(function(){

"use strict";

exports.name = "age";

exports.params = [ { name: "birthDate" }, { name: "currentDate" } ];

exports.run = function(birthDate, currentDate) {
  var getNormalizedDate = function (date, referenceDate) {
    var numberOfDaysInMonth = (new Date(date.getFullYear(), date.getMonth()+1, 0)).getDate();
    if (numberOfDaysInMonth < referenceDate.getDate()) {
      return numberOfDaysInMonth;
    }
    else {
      return referenceDate.getDate();
    }
  }
  var getAgeString = function (birthDate, currentDate) {
    var tmpBirthDate = new Date(birthDate);
    var tmpCurrentDate = new Date(currentDate.getFullYear(), currentDate.getMonth(), currentDate.getDate());
    if (tmpCurrentDate < tmpBirthDate) return "not yet born";
    tmpCurrentDate.setHours(12);
    var ageDays = 0;
    while (tmpCurrentDate.getDate() != getNormalizedDate(tmpCurrentDate, tmpBirthDate)) {
      ageDays++;
      tmpCurrentDate.setDate(tmpCurrentDate.getDate() - 1);
    }
    tmpCurrentDate.setDate(1);
    tmpBirthDate.setDate(1);
    var ageMonths = 0;
    while (tmpCurrentDate.getMonth() != tmpBirthDate.getMonth()) {
      ageMonths++;
      tmpCurrentDate.setMonth(tmpCurrentDate.getMonth() - 1);
    }
    var ageYears=0;
    while (tmpCurrentDate.getFullYear() != tmpBirthDate.getFullYear()) {
      ageYears++;
      tmpCurrentDate.setFullYear(tmpCurrentDate.getFullYear() - 1);
    }
    return ageYears + ' year' + (ageYears == 1 ? '' : 's') + ', ' + ageMonths + ' month' + (ageMonths == 1 ? '' : 's') + ' and ' + ageDays + ' day' + (ageDays == 1 ? '' : 's');
  };

  if (typeof(currentDate) == "undefined" || currentDate == "" || isNaN(currentDate)) {
    currentDate = new Date();
  }
  else
  {
    currentDate = new Date(currentDate.substring(0,4), currentDate.substring(4,6) - 1, currentDate.substring(6, 8));
  }
  if (typeof(birthDate) == "undefined" || birthDate == "" || isNaN(birthDate)) {
    birthDate = new Date();
  }
  else
  { 
    birthDate = new Date(birthDate.substring(0,4), birthDate.substring(4,6) - 1, birthDate.substring(6, 8));
  }
  return getAgeString(birthDate, currentDate);
};
})();