1 files changed, 131 insertions, 0 deletions
diff --git a/src/client/util/DragManager.ts b/src/client/util/DragManager.ts
new file mode 100644
index 000000000..f4dcce7c8
--- /dev/null
+++ b/src/client/util/DragManager.ts
@@ -0,0 +1,131 @@
+
+export namespace DragManager {
+    export function Root() {
+        const root = document.getElementById("root");
+        if (!root) {
+            throw new Error("No root element found");
+        }
+        return root;
+    }
+
+    let dragDiv: HTMLDivElement;
+
+    export enum DragButtons {
+        Left = 1, Right = 2, Both = Left | Right
+    }
+
+    interface DragOptions {
+        handlers: DragHandlers;
+
+        hideSource: boolean | (() => boolean);
+    }
+
+    export interface DragDropDisposer {
+        (): void;
+    }
+
+    export class DragCompleteEvent {
+    }
+
+    export interface DragHandlers {
+        dragComplete: (e: DragCompleteEvent) => void;
+    }
+
+    export interface DropOptions {
+        handlers: DropHandlers;
+    }
+
+    export class DropEvent {
+        constructor(readonly x: number, readonly y: number, readonly data: { [id: string]: any }) { }
+    }
+
+    export interface DropHandlers {
+        drop: (e: Event, de: DropEvent) => void;
+    }
+
+    export function MakeDropTarget(element: HTMLElement, options: DropOptions): DragDropDisposer {
+        if ("canDrop" in element.dataset) {
+            throw new Error("Element is already droppable, can't make it droppable again");
+        }
+        element.dataset["canDrop"] = "true";
+        const handler = (e: Event) => {
+            const ce = e as CustomEvent<DropEvent>;
+            options.handlers.drop(e, ce.detail);
+        };
+        element.addEventListener("dashOnDrop", handler);
+        return () => {
+            element.removeEventListener("dashOnDrop", handler);
+            delete element.dataset["canDrop"]
+        };
+    }
+
+
+    let _lastPointerX: number = 0;
+    let _lastPointerY: number = 0;
+    export function StartDrag(ele: HTMLElement, dragData: { [id: string]: any }, options: DragOptions) {
+        if (!dragDiv) {
+            dragDiv = document.createElement("div");
+            DragManager.Root().appendChild(dragDiv);
+        }
+        const w = ele.offsetWidth, h = ele.offsetHeight;
+        const rect = ele.getBoundingClientRect();
+        const scaleX = rect.width / w, scaleY = rect.height / h;
+        let x = rect.left, y = rect.top;
+        // const offsetX = e.x - rect.left, offsetY = e.y - rect.top;
+        let dragElement = ele.cloneNode(true) as HTMLElement;
+        dragElement.style.opacity = "0.7";
+        dragElement.style.position = "absolute";
+        dragElement.style.transformOrigin = "0 0";
+        dragElement.style.zIndex = "1000";
+        dragElement.style.transform = `translate(${x}px, ${y}px) scale(${scaleX}, ${scaleY})`;
+        dragDiv.appendChild(dragElement);
+        _lastPointerX = dragData["xOffset"] + rect.left;
+        _lastPointerY = dragData["yOffset"] + rect.top;
+
+        let hideSource = false;
+        if (typeof options.hideSource === "boolean") {
+            hideSource = options.hideSource;
+        } else {
+            hideSource = options.hideSource();
+        }
+        const wasHidden = ele.hidden;
+        if (hideSource) {
+            ele.hidden = true;
+        }
+
+        const moveHandler = (e: PointerEvent) => {
+            e.stopPropagation();
+            e.preventDefault();
+            x += e.clientX - _lastPointerX; _lastPointerX = e.clientX;
+            y += e.clientY - _lastPointerY; _lastPointerY = e.clientY;
+            dragElement.style.transform = `translate(${x}px, ${y}px) scale(${scaleX}, ${scaleY})`;
+        };
+        const upHandler = (e: PointerEvent) => {
+            document.removeEventListener("pointermove", moveHandler, true);
+            document.removeEventListener("pointerup", upHandler);
+            FinishDrag(dragElement, e, options, dragData);
+            if (hideSource && !wasHidden) {
+                ele.hidden = false;
+            }
+        };
+        document.addEventListener("pointermove", moveHandler, true);
+        document.addEventListener("pointerup", upHandler);
+    }
+
+    function FinishDrag(dragEle: HTMLElement, e: PointerEvent, options: DragOptions, dragData: { [index: string]: any }) {
+        dragDiv.removeChild(dragEle);
+        const target = document.elementFromPoint(e.x, e.y);
+        if (!target) {
+            return;
+        }
+        target.dispatchEvent(new CustomEvent<DropEvent>("dashOnDrop", {
+            bubbles: true,
+            detail: {
+                x: e.x,
+                y: e.y,
+                data: dragData
+            }
+        }));
+        options.handlers.dragComplete({});
+    }
+}
+\ No newline at end of file