/**
 * $Id: mxGraphLayout.js,v 1.48 2012-08-21 17:22:21 gaudenz Exp $
 * Copyright (c) 2006-2010, JGraph Ltd
 */
/**
 * Class: mxGraphLayout
 * 
 * Base class for all layout algorithms in mxGraph. Main public functions are
 * <move> for handling a moved cell within a layouted parent, and <execute> for
 * running the layout on a given parent cell.
 *
 * Known Subclasses:
 *
 * <mxCircleLayout>, <mxCompactTreeLayout>, <mxCompositeLayout>,
 * <mxFastOrganicLayout>, <mxParallelEdgeLayout>, <mxPartitionLayout>,
 * <mxStackLayout>
 * 
 * Constructor: mxGraphLayout
 *
 * Constructs a new layout using the given layouts.
 *
 * Arguments:
 * 
 * graph - Enclosing 
 */
function mxGraphLayout(graph)
{
	this.graph = graph;
};

/**
 * Variable: graph
 * 
 * Reference to the enclosing <mxGraph>.
 */
mxGraphLayout.prototype.graph = null;

/**
 * Variable: useBoundingBox
 *
 * Boolean indicating if the bounding box of the label should be used if
 * its available. Default is true.
 */
mxGraphLayout.prototype.useBoundingBox = true;

/**
 * Variable: parent
 *
 * The parent cell of the layout, if any
 */
mxGraphLayout.prototype.parent = null;

/**
 * Function: moveCell
 * 
 * Notified when a cell is being moved in a parent that has automatic
 * layout to update the cell state (eg. index) so that the outcome of the
 * layout will position the vertex as close to the point (x, y) as
 * possible.
 * 
 * Empty implementation.
 * 
 * Parameters:
 * 
 * cell - <mxCell> which has been moved.
 * x - X-coordinate of the new cell location.
 * y - Y-coordinate of the new cell location.
 */
mxGraphLayout.prototype.moveCell = function(cell, x, y) { };

/**
 * Function: execute
 * 
 * Executes the layout algorithm for the children of the given parent.
 * 
 * Parameters:
 * 
 * parent - <mxCell> whose children should be layed out.
 */
mxGraphLayout.prototype.execute = function(parent) { };

/**
 * Function: getGraph
 * 
 * Returns the graph that this layout operates on.
 */
mxGraphLayout.prototype.getGraph = function()
{
	return this.graph;
};

/**
 * Function: getConstraint
 * 
 * Returns the constraint for the given key and cell. The optional edge and
 * source arguments are used to return inbound and outgoing routing-
 * constraints for the given edge and vertex. This implementation always
 * returns the value for the given key in the style of the given cell.
 * 
 * Parameters:
 * 
 * key - Key of the constraint to be returned.
 * cell - <mxCell> whose constraint should be returned.
 * edge - Optional <mxCell> that represents the connection whose constraint
 * should be returned. Default is null.
 * source - Optional boolean that specifies if the connection is incoming
 * or outgoing. Default is null.
 */
mxGraphLayout.prototype.getConstraint = function(key, cell, edge, source)
{
	var state = this.graph.view.getState(cell);
	var style = (state != null) ? state.style : this.graph.getCellStyle(cell);
	
	return (style != null) ? style[key] : null;
};

/**
 * Function: traverse
 * 
 * Traverses the (directed) graph invoking the given function for each
 * visited vertex and edge. The function is invoked with the current vertex
 * and the incoming edge as a parameter. This implementation makes sure
 * each vertex is only visited once. The function may return false if the
 * traversal should stop at the given vertex.
 * 
 * Example:
 * 
 * (code)
 * mxLog.show();
 * var cell = graph.getSelectionCell();
 * graph.traverse(cell, false, function(vertex, edge)
 * {
 *   mxLog.debug(graph.getLabel(vertex));
 * });
 * (end)
 * 
 * Parameters:
 * 
 * vertex - <mxCell> that represents the vertex where the traversal starts.
 * directed - Optional boolean indicating if edges should only be traversed
 * from source to target. Default is true.
 * func - Visitor function that takes the current vertex and the incoming
 * edge as arguments. The traversal stops if the function returns false.
 * edge - Optional <mxCell> that represents the incoming edge. This is
 * null for the first step of the traversal.
 * visited - Optional array of cell paths for the visited cells.
 */
mxGraphLayout.traverse = function(vertex, directed, func, edge, visited)
{
	if (func != null && vertex != null)
	{
		directed = (directed != null) ? directed : true;
		visited = visited || [];
		var id = mxCellPath.create(vertex);
		
		if (visited[id] == null)
		{
			visited[id] = vertex;
			var result = func(vertex, edge);
			
			if (result == null || result)
			{
				var edgeCount = this.graph.model.getEdgeCount(vertex);
				
				if (edgeCount > 0)
				{
					for (var i = 0; i < edgeCount; i++)
					{
						var e = this.graph.model.getEdgeAt(vertex, i);
						var isSource = this.graph.model.getTerminal(e, true) == vertex;
												
						if (!directed || isSource)
						{
							var next = this.graph.view.getVisibleTerminal(e, !isSource);
							this.traverse(next, directed, func, e, visited);
						}
					}
				}
			}
		}
	}
};

/**
 * Function: isVertexMovable
 * 
 * Returns a boolean indicating if the given <mxCell> is movable or
 * bendable by the algorithm. This implementation returns true if the given
 * cell is movable in the graph.
 * 
 * Parameters:
 * 
 * cell - <mxCell> whose movable state should be returned.
 */
mxGraphLayout.prototype.isVertexMovable = function(cell)
{
	return this.graph.isCellMovable(cell);
};

/**
 * Function: isVertexIgnored
 * 
 * Returns a boolean indicating if the given <mxCell> should be ignored by
 * the algorithm. This implementation returns false for all vertices.
 * 
 * Parameters:
 * 
 * vertex - <mxCell> whose ignored state should be returned.
 */
mxGraphLayout.prototype.isVertexIgnored = function(vertex)
{
	return !this.graph.getModel().isVertex(vertex) ||
		!this.graph.isCellVisible(vertex);
};

/**
 * Function: isEdgeIgnored
 * 
 * Returns a boolean indicating if the given <mxCell> should be ignored by
 * the algorithm. This implementation returns false for all vertices.
 * 
 * Parameters:
 * 
 * cell - <mxCell> whose ignored state should be returned.
 */
mxGraphLayout.prototype.isEdgeIgnored = function(edge)
{
	var model = this.graph.getModel();
	
	return !model.isEdge(edge) ||
		!this.graph.isCellVisible(edge) ||
		model.getTerminal(edge, true) == null ||
		model.getTerminal(edge, false) == null;
};

/**
 * Function: setEdgeStyleEnabled
 * 
 * Disables or enables the edge style of the given edge.
 */
mxGraphLayout.prototype.setEdgeStyleEnabled = function(edge, value)
{
	this.graph.setCellStyles(mxConstants.STYLE_NOEDGESTYLE,
			(value) ? '0' : '1', [edge]);
};

/**
 * Function: setOrthogonalEdge
 * 
 * Disables or enables orthogonal end segments of the given edge.
 */
mxGraphLayout.prototype.setOrthogonalEdge = function(edge, value)
{
	this.graph.setCellStyles(mxConstants.STYLE_ORTHOGONAL,
			(value) ? '1' : '0', [edge]);
};

/**
 * Function: getParentOffset
 * 
 * Determines the offset of the given parent to the parent
 * of the layout
 */
mxGraphLayout.prototype.getParentOffset = function(parent)
{
	var result = new mxPoint();

	if (parent != null && parent != this.parent)
	{
		var model = this.graph.getModel();

		if (model.isAncestor(this.parent, parent))
		{
			var parentGeo = model.getGeometry(parent);

			while (parent != this.parent)
			{
				result.x = result.x + parentGeo.x;
				result.y = result.y + parentGeo.y;

				parent = model.getParent(parent);;
				parentGeo = model.getGeometry(parent);
			}
		}
	}

	return result;
};

/**
 * Function: setEdgePoints
 * 
 * Replaces the array of mxPoints in the geometry of the given edge
 * with the given array of mxPoints.
 */
mxGraphLayout.prototype.setEdgePoints = function(edge, points)
{
	if (edge != null)
	{
		var model = this.graph.model;
		var geometry = model.getGeometry(edge);

		if (geometry == null)
		{
			geometry = new mxGeometry();
			geometry.setRelative(true);
		}
		else
		{
			geometry = geometry.clone();
		}

		if (this.parent != null && points != null)
		{
			var parent = model.getParent(edge);

			var parentOffset = this.getParentOffset(parent);

			for (var i = 0; i < points.length; i++)
			{
				points[i].x = points[i].x - parentOffset.x;
				points[i].y = points[i].y - parentOffset.y;
			}
		}

		geometry.points = points;
		model.setGeometry(edge, geometry);
	}
};

/**
 * Function: setVertexLocation
 * 
 * Sets the new position of the given cell taking into account the size of
 * the bounding box if <useBoundingBox> is true. The change is only carried
 * out if the new location is not equal to the existing location, otherwise
 * the geometry is not replaced with an updated instance. The new or old
 * bounds are returned (including overlapping labels).
 * 
 * Parameters:
 * 
 * cell - <mxCell> whose geometry is to be set.
 * x - Integer that defines the x-coordinate of the new location.
 * y - Integer that defines the y-coordinate of the new location.
 */
mxGraphLayout.prototype.setVertexLocation = function(cell, x, y)
{
	var model = this.graph.getModel();
	var geometry = model.getGeometry(cell);
	var result = null;
	
	if (geometry != null)
	{
		result = new mxRectangle(x, y, geometry.width, geometry.height);
		
		// Checks for oversize labels and shifts the result
		// TODO: Use mxUtils.getStringSize for label bounds
		if (this.useBoundingBox)
		{
			var state = this.graph.getView().getState(cell);
			
			if (state != null && state.text != null && state.text.boundingBox != null)
			{
				var scale = this.graph.getView().scale;
				var box = state.text.boundingBox;
				
				if (state.text.boundingBox.x < state.x)
				{
					x += (state.x - box.x) / scale;
					result.width = box.width;
				}
				
				if (state.text.boundingBox.y < state.y)
				{
					y += (state.y - box.y) / scale;
					result.height = box.height;
				}
			}
		}

		if (this.parent != null)
		{
			var parent = model.getParent(cell);

			if (parent != null && parent != this.parent)
			{
				var parentOffset = this.getParentOffset(parent);

				x = x - parentOffset.x;
				y = y - parentOffset.y;
			}
		}

		if (geometry.x != x || geometry.y != y)
		{
			geometry = geometry.clone();
			geometry.x = x;
			geometry.y = y;
			
			model.setGeometry(cell, geometry);
		}
	}
	
	return result;
};

/**
 * Function: getVertexBounds
 * 
 * Returns an <mxRectangle> that defines the bounds of the given cell or
 * the bounding box if <useBoundingBox> is true.
 */
mxGraphLayout.prototype.getVertexBounds = function(cell)
{
	var geo = this.graph.getModel().getGeometry(cell);

	// Checks for oversize label bounding box and corrects
	// the return value accordingly
	// TODO: Use mxUtils.getStringSize for label bounds
	if (this.useBoundingBox)
	{
		var state = this.graph.getView().getState(cell);

		if (state != null && state.text != null && state.text.boundingBox != null)
		{
			var scale = this.graph.getView().scale;
			var tmp = state.text.boundingBox;

			var dx0 = Math.max(state.x - tmp.x, 0) / scale;
			var dy0 = Math.max(state.y - tmp.y, 0) / scale;
			var dx1 = Math.max((tmp.x + tmp.width) - (state.x + state.width), 0) / scale;
  			var dy1 = Math.max((tmp.y + tmp.height) - (state.y + state.height), 0) / scale;

			geo = new mxRectangle(geo.x - dx0, geo.y - dy0,
         							geo.width + dx0 + dx1, geo.height + dy0 + dy1);
		}
	}

	if (this.parent != null)
	{
		var parent = this.graph.getModel().getParent(cell);
		geo = geo.clone();

		if (parent != null && parent != this.parent)
		{
			var parentOffset = this.getParentOffset(parent);
			geo.x = geo.x + parentOffset.x;
			geo.y = geo.y + parentOffset.y;
		}
	}

	return new mxRectangle(geo.x, geo.y, geo.width, geo.height);
};

/**
 * Function: arrangeGroups
 * 
 * Updates the bounds of the given groups to include all children. Call
 * this with the groups in parent to child order, top-most group first, eg.
 * 
 * arrangeGroups(graph, mxUtils.sortCells(Arrays.asList(
 *   new Object[] { v1, v3 }), true).toArray(), 10);
 */
mxGraphLayout.prototype.arrangeGroups = function(groups, border)
{
	this.graph.getModel().beginUpdate();
	try
	{
		for (var i = groups.length - 1; i >= 0; i--)
		{
			var group = groups[i];
			var children = this.graph.getChildVertices(group);
			var bounds = this.graph.getBoundingBoxFromGeometry(children);
			var geometry = this.graph.getCellGeometry(group);
			var left = 0;
			var top = 0;

			// Adds the size of the title area for swimlanes
			if (this.graph.isSwimlane(group))
			{
				var size = this.graph.getStartSize(group);
				left = size.width;
				top = size.height;
			}

			if (bounds != null && geometry != null)
			{
				geometry = geometry.clone();
				geometry.x = geometry.x + bounds.x - border - left;
				geometry.y = geometry.y + bounds.y - border - top;
				geometry.width = bounds.width + 2 * border + left;
				geometry.height = bounds.height + 2 * border + top;
				this.graph.getModel().setGeometry(group, geometry);
				this.graph.moveCells(children, border + left - bounds.x,
						border + top - bounds.y);
			}
		}
	}
	finally
	{
		this.graph.getModel().endUpdate();
	}
};