/*
 * Copyright (c) 2001-2006 JGoodies Karsten Lentzsch. 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 Karsten Lentzsch 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 org.jvnet.lafwidget.utils;

import java.awt.*;
import java.util.*;
import java.util.List;

import javax.swing.*;

/**
 * Provides convenience behavior used by the JGoodies Looks.
 *
 * @author  Karsten Lentzsch
 * @version $Revision: 1.1 $
 */
public final class LookUtils {
    
    // Basics System Properties **********************************************

    /**
     * The <code>java.version</code> System Property.<p>
     *
     * Defaults to <code>null</code> if the runtime does not have security 
     * access to read this property or the property does not exist.
     */
    private static final String JAVA_VERSION = getSystemProperty("java.version");    
    
    /**
     * The <code>os.name</code> System Property. Operating system name.<p>
     *
     * Defaults to <code>null</code> if the runtime does not have security 
     * access to read this property or the property does not exist.
     */
    private static final String OS_NAME = getSystemProperty("os.name");

    /**
     * The <code>os.version</code> System Property. Operating system version.<p>
     *
     * Defaults to <code>null</code> if the runtime does not have security 
     * access to read this property or the property does not exist.
     */
    private static final String OS_VERSION = getSystemProperty("os.version");

    
    // Requesting the Java Version ******************************************** 

    /**
     * True if this is Java 1.4.
     */
    public static final boolean IS_JAVA_1_4 = 
        startsWith(JAVA_VERSION, "1.4"); 
    
    /**
     * True if this is Java 1.4.0_*.
     */
    public static final boolean IS_JAVA_1_4_0 = startsWith(JAVA_VERSION, "1.4.0");
    
    /**
     * True if this is Java 1.4.2 or later. Since we assume Java 1.4
     * we just check for 1.4.0 and 1.4.1.
     */
    public static final boolean IS_JAVA_1_4_2_OR_LATER = 
           !startsWith(JAVA_VERSION, "1.4.0") 
        && !startsWith(JAVA_VERSION, "1.4.1");

    /**
     * True if this is Java 5.x. We check for a prefix of 1.5.
     */
    public static final boolean IS_JAVA_5 = 
        startsWith(JAVA_VERSION, "1.5");

    /**
     * True if this is Java 5.x or later. Since we don't support Java 1.3,
     * we can check that it's not 1.4.
     */
    public static final boolean IS_JAVA_5_OR_LATER = 
        !IS_JAVA_1_4;

    /**
     * True if this is Java 6. We check for a prefix of 1.6.
     */
    public static final boolean IS_JAVA_6 = 
        startsWith(JAVA_VERSION, "1.6");

    /**
     * True if this is Java 6.x or later. Since we don't support Java 1.3,
     * we can check that it's neither 1.4 nor 1.5.
     */
    public static final boolean IS_JAVA_6_OR_LATER = 
           !IS_JAVA_1_4 
        && !IS_JAVA_5;


    /**
     * True if this is Java 1.4 or Java 5.
     */
    public static final boolean IS_JAVA_1_4_OR_5 = 
        IS_JAVA_1_4 || IS_JAVA_5;
    

    // Requesting the Operating System Name ***********************************
    
    /**
     * True if this is FreeBSD.
     */
    public static final boolean IS_OS_FREEBSD = 
        startsWithIgnoreCase(OS_NAME, "FreeBSD");

    /**
     * True if this is Linux.
     */
    public static final boolean IS_OS_LINUX = 
        startsWithIgnoreCase(OS_NAME, "Linux");

    /**
     * True if this is OS/2.
     */
    public static final boolean IS_OS_OS2 = 
        startsWith(OS_NAME, "OS/2");

    /**
     * True if this is the Mac OS X.
     */
    public static final boolean IS_OS_MAC = 
        startsWith(OS_NAME, "Mac");

    /**
     * True if this is Windows.
     */
    public static final boolean IS_OS_WINDOWS = 
        startsWith(OS_NAME, "Windows");

    /**
     * True if this is Windows 98/ME/2000/XP/VISTA.
     */
    public static final boolean IS_OS_WINDOWS_MODERN = 
        startsWith(OS_NAME, "Windows") && !startsWith(OS_VERSION, "4.0");

    /**
     * True if this is Windows 95.
     * 
     * @since 2.0
     */
    public static final boolean IS_OS_WINDOWS_95 =
        startsWith(OS_NAME, "Windows 9") && startsWith(OS_VERSION, "4.0");
    
    /**
     * True if this is Windows 98.
     * 
     * @since 2.0
     */
    public static final boolean IS_OS_WINDOWS_98 =
        startsWith(OS_NAME, "Windows 9") && startsWith(OS_VERSION, "4.1");
    
    /**
     * True if this is Windows NT.
     * 
     * @since 2.0
     */
    public static final boolean IS_OS_WINDOWS_NT =
        startsWith(OS_NAME, "Windows NT");
    
    /**
     * True if this is Windows ME.
     * 
     * @since 2.0
     */
    public static final boolean IS_OS_WINDOWS_ME =
        startsWith(OS_NAME, "Windows") && startsWith(OS_VERSION, "4.9");
    
    /**
     * True if this is Windows 2000.
     * 
     * @since 2.0
     */
    public static final boolean IS_OS_WINDOWS_2000 =
        startsWith(OS_NAME, "Windows") && startsWith(OS_VERSION, "5.0");
    
    /**
     * True if this is Windows XP.
     */
    public static final boolean IS_OS_WINDOWS_XP =
        startsWith(OS_NAME, "Windows") && startsWith(OS_VERSION, "5.1");
    
    /**
     * True if this is Windows Vista.
     * 
     * @since 2.0
     */
    public static final boolean IS_OS_WINDOWS_VISTA =
        startsWith(OS_NAME, "Windows") && startsWith(OS_VERSION, "6.0");
    
    /**
     * True if this is Solaris.
     */
    public static final boolean IS_OS_SOLARIS = 
        startsWith(OS_NAME, "Solaris");
    
    
    // Other Properties *******************************************************

    /**
     * True if the Windows XP Look&amp;Feel is enabled.
     */
    public static final boolean IS_LAF_WINDOWS_XP_ENABLED = isWindowsXPLafEnabled();
    
    /**
     * True if if the screen resolution is smaller than 120 dpi.
     * 
     * @see Toolkit#getScreenResolution()
     */
    public static final boolean IS_LOW_RESOLUTION = isLowResolution();
    
    private static boolean loggingEnabled = true;
    

    private LookUtils() {
        // Override default constructor; prevents instantiation.
    }
    
    
    // Accessing System Configuration *****************************************

    /**
     * Tries to look up the System property for the given key.
     * In untrusted environments this may throw a SecurityException.
     * In this case we catch the exception and answer <code>null</code>. 
     * 
     * @param key   the name of the system property
     * @return the system property's String value, or <code>null</code> if there's
     *     no such value, or a SecurityException has been caught
     */
    public static String getSystemProperty(String key) {
        try {
            return System.getProperty(key);
        } catch (SecurityException e) {
           // log("Can't read the System property " + key + ".");
            return null;
        }
    }

    /**
     * Tries to look up the System property for the given key.
     * In untrusted environments this may throw a SecurityException.
     * In this case, we catch the exception and answer the default value. 
     * 
     * @param key          the name of the system property
     * @param defaultValue the default value if no property exists.
     * @return the system property's String value, or the defaultValue 
     *     if there's no such value, or a SecurityException has been caught
     */
    public static String getSystemProperty(String key, String defaultValue) {
        try {
            return System.getProperty(key, defaultValue);
        } catch (SecurityException e) {
        //    log("Can't read the System property " + key + ".");
            return defaultValue;
        }
    }
    
    /**
     * Checks if a boolean system property has been set for the given key,
     * and returns the associated Boolean, or <code>null</code> if no value
     * has been set. The test for the property ignores case. 
     * If a Boolean value has been set, a message is logged 
     * with the given prefix. 
     * 
     * @param key          the key used to lookup the system property value
     * @param logMessage   a prefix used when a message is logged 
     * @return <code>Boolean.TRUE</code> if the system property has been set to 
     * "true" (case ignored), <code>Boolean.FALSE</code> if it has been set to 
     * "false", <code>null</code> otherwise
     */
    public static Boolean getBooleanSystemProperty(String key, String logMessage) {
        String value = getSystemProperty(key, "");
        Boolean result;
        if (value.equalsIgnoreCase("false"))
            result = Boolean.FALSE;
        else if (value.equalsIgnoreCase("true"))
            result = Boolean.TRUE;
        else 
            result = null;
        if (result != null) {
            LookUtils.log(
                logMessage 
                    + " have been "
                    + (result.booleanValue() ? "en" : "dis")
                    + "abled in the system properties.");
        }
        return result;
    }
    

    /**
     * Checks and answers whether the Windows XP style is enabled. 
     * This method is intended to be called only if a Windows look&feel
     * is about to be installed or already active in the UIManager.
     * The XP style of the Windows look&amp;feel is enabled by default on
     * Windows XP platforms since the J2SE 1.4.2; it can be disabled either 
     * in the Windows desktop as well as in the Java runtime by setting
     * a System property.<p>
     * 
     * First checks the platform, platform version and Java version. Then 
     * checks whether the desktop property <tt>win.xpstyle.themeActive</tt>
     * is set or not.
     * 
     * @return true if the Windows XP style is enabled
     */ 
    private static boolean isWindowsXPLafEnabled() {
        return (IS_OS_WINDOWS_XP || IS_OS_WINDOWS_VISTA) 
             && IS_JAVA_1_4_2_OR_LATER 
             && Boolean.TRUE.equals(Toolkit.getDefaultToolkit().
                     getDesktopProperty("win.xpstyle.themeActive"))
             && getSystemProperty("swing.noxp") == null;
    }
    
    
    /**
     * Checks and answers whether we have a true color system.
     * 
     * @param c   the component used to determine the toolkit
     * @return true if the component's toolkit has a pixel size >= 24
     */
    public static boolean isTrueColor(Component c) {
        return c.getToolkit().getColorModel().getPixelSize() >= 24;
    }
    
    
    /**
     * Checks and answers whether this toolkit provides native drop shadows
     * for popups such as the Mac OS X. Currently this is used to
     * determine if the Looks' popup drop shadow feature is active or not
     * - even if it's enabled.  
     * 
     * @return true if the toolkit provides native drop shadows
     * 
     * @see Options#isPopupDropShadowActive()
     */
    public static boolean getToolkitUsesNativeDropShadows() {
        return IS_OS_MAC;
    }
    
    
    /**
     * Computes and returns a Color that is slightly brighter
     * than the specified Color. 
     * 
     * @param color   the color used as basis for the brightened color
     * @return a slightly brighter color
     */
    public static Color getSlightlyBrighter(Color color) {
        return getSlightlyBrighter(color, 1.1f);
    }

    /**
     * Computes and returns a Color that is slightly brighter
     * than the specified Color. 
     * 
     * @param color   the color used as basis for the brightened color
     * @param factor  the factor used to compute the brightness
     * @return a slightly brighter color
     */
    public static Color getSlightlyBrighter(Color color, float factor) {
        float[] hsbValues = new float[3];
        Color.RGBtoHSB(
            color.getRed(),
            color.getGreen(),
            color.getBlue(),
            hsbValues);
        float hue = hsbValues[0];
        float saturation = hsbValues[1];
        float brightness = hsbValues[2];
        float newBrightness = Math.min(brightness * factor, 1.0f);
        return Color.getHSBColor(hue, saturation, newBrightness);
    }

    
    // Minimal logging ******************************************************

    /**
     * Enables or disables the Looks logging.
     * 
     * @param enabled   true to enable logging, false to disable it
     */
    public static void setLoggingEnabled(boolean enabled) {
        loggingEnabled = enabled;
    }

    /**
     * Prints a new line to the console if logging is enabled.
     */
    public static void log() {
        if (loggingEnabled) {
            System.out.println();
        }
    }

    /**
     * Prints the given message to the console if logging is enabled.
     * 
     * @param message  the message to print
     */
    public static void log(String message) {
        if (loggingEnabled) {
            System.out.println("JGoodies Looks: " + message);
        }
    }

    // Private Helper Methods ***********************************************

    /**
     * Checks and answers whether the screen resolution is low or high.
     * Resolutions below 120 dpi are considere low, all others are high.
     * 
     * @return true if the screen resolution is smaller than 120 dpi
     */
    private static boolean isLowResolution() {
        return Toolkit.getDefaultToolkit().getScreenResolution() < 120;
    }

    private static boolean startsWith(String str, String prefix) {
        return str != null && str.startsWith(prefix);
    }
    
    private static boolean startsWithIgnoreCase(String str, String prefix) {
        return str != null && str.toUpperCase(Locale.ENGLISH).startsWith(prefix.toUpperCase(Locale.ENGLISH));
    }


}
