/**
 * Page.java  1.00 96/10/07 Merlin Hughes
 *
 * Copyright (c) 1996 Prominence Dot Com, Inc. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * for non-commercial purposes and without fee is hereby granted
 * provided that this copyright notice appears in all copies.
 *
 * http://prominence.com/                  merlin@prominence.com
 */
import java.awt.*;
import java.util.*;
import java.net.*;

public class Page extends Canvas {
  Sextant parent;
  Scrollbar bar;
  Image doc, dir, open;

  Element root, selected;
  Stack tree = new Stack ();
  int treeDepth = 0;

  public Page (Scrollbar bar) {
    this.bar = bar;
  }

  public void init (Sextant parent) {
    this.parent = parent;
    doc = parent.getImage (parent.getDocumentBase (),
			   parent.getParameter ("doc", "images/doc.gif"));
    prepareImage (doc, this);
    dir = parent.getImage (parent.getDocumentBase (),
			   parent.getParameter ("dir", "images/dir.gif"));
    prepareImage (dir, this);
    open = parent.getImage (parent.getDocumentBase (),
			    parent.getParameter ("open", "images/openDir.gif"));
    prepareImage (open, this);
  }

  int docW, docH, dirW, dirH, openW, openH, textH, textA;

  void getDimensions () {
    docW = doc.getWidth (this);
    docH = doc.getHeight (this);
    dirW = dir.getWidth (this);
    dirH = dir.getHeight (this);
    openW = open.getWidth (this);
    openH = open.getHeight (this);
    textH = getFontMetrics (getFont ()).getHeight ();
    textA = getFontMetrics (getFont ()).getAscent ();
  }

  public void layout () {
    if ((size ().height > 0) && (root != null)) {
      getDimensions ();
      int h = root.getHeight () + 3;
      bar.setValues (bar.getValue (), size ().height, 0, h - size ().height);
      bar.setLineIncrement (textH);
      bar.setPageIncrement (size ().height);
    }
  }

  public void addLine (int depth, URL url, String name, String comment) {
    Element element = new Element (url, name, comment, this);
    if (root == null) {
      if (depth != 0)
	throw new RuntimeException ("Initial depth non-zero.");
      else
	tree.push (root = element);
    } else {
      if (depth == treeDepth) {
	tree.push (((Element) tree.pop ()).sibling = element);
      } else if (depth > treeDepth) {
	if (depth > treeDepth + 1)
	 throw new RuntimeException ("Depth change error: " + name);
	else
	  tree.push (((Element) tree.peek ()).offspring = element);
      } else if (depth < treeDepth) {
	for (int i = depth; i < treeDepth; ++ i)
	  tree.pop ();
	tree.push (((Element) tree.pop ()).sibling = element);
      }
      treeDepth = depth;
    }
  }

  public URL currentURL () {
    if (selected == null)
      return null;
    else
      return selected.url;
  }

  public void paint (Graphics g) {
    if (root != null) {
      getDimensions ();
      root.paint (g, -1, -bar.getValue (), new Point (10, 2 - bar.getValue ()));
    }
  }

  public boolean mouseDown (Event ev, int x, int y) {
    if (root != null) {
      boolean doRepaint = false;
      getDimensions ();
      Point xy = new Point (10, 2 - bar.getValue ());
      Element l = root.locate (x, y, xy);
      if ((l != null) && (l.offspring != null) && (x < xy.x + openW)) {
	l.open = !l.open;
	layout ();
	doRepaint = true;
      }
      if (selected != l) {
	if (selected != null)
	  selected.selected = false;
	selected = l;
	if (selected != null)
	  selected.selected = true;
	doRepaint = true;
	postEvent (new Event (this, Event.LIST_SELECT, (selected != null) ? selected.comment : ""));
      } else if ((selected != null) && (ev.clickCount == 2) &&
		 ((selected.offspring == null) || (x >= xy.x + openW))) {
	postEvent (new Event (this, Event.ACTION_EVENT, l.url));
      }
      if (doRepaint)
	repaint ();
    }
    return super.mouseDown (ev, x, y);
  }
}