/**
 * Copyright (c) 2006-2015, JGraph Ltd
 * Copyright (c) 2006-2015, Gaudenz Alder
 */
/**
 *
 * Class: mxCellStatePreview
 * 
 * Implements a live preview for moving cells.
 * 
 * Constructor: mxCellStatePreview
 * 
 * Constructs a move preview for the given graph.
 * 
 * Parameters:
 * 
 * graph - Reference to the enclosing <mxGraph>.
 */
function mxCellStatePreview(graph)
{
	this.deltas = new mxDictionary();
	this.graph = graph;
};

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

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

/**
 * Variable: count
 * 
 * Contains the number of entries in the map.
 */
mxCellStatePreview.prototype.count = 0;

/**
 * Function: isEmpty
 * 
 * Returns true if this contains no entries.
 */
mxCellStatePreview.prototype.isEmpty = function()
{
	return this.count == 0;
};

/**
 * Function: moveState
 */
mxCellStatePreview.prototype.moveState = function(state, dx, dy, add, includeEdges)
{
	add = (add != null) ? add : true;
	includeEdges = (includeEdges != null) ? includeEdges : true;
	
	var delta = this.deltas.get(state.cell);

	if (delta == null)
	{
		// Note: Deltas stores the point and the state since the key is a string.
		delta = {point: new mxPoint(dx, dy), state: state};
		this.deltas.put(state.cell, delta);
		this.count++;
	}
	else if (add)
	{
		delta.point.x += dx;
		delta.point.y += dy;
	}
	else
	{
		delta.point.x = dx;
		delta.point.y = dy;
	}
	
	if (includeEdges)
	{
		this.addEdges(state);
	}
	
	return delta.point;
};

/**
 * Function: show
 */
mxCellStatePreview.prototype.show = function(visitor)
{
	this.deltas.visit(mxUtils.bind(this, function(key, delta)
	{
		this.translateState(delta.state, delta.point.x, delta.point.y);
	}));
	
	this.deltas.visit(mxUtils.bind(this, function(key, delta)
	{
		this.revalidateState(delta.state, delta.point.x, delta.point.y, visitor);
	}));
};

/**
 * Function: translateState
 */
mxCellStatePreview.prototype.translateState = function(state, dx, dy)
{
	if (state != null)
	{
		var model = this.graph.getModel();
		
		if (model.isVertex(state.cell))
		{
			state.view.updateCellState(state);
			var geo = model.getGeometry(state.cell);
			
			// Moves selection cells and non-relative vertices in
			// the first phase so that edge terminal points will
			// be updated in the second phase
			if ((dx != 0 || dy != 0) && geo != null && (!geo.relative || this.deltas.get(state.cell) != null))
			{
				state.x += dx;
				state.y += dy;
			}
		}
	    
	    var childCount = model.getChildCount(state.cell);
	    
	    for (var i = 0; i < childCount; i++)
	    {
	    	this.translateState(state.view.getState(model.getChildAt(state.cell, i)), dx, dy);
	    }
	}
};

/**
 * Function: revalidateState
 */
mxCellStatePreview.prototype.revalidateState = function(state, dx, dy, visitor)
{
	if (state != null)
	{
		var model = this.graph.getModel();
		
		// Updates the edge terminal points and restores the
		// (relative) positions of any (relative) children
		if (model.isEdge(state.cell))
		{
			state.view.updateCellState(state);
		}

		var geo = this.graph.getCellGeometry(state.cell);
		var pState = state.view.getState(model.getParent(state.cell));
		
		// Moves selection vertices which are relative
		if ((dx != 0 || dy != 0) && geo != null && geo.relative &&
			model.isVertex(state.cell) && (pState == null ||
			model.isVertex(pState.cell) || this.deltas.get(state.cell) != null))
		{
			state.x += dx;
			state.y += dy;
		}
		
		this.graph.cellRenderer.redraw(state);
	
		// Invokes the visitor on the given state
		if (visitor != null)
		{
			visitor(state);
		}
						
	    var childCount = model.getChildCount(state.cell);
	    
	    for (var i = 0; i < childCount; i++)
	    {
	    	this.revalidateState(this.graph.view.getState(model.getChildAt(state.cell, i)), dx, dy, visitor);
	    }
	}
};

/**
 * Function: addEdges
 */
mxCellStatePreview.prototype.addEdges = function(state)
{
	var model = this.graph.getModel();
	var edgeCount = model.getEdgeCount(state.cell);

	for (var i = 0; i < edgeCount; i++)
	{
		var s = state.view.getState(model.getEdgeAt(state.cell, i));

		if (s != null)
		{
			this.moveState(s, 0, 0);
		}
	}
};