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;
        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)
        {
                g.drawRect(0,0,getSize().width -1, getSize().height -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);
                  }
                  else
                  g.drawString(tip[i], 3, (i+1)*fontHeight - 3);
                }
        }

        private void addToolTip()
        {
                mainContainer.setLayout(null);
                mainContainer.add(this, 0);
                mainContainer.validate();
                repaint();
                shown = true;
        }

        void setTip(String tip)
        {
          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);
        }

        void setTipLocation(int x, int y)
        {

          setLocation((owner.getLocationOnScreen().x - mainContainer.getLocationOnScreen().x) +x,
           (owner.getLocationOnScreen().y - mainContainer.getLocationOnScreen().y + VERTICAL_OFFSET)+y);



        // 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)
        {     }

        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)
            setTipLocation(me.getX(), me.getY());
          else
          {
            findMainContainer();
            addToolTip();
            setTipLocation(me.getX(), me.getY());
          }
        }

        public void mouseDragged(MouseEvent me)
        {}
}