import { Loader, LoadingManager } from "three";

import searchImageDataURL from "../images/smaa/searchImageDataURL";

import areaImageDataURL from "../images/smaa/areaImageDataURL";

/**

* An SMAA image loader.

*

* @deprecated Preloading the SMAA lookup textures is no longer required.

* @experimental Added for testing, API might change in patch or minor releases. Requires three >= r108.

*/

export class SMAAImageLoader extends Loader {

/**

* Loads the SMAA data images.

*

* @param {Function} [onLoad] - A callback that receives the search image and area image as a pair.

* @param {Function} [onError] - An error callback that receives the URL of the image that failed to load.

* @return {Promise<Image[]>} A promise that returns the search image and area image as a pair.

*/

load(onLoad = () => {}, onError = null) {

// Conform to the signature (url, onLoad, onProgress, onError).

if(arguments.length === 4) {

onLoad = arguments[1];

onError = arguments[3];

} else if(arguments.length === 3 || typeof arguments[0] !== "function") {

onLoad = arguments[1];

onError = null;

}

const externalManager = this.manager;

const internalManager = new LoadingManager();

return new Promise((resolve, reject) => {

const searchImage = new Image();

const areaImage = new Image();

internalManager.onError = (url) => {

externalManager.itemError(url);

if(onError !== null) {

onError(`Failed to load ${url}`);

resolve();

} else {

reject(`Failed to load ${url}`);

}

};

internalManager.onLoad = () => {

const result = [searchImage, areaImage];

onLoad(result);

resolve(result);

};

searchImage.addEventListener("error", (e) => {

internalManager.itemError("smaa-search");

});

areaImage.addEventListener("error", (e) => {

internalManager.itemError("smaa-area");

});

searchImage.addEventListener("load", () => {

externalManager.itemEnd("smaa-search");

internalManager.itemEnd("smaa-search");

});

areaImage.addEventListener("load", () => {

externalManager.itemEnd("smaa-area");

internalManager.itemEnd("smaa-area");

});

externalManager.itemStart("smaa-search");

externalManager.itemStart("smaa-area");

internalManager.itemStart("smaa-search");

internalManager.itemStart("smaa-area");

searchImage.src = searchImageDataURL;

areaImage.src = areaImageDataURL;

});

}

}