/*
 * Copyright (c) 2007, Romain Guy
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
 *   * Neither the name of the TimingFramework project nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Composite;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.GradientPaint;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.LinearGradientPaint;
import java.awt.Paint;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.KeyAdapter;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseMotionAdapter;
import javax.swing.JComponent;

/**
 *
 * @author Romain Guy
 */
public class ProgressGlassPane extends JComponent {
    private static final int BAR_WIDTH = 200;
    private static final int BAR_HEIGHT = 10;
    
    private static final Color TEXT_COLOR = new Color(0x333333);
    private static final Color BORDER_COLOR = new Color(0x333333);
    
    private static final float[] GRADIENT_FRACTIONS = new float[] {
        0.0f, 0.499f, 0.5f, 1.0f
    };
    private static final Color[] GRADIENT_COLORS = new Color[] {
        Color.GRAY, Color.DARK_GRAY, Color.BLACK, Color.GRAY
    };
    private static final Color GRADIENT_COLOR2 = Color.WHITE;
    private static final Color GRADIENT_COLOR1 = Color.GRAY;

    private String message = "Downloading file...";
    private int progress = 0;
    
    /** Creates a new instance of ProgressGlassPane */
    public ProgressGlassPane() {
        // blocks all user input
        addMouseListener(new MouseAdapter() { });
        addMouseMotionListener(new MouseMotionAdapter() { });
        addKeyListener(new KeyAdapter() { });
        
        setFocusTraversalKeysEnabled(false);
        addComponentListener(new ComponentAdapter() {
            public void componentShown(ComponentEvent evt) {
                requestFocusInWindow();
            }
        });
        
        setBackground(Color.WHITE);
        setFont(new Font("Default", Font.BOLD, 16));
    }

    public int getProgress() {
        return progress;
    }

    public void setProgress(int progress) {
        int oldProgress = this.progress;
        this.progress = progress;
        
        // computes the damaged area
        FontMetrics metrics = getGraphics().getFontMetrics(getFont()); 
        int w = (int) (BAR_WIDTH * ((float) oldProgress / 100.0f));
        int x = w + (getWidth() - BAR_WIDTH) / 2;
        int y = (getHeight() - BAR_HEIGHT) / 2;
        y += metrics.getDescent() / 2;
        
        w = (int) (BAR_WIDTH * ((float) progress / 100.0f)) - w;
        int h = BAR_HEIGHT;
        
        repaint(x, y, w, h);
    }
    
    @Override
    protected void paintComponent(Graphics g) {
        // enables anti-aliasing
        Graphics2D g2 = (Graphics2D) g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
        
        // gets the current clipping area
        Rectangle clip = g.getClipBounds();
        
        // sets a 65% translucent composite
        AlphaComposite alpha = AlphaComposite.SrcOver.derive(0.65f);
        Composite composite = g2.getComposite();
        g2.setComposite(alpha);
        
        // fills the background
        g2.setColor(getBackground());
        g2.fillRect(clip.x, clip.y, clip.width, clip.height);
        
        // centers the progress bar on screen
        FontMetrics metrics = g.getFontMetrics();        
        int x = (getWidth() - BAR_WIDTH) / 2;
        int y = (getHeight() - BAR_HEIGHT - metrics.getDescent()) / 2;
        
        // draws the text
        g2.setColor(TEXT_COLOR);
        g2.drawString(message, x, y);
        
        // goes to the position of the progress bar
        y += metrics.getDescent();
        
        // computes the size of the progress indicator
        int w = (int) (BAR_WIDTH * ((float) progress / 100.0f));
        int h = BAR_HEIGHT;
        
        // draws the content of the progress bar
        Paint paint = g2.getPaint();
        
        // bar's background
        Paint gradient = new GradientPaint(x, y, GRADIENT_COLOR1,
                x, y + h, GRADIENT_COLOR2);
        g2.setPaint(gradient);
        g2.fillRect(x, y, BAR_WIDTH, BAR_HEIGHT);
        
        // actual progress
        gradient = new LinearGradientPaint(x, y, x, y + h,
                GRADIENT_FRACTIONS, GRADIENT_COLORS);
        g2.setPaint(gradient);
        g2.fillRect(x, y, w, h);
        
        g2.setPaint(paint);
        
        // draws the progress bar border
        g2.drawRect(x, y, BAR_WIDTH, BAR_HEIGHT);
        
        g2.setComposite(composite);
    }
}
