// Copyright 2003 Adam Megacz, see the COPYING file for licensing [GPL]
package org.xwt;

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

/**
 *  A singleton class that acts as a repository for files obtained
 *  from xwar archives or the local filesystem.
 *
 *  All names are converted to resource names (dots instead of
 *  slashes) when they are loaded into this repository; however,
 *  filename extensions are left on, so queries (resolveResource(),
 *  getResource()) should include the extension when querying for
 *  resources.
 */
public class Resources {

    /** Holds resources added at runtime. Initialized to hold 2000 to work around a NetscapeJVM bug. */
    private static Hash bytes = new Hash(2000, 3);

    /** keeps track of which archive loaded templates into which package */
    private static Hash usedPackages = new Hash();

    /** Returns true iff <tt>name</tt> is a valid resource name */
    private static boolean validResourceName(String name) {
        if (name == null || name.equals("")) return true;
        if (name.endsWith("/box.xwt") || name.endsWith("/svg.xwt")) return false;
        if (name.equals("box.xwt") || name.equals("svg.xwt")) return false;
        if (!((name.charAt(0) >= 'A' && name.charAt(0) <= 'Z') ||
              (name.charAt(0) >= 'a' && name.charAt(0) <= 'z'))) return false;
        for(int i=1; i<name.length(); i++) {
            char c = name.charAt(i);
            if (!((c >= 'A' && c <= 'Z') ||
                  (c >= 'a' && c <= 'z') ||
                  c == '_' || c == '.' || 
                  (c >= '0' && c <= '9'))) return false;
        }
        return true;
    }

    /** Load a directory as if it were an archive */
    public static synchronized void loadDirectory(File dir) throws IOException { loadDirectory(dir, ""); }
    private static synchronized void loadDirectory(File dir, String prefix) throws IOException {
        String n = prefix.replace(File.separatorChar, '.');
        if (n.endsWith(".")) n = n.substring(0, n.length() - 1);
        new Static(n);
        String[] subfiles = dir.list();
        for(int i=0; i<subfiles.length; i++) {
            if (subfiles[i].equals("CVS") || !validResourceName(subfiles[i])) continue;
            String name = prefix + subfiles[i];
            File file = new File(dir.getPath() + File.separatorChar + subfiles[i]);
            if (file.isDirectory()) {
                loadDirectory(file, name + File.separatorChar);
            } else {
                if (name.endsWith(".xwt")) {
                    String name2 = name.substring(0, name.length() - 4);
                    Static.createStatic(name2.replace(File.separatorChar, '.'), false);
                }
                bytes.put(name.replace(File.separatorChar, '.'), file);
            }
        }
    }

    /** Load an archive from an inputstream. */
    public static synchronized void loadArchive(InputStream is) throws IOException { loadArchive(is, 0, null); }
    public static synchronized void loadArchive(InputStream is, final int length, final JS.Callable callback) throws IOException {

        // random placeholder
        Object thisArchive = new Object();

        ZipInputStream zis = new ZipInputStream(new FilterInputStream(is) {
                int bytesDownloaded = 0;
                boolean clear = true;
                public int read() throws IOException {
                    bytesDownloaded++;
                    return super.read();
                }
                public int read(byte[] b, int off, int len) throws IOException {
                    int ret = super.read(b, off, len);
                    if (clear && callback != null) {
                        clear = false;
                        ThreadMessage.newthread(new JS.Callable() {
                                public Object call(JS.Array args_) throws JS.Exn {
                                    try {
                                        JS.Array args = new JS.Array();
                                        args.addElement(new Double(bytesDownloaded));
                                        args.addElement(new Double(length));
                                        callback.call(args);
                                    } finally {
                                        clear = true;
                                    }
                                    return null;
                                }                            
                            });
                    }
                    bytesDownloaded += ret;
                    return ret;
                }
            });

        Template.TemplateHelper t = new Template.TemplateHelper();

        for(ZipEntry ze = zis.getNextEntry(); ze != null; ze = zis.getNextEntry()) {
            String name = ze.getName();
            if (!validResourceName(name.substring(name.lastIndexOf('/') + 1))) {
                if (Log.on) Log.log(Resources.class, "WARNING: ignoring xwar entry with invalid name: " + name);
                continue;
            }

            if (name.endsWith(".xwt")) {
                // placeholder so resolveResource() works properly
                bytes.put(name.replace('/', '.'), new byte[] { });
                name = name.substring(0, name.length() - 4);
                Static.createStatic(name.replace('/', '.'), false);
                Template.buildTemplate(zis, name.replace('/', '.'), t);

            } else {
                bytes.put(name.replace('/', '.'), isToByteArray(zis));
            }
        }
        if (Log.verbose) Log.log(Resources.class, "done loading archive");
    }

    /** holds the current theme mappings */
    static Vector mapFrom = new Vector();

    /** holds the current theme mappings */
    static Vector mapTo = new Vector();
    static {
        mapFrom.addElement("xwt.standard");
        mapTo.addElement("org.xwt.themes.monopoly");
    }

    /**
     *  Resolves the partial resource name <tt>name</tt> to a fully
     *  resolved resource name, using <tt>importlist</tt> as a search
     *  list, or null if no resource was found.
     *
     *  Both the arguments and return values from this function SHOULD
     *  include extensions (".xwt", ".xwf", etc) and SHOULD use dots
     *  (".") instead of slashes ("/").
     */
    public static String resolve(String name, String[] importlist) {
        final int imax = importlist == null ? 0 : importlist.length;
        for(int i=-1; i < imax; i++) {
            String resolved = i == -1 ? name : (importlist[i] + '.' + name);
            for(int j=mapFrom.size() - 1; j>=0; j--) {
                String from = mapFrom.elementAt(j).toString();
                if (resolved.startsWith(from) && (resolved.endsWith(".xwt") || resolved.endsWith(".xwf"))) {
                    String tryme = mapTo.elementAt(j) + resolved.substring(from.length());
                    if (bytes.get(tryme) != null) return tryme;
                }
            }
            if (bytes.get(resolved) != null) return resolved;
        }
        return null;
    }

    /** Returns the named resource as a byte[].
     *  @param name A fully resolved resource name, using slashes
     *              instead of periods. If it is null, this function
     *              will return null.
     */
    public static byte[] getResource(String name) {
        if (name == null) return null;
        synchronized(bytes) {
            Object o = bytes.get(name);
            if (o == null) return null;
            if (o instanceof byte[]) return ((byte[])o);
            if (o instanceof File) {
                try {
                    FileInputStream fi = new FileInputStream((File)o);
                    byte[] b = isToByteArray(fi);
                    bytes.put(name, b);
                    return b;
                } catch (Exception e) {
                    if (Log.on) Log.log(Resources.class, "Exception while reading from file " + o);
                    if (Log.on) Log.log(Resources.class, e);
                    return null;
                }
            }
            return null;
        }
    }
    
    /** scratch space for isToByteArray() */
    private static byte[] workspace = new byte[16 * 1024];

    /** Trivial method to completely read an InputStream */
    public static synchronized byte[] isToByteArray(InputStream is) throws IOException {
        int pos = 0;
        while (true) {
            int numread = is.read(workspace, pos, workspace.length - pos);
            if (numread == -1) break;
            else if (pos + numread < workspace.length) pos += numread;
            else {
                pos += numread;
                byte[] temp = new byte[workspace.length * 2];
                System.arraycopy(workspace, 0, temp, 0, workspace.length);
                workspace = temp;
            }
        }
        byte[] ret = new byte[pos];
        System.arraycopy(workspace, 0, ret, 0, pos);
        return ret;
    }
}