import Ember from 'ember';

import _ from 'lodash';

import store from 'corpus-common-addon/utils/store';

const DEFAULT_DEBOUNCE = 10;

export default Ember.Service.extend({

  promises: null,

  queryRegister: null,

  storeKeyBase: null,

  apiPath: null,

  resDocRoot: null,

  processId: function (id) {

    return id;

  },

  getReturnDictKey: function (id) {

    return id;

  },

  init(...args) {

    this._super(...args);

    this.set('promises', []);

    this.set('queryRegister', {});

    this.doQuery = _.debounce(this._doQuery, DEFAULT_DEBOUNCE);

  },

  env: function () {

    return Ember.getOwner(this).resolveRegistration('config:environment');

  },

  _getStoreKey: function (id) {

    return this.storeKeyBase + ':' + id;

  },

  _doQuery: function () {

    const queryRegister = this.get('queryRegister');

    this.set('queryRegister', {});

    const ids = Object.keys(queryRegister).join(',');

    if (!ids) {

      _.each(queryRegister, resolveReject=> {

        resolveReject[0]({});

      });

    }

    Ember.$.ajax({

      // TODO Configuration ?

      url: this.env().APP.backRootURL.replace(/\/$/, '') + this.apiPath + ids,

      success: itemDoc=> {

        _.each(queryRegister, resolveReject=> {

          resolveReject[0](itemDoc[this.resDocRoot]);

        });

      },

      error: (req, status, error)=> {

        _.each(queryRegister, resolveReject=> {

          resolveReject[1](status + ':' + error);

        });

      }

    });

  },

  // make the query for the name.

  // return a Promise

  queryName: function (id) {

    const queryRegister = this.get('queryRegister');

    return new Ember.RSVP.Promise(function (resolve, reject) {

      queryRegister[id] = [resolve, reject];

      this.doQuery(this);

    }.bind(this));

  },

  getName: function (id) {

    if (!id) {

      return new Ember.RSVP.Promise(function (resolve/* , reject*/) {

        resolve('');

      });

    }

    const objectId = this.processId(id);

    let namePromise = null;

    const storeKey = this._getStoreKey(id);

    const name = store.get(storeKey);

    if (name !== null) {

      namePromise = new Ember.RSVP.Promise(function (resolve/* , reject*/) {

        resolve(name);

      });

    } else if (storeKey in this.get('promises')) {

      namePromise = this.get('promises')[storeKey];

    } else {

      // handle error !!!

      namePromise = this.queryName(objectId)

        .then(function (names) {

          return store.set(storeKey, names[this.getReturnDictKey(objectId)]);

        }.bind(this));

      this.get('promises')[storeKey] = namePromise;

    }

    return namePromise;

  }

});