import { Cache } from './Cache.js';
import { Loader } from './Loader.js';
import { createElementNS } from '../utils.js';

class ImageLoader extends Loader {
	constructor(manager) {
		super(manager);
	}

	load(url, onLoad, onProgress, onError) {
		if (this.path !== undefined) url = this.path + url;

		url = this.manager.resolveURL(url);

		const scope = this;

		const cached = Cache.get(url);

		if (cached !== undefined) {
			scope.manager.itemStart(url);

			setTimeout(function () {
				if (onLoad) onLoad(cached);

				scope.manager.itemEnd(url);
			}, 0);

			return cached;
		}

		const image = createElementNS('img');

		function onImageLoad() {
			removeEventListeners();

			Cache.add(url, this);

			if (onLoad) onLoad(this);

			scope.manager.itemEnd(url);
		}

		function onImageError(event) {
			removeEventListeners();

			if (onError) onError(event);

			scope.manager.itemError(url);
			scope.manager.itemEnd(url);
		}

		function removeEventListeners() {
			image.removeEventListener('load', onImageLoad, false);
			image.removeEventListener('error', onImageError, false);
		}

		image.addEventListener('load', onImageLoad, false);
		image.addEventListener('error', onImageError, false);

		if (url.substr(0, 5) !== 'data:') {
			if (this.crossOrigin !== undefined) image.crossOrigin = this.crossOrigin;
		}

		scope.manager.itemStart(url);

		image.src = url;

		return image;
	}
}

export { ImageLoader };