FilterHandler = { }

var currQueryString = Common.getQueryString();
var LEFT_PAREN = "(", RIGHT_PAREN = ")", COMMA = ",";

/**************
 * The removeRangeFilter function removes the Nf and eT (Tab selection) parameter from the current querystring
 */
FilterHandler.removeRangeFilter = function() {
	var newString = FilterHandler.removeQueryParameter(currQueryString, "Nf");
	newString = FilterHandler.removeQueryParameter(newString, "eT");
	return newString;
}

/***********
 * The removeQueryParameter function removes a specific parameter from a querystring 
 * and returns the resulting new querystring
 */
FilterHandler.removeQueryParameter = function(querystring, param) {
	var qString = (querystring == "" ? currQueryString : querystring);
	var tmpString;

	var start = qString.indexOf(param + '=');
	if (start > -1) {
		var end = qString.indexOf('&', start);
		if (end > -1) {
			tmpString = qString.substring(0, start-1) + qString.substring(end);
		} else {
			tmpString = qString.substring(0, start-1);
		}
		return tmpString;
	} else {
		return qString;
	}
}

FilterHandler.addQueryParameter = function (querystring, param, value) {
	var qString = (querystring == "" ? currQueryString : querystring);
	var tmpString;

	var start = qString.indexOf(param + '=');
	if (start > -1) {
		var end = qString.indexOf('&', start);
		if (end > -1) {
			tmpString = qString.substring(0, start-1) + qString.substring(end);
		} else {
			tmpString = qString.substring(0, start-1);
		}
		return (tmpString == "" ? "?" : "&") + tmpString + param + "=" + value;
	} else {
		return (qString == "" ? "?" : "&") + qString + param + "=" + value;
	}
}

/**************
 * The setRangeFilter function adds or appends the Nf parameter to the current querystring
 * It takes the field name, range operator, and one or two numbers space separated
 */
FilterHandler.setRangeFilter = function(field, operator, number) {
	
	var newQuerystring;	
	if (currQueryString.indexOf('Nf=') > -1) {
		newQueryString = FilterHandler.appendRangeFilter(field, operator, number);
	} else {
		newQueryString = FilterHandler.addRangeFilter(field, operator, number);
	}
	return newQueryString;
}

/**************
 * The updateRangeFilter function adds/replaces the Nf parameter in the current querystring
 * It takes the field name, range operator, and one or two numbers space separated
 */
FilterHandler.updateRangeFilter = function(field, operator, number) {
	
	var newQueryString = FilterHandler.removeRangeFilter();
	var separator = (newQueryString == '' ? '?' : '&');
	newQueryString = newQueryString + separator + "Nf=" + field + "|" + operator + " " + number;
	
	return newQueryString;
}

/*************
 * The addRangeFilter function adds a new Nf parameter to the current querystring
 */
FilterHandler.addRangeFilter = function(field, operator, number) {

	var separator = (currQueryString == '' ? '?' : '&');
	var newQueryString = currQueryString + separator + "Nf=" + field + "|" + operator + " " + number;
	
	return newQueryString;
	
}
/************
 * The addRangeFilter function appends to the existing Nf parameter in the current querystring
 */
FilterHandler.appendRangeFilter = function(field, operator, number) {

	var currFilter, newFilter;
	var start = currQueryString.indexOf('Nf=') + 3;
	var end = currQueryString.indexOf('&', start);
	
	if (end == -1) {
		end = currQueryString.length;
	}
	currFilter = currQueryString.substring(start, end);
	newFilter = currFilter + "|" + field + "|" + operator + " " + number; 
	
	var newQueryString = currQueryString.substring(1, start) + newFilter + currQueryString.substring(end);
	
	return newQueryString;
}

/*******
 * The updateItemFilter function adds a single filter parameter to the querystring using the specified field, operator
 */
FilterHandler.updateRecordFilter = function(field, operand, value, querystring) {

	var newFilter = FilterHandler.addRecordFilter(field, operand, value, querystring);
	var newString = FilterHandler.removeQueryParameter(querystring, "Nr");
	var separator = (newString == '' ? '?' : '&');
	
	return newString + separator + "Nr=" + newFilter;
		
}

/*******
 * The addItemFilter function adds a single filter parameter to the querystring using the specified field, operator
 * If no querystring parameter is passed in, it will use the current page querystring
 */
FilterHandler.addRecordFilter = function(field, operand, value, querystring) {
	var newFilter = "";
	var filter = field + ":" + value;
	var recordFilter = Common.getKeyValue((querystring == "" ? currQueryString : querystring), "Nr");
	// If a filter already exists, add the new value to existing string.  Otherwise, set the value.
	if (!FilterHandler.isFilterApplied(filter)) {
		if (recordFilter != null ? recordFilter !="" : false) {
			newFilter = recordFilter.substring(0,recordFilter.lastIndexOf(RIGHT_PAREN)) + COMMA + filter + RIGHT_PAREN; 
		} else {
			newFilter = operand + LEFT_PAREN + filter + RIGHT_PAREN;				
		}
	} else {
		newFilter = recordFilter;
	}
	return newFilter;
}


/*****
 * The removeItemFilter function removes the specified filterkey (value) and ensures syntax is valid
 */
FilterHandler.removeRecordFilter = function(value) {
	var recordFilter = Common.getKeyValue(currQueryString, "Nr");	
	
	if (recordFilter != "") {
		var newFilter = recordFilter.replace(value, "");
		newFilter = newFilter.replace("AND()", "");
		newFilter = newFilter.replace(",)", ")");
		newFilter = newFilter.replace("(,", "(");	
		
		return newFilter;
	} else {
		return "";
	}
}

/*******
 * The isFilterApplied function returns a boolean indicating if the specified filter is already applied
 */
FilterHandler.isFilterApplied = function(filter) {
	
	var recordFilter = Common.getKeyValue(currQueryString, "Nr");		
	return (recordFilter.indexOf(filter) > -1 ? true : false);			
}