EventCallbackReg';
import IEventCallback from './IEventCallback';
import IEventHandler from './IEventHandler';
import {
	isArray
} from './Type';

export class EventHandler implements IEventHandler {
	private callbacksByType: { [s: string]: EventCallbackReg[] } = {};

	getCallbackRegsByType(type: string): EventCallbackReg[] {
		var result = this.callbacksByType[type];
		if (!isArray(result)) result = [];
		return result;
	}

	getEventParent(): IEventHandler {
		return null;
	}

	addEventCallback(type: string, cb: IEventCallback, thisObj: Object): void {
		var reg = new EventCallbackReg(cb, thisObj);
		if (isArray(this.callbacksByType[type])) {
			this.removeEventCallback(type, cb, thisObj);
			this.callbacksByType[type].push(reg);
		} else {
			this.callbacksByType[type] = [reg];
		}

	}

	removeEventCallback(type: string, cb: IEventCallback, thisObj: Object): void {
		var callbacks = this.callbacksByType[type];
		if (isArray(callbacks)) {
			for (var i = 0, n = callbacks.length; i < n; i++) {
				var callback = callbacks[i];
				if (callback.callback === cb && callback.thisObj === thisObj) {
					callbacks.splice(i, 1);
					break;
				}
			}
		}
	}

	removeAllEventCallbacks(): void {
		this.callbacksByType = {};
	}
}

export default EventHandler;