package org.apache.commons.graph.visualize;

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 * The Apache Software License, Version 1.1
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 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
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 * This software consists of voluntary contributions made by many
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import java.io.OutputStream;

import org.apache.commons.graph.GraphConstants;
import org.apache.commons.graph.Edge;
import org.apache.commons.graph.Graph;
import org.apache.commons.graph.Sequential;
import org.apache.commons.graph.Vertex;

/**
 * Visualizes directed graphs into the
 * <A HREF="http://www.informatik.uni-bremen.de/~inform/forschung/daVinci/daVinci.html">
 * DaVinci</A> format. It can only be used for directed graphs and does not support
 * labeled edges very well, unfortunately. They have to be simulated via dummy vertices.
 *
 * Traverses graph with the Sequential visitor, since it uses invariants of that algorithm.
 *
 * @version $Id: DaVinciVisualizer.java,v 1.3 2002/01/16 20:38:30 jvanzyl Exp $
 * @author  <A HREF="http://www.inf.fu-berlin.de/~dahm">M. Dahm</A>
 */
public class DaVinciVisualizer extends GraphVisualizer implements GraphConstants {
  private Graph        graph;
  private int          no_edges, edges;
  private int          no_vertices, vertices;

  /**
   * @param out stream to print output to
   * @param verbose toggle verbosity of output
   */
  public DaVinciVisualizer(OutputStream out, int verbose) {
    super(out, verbose);
  }

  public void discoverGraph(Graph g) {
    graph = g;

    no_vertices = g.getNoVertices();
    vertices    = 0;
    out.println("[");
  }

  public void finishGraph(Graph g) {
    out.println("]");
    out.close();
  }

  public void discoverVertex(Vertex v) {
    String label = convertString(v.toString(verbose));
    //System.out.println("vertex:" + v.getIdent() + ":" + v);
    
    println(1, "l(\"" + v.getIdent() + "\",");
    println(1, "n(\"anything\", [");
    println(2, "a(\"OBJECT\", \"" + label + "\"),");
    println(2, "a(\"FONTSTYLE\", \"bold\"),");
    println(2, "a(\"FONTFAMILY\", \"courier\")],");
    println(1, "["); // array of successor nodes

    no_edges = graph.getNoEdges(v);
    edges    = 0;
  }

  public void finishVertex(Vertex v) {
    String str = (vertices < no_vertices - 1)? "]))," : "]))";
    println(1, str);
    vertices++;
  }

  private static int label_counter=0;

  private final String getEdgeAttribute() {
    if(graph.isDirected())
      return "";
    else
      return "a(\"_DIR\", \"none\"";
  }

  public void discoverEdge(Edge e) {
    int    u     = graph.getSource(e).getIdent();
    int    v     = graph.getTarget(e).getIdent();
    String label = convertString(e.toString(verbose));

    if(label.equals("")) {
      print(2, "l(\"" + u + "->" + v + "\", e(\"\", [" + getEdgeAttribute() +
	    "], r(\"" + v + "\")))");
    } else { // Simulate labeled edge with intermediate node
      String dummy = "label" + label_counter++; // Dummy name for intermediate node

      print(2, "l(\"" + u + "->" + dummy + "\", e(\"\", [a(\"_DIR\", \"none\")], " +
	    "l(\"" + dummy + "\", n(\"anything\",[a(\"OBJECT\", \"" + label +
	    "\"), a(\"_GO\", \"text\")], [l(\"" + dummy + "->" + v +
	    "\", e(\"\",[" + getEdgeAttribute() + "], r(\"" + v + "\")))]))))");
      //System.out.println(graph.getTarget(e).getIdent() + ":" + graph.getTarget(e));
    }
  }

  public void finishEdge(Edge e) {
    if(edges < no_edges - 1)
      out.println(", ");
    else
      out.print('\n');

    edges++;
  }

  /**
   * Visualize graph g with this Visualizer.
   *
   * @param g graph to visualize
   * @param start node to start at
   */
  public void visualize(Graph g, Vertex start) {
    new Sequential(this).start(g);
  }
}