// 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';

  var EventType = {
    HISTORY: 'history',
    SHOW_CHANGE: 'showchange',
    SUBMIT_CHANGE: 'submitchange',
    COMMENT: 'comment',
  };

  var Element = {
    CHANGE_ACTIONS: 'changeactions',
  };

  Polymer({
    is: 'gr-js-api-interface',

    properties: {
      _elements: {
        type: Object,
        value: {},  // Shared across all instances.
      },
      _eventCallbacks: {
        type: Object,
        value: {},  // Shared across all instances.
      },
    },

    Element: Element,
    EventType: EventType,

    handleEvent: function(type, detail) {
      switch (type) {
        case EventType.HISTORY:
          this._handleHistory(detail);
          break;
        case EventType.SHOW_CHANGE:
          this._handleShowChange(detail);
          break;
        case EventType.COMMENT:
          this._handleComment(detail);
          break;
        default:
          console.warn('handleEvent called with unsupported event type:', type);
          break;
      }
    },

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

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

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

    canSubmitChange: function() {
      var submitCallbacks = this._getEventCallbacks(EventType.SUBMIT_CHANGE);
      var cancelSubmit = submitCallbacks.some(function(callback) {
        try {
          return callback() === false;
        } catch (err) {
          console.error(err);
        }
        return false;
      });

      return !cancelSubmit;
    },

    _removeEventCallbacks: function() {
      for (var k in EventType) {
        this._eventCallbacks[EventType[k]] = [];
      }
    },

    _handleHistory: function(detail) {
      this._getEventCallbacks(EventType.HISTORY).forEach(function(cb) {
        try {
          cb(detail.path);
        } catch (err) {
          console.error(err);
        }
      });
    },

    _handleShowChange: function(detail) {
      this._getEventCallbacks(EventType.SHOW_CHANGE).forEach(function(cb) {
        var change = detail.change;
        var patchNum = detail.patchNum;
        var revision;
        for (var rev in change.revisions) {
          if (change.revisions[rev]._number == patchNum) {
            revision = change.revisions[rev];
            break;
          }
        }
        try {
          cb(change, revision);
        } catch (err) {
          console.error(err);
        }
      });
    },

    _handleComment: function(detail) {
      this._getEventCallbacks(EventType.COMMENT).forEach(function(cb) {
        try {
          cb(detail.node);
        } catch (err) {
          console.error(err);
        }
      });
    },

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