/*
 * Copyright (c) 2009-2013 JGoodies Software GmbH. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  o Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 *  o 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.
 *
 *  o Neither the name of JGoodies Software GmbH 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.
 */

package com.jgoodies.common.internal;

import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsDevice;
import java.awt.PrintGraphics;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.print.PrinterGraphics;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import javax.swing.JComponent;
import javax.swing.plaf.basic.BasicGraphicsUtils;

/**
 * Provides convenience behavior for drawing strings, underline chars,
 * and accessing font metrics.<p>
 *
 * <strong>Note:</strong> This class is not part of the public
 * JGoodies Common API.
 * It should be treated as library internal and should not be used by
 * API users. It may be removed or changed without further notice.
 *
 * @author  Karsten Lentzsch
 */
public final class RenderingUtils {

    private static final String PROP_DESKTOPHINTS = "awt.font.desktophints";

    private static final String SWING_UTILITIES2_NAME = "sun.swing.SwingUtilities2";

    /**
     * Holds the public static method {@code SwingUtilities2#drawString}.
     */
    private static Method drawStringMethod = null;

    /**
     * Holds the public static method
     * {@code SwingUtilities2#drawStringUnderlinedAt}.
     */
    private static Method drawStringUnderlineCharAtMethod = null;

    /**
     * Holds the public static method {@code SwingUtilities2#getFontMetrics}.
     */
    private static Method getFontMetricsMethod = null;

    static {
        drawStringMethod                = getMethodDrawString();
        drawStringUnderlineCharAtMethod = getMethodDrawStringUnderlineCharAt();
        getFontMetricsMethod            = getMethodGetFontMetrics();
    }


    private RenderingUtils() {
        // Overrides default constructor; prevents instantiation.
    }

    /**
     * Draws the string at the specified location underlining the specified
     * character.
     *
     * @param c JComponent that will display the string, may be null
     * @param g Graphics to draw the text to
     * @param text String to display
     * @param x X coordinate to draw the text at
     * @param y Y coordinate to draw the text at
     */
    public static void drawString(JComponent c, Graphics g, String text, int x, int y) {
        if (drawStringMethod != null) {
            try {
                drawStringMethod.invoke(null,
                        c, g, text, Integer.valueOf(x), Integer.valueOf(y));
                return;
            } catch (IllegalArgumentException e) {
                // Use the BasicGraphicsUtils as fallback
            } catch (IllegalAccessException e) {
                // Use the BasicGraphicsUtils as fallback
            } catch (InvocationTargetException e) {
                // Use the BasicGraphicsUtils as fallback
            }
        }
        Graphics2D g2 = (Graphics2D) g;
        Map<?, ?> oldRenderingHints = installDesktopHints(g2);
        BasicGraphicsUtils.drawStringUnderlineCharAt(g, text, -1, x, y);
        if (oldRenderingHints != null) {
            g2.addRenderingHints(oldRenderingHints);
        }
    }


    /**
     * Draws the string at the specified location underlining the specified
     * character.
     *
     * @param c JComponent that will display the string, may be null
     * @param g Graphics to draw the text to
     * @param text String to display
     * @param underlinedIndex Index of a character in the string to underline
     * @param x X coordinate to draw the text at
     * @param y Y coordinate to draw the text at
     */
    public static void drawStringUnderlineCharAt(JComponent c, Graphics g,
                           String text, int underlinedIndex, int x, int y) {
        if (drawStringUnderlineCharAtMethod != null) {
            try {
                drawStringUnderlineCharAtMethod.invoke(null,
                        new Object[] {c, g, text, new Integer(underlinedIndex),
                                      new Integer(x), new Integer(y)});
                return;
            } catch (IllegalArgumentException e) {
                // Use the BasicGraphicsUtils as fallback
            } catch (IllegalAccessException e) {
                // Use the BasicGraphicsUtils as fallback
            } catch (InvocationTargetException e) {
                // Use the BasicGraphicsUtils as fallback
            }
        }
        Graphics2D g2 = (Graphics2D) g;
        Map oldRenderingHints = installDesktopHints(g2);
        BasicGraphicsUtils.drawStringUnderlineCharAt(g, text, underlinedIndex, x, y);
        if (oldRenderingHints != null) {
            g2.addRenderingHints(oldRenderingHints);
        }
    }


    /**
     * Returns the FontMetrics for the current Font of the passed
     * in Graphics.  This method is used when a Graphics
     * is available, typically when painting.  If a Graphics is not
     * available the JComponent method of the same name should be used.
     * <p>
     * Callers should pass in a non-null JComponent, the exception
     * to this is if a JComponent is not readily available at the time of
     * painting.
     * <p>
     * This does not necessarily return the FontMetrics from the
     * Graphics.
     *
     * @param c JComponent requesting FontMetrics, may be null
     * @param g Graphics Graphics
     * @return the FontMetrics
     */
    public static FontMetrics getFontMetrics(JComponent c, Graphics g) {
        if (getFontMetricsMethod != null) {
            try {
                return (FontMetrics) getFontMetricsMethod.invoke(null, new Object[] {c, g});
            } catch (IllegalArgumentException e) {
                // Use the fallback
            } catch (IllegalAccessException e) {
                // Use the fallback
            } catch (InvocationTargetException e) {
                // Use the fallback
            }
        }
        return c.getFontMetrics(g.getFont());
    }


    // Private Helper Code ****************************************************

    private static Method getMethodDrawString() {
        try {
            Class<?> clazz = Class.forName(SWING_UTILITIES2_NAME);
            return clazz.getMethod(
                    "drawString",
                    new Class[] {JComponent.class, Graphics.class, String.class, Integer.TYPE, Integer.TYPE}
                    );
        } catch (ClassNotFoundException e) {
            // returns null
        } catch (SecurityException e) {
            // returns null
        } catch (NoSuchMethodException e) {
            // returns null
        }
        return null;
    }


    private static Method getMethodDrawStringUnderlineCharAt() {
        try {
            Class clazz = Class.forName(SWING_UTILITIES2_NAME);
            return clazz.getMethod(
                    "drawStringUnderlineCharAt",
                    new Class[] {JComponent.class, Graphics.class, String.class, Integer.TYPE, Integer.TYPE, Integer.TYPE}
                    );
        } catch (ClassNotFoundException e) {
            // returns null
        } catch (SecurityException e) {
            // returns null
        } catch (NoSuchMethodException e) {
            // returns null
        }
        return null;
    }


    private static Method getMethodGetFontMetrics() {
        try {
            Class clazz = Class.forName(SWING_UTILITIES2_NAME);
            return clazz.getMethod(
                    "getFontMetrics",
                    new Class[] {JComponent.class, Graphics.class}
                    );
        } catch (ClassNotFoundException e) {
            // returns null
        } catch (SecurityException e) {
            // returns null
        } catch (NoSuchMethodException e) {
            // returns null
        }
        return null;
    }


    private static Map installDesktopHints(Graphics2D g2) {
        Map oldRenderingHints = null;
        Map desktopHints = desktopHints(g2);
        if (desktopHints != null && !desktopHints.isEmpty()) {
            oldRenderingHints = new HashMap(desktopHints.size());
            RenderingHints.Key key;
            for (Iterator i = desktopHints.keySet().iterator(); i.hasNext();) {
                key = (RenderingHints.Key) i.next();
                oldRenderingHints.put(key, g2.getRenderingHint(key));
            }
            g2.addRenderingHints(desktopHints);
        }
        return oldRenderingHints;
    }


    private static Map desktopHints(Graphics2D g2) {
        if (isPrinting(g2)) {
            return null;
        }
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        GraphicsDevice device = g2.getDeviceConfiguration().getDevice();
        Map desktopHints = (Map) toolkit.getDesktopProperty(
                PROP_DESKTOPHINTS + '.' + device.getIDstring());
        if (desktopHints == null) {
            desktopHints = (Map) toolkit.getDesktopProperty(PROP_DESKTOPHINTS);
        }
        // It is possible to get a non-empty map but with disabled AA.
        if (desktopHints != null) {
            Object aaHint = desktopHints.get(RenderingHints.KEY_TEXT_ANTIALIASING);
            if (   aaHint == RenderingHints.VALUE_TEXT_ANTIALIAS_OFF
            	|| aaHint == RenderingHints.VALUE_TEXT_ANTIALIAS_DEFAULT) {
                desktopHints = null;
            }
        }
        return desktopHints;
    }


    private static boolean isPrinting(Graphics g) {
        return g instanceof PrintGraphics || g instanceof PrinterGraphics;
    }


}
