"use strict";
/*
*  Copyright (C) 1998-2018 by Northwoods Software Corporation. All Rights Reserved.
*/

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

/**
* @constructor
* @extends CommandHandler
* @class 
* This CommandHandler class allows the user to position selected Parts in a diagram
* relative to the first part selected, in addition to overriding the doKeyDown method
* of the CommandHandler for handling the arrow keys in additional manners.
* <p>
* Typical usage:
* <pre>
*   $(go.Diagram, "myDiagramDiv",
*     {
*       commandHandler: $(DrawCommandHandler),
*       . . .
*     }
*   )
* </pre>
* or:
* <pre>
*    myDiagram.commandHandler = new DrawCommandHandler();
* </pre>*/
export class DrawCommandHandler extends go.CommandHandler {
	private _arrowKeyBehavior: string = "move";
	private _pasteOffset: go.Point = new go.Point(10, 10);
	private _lastPasteOffset: go.Point = new go.Point(0, 0);

  /**
  * This controls whether or not the user can invoke the {@link #alignLeft}, {@link #alignRight}, 
  * {@link #alignTop}, {@link #alignBottom}, {@link #alignCenterX}, {@link #alignCenterY} commands.
  * @this {DrawCommandHandler}
  * @return {boolean}
  * This returns true:
  * if the diagram is not {@link Diagram#isReadOnly},
  * if the model is not {@link Model#isReadOnly}, and
  * if there are at least two selected {@link Part}s.
  */
	public canAlignSelection(): boolean {
		var diagram = this.diagram;
		if (diagram === null || diagram.isReadOnly || diagram.isModelReadOnly) return false;
		if (diagram.selection.count < 2) return false;
		return true;
	};

  /**
  * Aligns selected parts along the left-most edge of the left-most part.
  * @this {DrawCommandHandler}
  */
	public alignLeft() {
		var diagram = this.diagram;
		diagram.startTransaction("aligning left");
		var minPosition = Infinity;
		diagram.selection.each( (current) => {
			if (current instanceof go.Link) return; // skips over go.Link
			minPosition = Math.min(current.position.x, minPosition);
		});
		diagram.selection.each((current) => {
			if (current instanceof go.Link) return; // skips over go.Link
			current.move(new go.Point(minPosition, current.position.y));
		});
		diagram.commitTransaction("aligning left");
	};

  /**
  * Aligns selected parts at the right-most edge of the right-most part.
  * @this {DrawCommandHandler}
  */
	public alignRight() {
		var diagram = this.diagram;
		diagram.startTransaction("aligning right");
		var maxPosition = -Infinity;
		diagram.selection.each((current) => {
			if (current instanceof go.Link) return; // skips over go.Link
			var rightSideLoc = current.actualBounds.x + current.actualBounds.width;
			maxPosition = Math.max(rightSideLoc, maxPosition);
		});
		diagram.selection.each((current) => {
			if (current instanceof go.Link) return; // skips over go.Link
			current.move(new go.Point(maxPosition - current.actualBounds.width, current.position.y));
		});
		diagram.commitTransaction("aligning right");
	};

  /**
  * Aligns selected parts at the top-most edge of the top-most part.
  * @this {DrawCommandHandler}
  */
	public alignTop() {
		var diagram = this.diagram;
		diagram.startTransaction("alignTop");
		var minPosition = Infinity;
		diagram.selection.each((current) => {
			if (current instanceof go.Link) return; // skips over go.Link
			minPosition = Math.min(current.position.y, minPosition);
		});
		diagram.selection.each((current) => {
			if (current instanceof go.Link) return; // skips over go.Link
			current.move(new go.Point(current.position.x, minPosition));
		});
		diagram.commitTransaction("alignTop");
	};

  /**
  * Aligns selected parts at the bottom-most edge of the bottom-most part.
  * @this {DrawCommandHandler}
  */
	public alignBottom() {
		var diagram = this.diagram;
		diagram.startTransaction("aligning bottom");
		var maxPosition = -Infinity;
		diagram.selection.each((current) => {
			if (current instanceof go.Link) return; // skips over go.Link
			var bottomSideLoc = current.actualBounds.y + current.actualBounds.height;
			maxPosition = Math.max(bottomSideLoc, maxPosition);
		});
		diagram.selection.each((current) => {
			if (current instanceof go.Link) return; // skips over go.Link
			current.move(new go.Point(current.actualBounds.x, maxPosition - current.actualBounds.height));
		});
		diagram.commitTransaction("aligning bottom");
	};

  /**
  * Aligns selected parts at the x-value of the center point of the first selected part. 
  * @this {DrawCommandHandler}
  */
	public alignCenterX() {
		var diagram = this.diagram;
		var firstSelection = diagram.selection.first();
		if (!firstSelection) return;
		diagram.startTransaction("aligning Center X");
		var centerX = firstSelection.actualBounds.x + firstSelection.actualBounds.width / 2;
		diagram.selection.each((current) => {
			if (current instanceof go.Link) return; // skips over go.Link
			current.move(new go.Point(centerX - current.actualBounds.width / 2, current.actualBounds.y));
		});
		diagram.commitTransaction("aligning Center X");
	};


  /**
  * Aligns selected parts at the y-value of the center point of the first selected part. 
  * @this {DrawCommandHandler}
  */
	public alignCenterY() {
		var diagram = this.diagram;
		var firstSelection = diagram.selection.first();
		if (!firstSelection) return;
		diagram.startTransaction("aligning Center Y");
		var centerY = firstSelection.actualBounds.y + firstSelection.actualBounds.height / 2;
		diagram.selection.each((current) => {
			if (current instanceof go.Link) return; // skips over go.Link
			current.move(new go.Point(current.actualBounds.x, centerY - current.actualBounds.height / 2));
		});
		diagram.commitTransaction("aligning Center Y");
	};


  /**
  * Aligns selected parts top-to-bottom in order of the order selected.
  * Distance between parts can be specified. Default distance is 0.
  * @this {DrawCommandHandler}
  * @param {number} distance 
  */
	public alignColumn(distance: number) {
		var diagram = this.diagram;
		diagram.startTransaction("align Column");
		if (distance === undefined) distance = 0; // for aligning edge to edge
		distance = parseFloat(distance.toString());
		var selectedParts = new Array();
		diagram.selection.each((current) => {
			if (current instanceof go.Link) return; // skips over go.Link
			selectedParts.push(current);
		});
		for (var i = 0; i < selectedParts.length - 1; i++) {
			var current = selectedParts[i];
			// adds distance specified between parts
			var curBottomSideLoc = current.actualBounds.y + current.actualBounds.height + distance;
			var next = selectedParts[i + 1];
			next.move(new go.Point(current.actualBounds.x, curBottomSideLoc));
		}
		diagram.commitTransaction("align Column");
	};

  /**
  * Aligns selected parts left-to-right in order of the order selected.
  * Distance between parts can be specified. Default distance is 0.
  * @this {DrawCommandHandler}
  * @param {number} distance 
  */
	public alignRow(distance: number) {
		if (distance === undefined) distance = 0; // for aligning edge to edge
		distance = parseFloat(distance.toString());
		var diagram = this.diagram;
		diagram.startTransaction("align Row");
		var selectedParts = new Array();
		diagram.selection.each((current) => {
			if (current instanceof go.Link) return; // skips over go.Link
			selectedParts.push(current);
		});
		for (var i = 0; i < selectedParts.length - 1; i++) {
			var current = selectedParts[i];
			// adds distance specified between parts
			var curRightSideLoc = current.actualBounds.x + current.actualBounds.width + distance;
			var next = selectedParts[i + 1];
			next.move(new go.Point(curRightSideLoc, current.actualBounds.y));
		}
		diagram.commitTransaction("align Row");
	};


  /**
  * This controls whether or not the user can invoke the {@link #rotate} command.
  * @this {DrawCommandHandler}
  * @param {number=} angle the positive (clockwise) or negative (counter-clockwise) change in the rotation angle of each Part, in degrees.
  * @return {boolean}
  * This returns true:
  * if the diagram is not {@link Diagram#isReadOnly},
  * if the model is not {@link Model#isReadOnly}, and
  * if there is at least one selected {@link Part}.
  */
	public canRotate(number: number): boolean {
		var diagram = this.diagram;
		if (diagram === null || diagram.isReadOnly || diagram.isModelReadOnly) return false;
		if (diagram.selection.count < 1) return false;
		return true;
	};

  /**
  * Change the angle of the parts connected with the given part. This is in the command handler
  * so it can be easily accessed for the purpose of creating commands that change the rotation of a part. 
  * @this {DrawCommandHandler}
  * @param {number=} angle the positive (clockwise) or negative (counter-clockwise) change in the rotation angle of each Part, in degrees.
  */
	public rotate(angle: number) {
		if (angle === undefined) angle = 90;
		var diagram = this.diagram;
		diagram.startTransaction("rotate " + angle.toString());
		var diagram = this.diagram;
		diagram.selection.each((current) => {
			if (current instanceof go.Link || current instanceof go.Group) return; // skips over Links and Groups
			current.angle += angle;
		});
		diagram.commitTransaction("rotate " + angle.toString());
	};


  /**
  * This implements custom behaviors for arrow key keyboard events.
  * Set {@link #arrowKeyBehavior} to "select", "move" (the default), "scroll" (the standard behavior), or "none"
  * to affect the behavior when the user types an arrow key.
  * @this {DrawCommandHandler}*/
	public doKeyDown() {
		var diagram = this.diagram;
		if (diagram === null) return;
		var e = diagram.lastInput;

		// determines the function of the arrow keys
		if (e.key === "Up" || e.key === "Down" || e.key === "Left" || e.key === "Right") {
			var behavior = this.arrowKeyBehavior;
			if (behavior === "none") {
				// no-op
				return;
			} else if (behavior === "select") {
				this._arrowKeySelect();
				return;
			} else if (behavior === "move") {
				this._arrowKeyMove();
				return;
			}
			// otherwise drop through to get the default scrolling behavior
		}

		// otherwise still does all standard commands
		super.doKeyDown.call(this);
	};

  /**
  * Collects in an Array all of the non-Link Parts currently in the Diagram.
  * @this {DrawCommandHandler}
  * @return {Array}
  */
	public _getAllParts(): Array<any> {
		var allParts = new Array();
		this.diagram.nodes.each((node) => { allParts.push(node); });
		this.diagram.parts.each((part) => { allParts.push(part); });
		// note that this ignores Links
		return allParts;
	};

  /**
  * To be called when arrow keys should move the Diagram.selection.
  * @this {DrawCommandHandler}
  */
	public _arrowKeyMove() {
		var diagram = this.diagram;
		var e = diagram.lastInput;
		// moves all selected parts in the specified direction
		var vdistance = 0;
		var hdistance = 0;
		// if control is being held down, move pixel by pixel. Else, moves by grid cell size    
		if (e.control || e.meta) {
			vdistance = 1;
			hdistance = 1;
		} else if (diagram.grid !== null) {
			var cellsize = diagram.grid.gridCellSize;
			hdistance = cellsize.width;
			vdistance = cellsize.height;
		}
		diagram.startTransaction("arrowKeyMove");
		diagram.selection.each((part) => {
			if (e.key === "Up") {
				part.move(new go.Point(part.actualBounds.x, part.actualBounds.y - vdistance));
			} else if (e.key === "Down") {
				part.move(new go.Point(part.actualBounds.x, part.actualBounds.y + vdistance));
			} else if (e.key === "Left") {
				part.move(new go.Point(part.actualBounds.x - hdistance, part.actualBounds.y));
			} else if (e.key === "Right") {
				part.move(new go.Point(part.actualBounds.x + hdistance, part.actualBounds.y));
			}
		});
		diagram.commitTransaction("arrowKeyMove");
	};

  /**
  * To be called when arrow keys should change selection.
  * @this {DrawCommandHandler}
  */
	public _arrowKeySelect() {
		var diagram = this.diagram;
		var e = diagram.lastInput;
		// with a part selected, arrow keys change the selection
		// arrow keys + shift selects the additional part in the specified direction
		// arrow keys + control toggles the selection of the additional part
		var nextPart = null;
		if (e.key === "Up") {
			nextPart = this._findNearestPartTowards(270);
		} else if (e.key === "Down") {
			nextPart = this._findNearestPartTowards(90);
		} else if (e.key === "Left") {
			nextPart = this._findNearestPartTowards(180);
		} else if (e.key === "Right") {
			nextPart = this._findNearestPartTowards(0);
		}
		if (nextPart !== null) {
			if (e.shift) {
				nextPart.isSelected = true;
			} else if (e.control || e.meta) {
				nextPart.isSelected = !nextPart.isSelected;
			} else {
				diagram.select(nextPart);
			}
		}
	};

  /**
  * Finds the nearest Part in the specified direction, based on their center points.
  * if it doesn't find anything, it just returns the current Part.
  * @this {DrawCommandHandler}
  * @param {number} dir the direction, in degrees
  * @return {Part} the closest Part found in the given direction
  */
	public _findNearestPartTowards(dir: number): go.Part {
		var originalPart = this.diagram.selection.first();
		if (originalPart === null) return null;
		var originalPoint = originalPart.actualBounds.center;
		var allParts = this._getAllParts();
		var closestDistance = Infinity;
		var closest = originalPart;  // if no parts meet the criteria, the same part remains selected

		for (var i = 0; i < allParts.length; i++) {
			var nextPart = allParts[i];
			if (nextPart === originalPart) continue;  // skips over currently selected part
			var nextPoint = nextPart.actualBounds.center;
			var angle = originalPoint.directionPoint(nextPoint);
			var anglediff = this._angleCloseness(angle, dir);
			if (anglediff <= 45) {  // if this part's center is within the desired direction's sector,
				var distance = originalPoint.distanceSquaredPoint(nextPoint);
				distance *= 1 + Math.sin(anglediff * Math.PI / 180);  // the more different from the intended angle, the further it is
				if (distance < closestDistance) {  // and if it's closer than any other part,
					closestDistance = distance;      // remember it as a better choice
					closest = nextPart;
				}
			}
		}
		return closest;
	};

  /**
  * @this {DrawCommandHandler}
  * @param {number} a
  * @param {number} dir
  * @return {number}
  */
	public _angleCloseness(a: number, dir: number): number {
		return Math.min(Math.abs(dir - a), Math.min(Math.abs(dir + 360 - a), Math.abs(dir - 360 - a)));
	};

  /**
  * Reset the last offset for pasting.
  * @override
  * @this {DrawCommandHandler}
  * @param {Iterable.<Part>} coll a collection of {@link Part}s.
  */
	public copyToClipboard(coll: go.Iterable<go.Part>) {
		super.copyToClipboard.call(this, coll);
		this._lastPasteOffset.set(this.pasteOffset);
	};

  /**
  * Paste from the clipboard with an offset incremented on each paste, and reset when copied.
  * @override
  * @this {DrawCommandHandler}
  * @return {Set.<Part>} a collection of newly pasted {@link Part}s
  */
	public pasteFromClipboard(): go.Set<go.Part> {
		var coll: any = super.pasteFromClipboard.call(this);
		this.diagram.moveParts(coll, this._lastPasteOffset, false);
		this._lastPasteOffset.add(this.pasteOffset);
		return coll;
	};

  /**
  * Gets or sets the arrow key behavior. Possible values are "move", "select", and "scroll".  
  * The default value is "move".
  * @name DrawCommandHandler#arrowKeyBehavior
  * @function.
  * @return {string}
  */
	get arrowKeyBehavior(): string { return this._arrowKeyBehavior; }
	set arrowKeyBehavior(val: string) {
		if (val !== "move" && val !== "select" && val !== "scroll" && val !== "none") {
			throw new Error("DrawCommandHandler.arrowKeyBehavior must be either \"move\", \"select\", \"scroll\", or \"none\", not: " + val);
		}
		this._arrowKeyBehavior = val;
	}

  /**
  * Gets or sets the offset at which each repeated pasteSelection() puts the new copied parts from the clipboard.
  * @name DrawCommandHandler#pasteOffset
  * @function.
  * @return {Point}
  */
	get pasteOffset(): go.Point { return this._pasteOffset; }
	set pasteOffset(val: go.Point) {
		if (!(val instanceof go.Point)) throw new Error("DrawCommandHandler.pasteOffset must be a Point, not: " + val);
		this._pasteOffset.set(val);
	}
}