package graph.dot;
import graph.*;
import java.io.*; 
import java.util.*;

/**
 * Output a graph into a .DOT file format
 *
 * @author Michael Shilman (michaels@eecs.berkeley.edu)
 * @version $Id$
 */
public class DotWriter {
	public static int s_dotIndex = AttributeManager.NO_INDEX;
	
	/**
	 * Output a graph into a .DOT file format
	 */
	public static void write(Graph g, OutputStream s) 
	throws IOException {
		DataOutputStream os = new DataOutputStream(s);
		os.writeChars("graph \"" + concat(g.name) + "\" {\n");
    	Node n;
        for(Enumeration e = g.nodes.elements(); e.hasMoreElements(); ) {
            n = (Node)e.nextElement();
            writeNode(n, os);
        }
        for(Enumeration e = g.nodes.elements(); e.hasMoreElements(); ) {
            n = (Node)e.nextElement();
            writeEdges(n, os);
        }
		os.writeChars("}\n");
	}

	/**
	 * Write out the properties of this node
	 */
	protected static void writeNode(Node n, DataOutputStream os) 
	throws IOException {
		os.writeChars("\t" + concat(n.name) + " [ ");
		os.writeChars("pos=\"" + n.x + "," + n.y + "\"");
		//XXX actually get the properties
		os.writeChars(" ];\n");
	}
	
	/**
	 * Write out the outgoing edges of this node
	 */
	protected static void writeEdges(Node n, DataOutputStream os) 
	throws IOException {
		Edge e;
    	for(int i = 0; i < n.out.size(); i++) {
    		e = (Edge)n.out.elementAt(i);
    		os.writeChars("\t" + concat(e.tail.name) + 
    						(e.directed ? " -> " : " -- ") +
    						concat(e.head.name) + "\n");
    	}
	}
	
	public static String concat(String s) {
		return ((s == null) ? s : s.replace(' ', '_'));
	}
}