/*
 * Jalview - A Sequence Alignment Editor and Viewer
 * Copyright (C) 2006 AM Waterhouse, J Procter, G Barton, M Clamp, S Searle
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */

package jalview.appletgui;

import java.awt.*;
import java.applet.*;
import java.awt.event.*;
import java.util.*;

public class Tooltip extends Canvas implements MouseListener,
    MouseMotionListener
{
        private String [] tip;
        private String lastTip="";
        private boolean setPosition = false;
        protected Component owner;

        private Container mainContainer;
        private LayoutManager mainLayout;

        private boolean shown;

        private final int VERTICAL_OFFSET = 20;
        private final int HORIZONTAL_ENLARGE = 10;

        int fontHeight = 0;

        Image linkImage;

        FontMetrics fm;

        public Tooltip(String tip, Component owner)
        {
          this.owner = owner;
          owner.addMouseListener(this);
          owner.addMouseMotionListener(this);
          setBackground(new Color(255, 255, 220));
          setTip(tip);
          java.net.URL url = getClass().getResource("/images/link.gif");
          if (url != null)
          {
            linkImage = java.awt.Toolkit.getDefaultToolkit().getImage(url);
          }
        }

        public void paint(Graphics g)
        {
          int w = getSize().width;
          int h = getSize().height;

          g.drawRect(0, 0, w - 1, h - 1);
          int lindex, x;
          for (int i = 0; i < tip.length; i++)
          {
            x = 3;
            lindex = tip[i].indexOf("%LINK%");
            if (lindex != -1)
            {
              if (lindex > 0)
              {
                g.drawString(tip[i].substring(0, lindex), 3, (i + 1) * fontHeight - 3);
                x += fm.stringWidth(tip[i].substring(0, lindex) + 3);
              }
              g.drawImage(linkImage, x, i * fontHeight + 1, this);
              if (lindex + 6 < tip[i].length())
              {
                g.drawString(tip[i].substring(lindex + 6),
                             x + linkImage.getWidth(this),
                             (i + 1) * fontHeight - 3);
              }
            }
            else
            {
              g.drawString(tip[i], 3, (i + 1) * fontHeight - 3);
            }
          }
        }

        synchronized void setTip(String tip)
        {
          if(tip==null)
          {
            setTip("");
            return;
          }

          if(lastTip.equals(tip))
            return;

          lastTip = tip;
          setPosition = true;

          fm = getFontMetrics(owner.getFont());
          fontHeight = fm.getHeight();

          int longestLine = 0;
          StringTokenizer st = new StringTokenizer(tip, "\n");
          this.tip = new String[st.countTokens()];
          int index = 0;
          while(st.hasMoreElements())
          {
            this.tip[index] = st.nextToken();
            if(fm.stringWidth(this.tip[index])>longestLine)
              longestLine = fm.stringWidth(this.tip[index]);
            index ++;
          }

          setSize(longestLine + HORIZONTAL_ENLARGE,
                  fontHeight*this.tip.length);

          repaint();

        }

        void setTipLocation(MouseEvent evt)
        {
          setLocation( (owner.getLocationOnScreen().x
                        - mainContainer.getLocationOnScreen().x) + evt.getX(),
                      (owner.getLocationOnScreen().y -
                       mainContainer.getLocationOnScreen().y
                       + VERTICAL_OFFSET) + evt.getY());

        // correction, whole tool tip must be visible
          if (mainContainer.getSize().width < (getLocation().x + getSize().width))
          {
            setLocation(mainContainer.getSize().width - getSize().width,
                        getLocation().y);
          }
        }


        private void removeToolTip() {
                if (shown) {
                        mainContainer.remove(0);
                        mainContainer.setLayout(mainLayout);
                        mainContainer.validate();
                }
                shown = false;
        }

        private void findMainContainer() {
                Container parent = owner.getParent();
                while (true) {
                        if ((parent instanceof Applet) || (parent instanceof Frame)) {
                                mainContainer = parent;
                                break;
                        } else {
                                parent = parent.getParent();
                        }
                }
                mainLayout = mainContainer.getLayout();
        }

        public void mouseEntered(MouseEvent me)
        {
          setTipLocation(me);
        }

        public void mouseExited(MouseEvent me)
        {
          removeToolTip();
        }

        public void mousePressed(MouseEvent me)
        {
          removeToolTip();
        }

        public void mouseReleased(MouseEvent me)
        {}

        public void mouseClicked(MouseEvent me)
        {}

        public void mouseMoved(MouseEvent me)
        {
         if(!shown)
          {
            findMainContainer();
            mainContainer.setLayout(null);
            mainContainer.add(this, 0);
            mainContainer.validate();
            shown = true;
            setTipLocation(me);
          }
          else if (setPosition)
          {
            setTipLocation(me);
            setPosition = false;
          }
        }

        public void mouseDragged(MouseEvent me)
        {}
}