/*

 * Copyright (c) 2017, 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.

 *

 * 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.

 */

import java.io.InputStream;

import java.io.IOException;

import java.lang.module.ModuleReader;

import java.lang.module.ModuleReference;

import java.net.URI;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import jdk.internal.module.ModuleInfo;

import jdk.internal.module.ModuleInfo.Attributes;

public class ModuleTargetHelper {

    private ModuleTargetHelper() {}

    public static final class ModuleTarget {

        private String targetPlatform;

        public ModuleTarget(String targetPlatform) {

            this.targetPlatform = targetPlatform;

        }

        public String targetPlatform() {

            return targetPlatform;

        }

    }

    public static ModuleTarget getJavaBaseTarget() throws IOException {

        Path p = Paths.get(URI.create("jrt:/modules/java.base/module-info.class"));

        try (InputStream in = Files.newInputStream(p)) {

            return read(in);

        }

    }

    public static ModuleTarget read(InputStream in) throws IOException {

        ModuleInfo.Attributes attrs = ModuleInfo.read(in, null);

        if (attrs.target() != null) {

            return new ModuleTarget(attrs.target().targetPlatform());

        } else {

            return null;

        }

    }

    public static ModuleTarget read(ModuleReference modRef) throws IOException {

        ModuleReader reader = modRef.open();

        try (InputStream in = reader.open("module-info.class").get()) {

            return read(in);

        } finally {

            reader.close();

        }

    }

}