package com.algomagic.atn;

import java.util.*;
import att.grappa.*;

public class EdgeUpdate 
    extends AbstractUpdate 
    implements Update, VisualizationConstants
{
    private String _parentNodeName;
    private NodeUpdate _childNode;
    private String _type;
    private Collection _evidence;
    private boolean _local;

    public EdgeUpdate( String parentNodeName,
		       NodeUpdate childNode,
		       String type,
		       boolean local,
		       Collection evidence,
		       int side ) {
	_parentNodeName = parentNodeName;
	_childNode = childNode;
	_type = type;
	_local = local;
	_evidence = evidence;
	_side = side;
    }

    public int initialize( VisualizationPanel visPanel ) {
	Graph graph = visPanel.getGraph( );

	_childNode.initialize( visPanel );
	Node n1 = graph.findNodeByName( _parentNodeName );
	Node n2 = graph.findNodeByName( _childNode.getName( ) );

	if( n1 != null && n2 != null ) {
	    new Edge( graph, n1, n2 );
	} else {
	    if( n1 == null && n1 == null ) {
		throw new RuntimeException( _parentNodeName + " === " + _childNode.getName( ) );
	    } else if( n1 == null ) {
		throw new RuntimeException( _parentNodeName );
	    } else if( n2 == null ) {
		throw new RuntimeException( _childNode.getName( ) );
	    }
	}

	if( _local ) {
	    visPanel.addCredentials( _evidence, _local );
	}
	    
	return 3;
    }


    public Collection getEvidence( ) {
	return _evidence;
    }

    public boolean getLocal( ) {
	return _local;
    }

    public String getType( ) {
	return _type;
    }


    public boolean apply( VisualizationPanel visPanel ) {
	Graph graph = visPanel.getGraph( );
	Node n1 = graph.findNodeByName( _parentNodeName );
	Node n2 = graph.findNodeByName( _childNode.getName( ) );

	Edge e = getEdgeBetween( graph, n1, n2 );
	visPanel.setEdgeProperties( e, _type, _local );

	visPanel.clearSelection( );
	
	_childNode.setNew( );
	_childNode.apply( visPanel );

	if( _local == false ) {
	    visPanel.addCredentials( _evidence, _local );
	}

	visPanel.highlightCredentials( _evidence, _local );

	return true;
    }

    public void undo( VisualizationPanel visPanel ) {
	Graph graph = visPanel.getGraph( );
	Node n1 = graph.findNodeByName( _parentNodeName );
	Node n2 = graph.findNodeByName( _childNode.getName( ) );

	Edge e = getEdgeBetween( graph, n1, n2 );
	_childNode.undo( visPanel );


	if( visPanel.getLocal( ) == false ) {
	    visPanel.setShadow( e );
	} else {
	    visPanel.setInvis( e );
	}
	
    }


    public Element getElement( VisualizationPanel visPanel ) {
	Graph graph = visPanel.getGraph( );
	Node n1 = graph.findNodeByName( _parentNodeName );
	Node n2 = graph.findNodeByName( _childNode.getName( ) );

	return getEdgeBetween( graph, n1, n2 );
    }

    public Node getChild( VisualizationPanel visPanel ) {
	Graph graph = visPanel.getGraph( );
	return graph.findNodeByName( _childNode.getName( ) );
    }

    public String getChildName( ) {
	return _childNode.getName( );
    }



    private Edge getEdgeBetween( Graph g, Node head, Node tail ) {
	Enumeration edges = head.edgeElements( );
	while( edges.hasMoreElements( ) ) {
	    Edge e = (Edge) edges.nextElement( );
	    Node t = e.getHead( );
	    Node h = e.getTail( );
	    
	    if( h.getName( ).equals( head.getName( ) ) && t.getName( ).equals( tail.getName( ) ) ) {
		return e;
	    }
	}

	return null;
    }


}