define([
    "jquery",
    "underscore",
    "lib/FileSaver"
], function($, _) {
	
	var utils = {};

	// Return a parameter from the URL
	utils.getURLParameter = function(name) {
		var regex = new RegExp(name + "=(.+?)(&|$)");
		try {
			return decodeURIComponent(regex.exec(location.search)[1]);
		} catch (e) {
			return undefined;
		}
	};
	
	// Transform a selector into a jQuery object
	function jqElt(element) {
		if(_.isString(element)) {
			return $(element);
		}
		return element;
	}
	
	// For input control
	function inputError(element, event) {
		if(event !== undefined) {
			element.stop(true, true).addClass("error").delay(1000).switchClass("error");
			event.stopPropagation();
		}
	}
	
	// Return input value
	utils.getInputValue = function(element) {
		element = jqElt(element);
		return element.val();
	};
	
	// Set input value
	utils.setInputValue = function(element, value) {
		element = jqElt(element);
		element.val(value);
	};
	
	// Return input text value 
	utils.getInputTextValue = function(element, event, validationRegex) {
		element = jqElt(element);
		var value = element.val();
		if (value === undefined) {
			inputError(element, event);
			return undefined;
		}
		// trim
		value = utils.trim(value);
		if((value.length === 0)
			|| (validationRegex !== undefined && !value.match(validationRegex))) {
			inputError(element, event);
			return undefined;
		}
		return value;
	};
	
	// Return input integer value 
	utils.getInputIntValue = function(element, event, min, max) {
		element = jqElt(element);
		var value = utils.getInputTextValue(element, event);
		if(value === undefined) {
			return undefined;
		}
		value = parseInt(value);
		if((value === NaN)
			|| (min !== undefined && value < min)
			|| (max !== undefined && value > max)) {
			inputError(element, event);
			return undefined;
		}
		return value;
	};
	
	// Return checkbox boolean value 
	utils.getInputChecked = function(element) {
		element = jqElt(element);
		return element.prop("checked");
	};
	
	// Set checkbox state
	utils.setInputChecked = function(element, checked) {
		element = jqElt(element);
		element.prop("checked", checked);
	};
	
	// Get radio button value
	utils.getInputRadio = function(name) {
		return $("input:radio[name=" + name + "]:checked").prop("value");
	};
	
	// Set radio button value
	utils.setInputRadio = function(name, value) {
		$("input:radio[name=" + name + "][value=" + value + "]").prop("checked", true);
	};
	
	// Reset input control in all modals
	utils.resetModalInputs = function() {
		$(".modal input[type=text]:not([disabled]), .modal input[type=password]").val("");
	};
	
	// Basic trim function
	utils.trim = function(str) {
		return $.trim(str);
	};
	
	// Slug function
	utils.slugify = function(text) {
		return text.toLowerCase()
		  	.replace(/\s+/g, '-') // Replace spaces with -
			.replace(/[^\w\-]+/g, '') // Remove all non-word chars
			.replace(/\-\-+/g, '-') // Replace multiple - with single -
			.replace(/^-+/, '') // Trim - from start of text
			.replace(/-+$/, ''); // Trim - from end of text
	};
	
	// Check an URL
	utils.checkUrl = function(url, addSlash) {
		if(!url) {
			return url;
		}
		if(url.indexOf("http") !== 0) {
			url = "http://" + url;
		}
		if(addSlash && url.indexOf("/", url.length - 1) === -1) {
			url += "/";
		}
		return url;
	};
	
	// Base64 conversion
	utils.encodeBase64 = function(str) {
	    if (str.length === 0) {
	        return "";
	    }
	    
		// UTF-8 to byte array
		var bytes = [], offset = 0, length, char;

		str = encodeURI(str);
		length = str.length;

		while (offset < length) {
			char = str[offset];
			offset += 1;

			if ('%' !== char) {
				bytes.push(char.charCodeAt(0));
			} else {
				char = str[offset] + str[offset + 1];
				bytes.push(parseInt(char, 16));
				offset += 2;
			}
		}

		// byte array to base64
	    var padchar = '=';
	    var alpha   = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';

	    var i, b10;
	    var x = [];

	    var imax = bytes.length - bytes.length % 3;

	    for (i = 0; i < imax; i += 3) {
	        b10 = (bytes[i] << 16) | (bytes[i+1] << 8) | bytes[i+2];
	        x.push(alpha.charAt(b10 >> 18));
	        x.push(alpha.charAt((b10 >> 12) & 0x3F));
	        x.push(alpha.charAt((b10 >> 6) & 0x3f));
	        x.push(alpha.charAt(b10 & 0x3f));
	    }
	    switch (bytes.length - imax) {
	    case 1:
	        b10 = bytes[i] << 16;
	        x.push(alpha.charAt(b10 >> 18) + alpha.charAt((b10 >> 12) & 0x3F) +
	               padchar + padchar);
	        break;
	    case 2:
	        b10 = (bytes[i] << 16) | (bytes[i+1] << 8);
	        x.push(alpha.charAt(b10 >> 18) + alpha.charAt((b10 >> 12) & 0x3F) +
	               alpha.charAt((b10 >> 6) & 0x3f) + padchar);
	        break;
	    }
	    return x.join('');
	};
	
	// CRC32 algorithm
	var mHash = [ 0, 1996959894, 3993919788, 2567524794, 124634137,
		1886057615, 3915621685, 2657392035, 249268274, 2044508324,
		3772115230, 2547177864, 162941995, 2125561021, 3887607047,
		2428444049, 498536548, 1789927666, 4089016648, 2227061214,
		450548861, 1843258603, 4107580753, 2211677639, 325883990,
		1684777152, 4251122042, 2321926636, 335633487, 1661365465,
		4195302755, 2366115317, 997073096, 1281953886, 3579855332,
		2724688242, 1006888145, 1258607687, 3524101629, 2768942443,
		901097722, 1119000684, 3686517206, 2898065728, 853044451,
		1172266101, 3705015759, 2882616665, 651767980, 1373503546,
		3369554304, 3218104598, 565507253, 1454621731, 3485111705,
		3099436303, 671266974, 1594198024, 3322730930, 2970347812,
		795835527, 1483230225, 3244367275, 3060149565, 1994146192,
		31158534, 2563907772, 4023717930, 1907459465, 112637215,
		2680153253, 3904427059, 2013776290, 251722036, 2517215374,
		3775830040, 2137656763, 141376813, 2439277719, 3865271297,
		1802195444, 476864866, 2238001368, 4066508878, 1812370925,
		453092731, 2181625025, 4111451223, 1706088902, 314042704,
		2344532202, 4240017532, 1658658271, 366619977, 2362670323,
		4224994405, 1303535960, 984961486, 2747007092, 3569037538,
		1256170817, 1037604311, 2765210733, 3554079995, 1131014506,
		879679996, 2909243462, 3663771856, 1141124467, 855842277,
		2852801631, 3708648649, 1342533948, 654459306, 3188396048,
		3373015174, 1466479909, 544179635, 3110523913, 3462522015,
		1591671054, 702138776, 2966460450, 3352799412, 1504918807,
		783551873, 3082640443, 3233442989, 3988292384, 2596254646,
		62317068, 1957810842, 3939845945, 2647816111, 81470997, 1943803523,
		3814918930, 2489596804, 225274430, 2053790376, 3826175755,
		2466906013, 167816743, 2097651377, 4027552580, 2265490386,
		503444072, 1762050814, 4150417245, 2154129355, 426522225,
		1852507879, 4275313526, 2312317920, 282753626, 1742555852,
		4189708143, 2394877945, 397917763, 1622183637, 3604390888,
		2714866558, 953729732, 1340076626, 3518719985, 2797360999,
		1068828381, 1219638859, 3624741850, 2936675148, 906185462,
		1090812512, 3747672003, 2825379669, 829329135, 1181335161,
		3412177804, 3160834842, 628085408, 1382605366, 3423369109,
		3138078467, 570562233, 1426400815, 3317316542, 2998733608,
		733239954, 1555261956, 3268935591, 3050360625, 752459403,
		1541320221, 2607071920, 3965973030, 1969922972, 40735498,
		2617837225, 3943577151, 1913087877, 83908371, 2512341634,
		3803740692, 2075208622, 213261112, 2463272603, 3855990285,
		2094854071, 198958881, 2262029012, 4057260610, 1759359992,
		534414190, 2176718541, 4139329115, 1873836001, 414664567,
		2282248934, 4279200368, 1711684554, 285281116, 2405801727,
		4167216745, 1634467795, 376229701, 2685067896, 3608007406,
		1308918612, 956543938, 2808555105, 3495958263, 1231636301,
		1047427035, 2932959818, 3654703836, 1088359270, 936918000,
		2847714899, 3736837829, 1202900863, 817233897, 3183342108,
		3401237130, 1404277552, 615818150, 3134207493, 3453421203,
		1423857449, 601450431, 3009837614, 3294710456, 1567103746,
		711928724, 3020668471, 3272380065, 1510334235, 755167117 ];
	utils.crc32 = function(str) {
		var n = 0, crc = -1;
		for ( var i = 0; i < str.length; i++) {
			n = (crc ^ str.charCodeAt(i)) & 0xFF;
			crc = (crc >>> 8) ^ mHash[n];
		}
		crc = crc ^ (-1);
		if (crc < 0) {
	    	crc = 0xFFFFFFFF + crc + 1;
	    }
	    return crc.toString(16);
	};
	
	// Create an centered popup window
	utils.popupWindow = function(url, title, width, height) {
		var left = (screen.width / 2) - (width / 2);
		var top = (screen.height / 2) - (height / 2);
		return window.open(
			url,
			title,
			'toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=no, resizable=no, copyhistory=no, width='
				+ width
				+ ', height='
				+ height
				+ ', top='
				+ top
				+ ', left='
				+ left);
	};
	
	// Export data on disk
	utils.saveAs = function(content, filename) {
		if(saveAs !== undefined) {
			var blob = new Blob([content], {type: "text/plain;charset=utf-8"});
			saveAs(blob, filename);
		}
		else {
			var uriContent = "data:application/octet-stream;base64,"
				+ utils.encodeBase64(content);
			window.open(uriContent, 'file');
		}
	};

	// Generates a random string
	utils.randomString = function() {
		return _.random(4294967296).toString(36);
	};
	
	// Time shared by others modules
	utils.updateCurrentTime = function() {
		utils.currentTime = new Date().getTime();
	};
	utils.updateCurrentTime();
	
	
	// Serialize sync/publish attributes
	utils.serializeAttributes = function(attributes) {
		// Don't store sync/publish index
		attributes = _.omit(attributes, "syncIndex", "publishIndex");
		// Store providerId instead of provider
		attributes.provider = attributes.provider.providerId;
		return JSON.stringify(attributes);
	};

	return utils;

});