/*
 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package build.tools.symbolgenerator;

import com.sun.source.util.JavacTask;
import com.sun.tools.javac.api.JavacTool;
import com.sun.tools.javac.util.Context;
import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.EnumSet;
import java.util.List;
import java.util.Set;

import javax.tools.JavaFileManager;
import javax.tools.JavaFileManager.Location;
import javax.tools.JavaFileObject;
import javax.tools.JavaFileObject.Kind;
import javax.tools.StandardLocation;

/**A tool to dump the content of the default javac's bootclasspath. This tool should not use any
 * features not available on the oldest supported target JDK, or not available in the boot JDK.
 *
 * For more information on use of this site, please see CreateSymbols.
 */
public class ProbeModular {

    public static void main(String... args) throws IOException {
        if (args.length != 1) {
            System.err.println("Not enough arguments.");
            System.err.println("Usage:");
            System.err.println("    java " +
                               ProbeModular.class.getName() +
                               " <output-file>");
            return ;
        }

        File outFile = new File(args[0]);
        Charset cs = Charset.forName("UTF-8");
        JavacTool tool = JavacTool.create();
        Context ctx = new Context();
        String version = System.getProperty("java.specification.version");
        JavacTask task = tool.getTask(null, null, null,
                                      Arrays.asList("--release", version),
                                      null, null, ctx);
        task.getElements().getTypeElement("java.lang.Object");
        JavaFileManager fm = ctx.get(JavaFileManager.class);

        try (OutputStream out = new FileOutputStream(outFile)) {
            for (Location modLoc : LOCATIONS) {
                for (Set<JavaFileManager.Location> module :
                        fm.listLocationsForModules(modLoc)) {
                    for (JavaFileManager.Location loc : module) {
                        Iterable<JavaFileObject> files =
                                fm.list(loc,
                                        "",
                                        EnumSet.of(Kind.CLASS),
                                        true);

                        for (JavaFileObject jfo : files) {
                            try (InputStream is = jfo.openInputStream();
                                 InputStream in =
                                         new BufferedInputStream(is)) {
                                ByteArrayOutputStream baos =
                                        new ByteArrayOutputStream();
                                StringBuilder textual = new StringBuilder();
                                int read;

                                while ((read = in.read()) != (-1)) {
                                    baos.write(read);
                                    String hex = String.format("%02x", read);
                                    textual.append(hex);
                                }

                                textual.append("\n");
                                out.write(textual.toString().getBytes(cs));
                            }
                        }
                    }
                }
            }
        }
    }
    //where:
        private static final List<StandardLocation> LOCATIONS =
                Arrays.asList(StandardLocation.SYSTEM_MODULES,
                              StandardLocation.UPGRADE_MODULE_PATH);

}