// Copyright 2004 Adam Megacz, see the COPYING file for licensing [GPL]
package org.xwt;

import java.lang.reflect.*;
import java.net.*;
import java.io.*;
import java.util.*;
import org.xwt.js.*;
import org.xwt.util.*;

/** 
 *  Abstracts away the small irregularities in JVM implementations.
 *
 *  The default Platform class supports a vanilla JDK 1.1
 *  JVM. Subclasses are provided for other VMs. Methods whose names
 *  start with an underscore are meant to be overridden by
 *  subclasses. If you create a subclass of Platform, you should put
 *  it in the org.xwt.plat package, and add code to this file's static
 *  block to detect the new platform.
 */
public abstract class Platform {

    public Platform() { platform = this; }

    // Static Data /////////////////////////////////////////////////////////////////////////////////////

    static boolean clipboardReadEnabled = false;       ///< true iff inside a C-v/A-v/Press3 trap handler
    static Platform platform = null;                   ///< The appropriate Platform object for this JVM
    static boolean alreadyDetectedProxy = false;       ///< true if proxy autodetection has already been run
    static org.xwt.HTTP.Proxy cachedProxyInfo = null;  ///< the result of proxy autodetection
    public static String build = "unknown";            ///< the current build

    // VM Detection Logic /////////////////////////////////////////////////////////////////////

    // If you create a new subclass of Platform, you should add logic
    // here to detect it. Do not reference your class directly -- use
    // reflection.

    public static void forceLoad() {
        System.err.print("Detecting JVM...");
        try {
            String vendor = System.getProperty("java.vendor", "");
            String version = System.getProperty("java.version", "");
            String os_name = System.getProperty("os.name", "");
            String os_version = System.getProperty("os.version", "");
            String platform_class = null;
            
            if (vendor.startsWith("Free Software Foundation")) {
                if (os_name.startsWith("Window")) platform_class = "Win32";
                else if (os_name.startsWith("Linux")) platform_class = "Linux";
                else if (os_name.startsWith("SunOS")) platform_class = "Solaris";
                else if (os_name.startsWith("Solaris")) platform_class = "Solaris";
                else platform_class = "X11";
            }
            else if (!version.startsWith("1.0") && !version.startsWith("1.1")) platform_class = "Java2";

            if (platform_class == null) {
                Log.error(Platform.class, "Unable to detect JVM");
                criticalAbort("Unable to detect JVM");
            }
            
            System.err.println(" " + os_name + " ==> org.xwt.plat." + platform_class);
            try {
                if (platform_class != null) Class.forName("org.xwt.plat." + platform_class).newInstance();
            } catch (InstantiationException e) {
                throw e.getCause();
            }

            String term = Platform.getEnv("TERM");
            Log.color = term != null && term.length() != 0 && !term.equals("cygwin");
            
            try {
                build = (String)Class.forName("org.xwt.Build").getField("build").get(null);
                Log.diag(Platform.class, "XWT build: " + build);
            } catch (ClassNotFoundException cnfe) {
                Log.warn(Platform.class, "XWT build: unknown");
            } catch (Exception e) {
                Log.info(Platform.class, "exception while detecting build:");
                Log.info(Platform.class, e);
            }

            Log.diag(Platform.class, "XWT VM detection:   vendor = " + vendor);
            Log.diag(Platform.class, "                   version = " + version);
            Log.diag(Platform.class, "                        os = " + os_name + " [version " + os_version + "]");
            Log.diag(Platform.class, "                  platform = " + platform.getDescriptiveName());
            Log.diag(Platform.class, "                     class = " + platform.getClass().getName());
            platform.postInit();

        } catch (Throwable e) {
            Log.error(Platform.class, "Exception while trying to detect JVM");
            Log.error(Platform.class, e);
            criticalAbort("Unable to detect JVM");
        }

    }


    // Methods to be Overridden ///////////////////////////////////////////////////////////////////

    protected Surface _createSurface(Box b, boolean framed) { return null; }
    protected Picture _createPicture(JS r) { return null; }
    protected PixelBuffer _createPixelBuffer(int w, int h, Surface owner) { return null; }
    protected Font.Glyph _createGlyph(org.xwt.Font f, char c) { return new DefaultGlyph(f, c); }

    public static PixelBuffer createPixelBuffer(int w, int h, Surface s) { return platform._createPixelBuffer(w, h, s); }
    public static Picture createPicture(JS r) { return platform._createPicture(r); }
    public static Font.Glyph createGlyph(org.xwt.Font f, char c) { return platform._createGlyph(f, c); }
    public static Surface createSurface(Box b, boolean framed, boolean refreshable) {
        Surface ret = platform._createSurface(b, framed);
        ret.setInvisible(false);
        if (refreshable) {
            Surface.allSurfaces.addElement(ret);
            ret.dirty(0, 0, b.width, b.height);
            ret.Refresh();
        }
        try {
            if (b.get("titlebar") != null) ret.setTitleBarText((String)b.get("titlebar"));
        } catch (JSExn e) {
            Log.warn(Platform.class, e);
        }
        return ret;
    }

    /** a string describing the VM */
    protected String getDescriptiveName() { return "Generic Java 1.1 VM"; }

    /** invoked after initialization messages have been printed; useful for additional platform detection log messages */
    protected void postInit() { }

    /** the human-readable name of the key mapped to XWT's 'alt' key */
    public static String altKeyName() { return platform._altKeyName(); }
    protected String _altKeyName() { return "alt"; }

    /** returns the contents of the clipboard */    
    public static Object getClipBoard() { return clipboardReadEnabled ? platform._getClipBoard() : null; }
    protected String _getClipBoard() { return null; }

    /** sets the contents of the clipboard */
    public static void setClipBoard(String s) { platform._setClipBoard(s); }
    protected void _setClipBoard(String s) { }

    /** returns the width of the screen, in pixels */
    public static int getScreenWidth() { return platform._getScreenWidth(); }
    protected int _getScreenWidth() { return 640; }

    /** returns the height of the screen, in pixels */
    public static int getScreenHeight() { return platform._getScreenHeight(); }
    protected int _getScreenHeight() { return 480; }

    /** used to notify the user of very serious failures; usually used when logging is not working or unavailable */
    protected void _criticalAbort(String message) { System.exit(-1); }
    public static void criticalAbort(String message) {
        Log.info(Platform.class, "Critical Abort:");
        Log.info(Platform.class, message);
        platform._criticalAbort(message);
    }

    /** if true, org.xwt.Surface will generate a Click automatically after a press and a release */
    public static boolean needsAutoClick() { return platform._needsAutoClick(); }
    protected boolean _needsAutoClick() { return false; }

    /** if true, org.xwt.Surface will generate a DoubleClick automatically after recieving two clicks in a short period of time */
    public static boolean needsAutoDoubleClick() { return platform._needsAutoDoubleClick(); }
    protected boolean _needsAutoDoubleClick() { return false; }

    /** returns true iff the platform has a case-sensitive filesystem */
    public static boolean isCaseSensitive() { return platform._isCaseSensitive(); }
    protected boolean _isCaseSensitive() { return true; }

    /** returns an InputStream to the builtin xwar */
    public static InputStream getBuiltinInputStream() { return platform._getBuiltinInputStream(); }
    protected InputStream _getBuiltinInputStream() {return getClass().getClassLoader().getResourceAsStream("org/xwt/builtin.jar");}

    /** returns the value of the environment variable key, or null if no such key exists */
    public static String getEnv(String key) { return platform._getEnv(key); }
    protected String _getEnv(String key) {
        try {
            String os = System.getProperty("os.name").toLowerCase();
            Process p;
            if (os.indexOf("windows 9") != -1 || os.indexOf("windows me") != -1) {
                // hack -- jdk1.2/1.3 on Win32 pop open an ugly DOS box; 1.4 does not
                if (platform.getClass().getName().endsWith("Java12")) return null;
                p = Runtime.getRuntime().exec("command.com /c set");
            } else if (os.indexOf("windows") > -1) {
                // hack -- jdk1.2/1.3 on Win32 pop open an ugly DOS box; 1.4 does not
                if (platform.getClass().getName().endsWith("Java12")) return null;
                p = Runtime.getRuntime().exec("cmd.exe /c set");
            } else {  
                p = Runtime.getRuntime().exec("env");
            }
            BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
            String s;
            while ((s = br.readLine()) != null)
                if (s.startsWith(key + "="))
                    return s.substring(key.length() + 1);
        } catch (Exception e) {
            Log.info(this, "Exception while reading from environment:");
            Log.info(this, e);
        }
        return null;
    }

    /** convert a JPEG into an Image */
    public static synchronized void decodeJPEG(InputStream is, Picture p) { platform._decodeJPEG(is, p); }
    protected abstract void _decodeJPEG(InputStream is, Picture p);

    /** displays a platform-specific "open file" dialog and returns the chosen filename, or null if the user hit cancel */
    protected String _fileDialog(String suggestedFileName, boolean write) { return null; }
    public static String fileDialog(String suggestedFileName, boolean write) throws org.xwt.js.JSExn {
        return platform._fileDialog(suggestedFileName, write);
    }

    /** default implementation is Eric Albert's BrowserLauncher.java */
    protected void _newBrowserWindow(String url) {
        try {
            Class c = Class.forName("edu.stanford.ejalbert.BrowserLauncher");
            Method m = c.getMethod("openURL", new Class[] { String.class });
            m.invoke(null, new String[] { url });
        } catch (Exception e) {
            Log.warn(this, "exception trying to open a browser window");
            Log.warn(this, e);
        }
    }

    /** opens a new browser window */
    public static void newBrowserWindow(String url) {
        if (!(url.startsWith("https://") || url.startsWith("http://") || url.startsWith("ftp://") || url.startsWith("mailto:"))) {
            Log.info(Platform.class, "xwt.newBrowserWindow() only supports http and https urls");
            return;
        }
        // check the URL for well-formedness, as a defense against buffer overflow attacks
        try {
            String u = url;
            if (u.startsWith("https")) u = "http" + u.substring(5);
            new URL(u);
        } catch (MalformedURLException e) {
            Log.info(Platform.class, "URL " + url + " is not well-formed");
            Log.info(Platform.class, e);
        }
        Log.info(Platform.class, "newBrowserWindow, url = " + url);
        platform._newBrowserWindow(url);
    }

    /** detects proxy settings */
    protected synchronized org.xwt.HTTP.Proxy _detectProxy() { return null; }
    public static synchronized org.xwt.HTTP.Proxy detectProxy() {

        if (cachedProxyInfo != null) return cachedProxyInfo;
        if (alreadyDetectedProxy) return null;
        alreadyDetectedProxy = true;

        Log.info(Platform.class, "attempting environment-variable DNS proxy detection");
        cachedProxyInfo = org.xwt.HTTP.Proxy.detectProxyViaManual();
        if (cachedProxyInfo != null) return cachedProxyInfo;

        Log.info(Platform.class, "attempting " + platform.getClass().getName() + " proxy detection");
        cachedProxyInfo = platform._detectProxy();
        if (cachedProxyInfo != null) return cachedProxyInfo;

        return cachedProxyInfo;
   } 

    /** returns a Scheduler instance; used to implement platform-specific schedulers */
    protected Scheduler _getScheduler() { return new Scheduler(); }
    public static Scheduler getScheduler() { return platform._getScheduler(); }

    // FEATURE: be more efficient for many of the subclasses
    public static class DefaultGlyph extends Font.Glyph {
        private Picture p = null;
        public DefaultGlyph(org.xwt.Font f, char c) { super(f, c); }
        public Picture getPicture() {
            if (p == null && isLoaded) {
                Picture p = createPicture(null);
                p.data = new int[data.length];
                for(int i=0; i<data.length; i++) p.data[i] = (data[i] & 0xff) << 24;
                this.data = null;
                p.width = this.width;
                p.height = this.height;
                p.isLoaded = true;
                this.p = p;
            }
            return p;
        }
    }
}