/**
 * Copyright 2016, Yahoo! Inc.
 * Copyrights licensed under the New BSD License. See the accompanying LICENSE file for terms.
 */

import Ember from 'ember';
import Base from 'ember-cp-validations/validators/base';

const {
  canInvoke
} = Ember;

/**
 *  Identifies a `has-many` relationship in an Ember Data Model or Ember.Object.
 *  This is used to create a validation collection of the `has-many` validations.
 *
 *  _**Note:** Validations must exist on **all** models/objects_
 *
 *  ### Ember Models
 *
 *  ```javascript
 *  // model/users.js
 *
 *  const Validations = buildValidations({
 *    friends: validator('has-many')
 *  });
 *
 *  export default DS.Model.extend(Validations, {
 *    friends: DS.hasMany('user')
 *  });
 *  ```
 *
 *  ### Ember Objects
 *
 *  ```javascript
 *  // model/users.js
 *
 *  const Validations = buildValidations({
 *    friends: validator('has-many')
 *  });
 *
 *  export default Ember.Object.extend(Validations, {
 *    friends: null
 *  });
 *  ```
 *
 *  From our `user` model, we can now check validation properties on the `friends` attribute.
 *
 *  ```javascript
 *  get(model, 'validations.attrs.friends.isValid')
 *  get(model, 'validations.attrs.friends.messages')
 *  ```
 *
 *  @class Has Many
 *  @module Validators
 *  @extends Base
 */
const HasMany = Base.extend({
  validate(value) {
    if (value) {
      if (canInvoke(value, 'then')) {
        return value.then(models => models ? models.map(m => m.get('validations')) : true);
      }
      return value.map(m => m.get('validations'));
    }

    return true;
  }
});

HasMany.reopenClass({
  getDependentsFor(attribute) {
    return [ `_model.${attribute}.[]`, `${attribute}.@each.isTruelyValid` ];
  }
});

export default HasMany;