/**
 * @license
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
(function() {
  'use strict';

  const MAX_AUTOCOMPLETE_RESULTS = 10;
  const SELF_EXPRESSION = 'self';
  const ME_EXPRESSION = 'me';

  /**
   * @appliesMixin Gerrit.DisplayNameMixin
   * @extends Polymer.Element
   */
  class GrSmartSearch extends Polymer.mixinBehaviors( [
    Gerrit.DisplayNameBehavior,
  ], Polymer.GestureEventListeners(
      Polymer.LegacyElementMixin(
          Polymer.Element))) {
    static get is() { return 'gr-smart-search'; }

    static get properties() {
      return {
        searchQuery: String,
        _config: Object,
        _projectSuggestions: {
          type: Function,
          value() {
            return this._fetchProjects.bind(this);
          },
        },
        _groupSuggestions: {
          type: Function,
          value() {
            return this._fetchGroups.bind(this);
          },
        },
        _accountSuggestions: {
          type: Function,
          value() {
            return this._fetchAccounts.bind(this);
          },
        },
      };
    }

    /** @override */
    attached() {
      super.attached();
      this.$.restAPI.getConfig().then(cfg => {
        this._config = cfg;
      });
    }

    _handleSearch(e) {
      const input = e.detail.inputVal;
      if (input) {
        Gerrit.Nav.navigateToSearchQuery(input);
      }
    }

    _accountOrAnon(name) {
      return this.getUserName(this._serverConfig, name, false);
    }

    /**
     * Fetch from the API the predicted projects.
     *
     * @param {string} predicate - The first part of the search term, e.g.
     *     'project'
     * @param {string} expression - The second part of the search term, e.g.
     *     'gerr'
     * @return {!Promise} This returns a promise that resolves to an array of
     *     strings.
     */
    _fetchProjects(predicate, expression) {
      return this.$.restAPI.getSuggestedProjects(
          expression,
          MAX_AUTOCOMPLETE_RESULTS)
          .then(projects => {
            if (!projects) { return []; }
            const keys = Object.keys(projects);
            return keys.map(key => { return {text: predicate + ':' + key}; });
          });
    }

    /**
     * Fetch from the API the predicted groups.
     *
     * @param {string} predicate - The first part of the search term, e.g.
     *     'ownerin'
     * @param {string} expression - The second part of the search term, e.g.
     *     'polyger'
     * @return {!Promise} This returns a promise that resolves to an array of
     *     strings.
     */
    _fetchGroups(predicate, expression) {
      if (expression.length === 0) { return Promise.resolve([]); }
      return this.$.restAPI.getSuggestedGroups(
          expression,
          MAX_AUTOCOMPLETE_RESULTS)
          .then(groups => {
            if (!groups) { return []; }
            const keys = Object.keys(groups);
            return keys.map(key => { return {text: predicate + ':' + key}; });
          });
    }

    /**
     * Fetch from the API the predicted accounts.
     *
     * @param {string} predicate - The first part of the search term, e.g.
     *     'owner'
     * @param {string} expression - The second part of the search term, e.g.
     *     'kasp'
     * @return {!Promise} This returns a promise that resolves to an array of
     *     strings.
     */
    _fetchAccounts(predicate, expression) {
      if (expression.length === 0) { return Promise.resolve([]); }
      return this.$.restAPI.getSuggestedAccounts(
          expression,
          MAX_AUTOCOMPLETE_RESULTS)
          .then(accounts => {
            if (!accounts) { return []; }
            return this._mapAccountsHelper(accounts, predicate);
          })
          .then(accounts => {
            // When the expression supplied is a beginning substring of 'self',
            // add it as an autocomplete option.
            if (SELF_EXPRESSION.startsWith(expression)) {
              return accounts.concat(
                  [{text: predicate + ':' + SELF_EXPRESSION}]);
            } else if (ME_EXPRESSION.startsWith(expression)) {
              return accounts.concat([{text: predicate + ':' + ME_EXPRESSION}]);
            } else {
              return accounts;
            }
          });
    }

    _mapAccountsHelper(accounts, predicate) {
      return accounts.map(account => {
        return {
          label: account.name || '',
          text: account.email ?
            `${predicate}:${account.email}` :
            `${predicate}:"${this._accountOrAnon(account)}"`,
        };
      });
    }
  }

  customElements.define(GrSmartSearch.is, GrSmartSearch);
})();