/**
 * @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 EventType = {
    HISTORY: 'history',
    LABEL_CHANGE: 'labelchange',
    SHOW_CHANGE: 'showchange',
    SUBMIT_CHANGE: 'submitchange',
    COMMIT_MSG_EDIT: 'commitmsgedit',
    COMMENT: 'comment',
    REVERT: 'revert',
    REVERT_SUBMISSION: 'revert_submission',
    POST_REVERT: 'postrevert',
    ANNOTATE_DIFF: 'annotatediff',
    ADMIN_MENU_LINKS: 'admin-menu-links',
    HIGHLIGHTJS_LOADED: 'highlightjs-loaded',
  };

  const Element = {
    CHANGE_ACTIONS: 'changeactions',
    REPLY_DIALOG: 'replydialog',
  };

  /**
   * @appliesMixin Gerrit.PatchSetMixin
   * @extends Polymer.Element
   */
  class GrJsApiInterface extends Polymer.mixinBehaviors( [
    Gerrit.PatchSetBehavior,
  ], Polymer.GestureEventListeners(
      Polymer.LegacyElementMixin(
          Polymer.Element))) {
    static get is() { return 'gr-js-api-interface'; }

    constructor() {
      super();
      this.Element = Element;
      this.EventType = EventType;
    }

    static get properties() {
      return {
        _elements: {
          type: Object,
          value: {}, // Shared across all instances.
        },
        _eventCallbacks: {
          type: Object,
          value: {}, // Shared across all instances.
        },
      };
    }

    handleEvent(type, detail) {
      Gerrit.awaitPluginsLoaded().then(() => {
        switch (type) {
          case EventType.HISTORY:
            this._handleHistory(detail);
            break;
          case EventType.SHOW_CHANGE:
            this._handleShowChange(detail);
            break;
          case EventType.COMMENT:
            this._handleComment(detail);
            break;
          case EventType.LABEL_CHANGE:
            this._handleLabelChange(detail);
            break;
          case EventType.HIGHLIGHTJS_LOADED:
            this._handleHighlightjsLoaded(detail);
            break;
          default:
            console.warn('handleEvent called with unsupported event type:',
                type);
            break;
        }
      });
    }

    addElement(key, el) {
      this._elements[key] = el;
    }

    getElement(key) {
      return this._elements[key];
    }

    addEventCallback(eventName, callback) {
      if (!this._eventCallbacks[eventName]) {
        this._eventCallbacks[eventName] = [];
      }
      this._eventCallbacks[eventName].push(callback);
    }

    canSubmitChange(change, revision) {
      const submitCallbacks = this._getEventCallbacks(EventType.SUBMIT_CHANGE);
      const cancelSubmit = submitCallbacks.some(callback => {
        try {
          return callback(change, revision) === false;
        } catch (err) {
          console.error(err);
        }
        return false;
      });

      return !cancelSubmit;
    }

    _removeEventCallbacks() {
      for (const k in EventType) {
        if (!EventType.hasOwnProperty(k)) { continue; }
        this._eventCallbacks[EventType[k]] = [];
      }
    }

    _handleHistory(detail) {
      for (const cb of this._getEventCallbacks(EventType.HISTORY)) {
        try {
          cb(detail.path);
        } catch (err) {
          console.error(err);
        }
      }
    }

    _handleShowChange(detail) {
      // Note (issue 8221) Shallow clone the change object and add a mergeable
      // getter with deprecation warning. This makes the change detail appear as
      // though SKIP_MERGEABLE was not set, so that plugins that expect it can
      // still access.
      //
      // This clone and getter can be removed after plugins migrate to use
      // info.mergeable.
      const change = Object.assign({
        get mergeable() {
          console.warn('Accessing change.mergeable from SHOW_CHANGE is ' +
              'deprecated! Use info.mergeable instead.');
          return detail.info.mergeable;
        },
      }, detail.change);
      const patchNum = detail.patchNum;
      const info = detail.info;

      let revision;
      for (const rev of Object.values(change.revisions || {})) {
        if (this.patchNumEquals(rev._number, patchNum)) {
          revision = rev;
          break;
        }
      }

      for (const cb of this._getEventCallbacks(EventType.SHOW_CHANGE)) {
        try {
          cb(change, revision, info);
        } catch (err) {
          console.error(err);
        }
      }
    }

    handleCommitMessage(change, msg) {
      for (const cb of this._getEventCallbacks(EventType.COMMIT_MSG_EDIT)) {
        try {
          cb(change, msg);
        } catch (err) {
          console.error(err);
        }
      }
    }

    _handleComment(detail) {
      for (const cb of this._getEventCallbacks(EventType.COMMENT)) {
        try {
          cb(detail.node);
        } catch (err) {
          console.error(err);
        }
      }
    }

    _handleLabelChange(detail) {
      for (const cb of this._getEventCallbacks(EventType.LABEL_CHANGE)) {
        try {
          cb(detail.change);
        } catch (err) {
          console.error(err);
        }
      }
    }

    _handleHighlightjsLoaded(detail) {
      for (const cb of this._getEventCallbacks(EventType.HIGHLIGHTJS_LOADED)) {
        try {
          cb(detail.hljs);
        } catch (err) {
          console.error(err);
        }
      }
    }

    modifyRevertMsg(change, revertMsg, origMsg) {
      for (const cb of this._getEventCallbacks(EventType.REVERT)) {
        try {
          revertMsg = cb(change, revertMsg, origMsg);
        } catch (err) {
          console.error(err);
        }
      }
      return revertMsg;
    }

    modifyRevertSubmissionMsg(change, revertSubmissionMsg, origMsg) {
      for (const cb of this._getEventCallbacks(EventType.REVERT_SUBMISSION)) {
        try {
          revertSubmissionMsg = cb(change, revertSubmissionMsg, origMsg);
        } catch (err) {
          console.error(err);
        }
      }
      return revertSubmissionMsg;
    }

    getDiffLayers(path, changeNum, patchNum) {
      const layers = [];
      for (const annotationApi of
        this._getEventCallbacks(EventType.ANNOTATE_DIFF)) {
        try {
          const layer = annotationApi.getLayer(path, changeNum, patchNum);
          layers.push(layer);
        } catch (err) {
          console.error(err);
        }
      }
      return layers;
    }

    /**
     * Retrieves coverage data possibly provided by a plugin.
     *
     * Will wait for plugins to be loaded. If multiple plugins offer a coverage
     * provider, the first one is returned. If no plugin offers a coverage provider,
     * will resolve to null.
     *
     * @return {!Promise<?GrAnnotationActionsInterface>}
     */
    getCoverageAnnotationApi() {
      return Gerrit.awaitPluginsLoaded()
          .then(() => this._getEventCallbacks(EventType.ANNOTATE_DIFF)
              .find(api => api.getCoverageProvider()));
    }

    getAdminMenuLinks() {
      const links = [];
      for (const adminApi of
        this._getEventCallbacks(EventType.ADMIN_MENU_LINKS)) {
        links.push(...adminApi.getMenuLinks());
      }
      return links;
    }

    getLabelValuesPostRevert(change) {
      let labels = {};
      for (const cb of this._getEventCallbacks(EventType.POST_REVERT)) {
        try {
          labels = cb(change);
        } catch (err) {
          console.error(err);
        }
      }
      return labels;
    }

    _getEventCallbacks(type) {
      return this._eventCallbacks[type] || [];
    }
  }

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