/*

 * Copyright (c) 2016, 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.

 */

package p1;

import java.io.InputStream;

import java.io.IOException;

import java.lang.module.ModuleDescriptor;

import java.net.URI;

import java.nio.file.FileSystem;

import java.nio.file.FileSystems;

import java.nio.file.Files;

import java.nio.file.Path;

import java.util.Collections;

import java.util.Set;

import jdk.internal.module.ClassFileAttributes;

import jdk.internal.module.ClassFileAttributes.ModuleTargetAttribute;

import jdk.internal.module.ClassFileConstants;

import jdk.internal.org.objectweb.asm.Attribute;

import jdk.internal.org.objectweb.asm.ClassReader;

import jdk.internal.org.objectweb.asm.ClassVisitor;

import jdk.internal.org.objectweb.asm.Opcodes;

public class Main {

    private static boolean hasModuleTarget(InputStream in) throws IOException {

        ModuleTargetAttribute[] modTargets = new ModuleTargetAttribute[1];

        ClassVisitor cv = new ClassVisitor(Opcodes.ASM5) {

            @Override

            public void visitAttribute(Attribute attr) {

                if (attr instanceof ModuleTargetAttribute) {

                    modTargets[0] = (ModuleTargetAttribute)attr;

                }

            }

        };

        // prototype of attributes that should be parsed

        Attribute[] attrs = new Attribute[] {

            new ModuleTargetAttribute()

        };

        // parse module-info.class

        ClassReader cr = new ClassReader(in);

        cr.accept(cv, attrs, 0);

        return modTargets[0] != null &&

            (modTargets[0].osName() != null || modTargets[0].osArch() != null);

    }

    public static void main(String... args) throws Exception {

        // load another package

        p2.T.test();

        // validate the module descriptor

        validate(Main.class.getModule());

        // validate the Moduletarget attribute for java.base

        FileSystem fs = FileSystems.newFileSystem(URI.create("jrt:/"),

                                                  Collections.emptyMap());

        Path path = fs.getPath("/", "modules", "java.base", "module-info.class");

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

            if (! hasModuleTarget(in)) {

                throw new RuntimeException("Missing ModuleTarget for java.base");

            }

        }

    }

    static void validate(Module module) throws IOException {

        ModuleDescriptor md = module.getDescriptor();

        // read m1/module-info.class

        FileSystem fs = FileSystems.newFileSystem(URI.create("jrt:/"),

                                                  Collections.emptyMap());

        Path path = fs.getPath("/", "modules", module.getName(), "module-info.class");

        ModuleDescriptor md1 = ModuleDescriptor.read(Files.newInputStream(path));

        // check the module descriptor of a system module and read from jimage

        checkPackages(md.packages(), "p1", "p2");

        checkPackages(md1.packages(), "p1", "p2");

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

            checkModuleTargetAttribute(in, "p1");

        }

    }

    static void checkPackages(Set<String> pkgs, String... expected) {

        if (!pkgs.equals(Set.of(expected))) {

            throw new RuntimeException(pkgs + " expected: " + Set.of(expected));

        }

    }

    static void checkModuleTargetAttribute(InputStream in, String modName) throws IOException {

        if (hasModuleTarget(in)) {

            throw new RuntimeException("ModuleTarget present for " + modName);

        }

    }

}