/*
 * MarginViewportUI.java
 *
 * Created on January 20, 2004, 6:35 PM
 */

package org.openide.explorer.propertysheet;

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.Rectangle;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.awt.event.ContainerEvent;
import java.awt.event.ContainerListener;
import javax.swing.JComponent;
import javax.swing.JViewport;
import javax.swing.UIManager;
import javax.swing.plaf.ComponentUI;
import javax.swing.plaf.ViewportUI;
import javax.swing.plaf.basic.BasicViewportUI;

/** Viewport UI which will paint a margin if the contained
 * SheetTable is showing one, so the margin appears to continue
 * down to the bottom of the component.
 *
 * @author  Tim Boudreau
 */
class MarginViewportUI extends ViewportUI implements ComponentListener, ContainerListener {
    private JViewport viewport;
    private int lastHeight = -1;
    private int stringWidth = -1;
    private int stringHeight = -1;
    private int ascent = -1;
    Rectangle scratch = new Rectangle();
    
    
    /** Creates a new instance of MarginViewportUI */
    private MarginViewportUI(JViewport jv) {
        this.viewport = jv;
    }

    /** Uses a single shared instance, as does BasicViewportUI */
    public static ComponentUI createUI(JComponent c) {
        return new MarginViewportUI ((JViewport)c);
    }
    
    public void installUI(JComponent c) {
        super.installUI(c);
        //Fetch the "no properties" string - it's not going to change
        //for the life of the session
//        noPropsString = NbBundle.getMessage(MarginViewportUI.class,
//            "CTL_NoProperties"); //NOI18N
        
        //Set an appropriate font and color.  Only really relevant on OS-X to
        //keep the font consistent with other NB fonts
        
        Color fg = UIManager.getColor ("controlShadow"); //NOI18N
        if (fg == null) {
            fg = Color.LIGHT_GRAY;
        }
        c.setForeground (fg);
        
        Color bg = UIManager.getColor ("window"); //NOI18N
        if (bg == null) {
            bg = Color.WHITE;
        }
        c.setBackground (bg);
        
        Font f = UIManager.getFont ("Tree.font"); //NOI18N
        if (f == null) {
            f = UIManager.getFont("controlFont"); //NOI18N
        }
        if (f != null) {
            c.setFont (f);
        }
        c.addContainerListener (this);
        Component[] kids = c.getComponents();
        for (int i=0; i < kids.length; i++) {
            //Should almost always be empty anyway, if not only one component,
            //but for completeness...
            kids[i].addComponentListener(this);
        }
    }
    
    public void uninstallUI (JComponent vp) {
        JViewport jv = (JViewport) vp;
        Component[] c = jv.getComponents();
        for (int i=0; i < c.length; i++) {
            c[i].removeComponentListener(this);
        }
        jv.removeContainerListener (this);
    }
    
    private String emptyString = "THIS IS A BUG"; //NOI18N
    public void setEmptyString (String s) {
        emptyString = s;
        stringWidth = -1;
        stringHeight = -1;
    }
    
    Color marginColor = UIManager.getColor("controlShadow"); //NOI18N
    public void setMarginColor (Color c) {
        marginColor = c;
    }
    
    private int marginWidth = PropUtils.getMarginWidth();
    public void setMarginWidth (int margin) {
        this.marginWidth = margin;
    }
    
    private boolean marginPainted = false;
    public void setMarginPainted (boolean val) {
        if (marginPainted != val) {
            marginPainted = val;
            viewport.repaint();
        }
    }
    
    Dimension lastKnownSize = new Dimension();
    /** Overridden to draw "no properties" if necessary */
    public void paint(Graphics g, JComponent c) {
        Component view = ((JViewport) c).getView();
        if (view != null) {
            lastKnownSize = view.getSize();
        }
        
        if (stringWidth == -1) {
            calcStringSizes (c.getFont(), g);
        }
        
        //Update will have set paintNoProps to the correct value
        if (shouldPaintEmptyMessage()) {
            //We need to paint centered "" text
            g.setFont (c.getFont());
            g.setColor (c.getForeground());

            Rectangle r = getEmptyMessageBounds();
            //See if we really need to do any painting
            if (g.hitClip (r.x, r.y, r.width, r.height)) {
                //Paint the string
                g.drawString(emptyString, r.x, r.y + ascent);
            }
        }
    }
    
    private void calcStringSizes (Font f, Graphics g) {
        FontMetrics fm = g.getFontMetrics (f);
        stringWidth = fm.stringWidth(emptyString);
        stringHeight = fm.getHeight();
        ascent = fm.getMaxAscent();
    }
    
    private Rectangle getEmptyMessageBounds() {
        Insets ins = viewport.getInsets();
        
        scratch.x = ins.left + (((viewport.getWidth() - 
            (ins.left + ins.right)) / 2) - (stringWidth / 2));
        
        scratch.y = ins.top + (((viewport.getHeight() - 
            (ins.top + ins.bottom)) / 2) - (stringHeight / 2));
        
        scratch.width = stringWidth;
        scratch.height = stringHeight;
        return scratch;
    }
    

    public void update(Graphics g, JComponent c) {
        g.setColor(c.getBackground());
        boolean margin = shouldPaintMargin();
        
        int leftEdge = margin ? marginWidth : 0;
        g.fillRect(leftEdge, 0, c.getWidth() - leftEdge,c.getHeight());
        if (margin) {
            g.setColor (marginColor);
            g.fillRect (0, 0, marginWidth, c.getHeight());
        }
	paint(g, c);
    }    
    
    
    private void scheduleRepaint(Dimension nuSize) {
        if (!marginPainted && ((nuSize.height > 10) == (lastKnownSize.height > 10))) {
//            return;
        }
        int heightDif = Math.abs(nuSize.height - lastKnownSize.height);
        if (heightDif == 0) {
//            return;
        }
//        if (heightDif != 0) {
            Insets ins = viewport.getInsets();
/*
            int left = ins.left;
            int top = nuSize.height + ins.top;
            int width = marginWidth;
            int height = lastKnownSize.height - nuSize.height;

            viewport.repaint (left, top, width, height);
            */
            viewport.repaint (ins.left, ins.top, marginWidth, viewport.getHeight() - (ins.top + ins.bottom));
//        }
//        if (nuSize.height < 10) {
            Rectangle r = getEmptyMessageBounds();
            viewport.repaint (r.x, r.y, r.width, r.height);
//        }
    }

    private boolean shouldPaintEmptyMessage() {
        Dimension d = viewport.getView().getSize();
        return d.height < 10;
    }

    private boolean shouldPaintMargin() {
        return marginPainted & !shouldPaintEmptyMessage();
    }


    public void componentAdded(ContainerEvent e) {
        e.getChild().addComponentListener(this);
    }

    public void componentHidden(ComponentEvent e) {
    }

    public void componentMoved(ComponentEvent e) {
    }

    public void componentRemoved(ContainerEvent e) {
        e.getChild().removeComponentListener(this);
    }

    public void componentResized(ComponentEvent e) {
        scheduleRepaint(((Component) e.getSource()).getSize());
    }

    public void componentShown(ComponentEvent e) {
        scheduleRepaint(((Component) e.getSource()).getSize());
    }

}