/*****************************************************************************
 * Open MCT Web, Copyright (c) 2014-2015, United States Government
 * as represented by the Administrator of the National Aeronautics and Space
 * Administration. All rights reserved.
 *
 * Open MCT Web is 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.
 *
 * Open MCT Web includes source code licensed under additional open source
 * licenses. See the Open Source Licenses file (LICENSES.md) included with
 * this source code distribution or the Licensing information page available
 * at runtime from the About dialog for additional information.
 *****************************************************************************/
/*global define,Promise*/

/**
 * Module defining DropGesture. Created by vwoeltje on 11/17/14.
 */
define(
    ['./GestureConstants',
     '../../../commonUI/edit/src/objects/EditableDomainObject',
     'uuid'],
    function (GestureConstants, EditableDomainObject, uuid) {
        "use strict";

        /**
         * A DropGesture adds and maintains event handlers upon an element
         * such that it may act as a drop target for drag-drop composition.
         *
         * @memberof platform/representation
         * @constructor
         * @param $q Angular's $q, for promise handling
         * @param element the jqLite-wrapped representation element
         * @param {DomainObject} domainObject the domain object whose
         *        composition should be modified as a result of the drop.
         */
        function DropGesture(dndService, $q, navigationService, objectService, instantiate, typeService, element, domainObject) {
            var actionCapability = domainObject.getCapability('action'),
                editableDomainObject,
                action; // Action for the drop, when it occurs
            
            function broadcastDrop(id, event) {
                // Find the relevant scope...
                var scope = element && element.scope && element.scope(),
                    rect;
                if (scope && scope.$broadcast) {
                    // Get the representation's bounds, to convert
                    // drop position
                    rect = element[0].getBoundingClientRect();

                    // ...and broadcast the event. This allows specific
                    // views to have post-drop behavior which depends on
                    // drop position.
                    scope.$broadcast(
                        GestureConstants.MCT_DROP_EVENT,
                        id,
                        {
                            x: event.pageX - rect.left,
                            y: event.pageY - rect.top
                        }
                    );
                }
            }
            
            function shouldCreateVirtualPanel(domainObject){
                return domainObject.useCapability('view').filter(function (view){
                    return view.key==='plot' && domainObject.getModel().type!== 'telemetry.panel'
                }).length > 0;
            }

            function dragOver(e) {
                //Refresh domain object on each dragOver to catch external
                // updates to the model
                //Don't use EditableDomainObject for folders, allow immediate persistence
                editableDomainObject = domainObject.hasCapability('editor') || domainObject.getModel().type==='folder' ? domainObject : new EditableDomainObject(domainObject, $q);
                actionCapability = editableDomainObject.getCapability('action');

                var event = (e || {}).originalEvent || e,
                    selectedObject = dndService.getData(
                        GestureConstants.MCT_EXTENDED_DRAG_TYPE
                    );

                if (selectedObject) {
                    // TODO: Vary this based on modifier keys
                    action = actionCapability.getActions({
                        key: 'compose',
                        selectedObject: selectedObject
                    })[0];
                    //TODO: Fix this. Define an action for creating new
                    // virtual panel
                    if (action || shouldCreateVirtualPanel(domainObject)) {
                        event.dataTransfer.dropEffect = 'move';

                        // Indicate that we will accept the drag
                        event.preventDefault(); // Required in Chrome?
                        return false;
                    }
                }
            }

            function createVirtualPanel(base, overlayId){

                var typeKey = 'telemetry.panel',
                    type = typeService.getType(typeKey),
                    model = type.getInitialModel(),
                    id = uuid(),
                    newPanel = undefined;

                model.type = typeKey;
                newPanel = new EditableDomainObject(instantiate(model, id), $q);

                [base.getId(), overlayId].forEach(function(id){
                    newPanel.getCapability('composition').add(id)
                });

                newPanel.getCapability('location').setPrimaryLocation(base.getCapability('location').getContextualLocation());

                //var virtualPanel = new EditableDomainObject(newPanel, $q);
                //virtualPanel.setOriginalObject(base);
                newPanel.setOriginalObject(base);
                //return virtualPanel;
                return newPanel;

            }

            function drop(e) {
                var event = (e || {}).originalEvent || e,
                    id = event.dataTransfer.getData(GestureConstants.MCT_DRAG_TYPE),
                    domainObjectType = editableDomainObject.getModel().type,
                    virtualObj;

                // If currently in edit mode allow drag and drop gestures to the
                // domain object. An exception to this is folders which have drop
                // gestures in browse mode.
                //if (domainObjectType === 'folder' || domainObject.hasCapability('editor')) {
                
                    // Handle the drop; add the dropped identifier to the
                    // destination domain object's composition, and persist
                    // the change.
                    if (id) {
                        if (shouldCreateVirtualPanel(domainObject)){
                            navigationService.setNavigation(createVirtualPanel(domainObject, id));
                            broadcastDrop(id, event);
                        } else {
                            $q.when(action && action.perform()).then(function (result) {
                                //Don't go into edit mode for folders
                                if (domainObjectType!=='folder') {
                                    navigationService.setNavigation(editableDomainObject);
                                }
                                broadcastDrop(id, event);
                            });
                        }
                    }
                //}
                // TODO: Alert user if drag and drop is not allowed
            }

            // We can only handle drops if we have access to actions...
            if (actionCapability) {
                // Listen for dragover,  to indicate we'll accept a drag
                element.on('dragover', dragOver);

                // Listen for the drop itself
                element.on('drop', drop);
            }

            this.element = element;
            this.dragOverCallback = dragOver;
            this.dropCallback = drop;
        }

        DropGesture.prototype.destroy = function () {
            this.element.off('dragover', this.dragOverCallback);
            this.element.off('drop', this.dropCallback);
        };


        return DropGesture;
    }
);