/**
 * Copyright (c) 2006-2015, JGraph Ltd
 * Copyright (c) 2006-2015, Gaudenz Alder
 */
/**
 * Class: mxCircleLayout
 * 
 * Extends <mxGraphLayout> to implement a circluar layout for a given radius.
 * The vertices do not need to be connected for this layout to work and all
 * connections between vertices are not taken into account.
 * 
 * Example:
 * 
 * (code)
 * var layout = new mxCircleLayout(graph);
 * layout.execute(graph.getDefaultParent());
 * (end)
 * 
 * Constructor: mxCircleLayout
 *
 * Constructs a new circular layout for the specified radius.
 *
 * Arguments:
 * 
 * graph - <mxGraph> that contains the cells.
 * radius - Optional radius as an int. Default is 100.
 */
function mxCircleLayout(graph, radius)
{
	mxGraphLayout.call(this, graph);
	this.radius = (radius != null) ? radius : 100;
};

/**
 * Extends mxGraphLayout.
 */
mxCircleLayout.prototype = new mxGraphLayout();
mxCircleLayout.prototype.constructor = mxCircleLayout;

/**
 * Variable: radius
 * 
 * Integer specifying the size of the radius. Default is 100.
 */
mxCircleLayout.prototype.radius = null;

/**
 * Variable: moveCircle
 * 
 * Boolean specifying if the circle should be moved to the top,
 * left corner specified by <x0> and <y0>. Default is false.
 */
mxCircleLayout.prototype.moveCircle = false;

/**
 * Variable: x0
 * 
 * Integer specifying the left coordinate of the circle.
 * Default is 0.
 */
mxCircleLayout.prototype.x0 = 0;

/**
 * Variable: y0
 * 
 * Integer specifying the top coordinate of the circle.
 * Default is 0.
 */
mxCircleLayout.prototype.y0 = 0;

/**
 * Variable: resetEdges
 * 
 * Specifies if all edge points of traversed edges should be removed.
 * Default is true.
 */
mxCircleLayout.prototype.resetEdges = true;

/**
 * Variable: disableEdgeStyle
 * 
 * Specifies if the STYLE_NOEDGESTYLE flag should be set on edges that are
 * modified by the result. Default is true.
 */
mxCircleLayout.prototype.disableEdgeStyle = true;

/**
 * Function: execute
 * 
 * Implements <mxGraphLayout.execute>.
 */
mxCircleLayout.prototype.execute = function(parent)
{
	var model = this.graph.getModel();

	// Moves the vertices to build a circle. Makes sure the
	// radius is large enough for the vertices to not
	// overlap
	model.beginUpdate();
	try
	{
		// Gets all vertices inside the parent and finds
		// the maximum dimension of the largest vertex
		var max = 0;
		var top = null;
		var left = null;
		var vertices = [];
		var childCount = model.getChildCount(parent);
		
		for (var i = 0; i < childCount; i++)
		{
			var cell = model.getChildAt(parent, i);
			
			if (!this.isVertexIgnored(cell))
			{
				vertices.push(cell);
				var bounds = this.getVertexBounds(cell);
				
				if (top == null)
				{
					top = bounds.y;
				}
				else
				{
					top = Math.min(top, bounds.y);
				}
				
				if (left == null)
				{
					left = bounds.x;
				}
				else
				{
					left = Math.min(left, bounds.x);
				}
				
				max = Math.max(max, Math.max(bounds.width, bounds.height));
			}
			else if (!this.isEdgeIgnored(cell))
			{
				// Resets the points on the traversed edge
				if (this.resetEdges)
				{
					this.graph.resetEdge(cell);
				}

			    if (this.disableEdgeStyle)
			    {
			    	this.setEdgeStyleEnabled(cell, false);
			    }
			}
		}
		
		var r = this.getRadius(vertices.length, max);

		// Moves the circle to the specified origin
		if (this.moveCircle)
		{
			left = this.x0;
			top = this.y0;
		}
		
		this.circle(vertices, r, left, top);
	}
	finally
	{
		model.endUpdate();
	}
};

/**
 * Function: getRadius
 * 
 * Returns the radius to be used for the given vertex count. Max is the maximum
 * width or height of all vertices in the layout.
 */
mxCircleLayout.prototype.getRadius = function(count, max)
{
	return Math.max(count * max / Math.PI, this.radius);
};

/**
 * Function: circle
 * 
 * Executes the circular layout for the specified array
 * of vertices and the given radius. This is called from
 * <execute>.
 */
mxCircleLayout.prototype.circle = function(vertices, r, left, top)
{
	var vertexCount = vertices.length;
	var phi = 2 * Math.PI / vertexCount;
	
	for (var i = 0; i < vertexCount; i++)
	{
		if (this.isVertexMovable(vertices[i]))
		{
			this.setVertexLocation(vertices[i],
				left + r + r * Math.sin(i*phi),
				top + r + r * Math.cos(i*phi));
		}
	}
};