/**

  * Back 2 Browser Bytecode Translator

  * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

  *

  * This program is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, version 2 of the License.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. Look for COPYING file in the top folder.

  * If not, see http://opensource.org/licenses/GPL-2.0.

  */

 package org.apidesign.bck2brwsr.vmzip;

 import java.io.ByteArrayInputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import org.apidesign.bck2brwsr.core.Exported;

 import org.apidesign.bck2brwsr.core.JavaScriptBody;

 import org.apidesign.bck2brwsr.emul.zip.FastJar;

 import org.apidesign.vm4brwsr.Bck2Brwsr;

 /** Conversion from classpath to load function.

  *

  * @author Jaroslav Tulach <jtulach@netbeans.org>

  */

 @Exported

 public final class ZipResources implements Bck2Brwsr.Resources {

     private final FastJar fj;

     @Exported

     public ZipResources(byte[] zipData) throws IOException {

 //        long bef = timeNow();

         fj = new FastJar(zipData);

         for (FastJar.Entry e : fj.list()) {

             putRes(e.name, e);

         }

 //        log("Iterating thru " + path + " took " + (timeNow() - bef) + "ms");

     }

     @JavaScriptBody(args = { "arr" }, body = "return arr.length;")

     private static native int length(Object arr);

     @JavaScriptBody(args = { "arr", "index", "value" }, body = "arr[index] = value; return value;")

     private static native Object set(Object arr, int index, Object value);

     @JavaScriptBody(args = { "msg" }, body = "if (typeof console !== 'undefined') console.log(msg.toString());")

     private static native void log(String msg);

     private byte[] findRes(String res) throws IOException {

         Object arr = findResImpl(res);

         if (arr instanceof FastJar.Entry) {

             long bef = timeNow();

             InputStream zip = fj.getInputStream((FastJar.Entry)arr);

             arr = readFully(new byte[512], zip);

             putRes(res, arr);

             log("Reading " + res + " took " + (timeNow() - bef) + "ms");

         }

         return (byte[]) arr;

     }

     @Override

     public InputStream get(String resource) throws IOException {

         byte[] arr = findRes(resource);

         return arr == null ? null : new ByteArrayInputStream(arr);

     }

     @JavaScriptBody(args = { "res" }, body = "var r = this[res]; return r ? r : null;")

     private native Object findResImpl(String res);

     @JavaScriptBody(args = { "res", "arr" }, body = "this[res] = arr;")

     private native void putRes(String res, Object arr);

     @JavaScriptBody(args = { "arr", "len" }, body = "while (arr.length < len) arr.push(0);")

     private static native void enlargeBytes(byte[] arr, int len);

     @JavaScriptBody(args = { "arr", "len" }, body = "arr.splice(len, arr.length - len);")

     private static native void sliceArray(byte[] arr, int len);

     private static Object readFully(byte[] arr, InputStream zip) throws IOException {

         int offset = 0;

         for (;;) {

             int len = zip.read(arr, offset, arr.length - offset);

             if (len == -1) {

                 break;

             }

             offset += len;

             if (offset == arr.length) {

                 enlargeBytes(arr, arr.length + 4096);

             }

         }

         sliceArray(arr, offset);

         return arr;

     }

     private static long timeNow() {

         double time = m();

         if (time >= 0) {

             return (long)time;

         }

         return org.apidesign.bck2brwsr.emul.lang.System.currentTimeMillis();

     }

     @JavaScriptBody(args = {}, body = 

         "if (typeof window.performance === 'undefined') return -1;\n"

       + "if (typeof window.performance.now === 'undefined') return -1;\n"

       + "return window.performance.now();"

     )

     private static native double m();

 }