/**
 * @module backbone-survey
 */
var BackboneSurvey = BackboneSurvey || {};

(function() {
  /**
   * @class ValidationResult
   * @uses Extendable
   * @constructor
   * @param {String} msg A result message
   */
  var ValidationResult = BackboneSurvey.ValidationResult = function(msg) {
    this.message = msg || "";
  };
  ValidationResult.prototype = {
   /**
    * Check a result is valid.
    * @property valid
    * @type {Boolean}
    */
    valid: true
  };
  _.extend(ValidationResult, BackboneSurvey.Extendable);

  /**
   * A valid result.
   *
   * @class ValidationResult.OK
   * @extends {ValidationResult}
   */
  ValidationResult.OK = ValidationResult.extend({ valid: true });

  /**
   * An invalid result.
   *
   * @class ValidationResult.Error
   * @extends {ValidationResult}
   */
  ValidationResult.Error = ValidationResult.extend({ valid: false });

  /**
   * @class Validator
   * @uses Extendable
   * @constructor
   * @param {Object} attr Merge into
 {{#crossLink "Validator/attributes:property"}}{{/crossLink}}
   */
  var Validator = BackboneSurvey.Validator = function(attr) {
   /**
    * @property attributes
    * @type {Object}
    */
    this.attributes = attr || {};
  };
  Validator.prototype = {
    /**
     * Run validation.
     *
     * @method validate
     * @param {Array} value An array of variables.
     * @param {Object} data
     * @return {ValidationResult}
     */
    validate: function(value, data) {
      return new ValidationResult.OK();
    }

    /**
     * Returns a validation message.
     *
     * @method message
     * @param {Object} [attr] Any template variables.
     * @return {String}
     */
  , message: function(attr) {
      attr = attr || {};
      return (_.isString(this.attributes.template)) ?
        _.template(this.attributes.template)(_.extend(this.attributes, attr)) :
        (this.attributes.message || "");
    }
  };
  _.extend(Validator, BackboneSurvey.Extendable);

  /**
   *
<pre><code>var validator = new RequiredValidator({
    message: "Name is Required."
});
</code></pre>
   *
   * @class RequiredValidator
   * @extends {Validator}
   */
  BackboneSurvey.RequiredValidator = Validator.extend({
    validate: function(value, data) {
      var vs = _.isArray(value) ? value : [value];
      var result;
      if (vs.length === 0) {
        result = new ValidationResult.Error(this.message());
      } else {
        var me = this;
        _.each(vs, function(v) {
          if (result) return;
          if (_.isNumber(v)) v = v.toString();
          if (_.isEmpty(v)) {
            result = new ValidationResult.Error(me.message());
          }
        });
        if (!result) {
            result = new ValidationResult.OK();
        }
      }
      return result;
    }
  });

  /**
   *
<pre><code>var validator = new PatternValidator({
    message: "Name must be [a-z] characters"
  , pattern: "^[a-z]+$" // new RegExp(...)
});</code></pre>
   *
   * @class PatternValidator
   * @extends {Validator}
   */
  BackboneSurvey.PatternValidator = Validator.extend({
    validate: function(value, data) {
      var vs = _.isArray(value) ? value : [value];
      var result;
      var regex = new RegExp(this.attributes.pattern);
      var me = this;
      _.each(vs, function(v) {
        if (result) return;
        if (!_.isString(v)) v = (typeof(v) !== "undefined" && v !== null) ? v.toString() : "";
        if (!v.match(regex)) {
          result = new ValidationResult.Error(me.message());
        }
      });
      if (!result) {
          result = new ValidationResult.OK();
      }
      return result;
    }
  });

  /**
   *
<pre><code>var validator = new RangeLengthValidator({
    message: "Name must be between 8 and 32."
  , min: 8
  , max: 32
});</code></pre>
   *
   * @class RangeLengthValidator
   * @extends {Validator}
   */
  BackboneSurvey.RangeLengthValidator = Validator.extend({
    validate: function(value, data) {
      var vs = _.isArray(value) ? value : [value];
      var result;
      var me = this;
      _.each(vs, function(v) {
        if (result) return;
        if (!_.isString(v)) v = (typeof(v) !== "undefined" && v !== null) ? v.toString() : "";
        var min = _.isNumber(me.attributes.min) ? me.attributes.min : null;
        var max = _.isNumber(me.attributes.max) ? me.attributes.max : null;
        if ((min && min > v.length) || (max && max < v.length)) {
          result = new ValidationResult.Error(me.message());
        }
      });
      if (!result) {
          result = new ValidationResult.OK();
      }
      return result;
    }
  });
})();