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: /**
michael@0:  * This singleton implements site dragging functionality.
michael@0:  */
michael@0: let gDrag = {
michael@0:   /**
michael@0:    * The site offset to the drag start point.
michael@0:    */
michael@0:   _offsetX: null,
michael@0:   _offsetY: null,
michael@0: 
michael@0:   /**
michael@0:    * The site that is dragged.
michael@0:    */
michael@0:   _draggedSite: null,
michael@0:   get draggedSite() this._draggedSite,
michael@0: 
michael@0:   /**
michael@0:    * The cell width/height at the point the drag started.
michael@0:    */
michael@0:   _cellWidth: null,
michael@0:   _cellHeight: null,
michael@0:   get cellWidth() this._cellWidth,
michael@0:   get cellHeight() this._cellHeight,
michael@0: 
michael@0:   /**
michael@0:    * Start a new drag operation.
michael@0:    * @param aSite The site that's being dragged.
michael@0:    * @param aEvent The 'dragstart' event.
michael@0:    */
michael@0:   start: function Drag_start(aSite, aEvent) {
michael@0:     this._draggedSite = aSite;
michael@0: 
michael@0:     // Mark nodes as being dragged.
michael@0:     let selector = ".newtab-site, .newtab-control, .newtab-thumbnail";
michael@0:     let parentCell = aSite.node.parentNode;
michael@0:     let nodes = parentCell.querySelectorAll(selector);
michael@0:     for (let i = 0; i < nodes.length; i++)
michael@0:       nodes[i].setAttribute("dragged", "true");
michael@0: 
michael@0:     parentCell.setAttribute("dragged", "true");
michael@0: 
michael@0:     this._setDragData(aSite, aEvent);
michael@0: 
michael@0:     // Store the cursor offset.
michael@0:     let node = aSite.node;
michael@0:     let rect = node.getBoundingClientRect();
michael@0:     this._offsetX = aEvent.clientX - rect.left;
michael@0:     this._offsetY = aEvent.clientY - rect.top;
michael@0: 
michael@0:     // Store the cell dimensions.
michael@0:     let cellNode = aSite.cell.node;
michael@0:     this._cellWidth = cellNode.offsetWidth;
michael@0:     this._cellHeight = cellNode.offsetHeight;
michael@0: 
michael@0:     gTransformation.freezeSitePosition(aSite);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Handles the 'drag' event.
michael@0:    * @param aSite The site that's being dragged.
michael@0:    * @param aEvent The 'drag' event.
michael@0:    */
michael@0:   drag: function Drag_drag(aSite, aEvent) {
michael@0:     // Get the viewport size.
michael@0:     let {clientWidth, clientHeight} = document.documentElement;
michael@0: 
michael@0:     // We'll want a padding of 5px.
michael@0:     let border = 5;
michael@0: 
michael@0:     // Enforce minimum constraints to keep the drag image inside the window.
michael@0:     let left = Math.max(scrollX + aEvent.clientX - this._offsetX, border);
michael@0:     let top = Math.max(scrollY + aEvent.clientY - this._offsetY, border);
michael@0: 
michael@0:     // Enforce maximum constraints to keep the drag image inside the window.
michael@0:     left = Math.min(left, scrollX + clientWidth - this.cellWidth - border);
michael@0:     top = Math.min(top, scrollY + clientHeight - this.cellHeight - border);
michael@0: 
michael@0:     // Update the drag image's position.
michael@0:     gTransformation.setSitePosition(aSite, {left: left, top: top});
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Ends the current drag operation.
michael@0:    * @param aSite The site that's being dragged.
michael@0:    * @param aEvent The 'dragend' event.
michael@0:    */
michael@0:   end: function Drag_end(aSite, aEvent) {
michael@0:     let nodes = gGrid.node.querySelectorAll("[dragged]")
michael@0:     for (let i = 0; i < nodes.length; i++)
michael@0:       nodes[i].removeAttribute("dragged");
michael@0: 
michael@0:     // Slide the dragged site back into its cell (may be the old or the new cell).
michael@0:     gTransformation.slideSiteTo(aSite, aSite.cell, {unfreeze: true});
michael@0: 
michael@0:     this._draggedSite = null;
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Checks whether we're responsible for a given drag event.
michael@0:    * @param aEvent The drag event to check.
michael@0:    * @return Whether we should handle this drag and drop operation.
michael@0:    */
michael@0:   isValid: function Drag_isValid(aEvent) {
michael@0:     let link = gDragDataHelper.getLinkFromDragEvent(aEvent);
michael@0: 
michael@0:     // Check that the drag data is non-empty.
michael@0:     // Can happen when dragging places folders.
michael@0:     if (!link || !link.url) {
michael@0:       return false;
michael@0:     }
michael@0: 
michael@0:     // Check that we're not accepting URLs which would inherit the caller's
michael@0:     // principal (such as javascript: or data:).
michael@0:     return gLinkChecker.checkLoadURI(link.url);
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Initializes the drag data for the current drag operation.
michael@0:    * @param aSite The site that's being dragged.
michael@0:    * @param aEvent The 'dragstart' event.
michael@0:    */
michael@0:   _setDragData: function Drag_setDragData(aSite, aEvent) {
michael@0:     let {url, title} = aSite;
michael@0: 
michael@0:     let dt = aEvent.dataTransfer;
michael@0:     dt.mozCursor = "default";
michael@0:     dt.effectAllowed = "move";
michael@0:     dt.setData("text/plain", url);
michael@0:     dt.setData("text/uri-list", url);
michael@0:     dt.setData("text/x-moz-url", url + "\n" + title);
michael@0:     dt.setData("text/html", "<a href=\"" + url + "\">" + url + "</a>");
michael@0: 
michael@0:     // Create and use an empty drag element. We don't want to use the default
michael@0:     // drag image with its default opacity.
michael@0:     let dragElement = document.createElementNS(HTML_NAMESPACE, "div");
michael@0:     dragElement.classList.add("newtab-drag");
michael@0:     let scrollbox = document.getElementById("newtab-scrollbox");
michael@0:     scrollbox.appendChild(dragElement);
michael@0:     dt.setDragImage(dragElement, 0, 0);
michael@0: 
michael@0:     // After the 'dragstart' event has been processed we can remove the
michael@0:     // temporary drag element from the DOM.
michael@0:     setTimeout(function () scrollbox.removeChild(dragElement), 0);
michael@0:   }
michael@0: };