"use strict";
/*
*  Copyright (C) 1998-2017 by Northwoods Software Corporation. All Rights Reserved.
*/

import * as go from "../release/go";

// A custom Tool for zooming into a selected area

/**
* @constructor
* @extends Tool
* @class
* The DragZoomingTool lets the user zoom into a diagram by stretching a box
* to indicate the new contents of the diagram's viewport (the area of the
* model shown by the Diagram).
* Hold down the Shift key in order to zoom out.
* <p/>
* The default drag selection box is a magenta rectangle.
* You can modify the {@link #box} to customize its appearance.
* <p/>
* The diagram that is zoomed by this tool is specified by the {@link #zoomedDiagram} property.
* If the value is null, the tool zooms its own {@link Tool#diagram}.
* <p/>
* You can use this tool in a modal manner by executing:
* <pre><code>
*   diagram.currentTool = new DragZoomingTool();
* </code></pre>
* <p/>
* Use this tool in a mode-less manner by executing:
* <pre><code>
*   myDiagram.toolManager.mouseMoveTools.insertAt(2, new DragZoomingTool());
* </code></pre>
* However when used mode-lessly as a mouse-move tool, in {@link ToolManager#mouseMoveTools},
* this cannot start running unless there has been a motionless delay
* after the mouse-down event of at least {@link #delay} milliseconds.
* <p/>
* This tool does not utilize any {@link Adornment}s or tool handles,
* but it does temporarily add the {@link #box} part to the diagram.
* This tool does not modify the model or conduct any transaction.
*/


export class DragZoomingTool extends go.Tool {
	public readonly name: string = "DragZooming";

	/** @type {Part} */
	private _box: go.Part;

	constructor() {
		super();
		const b: go.Part = new go.Part;
		const r: go.Shape = new go.Shape;
		b.layerName = "Tool";
		b.selectable = false;
		r.name = "SHAPE";
		r.figure = "Rectangle";
		r.fill = null;
		r.stroke = "magenta";
		r.position = new go.Point(0, 0);
		b.add(r);

		this._box = b;
	}

	/** @type {number} */
	private _delay: number = 175;

	/** @type {Diagram} */
	private _zoomedDiagram: go.Diagram = null;

  /**
  * This tool can run when there has been a mouse-drag, far enough away not to be a click,
  * and there has been delay of at least {@link #delay} milliseconds
  * after the mouse-down before a mouse-move.
  * <p/>
  * This method may be overridden.
  * @this {DragZoomingTool}
  * @return {boolean}
  */
	public canStart() {
		if (!this.isEnabled) return false;
		var diagram = this.diagram;
		if (diagram === null) return false;
		var e = diagram.lastInput;
		// require left button & that it has moved far enough away from the mouse down point, so it isn't a click
		if (!e.left) return false;
		// don't include the following checks when this tool is running modally
		if (diagram.currentTool !== this) {
			if (!this.isBeyondDragSize()) return false;
			// must wait for "delay" milliseconds before that tool can run
			if (e.timestamp - diagram.firstInput.timestamp < this.delay) return false;
		}
		return true;
	};

  /**
  * Capture the mouse and show the {@link #box}.
  * @this {DragZoomingTool}
  */
	public doActivate() {
		var diagram = this.diagram;
		if (diagram === null) return;
		this.isActive = true;
		diagram.isMouseCaptured = true;
		diagram.skipsUndoManager = true;
		diagram.add(this.box);
		this.doMouseMove();
	};

  /**
  * Release the mouse and remove any {@link #box}.
  * @this {DragZoomingTool}
  */
	public doDeactivate() {
		var diagram = this.diagram;
		if (diagram === null) return;
		diagram.remove(this.box);
		diagram.skipsUndoManager = false;
		diagram.isMouseCaptured = false;
		this.isActive = false;
	};

  /**
  * Update the {@link #box}'s position and size according to the value
  * of {@link #computeBoxBounds}.
  * @this {DragZoomingTool}
  */
	public doMouseMove() {
		var diagram = this.diagram;
		if (diagram === null) return;
		if (this.isActive && this.box !== null) {
			var r = this.computeBoxBounds();
			var shape = this.box.findObject("SHAPE");
			if (shape === null) shape = this.box.findMainElement();
			shape.desiredSize = r.size;
			this.box.position = r.position;
		}
	};

  /**
  * Call {@link #zoomToRect} with the value of a call to {@link #computeBoxBounds}.
  * @this {DragZoomingTool}
  */
	public doMouseUp() {
		if (this.isActive) {
			var diagram = this.diagram;
			diagram.remove(this.box);
			try {
				diagram.currentCursor = "wait";
				this.zoomToRect(this.computeBoxBounds());
			} finally {
				diagram.currentCursor = "";
			}
		}
		this.stopTool();
	};

  /**
  * This just returns a {@link Rect} stretching from the mouse-down point to the current mouse point
  * while maintaining the aspect ratio of the {@link #zoomedDiagram}.
  * <p/>
  * This method may be overridden.
  * @this {DragZoomingTool}
  * @return {Rect} a {@link Rect} in document coordinates.
  */
	public computeBoxBounds() {
		var diagram = this.diagram;
		if (diagram === null) return new go.Rect(0, 0, 0, 0);
		var start = diagram.firstInput.documentPoint;
		var latest = diagram.lastInput.documentPoint;
		var adx = latest.x - start.x;
		var ady = latest.y - start.y;

		var observed = this.zoomedDiagram;
		if (observed === null) observed = this.diagram;
		if (observed === null) {
			return new go.Rect(start, latest);
		}
		var vrect = observed.viewportBounds;
		if (vrect.height === 0 || ady === 0) {
			return new go.Rect(start, latest);
		}

		var vratio = vrect.width / vrect.height;
		var lx;
		var ly;
		if (Math.abs(adx / ady) < vratio) {
			lx = start.x + adx;
			ly = start.y + Math.ceil(Math.abs(adx) / vratio) * (ady < 0 ? -1 : 1);
		} else {
			lx = start.x + Math.ceil(Math.abs(ady) * vratio) * (adx < 0 ? -1 : 1);
			ly = start.y + ady;
		}
		return new go.Rect(start, new go.Point(lx, ly));
	};

  /**
  * This method is called to change the {@link #zoomedDiagram}'s viewport to match the given rectangle.
  * <p/>
  * This method may be overridden.
  * @this {DragZoomingTool}
  * @param {Rect} r a rectangular bounds in document coordinates.
  */
	public zoomToRect(r: go.Rect) {
		if (r.width < 0.1) return;
		var observed = this.zoomedDiagram;
		if (observed === null) observed = this.diagram;
		if (observed === null) return;

		// zoom out when using the Shift modifier
		if (this.diagram.lastInput.shift) {
			observed.scale = Math.max(observed.scale * r.width / observed.viewportBounds.width, observed.minScale);
			observed.centerRect(r);
		} else {
			// do scale first, so the Diagram's position normalization isn't constrained unduly when increasing scale
			observed.scale = Math.min(observed.viewportBounds.width * observed.scale / r.width, observed.maxScale);
			observed.position = new go.Point(r.x, r.y);
		}
	};


	// Public properties

  /**
  * Gets or sets the {@link Part} used as the "rubber-band zoom box"
  * that is stretched to follow the mouse, as feedback for what area will
  * be passed to {@link #zoomToRect} upon a mouse-up.
  * <p/>
  * Initially this is a {@link Part} containing only a simple magenta rectangular {@link Shape}.
  * The object to be resized should be named "SHAPE".
  * Setting this property does not raise any events.
  * <p/>
  * Modifying this property while this tool {@link Tool#isActive} might have no effect.
  * @name DragZoomingTool#box
  * @function.
  * @return {Part}
  */
	get box(): go.Part { return this._box; }
	set box(val: go.Part) { this._box = val; }

  /**
  * Gets or sets the time in milliseconds for which the mouse must be stationary
  * before this tool can be started.
  * The default value is 175 milliseconds.
  * Setting this property does not raise any events.
  * @name DragZoomingTool#delay
  * @function.
  * @return {number}
  */
	get delay(): number { return this._delay; }
	set delay(val: number) { this._delay = val; }

  /**
  * Gets or sets the {@link Diagram} whose {@link Diagram#position} and {@link Diagram#scale}
  * should be set to display the drawn {@link #box} rectangular bounds.
  * <p/>
  * The default value is null, which causes {@link #zoomToRect} to modify this tool's {@link Tool#diagram}.
  * Setting this property does not raise any events.
  * @name DragZoomingTool#zoomedDiagram
  * @function.
  * @return {Diagram}
  */
	get zoomedDiagram(): go.Diagram { return this._zoomedDiagram; }
	set zoomedDiagram(val: go.Diagram) { this._zoomedDiagram = val; }
}