/**
 * Various utilities.
 * 
 * @author Alain Pitiot
 * @version 3.1.4
 * @copyright (c) 2019 Ilixa Ltd. ({@link http://ilixa.com})
 * @license Distributed under the terms of the MIT License
 */


/**
 * Syntactic sugar for Mixins
 *
 * <p>This is heavily adapted from: http://justinfagnani.com/2015/12/21/real-mixins-with-javascript-classes/</p>
 *
 * @name module:util.MixinBuilder
 * @class
 * @param {Object} superclass
 *
 * @example
 * class BaseClass { ... }
 * let Mixin1 = (superclass) => class extends superclass { ... }
 * let Mixin2 = (superclass) => class extends superclass { ... }
 * class NewClass extends mix(BaseClass).with(Mixin1, Mixin2) { ... }
 */
export let mix = (superclass) => new MixinBuilder(superclass);
class MixinBuilder {  
  constructor(superclass) {
    this.superclass = superclass;
  }

	/**
	 *
	 * @param mixins
	 * @returns {*}
	 */
  with(...mixins) { 
    return mixins.reduce((c, mixin) => mixin(c), this.superclass);
  }
}


/**
 * Convert the resulting value of a promise into a tupple.
 *
 * @name module:util.promiseToTupple
 * @function
 * @public
 * @param {Promise} promise - the promise
 * @return {Object[]} the resulting value in the format [error, return data]
 * where error is null if there was no error
 */
export function promiseToTupple(promise) {
	return promise
		.then(data => [null, data])
		.catch(error => [error, null]);
}


/**
 * Get a Universally Unique Identifier (RFC4122 version 4)
 * <p> See details here: https://www.ietf.org/rfc/rfc4122.txt</p>
 *
 * @name module:util.makeUuid
 * @function
 * @public
 * @return {string} the uuid
 */
export function makeUuid()
{
	return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
		const r = Math.random() * 16 | 0, v = (c === 'x') ? r : (r & 0x3 | 0x8);
		return v.toString(16);
	});
}


/**
 * Get the error stack of the calling, exception-throwing function.
 *
 * @name module:util.getErrorStack
 * @function
 * @public
 * @return {string} the error stack as a string
 */
export function getErrorStack()
{
  try {
		throw Error('');
	} catch(error) {
		// we need to remove the second line since it references getErrorStack:
		let stack = error.stack.split("\n");
		stack.splice(1, 1);
			
		return JSON.stringify(stack.join('\n'));
	}
}


/**
 * Test if x is an 'empty' value.
 *
 * @name module:util.isEmpty
 * @function
 * @public
 * @param {Object} x the value to test
 * @return {boolean} true if x is one of the following: undefined, [], [undefined]
 */
export function isEmpty(x)
{
	if (typeof x === 'undefined') return true;
	if (!Array.isArray(x)) return false;
	if (x.length === 0) return true;
	if (x.length === 1 && typeof x[0] === 'undefined') return true;

	return false;
}


/**
 * Detect the user's browser.
 *
 * <p> Note: since user agent is easily spoofed, we use a more sophisticated approach, as described here:
 * https://stackoverflow.com/questions/9847580/how-to-detect-safari-chrome-ie-firefox-and-opera-browser </p>
 *
 * @name module:util.detectBrowser
 * @function
 * @public
 * @return {string} the detected browser, one of 'Opera', 'Firefox', 'Safari',
 * 'IE', 'Edge', 'Chrome', 'Blink", 'unknown'
 */
export function detectBrowser()
{
	// Opera 8.0+
	const isOpera = (!!window.opr && !!opr.addons) || !!window.opera || navigator.userAgent.indexOf(' OPR/') >= 0;
	if (isOpera) return 'Opera';

	// Firefox 1.0+
	const isFirefox = typeof InstallTrigger !== 'undefined';
	if (isFirefox) return 'Firefox';

	// Safari 3.0+ "[object HTMLElementConstructor]" 
	const isSafari = /constructor/i.test(window.HTMLElement) || (function (p) { return p.toString() === "[object SafariRemoteNotification]"; })(!window['safari'] || (typeof safari !== 'undefined' && safari.pushNotification));
	if (isSafari) return 'Safari';

	// Internet Explorer 6-11
	const isIE = /*@cc_on!@*/false || !!document.documentMode;
	if (isIE) return 'IE';

	// Edge 20+
	const isEdge = !isIE && !!window.StyleMedia;
	if (isEdge) return 'Edge';

	// Chrome 1+
	const isChrome = !!window.chrome && !!window.chrome.webstore;
	if (isChrome) return 'Chrome';

	// Blink engine detection
	const isBlink = (isChrome || isOpera) && !!window.CSS;
	if (isBlink) return 'Blink';

	return 'unknown';
}


/**
 * Convert obj to its numerical form.
 *
 * <ul>
 *   <li>number -> number, e.g. 2 -> 2</li>
 *   <li>[number] -> [number], e.g. [1,2,3] -> [1,2,3]</li>
 *   <li>numeral string -> number, e.g. "8" -> 8</li>
 *   <li>[number | numeral string] -> [number], e.g. [1, 2, "3"] -> [1,2,3]</li>
 * </ul>
 *
 * @name module:util.toNumerical
 * @function
 * @public
 * @param {Object} obj - the input object
 * @return {number | number[]} the numerical form of the input object
 */
export function toNumerical(obj)
{
	const response = { origin: 'util.toNumerical', context: 'when converting an object to its numerical form' };

	if (typeof obj === 'number')
		return obj;

	if (typeof obj === 'string')
		obj = [obj];

	if (Array.isArray(obj)) {
		return obj.map( e => {
			let n = Number.parseFloat(e);
			if (Number.isNaN(n))
				Object.assign(response, { error: 'unable to convert: ' + e + ' to a' +
						' number.'});
			return n;
		});
	}

}


/**
 * Check whether a point lies within a polygon
 * <p>We are using the algorithm described here: https://wrf.ecse.rpi.edu//Research/Short_Notes/pnpoly.html</p>
 *
 * @name module:util.IsPointInsidePolygon
 * @function
 * @public
 * @param {number[]} point - the point
 * @param {Object} vertices - the vertices defining the polygon
 * @return {boolean} whether or not the point lies within the polygon
 */
export function IsPointInsidePolygon(point, vertices)
{
	const x = point[0];
	const y = point[1];
    
	let isInside = false;
	for (let i = 0, j = vertices.length - 1; i < vertices.length; j = i++)
	{
  	const xi = vertices[i][0], yi = vertices[i][1];
    const xj = vertices[j][0], yj = vertices[j][1];
    const intersect = ((yi > y) !== (yj > y)) && (x < (xj - xi) * (y - yi) / (yj - yi) + xi);
    if (intersect) isInside = !isInside;
  }
    
  return isInside;
}


/**
 * Shuffle an array in place using the Fisher-Yastes's modern algorithm
 * <p>See details here: https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle#The_modern_algorithm</p>
 *
 * @name module:util.shuffle
 * @function
 * @public
 * @param {Object[]} array - the input 1-D array
 * @return {Object[]} the shuffled array
 */
export function shuffle(array)
{
	for (let i = array.length - 1; i > 0; i--)
	{
		const j = Math.floor(Math.random() * (i + 1));
		[array[i], array[j]] = [array[j], array[i]];
	}
	return array;
}


/**
 * Get the position of the object in pixel units
 *
 * @name module:util.getPositionFromObject
 * @function
 * @public
 * @param {Object} object - the input object
 * @param {string} units - the units
 * @returns {number[]} the position of the object in pixel units
 */
export function	getPositionFromObject(object, units)
{
	const response = { origin: 'util.getPositionFromObject', context: 'when getting the position of an object' };

	try {
		if (typeof object === 'undefined')
			throw 'cannot get the position of an undefined object';

		let objectWin = undefined;

		// object has a getPos function:
		if (typeof object.getPos === 'function') {
			units = object.units;
			objectWin = object.win;
			object = object.getPos();
		}

		// convert object to pixel units:
		return to_px(object, units, objectWin);
	}
	catch (error) {
		throw Object.assign(response, { error });
	}
}


/**
 * Convert the position to pixel units.
 *
 * @name module:util.to_px
 * @function
 * @public
 * @param {number[]} pos - the input position
 * @param {string} posUnit - the position units
 * @param {Window} win - the associated Window
 * @returns {number[]} the position in pixel units
 */
export function to_px(pos, posUnit, win)
{
	const response = { origin: 'util.to_px', context: 'when converting a position to pixel units' };
	
	if (posUnit === 'pix')
		return pos;
	else if (posUnit === 'norm')
		return [pos[0] * win.size[0]/2.0, pos[1] * win.size[1]/2.0];
	else if (posUnit === 'height') {
		const minSize = Math.min(win.size[0], win.size[1]);
		return [pos[0] * minSize, pos[1] * minSize];
	}
	else
		throw Object.assign(response, { error: `unknown position units: ${posUnit}` });
}


/**
 * Convert the position to norm units.
 *
 * @name module:util.to_norm
 * @function
 * @public
 * @param {number[]} pos - the input position
 * @param {string} posUnit - the position units
 * @param {Window} win - the associated Window
 * @returns {number[]} the position in norm units
 */
export function to_norm(pos, posUnit, win)
{
	const response = { origin: 'util.to_norm', context: 'when converting a position to norm units' };

	if (posUnit === 'norm')
		return pos;
	if (posUnit === 'pix')
		return [pos[0] / (win.size[0]/2.0), pos[1] / (win.size[1]/2.0)];
	if (posUnit === 'height') {
		const minSize = Math.min(win.size[0], win.size[1]);
		return [pos[0] * minSize / (win.size[0]/2.0), pos[1] * minSize / (win.size[1]/2.0)];
	}

	throw Object.assign(response, { error: `unknown position units: ${posUnit}` });
}


/**
 * Convert the position to height units.
 *
 * @name module:util.to_height
 * @function
 * @public
 * @param {number[]} pos - the input position
 * @param {string} posUnit - the position units
 * @param {Window} win - the associated Window
 * @returns {number[]} the position in height units
 */
export function to_height(pos, posUnit, win)
{
	const response = { origin: 'util.to_height', context: 'when converting a position to height units' };

	if (posUnit === 'height')
		return pos;
	if (posUnit === 'pix') {
		const minSize = Math.min(win.size[0], win.size[1]);
		return [pos[0] / minSize, pos[1] / minSize];
	}
	if (posUnit === 'norm') {
		const minSize = Math.min(win.size[0], win.size[1]);
		return [pos[0] * win.size[0]/2.0 / minSize, pos[1] * win.size[1]/2.0 / minSize];
	}

	throw Object.assign(response, { error: `unknown position units: ${posUnit}` });
}


/**
 * Convert the position to window units.
 *
 * @name module:util.to_win
 * @function
 * @public
 * @param {number[]} pos - the input position
 * @param {string} posUnit - the position units
 * @param {Window} win - the associated Window
 * @returns {number[]} the position in window units
 */
export function to_win(pos, posUnit, win)
{
	const response = { origin: 'util.to_win', context: 'when converting a position to window units' };

	try {
		if (win._units === 'pix')
			return to_px(pos, posUnit, win);
		if (win._units === 'norm')
			return to_norm(pos, posUnit, win);
		if (win._units === 'height')
			return to_height(pos, posUnit, win);

		throw `unknown window units: ${win._units}`;
	} catch (error) {
		throw Object.assign(response, { response, error });
	}
}


/**
 * Convert the position to given units.
 *
 * @name module:util.to_unit
 * @function
 * @public
 * @param {number[]} pos - the input position
 * @param {string} posUnit - the position units
 * @param {Window} win - the associated Window
 * @param {string} targetUnit - the target units
 * @returns {number[]} the position in target units
 */
export function to_unit(pos, posUnit, win, targetUnit)
{
	const response = { origin: 'util.to_unit', context: 'when converting a position to different units' };

	try {
		if (targetUnit === 'pix')
			return to_px(pos, posUnit, win);
		if (targetUnit === 'norm')
			return to_norm(pos, posUnit, win);
		if (targetUnit === 'height')
			return to_height(pos, posUnit, win);

		throw `unknown target units: ${targetUnit}`;
	} catch (error) {
		throw Object.assign(response, { error });
	}
}


/**
 * Convert a position to a PIXI Point.
 *
 * @name module:util.to_pixiPoint
 * @function
 * @public
 * @param {number[]} pos - the input position
 * @param {string} posUnit - the position units
 * @param {Window} win - the associated Window
 * @returns {number[]} the position as a PIXI Point
 */
export function to_pixiPoint(pos, posUnit, win)
{
	const pos_px = to_px(pos, posUnit, win);
	return new PIXI.Point(pos_px[0], pos_px[1]);
}


/**
 * Convert an object to its string representation, taking care of symbols.
 *
 * <p>Note: if the object is not already a string, we JSON stringify it and detect circularity.</p>
 *
 * @name module:util.toString
 * @function
 * @public
 * @param {Object} object - the input object
 * @return {string} a string representation of the object or 'Object (circular)'
 */
export function toString(object)
{
	if (typeof object === 'string')
		return object;
	
	try {
		const symbolReplacer = (key, value) => {
			if (typeof value === 'symbol')
				value = Symbol.keyFor(value);
			return value;
		};
		return JSON.stringify(object, symbolReplacer);
	} catch (e)
	{
		return 'Object (circular)';
	}
}


if (!String.prototype.format) {
  String.prototype.format = function() {
    var args = arguments;
    return this
		.replace(/{(\d+)}/g, function(match, number) { 
			return typeof args[number] != 'undefined' ? args[number] : match;
		})
		.replace(/{([$_a-zA-Z][$_a-zA-Z0-9]*)}/g, function(match, name) {
			//console.log("n=" + name + " args[0][name]=" + args[0][name]);
			return args.length > 0 &&  args[0][name] !== undefined
			? args[0][name]
			: match
			;
		});
  };
}


/**
 * Test whether an object is either an integer or the string representation of an integer.
 * <p>This is adapted from: https://stackoverflow.com/a/14794066</p>
 *
 * @name module:util.isInt
 * @function
 * @public
 * @param {Object} obj - the input object
 * @returns {boolean} whether or not the object is an integer or the string representation of an integer
 */
export function isInt(obj) {
	if (isNaN(obj))
	  return false;

	const x = parseFloat(obj);
	return (x | 0) === x;
}


/**
 * Get the URL parameters.
 *
 * @name module:util.getUrlParameters
 * @function
 * @public
 * @returns {URLSearchParams} the iterable URLSearchParams
 * 
 * @example
 * const urlParameters = util.getUrlParameters();
 * for (const [key, value] of urlParameters)
 *   console.log(key + ' = ' + value);
 * 
 */
export function getUrlParameters()
{
	const urlQuery = window.location.search.slice(1);
	return new URLSearchParams(urlQuery);

	/*let urlMap = new Map();
	for (const entry of urlParameters)
		urlMap.set(entry[0], entry[1])

	return urlMap;*/
}


/**
 * Add info extracted from the URL to the given dictionary.
 *
 * <p>We exclude all URL parameters starting with a double underscore
 * since those are reserved for client/server communication</p>
 *
 * @name module:util.addInfoFromUrl
 * @function
 * @public
 * @param {Object} info - the dictionary
 */
export function addInfoFromUrl(info)
{
	const infoFromUrl = getUrlParameters();

	// note: parameters starting with a double underscore are reserved for client/server communication,
	// we do not add them to info
	for (const [key, value] of infoFromUrl)
		if (key.indexOf('__') !== 0)
			info[key] = value;

	return info;
}


/**
 * Select values from an array.
 *
 * <p> 'selection' can be a single integer, an array of indices, or a string to be parsed, e.g.:
 * <ul>
 *   <li>5</li>
 *   <li>[1,2,3,10]</li>
 *   <li>'1,5,10'</li>
 *   <li>'1:2:5'</li>
 *   <li>'5:'</li>
 *   <li>'-5:-2, 9, 11:5:22'</li>
 * </ul></p>
 *
 * @name module:util.selectFromArray
 * @function
 * @public
 * @param {Array.<Object>} array - the input array
 * @param {number | Array.<number> | string} selection -  the selection
 * @returns {Object | Array.<Object>} the array of selected items
 */
export function selectFromArray(array, selection) {

	// if selection is an integer, or a string representing an integer, we treat it as an index in the array
	// and return that entry:
	if (isInt(selection))
		return array[parseInt(selection)];

	// if selection is an array, we treat it as a list of indices
	// and return an array with the entries corresponding to those indices:
	else if (Array.isArray(selection))
		return array.filter( (e,i) => (selection.includes(i)) );

	// if selection is a string, we decode it:
	else if (typeof selection === 'string') {
		if (selection.indexOf(',') > -1)
			return selection.split(',').map(a => selectFromArray(array, a));
			// return flattenArray( selection.split(',').map(a => selectFromArray(array, a)) );
		else if (selection.indexOf(':') > -1) {
			let sliceParams = selection.split(':').map(a => parseInt(a));
			if (sliceParams.length === 3)
				return sliceArray(array, sliceParams[0], sliceParams[2], sliceParams[1]);
			else
				return sliceArray(array, ...sliceParams);
		}
	}

	else
		throw { origin: 'selectFromArray', context: 'when selecting entries from an array', error: 'unknown selection type: ' + (typeof selection)};
}


/**
 * Recursively flatten an array of arrays.
 *
 * @name module:util.flattenArray
 * @function
 * @public
 * @param {Array.<Object>} array - the input array of arrays
 * @returns {Array.<Object>} the flatten array
 */
export function flattenArray(array) {
	return array.reduce(
		(flat, next) => {
			flat.push( (Array.isArray(next) && Array.isArray(next[0])) ? flattenArray(next) : next );
			return flat;
		},
		[]
	);
}


/**
 * Slice an array.
 *
 * @name module:util.sliceArray
 * @function
 * @public
 * @param {Array.<Object>} array - the input array
 * @param {number} [from= NaN] - the start of the slice
 * @param {number} [to= NaN] - the end of the slice
 * @param {number} [step= NaN] - the step of the slice
 * @returns {Array.<Object>} the array slice
 */
export function sliceArray(array, from = NaN, to = NaN, step = NaN)
{
	if (isNaN(from)) from = 0;
	if (isNaN(to)) to = array.length;

	let arraySlice = array.slice(from, to);

	if (isNaN(step))
		return arraySlice;

	if (step < 0)
		arraySlice.reverse();

	step = Math.abs(step);
	if (step == 1)
		return arraySlice;
	else
		return arraySlice.filter( (e,i) => (i % step == 0) );
}


/**
 * Offer data as download in the browser.
 *
 * @param {string} filename - the name of the file to be downloaded
 * @param {*} data - the data
 * @param {string} type - the MIME type of the data, e.g. 'text/csv' or 'application/json'
 */
export function offerDataForDownload(filename, data, type) {
	const blob = new Blob([data], { type });
	if (window.navigator.msSaveOrOpenBlob)
		window.navigator.msSaveBlob(blob, filename);
	else {
		let elem = window.document.createElement('a');
		elem.href = window.URL.createObjectURL(blob);
		elem.download = filename;
		document.body.appendChild(elem);
		elem.click();
		document.body.removeChild(elem);
	}
}