/*!
 * Envira Utilities
 */

/**
 * detect IE
 * returns version of IE or false, if browser is not Internet Explorer
 */
function detectIE() {
	var ua = window.navigator.userAgent;

	// Test values; Uncomment to check result …
	// IE 10
	// ua = 'Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Trident/6.0)';
	// IE 11
	// ua = 'Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like Gecko';
	// Edge 12 (Spartan)
	// ua = 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.71 Safari/537.36 Edge/12.0';
	// Edge 13
	// ua = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2486.0 Safari/537.36 Edge/13.10586';
	var msie = ua.indexOf('MSIE ');
	if (msie > 0) {
		// IE 10 or older => return version number
		return parseInt(ua.substring(msie + 5, ua.indexOf('.', msie)), 10);
	}

	var trident = ua.indexOf('Trident/');
	if (trident > 0) {
		// IE 11 => return version number
		var rv = ua.indexOf('rv:');
		return parseInt(ua.substring(rv + 3, ua.indexOf('.', rv)), 10);
	}

	var edge = ua.indexOf('Edge/');
	if (edge > 0) {
		// Edge (IE 12+) => return version number
		return parseInt(ua.substring(edge + 5, ua.indexOf('.', edge)), 10);
	}

	// other browser
	return false;
}

function isRetina() {
	if (window.matchMedia) {
		let mq = window.matchMedia(
			'only screen and (min--moz-device-pixel-ratio: 1.3), only screen and (-o-min-device-pixel-ratio: 2.6/2), only screen and (-webkit-min-device-pixel-ratio: 1.3), only screen  and (min-device-pixel-ratio: 1.3), only screen and (min-resolution: 1.3dppx)',
		);
		return (mq && mq.matches) || window.devicePixelRatio > 1;
	}
}
