/*******************************************************************************
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *******************************************************************************/
package org.ofbiz.base.start;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.management.ManagementFactory;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.List;
import java.util.ArrayList;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public final class InstrumenterWorker {

    public static final void copy(InputStream in, OutputStream out) throws IOException {
        byte[] buf = new byte[4096];
        int r;
        while ((r = in.read(buf)) != -1) {
            out.write(buf, 0, r);
        }
    }

    public static List<File> instrument(List<File> srcPaths, String instrumenterFileName, String instrumenterClassName) {
        if (instrumenterFileName == null) return srcPaths;
        if (instrumenterClassName == null) return srcPaths;
        Instrumenter instrumenter;
        try {
            List<URL> tmpUrls = new ArrayList<URL>();
            for (File file: srcPaths) {
                tmpUrls.add(file.toURI().toURL());
            }
            ClassLoader tmpLoader = new URLClassLoader(tmpUrls.toArray(new URL[tmpUrls.size()]), InstrumenterWorker.class.getClassLoader());
            instrumenter = (Instrumenter) tmpLoader.loadClass(instrumenterClassName).newInstance();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
            return srcPaths;
        } catch (InstantiationException e) {
            e.printStackTrace();
            return srcPaths;
        } catch (IOException e) {
            e.printStackTrace();
            return srcPaths;
        } catch (ClassNotFoundException e) {
            return srcPaths;
        }
        ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(ManagementFactory.getOperatingSystemMXBean().getAvailableProcessors());
        try {
            File instrumenterFile = new File(instrumenterFileName);
            instrumenterFile.delete();
            instrumenter.open(instrumenterFile, true);
            List<Future<File>> futures = new ArrayList<Future<File>>();
            for (File file: srcPaths) {
                String path = file.getPath();
                if (path.matches(".*/ofbiz[^/]*\\.(jar|zip)")) {
                    futures.add(executor.submit(new FileInstrumenter(instrumenter, file)));
                } else {
                    futures.add(new ConstantFutureFile(file));
                }
            }
            List<File> result = new ArrayList<File>(futures.size());
            for (Future<File> future: futures) {
                result.add(future.get());
            }
            instrumenter.close();
            return result;
        } catch (ExecutionException e) {
            e.printStackTrace();
            return srcPaths;
        } catch (InterruptedException e) {
            e.printStackTrace();
            return srcPaths;
        } catch (IOException e) {
            e.printStackTrace();
            return srcPaths;
        } finally {
            executor.shutdown();
        }
    }

    private static final class ConstantFutureFile implements Future<File> {
        private final File file;

        protected ConstantFutureFile(File file) {
            this.file = file;
        }

        public boolean cancel(boolean mayInterruptIfRunning) {
            return false;
        }

        public File get() {
            return file;
        }

        public File get(long timeout, TimeUnit  unit) {
            return file;
        }

        public boolean isCancelled() {
            return false;
        }

        public boolean isDone() {
            return true;
        }
    }

    private static final class FileInstrumenter implements Callable<File> {
        private final Instrumenter instrumenter;
        private final File file;
        private final String path;

        protected FileInstrumenter(Instrumenter instrumenter, File file) {
            this.instrumenter = instrumenter;
            this.file = file;
            this.path = file.getPath();
        }

        public File call() throws IOException {
            System.err.println(Thread.currentThread() + ":instrumenting " + path);
            String prefix = path.substring(0, path.length() - 4);
            int slash = prefix.lastIndexOf("/");
            if (slash != -1) prefix = prefix.substring(slash + 1);
            prefix += "-";
            File zipTmp = File.createTempFile("instrumented-" + prefix, path.substring(path.length() - 4));
            try {
                zipTmp.deleteOnExit();
                ZipInputStream zin = new ZipInputStream(new FileInputStream(file));
                ZipOutputStream zout = new ZipOutputStream(new FileOutputStream(zipTmp));
                ZipEntry entry;
                while ((entry = zin.getNextEntry()) != null) {
                    InputStream in;
                    long size;
                    if (entry.getName().endsWith(".class")) {
                        ByteArrayOutputStream baos = new ByteArrayOutputStream();
                        copy(zin, baos);
                        byte[] bytes = instrumenter.instrumentClass(baos.toByteArray());
                        size = bytes.length;
                        in = new ByteArrayInputStream(bytes);
                    } else {
                        in = zin;
                        size = entry.getSize();
                    }
                    ZipEntry newEntry = new ZipEntry(entry);
                    newEntry.setSize(size);
                    newEntry.setCompressedSize(-1);
                    zout.putNextEntry(newEntry);
                    copy(in, zout);
                    if (entry.getName().endsWith(".class")) {
                        in.close();
                    }
                }
                zout.close();
                return zipTmp;
            } catch (IOException e) {
                zipTmp.delete();
                throw e;
            }
        }
    }
}