export const REQUEST_TYPE_POST = 'POST';
export const REQUEST_TYPE_GET = 'GET';
export const REQUEST_TYPE_PUT = 'PUT';
export const REQUEST_TYPE_DELETE = 'DELETE';
export const CONTENT_TYPE_JSON = 'json';
export const CONTENT_TYPE_FORM = 'x-www-form-urlencoded';
import EventEmitter from '../events/EventEmitter';
class DataUtils extends EventEmitter {
	//--------------------------
	// constructor
	//--------------------------
	constructor() {
		super();
	}
	//--------------------------
	// methods
	//--------------------------
	request(
		requestURL,
		eventType,
		requestType = REQUEST_TYPE_GET,
		contentType = CONTENT_TYPE_JSON,
		requestData = null
	) {
		var self = this;
		return new Promise(function(resolve, reject) {
			var request = new XMLHttpRequest();
			request.upload.onprogress = self.handleLoadProgress;
			request.open(requestType, requestURL, true);
			request.onload = () => {
				if (request.status == 200) {
					resolve({
						request,
						eventType
					});
				} else {
					reject({
						request,
						eventType
					});
				}
			};
			if (requestType == REQUEST_TYPE_PUT || requestType == REQUEST_TYPE_POST) {
				switch (contentType) {
					case CONTENT_TYPE_JSON:
						request.setRequestHeader('Content-type', 'application/' + contentType);
						request.send(JSON.stringify(requestData));
						break;
					case CONTENT_TYPE_FORM:
						request.send(requestData);
						break;
				}
			} else {
				request.send();
			}
		});
	}
	imgLoad(url) {
		'use strict';
		// Create new promise with the Promise() constructor;
		// This has as its argument a function with two parameters, resolve and reject
		return new Promise(function(resolve, reject) {
			// Standard XHR to load an image
			var request = new XMLHttpRequest();
			request.open('GET', url);
			request.responseType = 'blob';
			// When the request loads, check whether it was successful
			request.onload = function() {
				if (request.status === 200) {
					// If successful, resolve the promise by passing back the request response
					resolve(request.response);
				} else {
					// If it fails, reject the promise with a error message
					reject(
						new Error(
							"Image didn't load successfully; error code:" + request.statusText
						)
					);
				}
			};
			request.onerror = function() {
				// Also deal with the case when the entire request fails to begin with
				// This is probably a network error, so reject the promise with an appropriate message
				reject(new Error('There was a network error.'));
			};
			// Send the request
			request.send();
		});
	}
	loadImage(src) {
		'use strict';
		let self = this;
		return new Promise(function(resolve, reject) {
			// Get a reference to the body element, and create a new image object
			var myImage = new Image();
			myImage.crossOrigin = ''; // or "anonymous"
			// Call the function with the URL we want to load, but then chain the
			// promise then() method on to the end of it. This contains two callbacks
			self.imgLoad(src).then(
				function(response) {
					// The first runs when the promise resolves, with the request.reponse specified within the resolve() method.
					var imageURL = window.URL.createObjectURL(response);
					resolve(imageURL);
					//$('background-content').setStyle('background-image', 'url('+imageURL+')') //myImage.src = imageURL;
					//console.log(imageURL);
					//body.appendChild(myImage);
					// The second runs when the promise is rejected, and logs the Error specified with the reject() method.
				},
				function(Error) {
					reject(Error);
				}
			);
		});
	}
	/**
	 * Create a function to convert the serialize and convert the form data to JSON
	 * @param : $('#form_example');
	 * @return a JSON Stringify
	 */
	formDataToJSON(form) {
		let object = {};
		let formData = new FormData(form);
		formData.forEach((value, key) => {
			if (!object.hasOwnProperty(key)) {
				object[key] = value;
				return;
			}
			if (!Array.isArray(object[key])) {
				object[key] = [object[key]];
			}
			object[key].push(value);
		});
		let json = JSON.stringify(object);
		return json;
	}
	//--------------------------
	// event handlers
	//--------------------------
	handleLoadProgress() {
		//var percentComplete = Math.ceil((e.loaded / e.total) * 100);
		//console.log(percentComplete);
	}
}
export default DataUtils;