/**
 * @license
 * Copyright (C) 2015 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.
 */
import '../../../styles/shared-styles.js';
import '../gr-change-list/gr-change-list.js';
import '../../shared/gr-button/gr-button.js';
import '../../shared/gr-dialog/gr-dialog.js';
import '../../shared/gr-overlay/gr-overlay.js';
import '../../shared/gr-rest-api-interface/gr-rest-api-interface.js';
import '../gr-create-commands-dialog/gr-create-commands-dialog.js';
import '../gr-create-change-help/gr-create-change-help.js';
import '../gr-create-destination-dialog/gr-create-destination-dialog.js';
import '../gr-user-header/gr-user-header.js';
import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners.js';
import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin.js';
import {PolymerElement} from '@polymer/polymer/polymer-element.js';
import {htmlTemplate} from './gr-dashboard-view_html.js';
import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
import {appContext} from '../../../services/app-context.js';
import {changeIsOpen} from '../../../utils/change-util.js';

const PROJECT_PLACEHOLDER_PATTERN = /\$\{project\}/g;

/**
 * @extends PolymerElement
 */
class GrDashboardView extends GestureEventListeners(
    LegacyElementMixin(PolymerElement)) {
  static get template() { return htmlTemplate; }

  static get is() { return 'gr-dashboard-view'; }
  /**
   * Fired when the title of the page should change.
   *
   * @event title-change
   */

  static get properties() {
    return {
      account: {
        type: Object,
        value: null,
      },
      preferences: Object,
      /** @type {{ selectedChangeIndex: number }} */
      viewState: Object,

      /** @type {{ project: string, user: string }} */
      params: {
        type: Object,
      },

      createChangeTap: {
        type: Function,
        value() {
          return e => this._createChangeTap(e);
        },
      },

      _results: Array,

      /**
       * For showing a "loading..." string during ajax requests.
       */
      _loading: {
        type: Boolean,
        value: true,
      },

      _showDraftsBanner: {
        type: Boolean,
        value: false,
      },

      _showNewUserHelp: {
        type: Boolean,
        value: false,
      },
    };
  }

  constructor() {
    super();
    this.reporting = appContext.reportingService;
  }

  static get observers() {
    return [
      '_paramsChanged(params.*)',
    ];
  }

  /** @override */
  attached() {
    super.attached();
    this._loadPreferences();
    this.addEventListener('reload', e => {
      e.stopPropagation();
      this._reload();
    });
  }

  _loadPreferences() {
    return this.$.restAPI.getLoggedIn().then(loggedIn => {
      if (loggedIn) {
        this.$.restAPI.getPreferences().then(preferences => {
          this.preferences = preferences;
        });
      } else {
        this.preferences = {};
      }
    });
  }

  _getProjectDashboard(project, dashboard) {
    const errFn = response => {
      this.dispatchEvent(new CustomEvent('page-error', {
        detail: {response},
        composed: true, bubbles: true,
      }));
    };
    return this.$.restAPI.getDashboard(
        project, dashboard, errFn).then(response => {
      if (!response) {
        return;
      }
      return {
        title: response.title,
        sections: response.sections.map(section => {
          const suffix = response.foreach ? ' ' + response.foreach : '';
          return {
            name: section.name,
            query: (section.query + suffix).replace(
                PROJECT_PLACEHOLDER_PATTERN, project),
          };
        }),
      };
    });
  }

  _computeTitle(user) {
    if (!user || user === 'self') {
      return 'My Reviews';
    }
    return 'Dashboard for ' + user;
  }

  _isViewActive(params) {
    return params.view === GerritNav.View.DASHBOARD;
  }

  _paramsChanged(paramsChangeRecord) {
    const params = paramsChangeRecord.base;

    if (!this._isViewActive(params)) {
      return Promise.resolve();
    }

    return this._reload();
  }

  /**
   * Reloads the element.
   *
   * @return {Promise<!Object>}
   */
  _reload() {
    this._loading = true;
    const {project, dashboard, title, user, sections} = this.params;
    const dashboardPromise = project ?
      this._getProjectDashboard(project, dashboard) :
      this.$.restAPI.getConfig().then(
          config => Promise.resolve(GerritNav.getUserDashboard(
              user,
              sections,
              title || this._computeTitle(user),
              config
          ))
      );

    const checkForNewUser = !project && user === 'self';
    return dashboardPromise
        .then(res => {
          if (res && res.title) {
            this.dispatchEvent(new CustomEvent('title-change', {
              detail: {title: res.title},
              composed: true, bubbles: true,
            }));
          }
          return this._fetchDashboardChanges(res, checkForNewUser);
        })
        .then(() => {
          this._maybeShowDraftsBanner();
          this.reporting.dashboardDisplayed();
        })
        .catch(err => {
          this.dispatchEvent(new CustomEvent('title-change', {
            detail: {
              title: title || this._computeTitle(user),
            },
            composed: true, bubbles: true,
          }));
          console.warn(err);
        })
        .then(() => { this._loading = false; });
  }

  /**
   * Fetches the changes for each dashboard section and sets this._results
   * with the response.
   *
   * @param {!Object} res
   * @param {boolean} checkForNewUser
   * @return {Promise}
   */
  _fetchDashboardChanges(res, checkForNewUser) {
    if (!res) { return Promise.resolve(); }

    let queries;

    if (window.PRELOADED_QUERIES
      && window.PRELOADED_QUERIES.dashboardQuery) {
      queries = window.PRELOADED_QUERIES.dashboardQuery;
      // we use preloaded query from index only on first page load
      window.PRELOADED_QUERIES.dashboardQuery = undefined;
    } else {
      queries = res.sections
          .map(section => (section.suffixForDashboard ?
            section.query + ' ' + section.suffixForDashboard :
            section.query));

      if (checkForNewUser) {
        queries.push('owner:self limit:1');
      }
    }

    return this.$.restAPI.getChanges(null, queries)
        .then(changes => {
          if (checkForNewUser) {
            // Last set of results is not meant for dashboard display.
            const lastResultSet = changes.pop();
            this._showNewUserHelp = lastResultSet.length == 0;
          }
          this._results = changes.map((results, i) => {
            return {
              name: res.sections[i].name,
              countLabel: this._computeSectionCountLabel(results),
              query: res.sections[i].query,
              results,
              isOutgoing: res.sections[i].isOutgoing,
            };
          }).filter((section, i) => i < res.sections.length && (
            !res.sections[i].hideIfEmpty ||
              section.results.length));
        });
  }

  _computeSectionCountLabel(changes) {
    if (!changes || !changes.length || changes.length == 0) {
      return '';
    }
    const more = changes[changes.length - 1]._more_changes;
    const numChanges = changes.length;
    const andMore = more ? ' and more' : '';
    return `(${numChanges}${andMore})`;
  }

  _computeUserHeaderClass(params) {
    if (!params || !!params.project || !params.user ||
        params.user === 'self') {
      return 'hide';
    }
    return '';
  }

  _handleToggleStar(e) {
    this.$.restAPI.saveChangeStarred(e.detail.change._number,
        e.detail.starred);
  }

  _handleToggleReviewed(e) {
    this.$.restAPI.saveChangeReviewed(e.detail.change._number,
        e.detail.reviewed);
  }

  /**
   * Banner is shown if a user is on their own dashboard and they have draft
   * comments on closed changes.
   */
  _maybeShowDraftsBanner() {
    this._showDraftsBanner = false;
    if (!(this.params.user === 'self')) { return; }

    const draftSection = this._results
        .find(section => section.query === 'has:draft');
    if (!draftSection || !draftSection.results.length) { return; }

    const closedChanges = draftSection.results
        .filter(change => !changeIsOpen(change));
    if (!closedChanges.length) { return; }

    this._showDraftsBanner = true;
  }

  _computeBannerClass(show) {
    return show ? '' : 'hide';
  }

  _handleOpenDeleteDialog() {
    this.$.confirmDeleteOverlay.open();
  }

  _handleConfirmDelete() {
    this.$.confirmDeleteDialog.disabled = true;
    return this.$.restAPI.deleteDraftComments('-is:open').then(() => {
      this._closeConfirmDeleteOverlay();
      this._reload();
    });
  }

  _closeConfirmDeleteOverlay() {
    this.$.confirmDeleteOverlay.close();
  }

  _computeDraftsLink() {
    return GerritNav.getUrlForSearchQuery('has:draft -is:open');
  }

  _createChangeTap(e) {
    this.$.destinationDialog.open();
  }

  _handleDestinationConfirm(e) {
    this.$.commandsDialog.branch = e.detail.branch;
    this.$.commandsDialog.open();
  }
}

customElements.define(GrDashboardView.is, GrDashboardView);