michael@0: #ifdef 0
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: #endif
michael@0: 
michael@0: // A little delay that prevents the grid from being too sensitive when dragging
michael@0: // sites around.
michael@0: const DELAY_REARRANGE_MS = 100;
michael@0: 
michael@0: /**
michael@0:  * This singleton implements site dropping functionality.
michael@0:  */
michael@0: let gDrop = {
michael@0:   /**
michael@0:    * The last drop target.
michael@0:    */
michael@0:   _lastDropTarget: null,
michael@0: 
michael@0:   /**
michael@0:    * Handles the 'dragenter' event.
michael@0:    * @param aCell The drop target cell.
michael@0:    */
michael@0:   enter: function Drop_enter(aCell) {
michael@0:     this._delayedRearrange(aCell);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Handles the 'dragexit' event.
michael@0:    * @param aCell The drop target cell.
michael@0:    * @param aEvent The 'dragexit' event.
michael@0:    */
michael@0:   exit: function Drop_exit(aCell, aEvent) {
michael@0:     if (aEvent.dataTransfer && !aEvent.dataTransfer.mozUserCancelled) {
michael@0:       this._delayedRearrange();
michael@0:     } else {
michael@0:       // The drag operation has been cancelled.
michael@0:       this._cancelDelayedArrange();
michael@0:       this._rearrange();
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Handles the 'drop' event.
michael@0:    * @param aCell The drop target cell.
michael@0:    * @param aEvent The 'dragexit' event.
michael@0:    */
michael@0:   drop: function Drop_drop(aCell, aEvent) {
michael@0:     // The cell that is the drop target could contain a pinned site. We need
michael@0:     // to find out where that site has gone and re-pin it there.
michael@0:     if (aCell.containsPinnedSite())
michael@0:       this._repinSitesAfterDrop(aCell);
michael@0: 
michael@0:     // Pin the dragged or insert the new site.
michael@0:     this._pinDraggedSite(aCell, aEvent);
michael@0: 
michael@0:     this._cancelDelayedArrange();
michael@0: 
michael@0:     // Update the grid and move all sites to their new places.
michael@0:     gUpdater.updateGrid();
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Re-pins all pinned sites in their (new) positions.
michael@0:    * @param aCell The drop target cell.
michael@0:    */
michael@0:   _repinSitesAfterDrop: function Drop_repinSitesAfterDrop(aCell) {
michael@0:     let sites = gDropPreview.rearrange(aCell);
michael@0: 
michael@0:     // Filter out pinned sites.
michael@0:     let pinnedSites = sites.filter(function (aSite) {
michael@0:       return aSite && aSite.isPinned();
michael@0:     });
michael@0: 
michael@0:     // Re-pin all shifted pinned cells.
michael@0:     pinnedSites.forEach(function (aSite) aSite.pin(sites.indexOf(aSite)), this);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Pins the dragged site in its new place.
michael@0:    * @param aCell The drop target cell.
michael@0:    * @param aEvent The 'dragexit' event.
michael@0:    */
michael@0:   _pinDraggedSite: function Drop_pinDraggedSite(aCell, aEvent) {
michael@0:     let index = aCell.index;
michael@0:     let draggedSite = gDrag.draggedSite;
michael@0: 
michael@0:     if (draggedSite) {
michael@0:       // Pin the dragged site at its new place.
michael@0:       if (aCell != draggedSite.cell)
michael@0:         draggedSite.pin(index);
michael@0:     } else {
michael@0:       let link = gDragDataHelper.getLinkFromDragEvent(aEvent);
michael@0:       if (link) {
michael@0:         // A new link was dragged onto the grid. Create it by pinning its URL.
michael@0:         gPinnedLinks.pin(link, index);
michael@0: 
michael@0:         // Make sure the newly added link is not blocked.
michael@0:         gBlockedLinks.unblock(link);
michael@0:       }
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Time a rearrange with a little delay.
michael@0:    * @param aCell The drop target cell.
michael@0:    */
michael@0:   _delayedRearrange: function Drop_delayedRearrange(aCell) {
michael@0:     // The last drop target didn't change so there's no need to re-arrange.
michael@0:     if (this._lastDropTarget == aCell)
michael@0:       return;
michael@0: 
michael@0:     let self = this;
michael@0: 
michael@0:     function callback() {
michael@0:       self._rearrangeTimeout = null;
michael@0:       self._rearrange(aCell);
michael@0:     }
michael@0: 
michael@0:     this._cancelDelayedArrange();
michael@0:     this._rearrangeTimeout = setTimeout(callback, DELAY_REARRANGE_MS);
michael@0: 
michael@0:     // Store the last drop target.
michael@0:     this._lastDropTarget = aCell;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Cancels a timed rearrange, if any.
michael@0:    */
michael@0:   _cancelDelayedArrange: function Drop_cancelDelayedArrange() {
michael@0:     if (this._rearrangeTimeout) {
michael@0:       clearTimeout(this._rearrangeTimeout);
michael@0:       this._rearrangeTimeout = null;
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Rearrange all sites in the grid depending on the current drop target.
michael@0:    * @param aCell The drop target cell.
michael@0:    */
michael@0:   _rearrange: function Drop_rearrange(aCell) {
michael@0:     let sites = gGrid.sites;
michael@0: 
michael@0:     // We need to rearrange the grid only if there's a current drop target.
michael@0:     if (aCell)
michael@0:       sites = gDropPreview.rearrange(aCell);
michael@0: 
michael@0:     gTransformation.rearrangeSites(sites, {unfreeze: !aCell});
michael@0:   }
michael@0: };