var netgis = netgis || {};

/**
 * General purpose pure static utility functions.
 */
netgis.util =
(
	function ()
	{
		"use strict";
		
		// Methods
		var isDefined = function( v )
		{
			return ( typeof v !== "undefined" );
		};
		
		var isString = function( v )
		{
			return ( typeof v === "string" || v instanceof String );
		};
		
		/**
		 * Replace all string occurences.
		 * @param {String} str
		 * @param {String} find
		 * @param {String} newstr
		 * @returns {String}
		 */
		var replace = function( str, find, newstr )
		{
			return str.replace( new RegExp( find, "g" ), newstr );
		};
		
		var foreach = function( obj, fn )
		{
			for ( var k in obj )
			{
				if ( obj.hasOwnProperty( k ) )
				{
					fn( k, obj[ k ] );
				}
			}
		};
		
		/**
		 * Replace template strings in html string.
		 * @param {type} html String with "{key}" placeholders.
		 * @param {type} data Object of key value pairs to insert.
		 * @returns {String} The modified html string.
		 */
		var template = function( html, data )
		{
			// Get Template: $( "#template-" + name ).text();
			
			foreach
			(
				data,
				function( key, value )
				{
					html = html.replace( new RegExp( "{" + key + "}", "g" ), value );
				}
			);
	
			return html;
		};
		
		/**
		 * Create HTML element from string.
		 * @param {String} html
		 * @returns {Element}
		 */
		var create = function( html )
		{
			var temp = document.createElement( "tbody" );
			temp.innerHTML = html;
			
			return temp.children[ 0 ];
		};
		
		/**
		 * Replace new line characters with HTML line breaks.
		 * @param {String} str
		 * @returns {String}
		 */
		var newlines = function( str )
		{
			return str.replace( new RegExp( "\n", "g" ), "<br />" );
		};
		
		/**
		 * Calculate the byte size of an object.
		 * @param {Object} json
		 * @returns {Object} Object with size info ( bytes, kilobytes, megabytes )
		 */
		var size = function( json )
		{
			var bytes = new TextEncoder().encode( JSON.stringify( json ) ).length;
			var kilobytes = bytes / 1024;
			var megabytes = kilobytes / 1024;
			
			return { bytes: bytes, kilobytes: kilobytes, megabytes: megabytes };
		};
		
		/**
		 * Send async GET request.
		 * @param {String} url
		 * @param {function} callback
		 */
		var request = function( url, callback )
		{
			var request = new XMLHttpRequest();
			request.onload = function() { callback( this.responseText ); };
			request.open( "GET", url, true );
			request.send();
		};
		
		/**
		 * Pad string with leading zeros.
		 * @param {String} s The string to pad.
		 * @param {Integer} n Minimum number of digits.
		 * @returns {String} The padded string.
		 */
		var padstr = function( s, n )
		{
			var o = s.toString();
			while ( o.length < n ) o = "0" + o;
			
			return o;
		};
		
		/**
		 * Merge object properties.
		 * @param {Object} target Merged object properties will be written to this.
		 * @param {Object} other The object to append to the target object.
		 * @returns {Object} The modified target object.
		 */
		var merge = function( target, other )
		{
			return Object.assign( target, other );
		};
		
		/**
		 * @returns {String} Formatted Date Time String (German Locale)
		 */
		var getTimeStamp = function()
		{
			var date = new Date();
			
			var timestamp = date.getDate() + "." + ( date.getMonth() + 1 ) + "." + date.getFullYear();
			timestamp += " " + date.getHours() + ":" + date.getMinutes();
			
			return timestamp;
		};
		
		/**
		 * @returns {String} The users language locale string (defaults to German)
		 */
		var getUserLanguage = function()
		{
			var lang = navigator.language || "de-DE";
			
			return lang;
		};
		
		/*
		 * @param {Number} area Raw Area in Square Meters
		 * @param {Boolean} decimals Output Rounded Decimals
		 * @param {Number} threshold Threshold for normal (square meters) vs. large (square kilometers) values
		 * @param {Boolean} seperate Use thousands seperators
		 * @returns {String} Formatted Area String (Square Meters/Square Kilometers)
		 */
		var formatArea = function( area, decimals, threshold, seperate )
		{
			var output;
			
			// Normal / Large Value
			threshold = threshold || 100000;
			var large = ( area > threshold );
			
			// Round Value
			var i = 0;
			
			if ( large )
			{
				var METERS_PER_KILOMETER = 1000000;
				
				if ( decimals )
					i = Math.round( area / METERS_PER_KILOMETER * 1000 ) / 1000;
				else
					i = Math.round( area / METERS_PER_KILOMETER );
			}
			else
			{
				if ( decimals )
					i = Math.round( area * 100 ) / 100;
				else
					i = Math.round( area );
			}
			
			if ( i === 0 ) large = false;
			
			// Thousands Seperators
			seperate = seperate || true;
			if ( seperate ) i = i.toLocaleString( getUserLanguage() );
			
			// Build String
			output = i + ( large ? " km²" : " m²" );
			
			// NOTE: HTML Superscript / Unicode (&sup2; etc.) not supported in OL Labels
			
			return output;
		};

		// Public Interface
		var iface =
		{
			isDefined: isDefined,
			isString: isString,
			replace: replace,
			foreach: foreach,
			template: template,
			newlines: newlines,
			create: create,
			size: size,
			request: request,
			padstr: padstr,
			merge: merge,
			getTimeStamp: getTimeStamp,
			getUserLanguage: getUserLanguage,
			formatArea: formatArea
		};

		return iface;
	}
)();