//package edu.stanford.ejalbert;
package net.wotonomy.web.util;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.File;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * <p>
 * BrowserLauncher is a class that provides one static method, openURL, which
 * opens the default web browser for the current user of the system to the given
 * URL. It may support other protocols depending on the system -- mailto, ftp,
 * etc. -- but that has not been rigorously tested and is not guaranteed to
 * work.
 * </p>
 *
 * <p>
 * Yes, this is platform-specific code, and yes, it may rely on classes on
 * certain platforms that are not part of the standard JDK. What we're trying to
 * do, though, is to take something that's frequently desirable but inherently
 * platform-specific -- opening a default browser -- and allow programmers (you,
 * for example) to do so without worrying about dropping into native code or
 * doing anything else similarly evil.
 * </p>
 *
 * <p>
 * Anyway, this code is completely in Java and will run on all JDK 1.1-compliant
 * systems without modification or a need for additional libraries. All classes
 * that are required on certain platforms to allow this to run are dynamically
 * loaded at runtime via reflection and, if not found, will not cause this to do
 * anything other than returning an error when opening the browser.
 * </p>
 *
 * <p>
 * There are certain system requirements for this class, as it's running through
 * Runtime.exec(), which is Java's way of making a native system call.
 * Currently, this requires that a Macintosh have a Finder which supports the
 * GURL event, which is true for Mac OS 8.0 and 8.1 systems that have the
 * Internet Scripting AppleScript dictionary installed in the Scripting
 * Additions folder in the Extensions folder (which is installed by default as
 * far as I know under Mac OS 8.0 and 8.1), and for all Mac OS 8.5 and later
 * systems. On Windows, it only runs under Win32 systems (Windows 95, 98, and NT
 * 4.0, as well as later versions of all). On other systems, this drops back
 * from the inherently platform-sensitive concept of a default browser and
 * simply attempts to launch Netscape via a shell command.
 * </p>
 *
 * <p>
 * This code is Copyright 1999-2001 by Eric Albert (ejalbert@cs.stanford.edu)
 * and may be redistributed or modified in any form without restrictions as long
 * as the portion of this comment from this paragraph through the end of the
 * comment is not removed. The author requests that he be notified of any
 * application, applet, or other binary that makes use of this code, but that's
 * more out of curiosity than anything and is not required. This software
 * includes no warranty. The author is not repsonsible for any loss of data or
 * functionality or any adverse or unexpected effects of using this software.
 * </p>
 *
 * Credits: <br>
 * Steven Spencer, JavaWorld magazine
 * (<a href="http://www.javaworld.com/javaworld/javatips/jw-javatip66.html">Java
 * Tip 66</a>) <br>
 * Thanks also to Ron B. Yeh, Eric Shapiro, Ben Engber, Paul Teitlebaum, Andrea
 * Cantatore, Larry Barowski, Trevor Bedzek, Frank Miedrich, and Ron Rabakukk
 *
 *
 * original author Eric Albert
 * (<a href="mailto:ejalbert@cs.stanford.edu">ejalbert@cs.stanford.edu</a>)
 * author's version 1.4b1 (Released June 20, 2001)
 * 
 * @author Copyright 2001, Intersect Software Corporation
 * @version $Revision: 905 $ $Date: 2006-02-18 20:44:03 -0500 (Sat, 18 Feb 2006)
 *          $
 */

public class BrowserLauncher {
	/**
	 * The Java virtual machine that we are running on. Actually, in most cases we
	 * only care about the operating system, but some operating systems require us
	 * to switch on the VM.
	 */
	private static int jvm;

	/** The browser for the system */
	private static Object browser;

	/**
	 * Caches whether any classes, methods, and fields that are not part of the JDK
	 * and need to be dynamically loaded at runtime loaded successfully.
	 * <p>
	 * Note that if this is <code>false</code>, <code>openURL()</code> will always
	 * return an IOException.
	 */
	private static boolean loadedWithoutErrors;

	/** The com.apple.mrj.MRJFileUtils class */
	private static Class mrjFileUtilsClass;

	/** The com.apple.mrj.MRJOSType class */
	private static Class mrjOSTypeClass;

	/** The com.apple.MacOS.AEDesc class */
	private static Class aeDescClass;

	/** The <init>(int) method of com.apple.MacOS.AETarget */
	private static Constructor aeTargetConstructor;

	/** The <init>(int, int, int) method of com.apple.MacOS.AppleEvent */
	private static Constructor appleEventConstructor;

	/** The <init>(String) method of com.apple.MacOS.AEDesc */
	private static Constructor aeDescConstructor;

	/** The findFolder method of com.apple.mrj.MRJFileUtils */
	private static Method findFolder;

	/** The getFileCreator method of com.apple.mrj.MRJFileUtils */
	private static Method getFileCreator;

	/** The getFileType method of com.apple.mrj.MRJFileUtils */
	private static Method getFileType;

	/** The openURL method of com.apple.mrj.MRJFileUtils */
	private static Method openURL;

	/** The makeOSType method of com.apple.MacOS.OSUtils */
	private static Method makeOSType;

	/** The putParameter method of com.apple.MacOS.AppleEvent */
	private static Method putParameter;

	/** The sendNoReply method of com.apple.MacOS.AppleEvent */
	private static Method sendNoReply;

	/** Actually an MRJOSType pointing to the System Folder on a Macintosh */
	private static Object kSystemFolderType;

	/** The keyDirectObject AppleEvent parameter type */
	private static Integer keyDirectObject;

	/** The kAutoGenerateReturnID AppleEvent code */
	private static Integer kAutoGenerateReturnID;

	/** The kAnyTransactionID AppleEvent code */
	private static Integer kAnyTransactionID;

	/** The linkage object required for JDirect 3 on Mac OS X. */
	private static Object linkage;

	/** The framework to reference on Mac OS X */
	private static final String JDirect_MacOSX = "/System/Library/Frameworks/Carbon.framework/Frameworks/HIToolbox.framework/HIToolbox";

	/** JVM constant for MRJ 2.0 */
	private static final int MRJ_2_0 = 0;

	/** JVM constant for MRJ 2.1 or later */
	private static final int MRJ_2_1 = 1;

	/** JVM constant for Java on Mac OS X 10.0 (MRJ 3.0) */
	private static final int MRJ_3_0 = 3;

	/** JVM constant for MRJ 3.1 */
	private static final int MRJ_3_1 = 4;

	/** JVM constant for any Windows NT JVM */
	private static final int WINDOWS_NT = 5;

	/** JVM constant for any Windows 9x JVM */
	private static final int WINDOWS_9x = 6;

	/** JVM constant for any other platform */
	private static final int OTHER = -1;

	/**
	 * The file type of the Finder on a Macintosh. Hardcoding "Finder" would keep
	 * non-U.S. English systems from working properly.
	 */
	private static final String FINDER_TYPE = "FNDR";

	/**
	 * The creator code of the Finder on a Macintosh, which is needed to send
	 * AppleEvents to the application.
	 */
	private static final String FINDER_CREATOR = "MACS";

	/** The name for the AppleEvent type corresponding to a GetURL event. */
	private static final String GURL_EVENT = "GURL";

	/**
	 * The first parameter that needs to be passed into Runtime.exec() to open the
	 * default web browser on Windows.
	 */
	private static final String FIRST_WINDOWS_PARAMETER = "/c";

	/** The second parameter for Runtime.exec() on Windows. */
	private static final String SECOND_WINDOWS_PARAMETER = "start";

	/**
	 * The third parameter for Runtime.exec() on Windows. This is a "title"
	 * parameter that the command line expects. Setting this parameter allows URLs
	 * containing spaces to work.
	 */
	private static final String THIRD_WINDOWS_PARAMETER = "\"\"";

	/**
	 * The shell parameters for Netscape that opens a given URL in an already-open
	 * copy of Netscape on many command-line systems.
	 */
	private static final String NETSCAPE_REMOTE_PARAMETER = "-remote";
	// private static final String NETSCAPE_OPEN_PARAMETER_START = "'openURL(";
	// private static final String NETSCAPE_OPEN_PARAMETER_END = ")'";
	private static final String NETSCAPE_OPEN_PARAMETER_START = "openURL(";
	private static final String NETSCAPE_OPEN_PARAMETER_END = ")";

	/**
	 * The message from any exception thrown throughout the initialization process.
	 */
	private static String errorMessage;

	/**
	 * An initialization block that determines the operating system and loads the
	 * necessary runtime data.
	 */
	static {
		loadedWithoutErrors = true;
		String osName = System.getProperty("os.name");
		if (osName.startsWith("Mac OS")) {
			String mrjVersion = System.getProperty("mrj.version");
			String majorMRJVersion = mrjVersion.substring(0, 3);
			try {
				double version = Double.valueOf(majorMRJVersion).doubleValue();
				if (version == 2) {
					jvm = MRJ_2_0;
				} else if (version >= 2.1 && version < 3) {
					// Assume that all 2.x versions of MRJ work the
					// same. MRJ 2.1 actually works via
					// Runtime.exec() and 2.2 supports that but has an
					// openURL() method as well that we currently
					// ignore.
					jvm = MRJ_2_1;
				} else if (version == 3.0) {
					jvm = MRJ_3_0;
				} else if (version >= 3.1) {
					// Assume that all 3.1 and later versions of MRJ
					// work the same.
					jvm = MRJ_3_1;
				} else {
					loadedWithoutErrors = false;
					errorMessage = "Unsupported MRJ version: " + version;
				}
			} catch (NumberFormatException nfe) {
				loadedWithoutErrors = false;
				errorMessage = "Invalid MRJ version: " + mrjVersion;
			}
		} else if (osName.startsWith("Windows")) {
			if (osName.indexOf("9") != -1) {
				jvm = WINDOWS_9x;
			} else {
				jvm = WINDOWS_NT;
			}
		} else {
			jvm = OTHER;
		}

		if (loadedWithoutErrors) { // if we haven't hit any errors yet
			loadedWithoutErrors = loadClasses();
		}
	}

	/** This class should be never be instantiated; this just ensures so. */
	private BrowserLauncher() {
	}

	/**
	 * Called by a static initializer to load any classes, fields, and methods
	 * required at runtime to locate the user's web browser.
	 * 
	 * @return <code>true</code> if all intialization succeeded <code>false</code>
	 *         if any portion of the initialization failed
	 */
	private static boolean loadClasses() {
		switch (jvm) {
		case MRJ_2_0:
			try {
				Class aeTargetClass = Class.forName("com.apple.MacOS.AETarget");
				Class osUtilsClass = Class.forName("com.apple.MacOS.OSUtils");
				Class appleEventClass = Class.forName("com.apple.MacOS.AppleEvent");
				Class aeClass = Class.forName("com.apple.MacOS.ae");
				aeDescClass = Class.forName("com.apple.MacOS.AEDesc");

				aeTargetConstructor = aeTargetClass.getDeclaredConstructor(new Class[] { int.class });
				appleEventConstructor = appleEventClass.getDeclaredConstructor(
						new Class[] { int.class, int.class, aeTargetClass, int.class, int.class });
				aeDescConstructor = aeDescClass.getDeclaredConstructor(new Class[] { String.class });

				makeOSType = osUtilsClass.getDeclaredMethod("makeOSType", new Class[] { String.class });
				putParameter = appleEventClass.getDeclaredMethod("putParameter",
						new Class[] { int.class, aeDescClass });
				sendNoReply = appleEventClass.getDeclaredMethod("sendNoReply", new Class[] {});

				Field keyDirectObjectField = aeClass.getDeclaredField("keyDirectObject");
				keyDirectObject = (Integer) keyDirectObjectField.get(null);
				Field autoGenerateReturnIDField = appleEventClass.getDeclaredField("kAutoGenerateReturnID");
				kAutoGenerateReturnID = (Integer) autoGenerateReturnIDField.get(null);
				Field anyTransactionIDField = appleEventClass.getDeclaredField("kAnyTransactionID");
				kAnyTransactionID = (Integer) anyTransactionIDField.get(null);
			} catch (ClassNotFoundException cnfe) {
				errorMessage = cnfe.getMessage();
				return false;
			} catch (NoSuchMethodException nsme) {
				errorMessage = nsme.getMessage();
				return false;
			} catch (NoSuchFieldException nsfe) {
				errorMessage = nsfe.getMessage();
				return false;
			} catch (IllegalAccessException iae) {
				errorMessage = iae.getMessage();
				return false;
			}
			break;
		case MRJ_2_1:
			try {
				mrjFileUtilsClass = Class.forName("com.apple.mrj.MRJFileUtils");
				mrjOSTypeClass = Class.forName("com.apple.mrj.MRJOSType");
				Field systemFolderField = mrjFileUtilsClass.getDeclaredField("kSystemFolderType");
				kSystemFolderType = systemFolderField.get(null);
				findFolder = mrjFileUtilsClass.getDeclaredMethod("findFolder", new Class[] { mrjOSTypeClass });
				getFileCreator = mrjFileUtilsClass.getDeclaredMethod("getFileCreator", new Class[] { File.class });
				getFileType = mrjFileUtilsClass.getDeclaredMethod("getFileType", new Class[] { File.class });
			} catch (ClassNotFoundException cnfe) {
				errorMessage = cnfe.getMessage();
				return false;
			} catch (NoSuchFieldException nsfe) {
				errorMessage = nsfe.getMessage();
				return false;
			} catch (NoSuchMethodException nsme) {
				errorMessage = nsme.getMessage();
				return false;
			} catch (SecurityException se) {
				errorMessage = se.getMessage();
				return false;
			} catch (IllegalAccessException iae) {
				errorMessage = iae.getMessage();
				return false;
			}
			break;
		case MRJ_3_0:
			try {
				Class linker = Class.forName("com.apple.mrj.jdirect.Linker");
				Constructor constructor = linker.getConstructor(new Class[] { Class.class });
				linkage = constructor.newInstance(new Object[] { BrowserLauncher.class });
			} catch (ClassNotFoundException cnfe) {
				errorMessage = cnfe.getMessage();
				return false;
			} catch (NoSuchMethodException nsme) {
				errorMessage = nsme.getMessage();
				return false;
			} catch (InvocationTargetException ite) {
				errorMessage = ite.getMessage();
				return false;
			} catch (InstantiationException ie) {
				errorMessage = ie.getMessage();
				return false;
			} catch (IllegalAccessException iae) {
				errorMessage = iae.getMessage();
				return false;
			}
			break;
		case MRJ_3_1:
			try {
				mrjFileUtilsClass = Class.forName("com.apple.mrj.MRJFileUtils");
				openURL = mrjFileUtilsClass.getDeclaredMethod("openURL", new Class[] { String.class });
			} catch (ClassNotFoundException cnfe) {
				errorMessage = cnfe.getMessage();
				return false;
			} catch (NoSuchMethodException nsme) {
				errorMessage = nsme.getMessage();
				return false;
			}
			break;
		default:
			break;
		}
		return true;
	}

	/**
	 * Attempts to locate the default web browser on the local system. Caches
	 * results so it only locates the browser once * for each use of this class per
	 * JVM instance.
	 * 
	 * @return The browser for the system. Note that this may not be what you would
	 *         consider to be a standard web browser; instead, it's the application
	 *         that gets called to open the default web browser. In some cases, this
	 *         will be a non-String object that provides the means of calling the
	 *         default browser.
	 */
	private static Object locateBrowser() {
		if (browser != null) {
			return browser;
		}
		switch (jvm) {
		case MRJ_2_0:
			try {
				Integer finderCreatorCode = (Integer) makeOSType.invoke(null, new Object[] { FINDER_CREATOR });
				Object aeTarget = aeTargetConstructor.newInstance(new Object[] { finderCreatorCode });
				Integer gurlType = (Integer) makeOSType.invoke(null, new Object[] { GURL_EVENT });
				Object appleEvent = appleEventConstructor.newInstance(
						new Object[] { gurlType, gurlType, aeTarget, kAutoGenerateReturnID, kAnyTransactionID });
				// Don't set browser = appleEvent because then the
				// next time we call locateBrowser(), we'll get the
				// same AppleEvent, to which we'll already have added
				// the relevant parameter. Instead, regenerate the
				// AppleEvent every time. There's probably a way to
				// do this better; if any has any ideas, please let me
				// know.
				return appleEvent;
			} catch (IllegalAccessException iae) {
				browser = null;
				errorMessage = iae.getMessage();
				return browser;
			} catch (InstantiationException ie) {
				browser = null;
				errorMessage = ie.getMessage();
				return browser;
			} catch (InvocationTargetException ite) {
				browser = null;
				errorMessage = ite.getMessage();
				return browser;
			}
		case MRJ_2_1:
			File systemFolder;
			try {
				systemFolder = (File) findFolder.invoke(null, new Object[] { kSystemFolderType });
			} catch (IllegalArgumentException iare) {
				browser = null;
				errorMessage = iare.getMessage();
				return browser;
			} catch (IllegalAccessException iae) {
				browser = null;
				errorMessage = iae.getMessage();
				return browser;
			} catch (InvocationTargetException ite) {
				browser = null;
				errorMessage = ite.getTargetException().getClass() + ": " + ite.getTargetException().getMessage();
				return browser;
			}
			String[] systemFolderFiles = systemFolder.list();
			// Avoid a FilenameFilter because that can't be stopped mid-list
			for (int i = 0; i < systemFolderFiles.length; i++) {
				try {
					File file = new File(systemFolder, systemFolderFiles[i]);
					if (!file.isFile()) {
						continue;
					}
					// We're looking for a file with a creator code of
					// 'MACS' and a type of 'FNDR'. Only requiring
					// the type results in non-Finder applications
					// being picked up on certain Mac OS 9 systems,
					// especially German ones, and sending a GURL
					// event to those applications results in a logout
					// under Multiple Users.
					Object fileType = getFileType.invoke(null, new Object[] { file });
					if (FINDER_TYPE.equals(fileType.toString())) {
						Object fileCreator = getFileCreator.invoke(null, new Object[] { file });
						if (FINDER_CREATOR.equals(fileCreator.toString())) {
							browser = file.toString(); // Actually the
							// Finder, but that's OK
							return browser;
						}
					}
				} catch (IllegalArgumentException iare) {
					// WTF? browser = browser;
					errorMessage = iare.getMessage();
					return null;
				} catch (IllegalAccessException iae) {
					browser = null;
					errorMessage = iae.getMessage();
					return browser;
				} catch (InvocationTargetException ite) {
					browser = null;
					errorMessage = ite.getTargetException().getClass() + ": " + ite.getTargetException().getMessage();
					return browser;
				}
			}
			browser = null;
			break;
		case MRJ_3_0:
		case MRJ_3_1:
			browser = ""; // Return something non-null
			break;
		case WINDOWS_NT:
			browser = "cmd.exe";
			break;
		case WINDOWS_9x:
			browser = "command.com";
			break;
		case OTHER:
		default:
			browser = "netscape";
			break;
		}
		return browser;
	}

	/**
	 * Attempts to open the default web browser to the given URL.
	 * 
	 * @param url The URL to open
	 * @throws IOException If the web browser could not be located or does not run
	 */
	public static void openURL(String url) throws IOException {
		if (!loadedWithoutErrors) {
			throw new IOException("Exception in finding browser: " + errorMessage);
		}
		Object browser = locateBrowser();
		if (browser == null) {
			throw new IOException("Unable to locate browser: " + errorMessage);
		}

		switch (jvm) {
		case MRJ_2_0:
			Object aeDesc = null;
			try {
				aeDesc = aeDescConstructor.newInstance(new Object[] { url });
				putParameter.invoke(browser, new Object[] { keyDirectObject, aeDesc });
				sendNoReply.invoke(browser, new Object[] {});
			} catch (InvocationTargetException ite) {
				throw new IOException("InvocationTargetException while creating" + " AEDesc: " + ite.getMessage());
			} catch (IllegalAccessException iae) {
				throw new IOException("IllegalAccessException while building " + "AppleEvent: " + iae.getMessage());
			} catch (InstantiationException ie) {
				throw new IOException("InstantiationException while creating " + "AEDesc: " + ie.getMessage());
			} finally {
				aeDesc = null; // Encourage it to get disposed if it
				// was created
				browser = null; // Ditto
			}
			break;
		case MRJ_2_1:
			Runtime.getRuntime().exec(new String[] { (String) browser, url });
			break;
		case MRJ_3_0:
			int[] instance = new int[1];
			int result = ICStart(instance, 0);
			if (result == 0) {
				int[] selectionStart = new int[] { 0 };
				byte[] urlBytes = url.getBytes();
				int[] selectionEnd = new int[] { urlBytes.length };
				result = ICLaunchURL(instance[0], new byte[] { 0 }, urlBytes, urlBytes.length, selectionStart,
						selectionEnd);
				if (result == 0) {
					// Ignore the return value; the URL was launched
					// successfully regardless of what happens here.
					ICStop(instance);
				} else {
					throw new IOException("Unable to launch URL: " + result);
				}
			} else {
				throw new IOException("Unable to create an Internet Config " + "instance: " + result);
			}
			break;
		case MRJ_3_1:
			try {
				openURL.invoke(null, new Object[] { url });
			} catch (InvocationTargetException ite) {
				throw new IOException("InvocationTargetException while calling " + "openURL: " + ite.getMessage());
			} catch (IllegalAccessException iae) {
				throw new IOException("IllegalAccessException while calling " + "openURL: " + iae.getMessage());
			}
			break;
		case WINDOWS_NT:
			// Add quotes around the URL to allow ampersands and other special
			// characters to work.
			Process process = Runtime.getRuntime().exec(new String[] { (String) browser, FIRST_WINDOWS_PARAMETER,
					SECOND_WINDOWS_PARAMETER, THIRD_WINDOWS_PARAMETER, '"' + url + '"' });
			// This avoids a memory leak on some versions of Java on
			// Windows. That's hinted at in
			// <http://developer.java.sun.com/developer/qow/archive/68/>.
			try {
				process.waitFor();
				process.exitValue();
			} catch (InterruptedException ie) {
				throw new IOException("InterruptedException while launching " + "browser: " + ie.getMessage());
			}
			break;
		case WINDOWS_9x:
			// Add quotes around the URL to allow ampersands and other special
			// characters to work.
			// Note: windows 98 doesn't expect the THIRD_WINDOWS_PARAMETER for
			// its title.
			process = Runtime.getRuntime().exec(new String[] { (String) browser, FIRST_WINDOWS_PARAMETER,
					SECOND_WINDOWS_PARAMETER, '"' + url + '"' });
			// This avoids a memory leak on some versions of Java on
			// Windows. That's hinted at in
			// <http://developer.java.sun.com/developer/qow/archive/68/>.
			try {
				process.waitFor();
				process.exitValue();
			} catch (InterruptedException ie) {
				throw new IOException("InterruptedException while launching " + "browser: " + ie.getMessage());
			}
			break;
		case OTHER:
			// Assume that we're on Unix and that Netscape is installed

			// First, attempt to open the URL in a currently running
			// session of Netscape
			process = Runtime.getRuntime().exec(new String[] { (String) browser, NETSCAPE_REMOTE_PARAMETER,
					NETSCAPE_OPEN_PARAMETER_START + url + NETSCAPE_OPEN_PARAMETER_END });
			try {
				int exitCode = process.waitFor();
				if (exitCode != 0) { // if the command had an error
					Runtime.getRuntime().exec(new String[] { (String) browser, url });
				} else if (process.getErrorStream() != null) {
					// Netscape may not be open, so the command may not have an
					// error, it just wouldn't have a process to attach to...
					BufferedReader reader = new BufferedReader(new InputStreamReader(process.getErrorStream()));
					String errorStr = reader.readLine();

					if (errorStr != null) {
						// Command failed, start up the browser
						process = Runtime.getRuntime().exec(new String[] { (String) browser, url });
					}
				}
			} catch (InterruptedException ie) {
				throw new IOException("InterruptedException while launching " + "browser: " + ie.getMessage());
			}
			break;
		default:
			// This should never occur, but if it does, we'll try the
			// simplest thing possible
			Runtime.getRuntime().exec(new String[] { (String) browser, url });
			break;
		}
	}

	/**
	 * Methods required for Mac OS X. The presence of native methods does not cause
	 * any problems on other platforms.
	 */
	private native static int ICStart(int[] instance, int signature);

	private native static int ICStop(int[] instance);

	private native static int ICLaunchURL(int instance, byte[] hint, byte[] data, int len, int[] selectionStart,
			int[] selectionEnd);
}