package G4ip;

import pizza.util.Hashtable;

import java.awt.*;

import G4ip.Form.*;

/** A label with a surrounding box.

  */

class MyLabel extends Label {

  public MyLabel() { super(); }

  public MyLabel(String s) { super(s); }

  public void paint(Graphics g) {

    Dimension d = this.size();

    g.setColor(Color.gray);

    g.drawRect(0,0,d.width-1,d.height-1);

  }

}

/** Draws a frame on the screen containing a proof.

  */

public class ProofDisplay extends Frame {

  Button ok;

  Hashtable<int,Sequent> proof;      // contains the indexed sequents 

  /** The proof is represented in the hashtable.

    * @param proof is a hashtable; the structure of the proof (or tree) 

    * is mapped onto a sequence of integers; each integer is a key for

    * a sequent stored in the hashtable.

    */

  public ProofDisplay(Hashtable<int,Sequent> iproof) {

    super("Proof");

    ok = new Button("Close");

    proof = iproof;

    setLayout(new BorderLayout());

    // SOUTH

    Panel p = new Panel();

    p.add(ok);

    add("South",p);

    //CENTER

    Panel display = new Panel();

    printproof(display,1);

    add("Center", display);

    pack();

    show();

  }

  /** Recovers the structure of the proofs from the hashtable representation.

    */

  public void printproof(Panel p,int index) {

    MyLabel l = new MyLabel(proof.get(index).toString());

    l.setAlignment(MyLabel.CENTER);

    p.setLayout(new BorderLayout());

    p.add("South",l); 

    // axiom (do nothing)

    if ((proof.get(2*index) == null) && (proof.get(2*index+1) == null)) { 

      return;    

    }

    // rule with a single premise

    if ((proof.get(2*index) != null) && (proof.get(2*index+1) == null)) { 

      Panel np = new Panel();

      printproof(np,2*index);

      p.add("Center",np);

      return;  

    }

    // rule with two premises

    if ((proof.get(2*index) != null) && (proof.get(2*index+1) != null)) { 

      Panel np1 = new Panel();

      Panel np2 = new Panel();

      printproof(np1,2*index);

      printproof(np2,2*index+1);

      p.add("West",np1);

      p.add("East",np2);

      return;

    }

  }

  /** If either the "Close" or the "Window-destroy" button

    * is pressed, then close the window.

    */

  public boolean handleEvent(Event e)  {

    if (e.id == Event.ACTION_EVENT && e.target == ok) {

      this.finalize(); 

      return true;

    }

    if (e.id == Event.WINDOW_DESTROY) {

      this.finalize(); 

      return true;

    }

    return false;

  }

  /** Closes the window.

    */

  public void finalize()

    { this.dispose();  }

}