/*
 *  Copyright 1998-2025 by Northwoods Software Corporation. All Rights Reserved.
 */

/*
 * This is an extension and not part of the main GoJS library.
 * The source code for this is at extensionsJSM/NonRealtimeDraggingTool.ts.
 * Note that the API for this class may change with any version, even point releases.
 * If you intend to use an extension in production, you should copy the code to your own source directory.
 * Extensions can be found in the GoJS kit under the extensions or extensionsJSM folders.
 * See the Extensions intro page (https://gojs.net/latest/intro/extensions.html) for more information.
 */

import * as go from 'gojs';

/**
 * The NonRealtimeDraggingTool class lets the user drag an image instead of actually moving any selected nodes,
 * until the mouse-up event.
 *
 * If you want to experiment with this extension, try the <a href="../../samples/NonRealtimeDragging.html">Non Realtime Dragging</a> sample.
 * @category Tool Extension
 */
export class NonRealtimeDraggingTool extends go.DraggingTool {
  private _duration: number; // duration of movement animation; <= 0 to disable
  private _imagePart: go.Part | null; // a Part holding a translucent image of what would be dragged
  private _ghostDraggedParts: go.Map<go.Part, go.DraggingInfo> | null; // a Map of the _imagePart and its dragging information
  private _originalDraggedParts: go.Map<go.Part, go.DraggingInfo> | null; // the saved normal value of DraggingTool.draggedParts

  constructor(init?: Partial<NonRealtimeDraggingTool>) {
    super();
    this._duration = 0;
    this._imagePart = null;
    this._ghostDraggedParts = null;
    this._originalDraggedParts = null;
    if (init) Object.assign(this, init);
  }

  /**
   * Gets or sets how long the movement animation should be to move the actual parts upon a mouse-up.
   * The default value is zero -- there is no animation of the movement.
   */
  get duration(): number {
    return this._duration;
  }
  set duration(val: number) {
    if (typeof val !== 'number' || isNaN(val) || val < 0) throw new Error('New value for NonRealtimeDraggingTool.duration must be a non-negative number.');
    this._duration = val;
  }

  /**
   * Call the base method, and then make an image of the returned collection,
   * show it using a Picture, and hold the Picture in a temporary Part, as _imagePart.
   * @param parts - A {@link go.Set} or {@link go.List} of {@link go.Part}s.
   */
  override computeEffectiveCollection(parts: go.Iterable<go.Part>): go.Map<go.Part, go.DraggingInfo> {
    const map = super.computeEffectiveCollection(parts, this.dragOptions);
    if (this.isActive && this._imagePart === null) {
      const bounds = this.diagram.computePartsBounds(map.toKeySet());
      const offset = this.diagram.lastInput.documentPoint.copy().subtract(bounds.position);
      this._imagePart = new go.Part(
        { layerName: 'Tool', opacity: 0.5, locationSpot: new go.Spot(0, 0, offset.x, offset.y) })
        .add(
          new go.Picture({ source: this.diagram.makeImageData({ parts: map.toKeySet() }) as string })
        );
    }
    return map;
  }

  /**
   * When activated, replace the {@link draggedParts} with the ghost dragged parts, which
   * consists of just one Part, the image, added to the Diagram at the current mouse point.
   */
  override doActivate(): void {
    super.doActivate();
    if (this._imagePart !== null) {
      this._imagePart.location = this.diagram.lastInput.documentPoint;
      this.diagram.add(this._imagePart);
      this._originalDraggedParts = this.draggedParts;
      this._ghostDraggedParts = super.computeEffectiveCollection(
        new go.List<go.Part>().add(this._imagePart),
        this.dragOptions
      );
      this.draggedParts = this._ghostDraggedParts;
    }
  }

  /**
   * When deactivated, make sure any image is removed from the Diagram and all references are cleared out.
   */
  override doDeactivate(): void {
    if (this._imagePart !== null) {
      this.diagram.remove(this._imagePart);
    }
    this._imagePart = null;
    this._ghostDraggedParts = null;
    this._originalDraggedParts = null;
    super.doDeactivate();
  }

  /**
   * Do the normal mouse-up behavior, but only after restoring {@link draggedParts}.
   */
  override doMouseUp(): void {
    const partsmap = this._originalDraggedParts;
    if (partsmap !== null) {
      this.draggedParts = partsmap;
    }
    super.doMouseUp();
    if (partsmap !== null && this.duration > 0) {
      const anim = new go.Animation();
      anim.duration = this.duration;
      partsmap.each((kvp) => {
        const part = kvp.key;
        anim.add(part, 'location', kvp.value.point, part.location);
      });
      anim.start();
    }
  }

  /**
   * If the user changes to "copying" mode by holding down the Control key,
   * return to the regular behavior and remove the image.
   */
  override doKeyDown(): void {
    if (
      this._imagePart !== null &&
      this._originalDraggedParts !== null &&
      (this.diagram.lastInput.control || this.diagram.lastInput.meta) &&
      this.mayCopy()
    ) {
      this.draggedParts = this._originalDraggedParts;
      this.diagram.remove(this._imagePart);
    }
    super.doKeyDown();
  }

  /**
   * If the user changes back to "moving" mode,
   * show the image again and go back to dragging the ghost dragged parts.
   */
  override doKeyUp(): void {
    if (this._imagePart !== null && this._ghostDraggedParts !== null && this.mayMove()) {
      this._imagePart.location = this.diagram.lastInput.documentPoint;
      this.diagram.add(this._imagePart);
      this.draggedParts = this._ghostDraggedParts;
    }
    super.doKeyUp();
  }
}