/**
 * @description Handles validation of template strings so users cannot submit/save bad templates
 * NOTE: Also replaces values with predefined default
 * @type {Class}
 */
var TemplateValidator = Class.create();
TemplateValidator.prototype = Object.extendsObject(global.AbstractAjaxProcessor, {
	/**
	 * @description The table for holding template validations
	 * @type {String}
	 */
	VALIDATIONS: 'x_scni_template_va_template_validations',
	/**
	 * @description The ServiceNow ArrayUtil
	 * @type {ArrayUtil}
	 */
	AU: new global.ArrayUtil(),
	/**
	 * @description An array of error messages
	 * @type {Array}
	 */
	ERRORS: [],
	CURRENT : {},
	/**
	 * @description Validates a template based on conditions set
	 * @param  {String} template The template string
	 * @param  {String} table    The table for the template
	 * @return {String}          A string of errors
	 */
	validate: function(template, table, current) {
		var validations = this.getValidations(table),
			templateArray = template.toString().split('^'),
			temp;
		this.CURRENT = current;
		while (validations.next()) {
			this.validateTemplates(validations, templateArray);
		}
		current = this.CURRENT;
		return this.ERRORS.toString();
	},	
	/**
	 * @description The AJAX Handler for the main method
	 * @return {String} A string of errors
	 */
	validateAJAX: function() {
		return this.validate(this.getParameter('sysparm_template_string'), 
			this.getParameter('sysparm_current_table'));
	},
	/**
	 * @description Gets validation records from the validation table
	 * @param  {String} table The name of a table
	 * @return {GlideRecord}       Records that match the table
	 */
	getValidations: function(table) {
		var validations = new GlideRecord(this.VALIDATIONS);
		validations.addQuery('table.name', table);
		validations.query();
		return validations;
	},
	/**
	 * @description Processes the validations for each value in the template array
	 * @param  {GlideRecord} validations   The validation record
	 * @param  {Array} templateArray The array of template fields and values
	 */
	validateTemplates: function(validations, templateArray) {
		for (var temp in templateArray) {
			if (templateArray.hasOwnProperty(temp)) {
				this.checkValues(validations, templateArray[temp]);
			}
		}
	},
	/**
	 * @description Determines if the value in the template needs to be pushed to ERRORS
	 * @param  {GlideRecord} validations The validation record
	 * @param  {String} temp        The template field and value
	 */
	checkValues: function(validations, temp) {
		var item = temp.toString().split('=');
		if (validations.field_name.element == item[0]) {
			if (!this.isValueValid(validations.unacceptable_values, item[1])) {
				this.CURRENT.template = this.CURRENT.template.toString().replace(item[0] + "=" + item[1],
																				 item[0] + "=" + validations.default);
				this.ERRORS.push(this.generateMessage(validations, item));
			}
		}
	},
	/**
	 * @description Generates an error message	 
	 * @param  {GlideRecord} validations The validation record
	 * @param  {Array} item        The template item (field/value)
	 * @return {String}             [description]
	 */
	generateMessage: function(validations, item) {
		return item[0] + " has an invalid value of " + item[1] + 
					".  It cannot be " + validations.unacceptable_values + ".";
	},
	/**
	 * @description Uses the ServiceNow ArrayUtil to check if a value is ok
	 * @param  {String} test  The value to test against
	 * @param  {String} value The value from the template
	 * @return {Boolean}       True if the value is ok
	 */
	isValueValid: function(test, value) {
		var testArray = test.toString().split(',');
		if (this.AU.contains(testArray, value)) {
			return false;
		}
		return true;
	},
	/**
	 * @description Returns a reference qualifier that gets fields based on the table
	 * Note: GlideTableHierarchy would be nice here, but it doesn't work right now.  Instead, we'll hope task is all we're doing.
	 * @param  {GlideRecord} current The current validation record
	 * @return {String}         A reference qualifier for the field name
	 */
	fieldRefQual: function(current) {
		return 'nameIN' + current.table.name + ",task";
	},
	'type' : 'TemplateValidator'
});