var Modeling = require('modeling');

var Thing = Modeling("Thing", {
  name: {
    label: 'Name',
    description: 'The name of the item',
    type: 'string',
    rules: [
      ['required']
    ]
  },
  description: {
    label: 'Description',
    description: 'A short description of the item.',
    type: 'string',
    rules: [
      {name: 'length', max: 255}
    ]
  },
  url: {
    label: 'URL',
    description: 'A URL identifiying the item.',
    type: 'string',
    rules: [
      ['url']
    ]
  }
});

var Person = Thing.extend("Person", {
  dateOfBirth: {
    label: 'Date of Birth',
    description: "The person's date of birth.",
    type: Date,
    rules: [
      ['date']
    ]
  },
  age: {
    label: 'Age',
    description: "The person's age.",
    type: Number,
    get: function () {
      var birthday = this.dateOfBirth;
      if (!birthday) {
        return false;
      }
      var ageDifMs = Date.now() - birthday.getTime();
      var ageDate = new Date(ageDifMs); // miliseconds from epoch
      return Math.abs(ageDate.getFullYear() - 1970);
    }
  }
});

var person = new Person({
  name: 'Bob',
  url: 'http://codemix.com/',
  dateOfBirth: '1980-01-01'
});

console.log(person.age);

console.log(JSON.stringify(person, null, 2));