/*

 * Copyright (c) 2019, 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 org.graalvm.compiler.test;

import java.io.IOException;

import java.lang.module.ModuleDescriptor.Requires;

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.ArrayList;

import java.util.Collections;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

import org.graalvm.compiler.debug.DebugOptions;

import jdk.internal.module.Modules;

public class ModuleSupport {

    public static void exportPackageTo(Class<?> moduleMember, String packageName, Class<?> requestor) {

        Module moduleToExport = moduleMember.getModule();

        Module requestorModule = requestor.getModule();

        if (moduleToExport != requestorModule) {

            Modules.addExports(moduleToExport, packageName, requestorModule);

        }

    }

    public static void exportAllPackagesTo(Class<?> moduleMember, Class<?> requestor) {

        Module moduleToExport = moduleMember.getModule();

        Module requestorModule = requestor.getModule();

        if (moduleToExport != requestorModule) {

            for (String packageName : moduleToExport.getPackages()) {

                Modules.addExports(moduleToExport, packageName, requestorModule);

            }

        }

    }

    public static void exportAllPackagesTo(Class<?> moduleMember, ClassLoader cl) {

        Module moduleToExport = moduleMember.getModule();

        Module unnamedModule = cl.getUnnamedModule();

        for (String packageName : moduleToExport.getPackages()) {

            Modules.addExports(moduleToExport, packageName, unnamedModule);

        }

    }

    @SuppressWarnings("unused")

    public static void exportAndOpenAllPackagesToUnnamed(String name) {

        Module module = ModuleLayer.boot().findModule(name).orElseThrow();

        Set<String> packages = module.getPackages();

        for (String pkg : packages) {

            Modules.addExportsToAllUnnamed(module, pkg);

            Modules.addOpensToAllUnnamed(module, pkg);

        }

    }

    public static List<String> getJRTGraalClassNames() throws IOException {

        List<String> classNames = new ArrayList<>();

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

        Module graalModule = DebugOptions.class.getModule();

        Set<String> graalModuleSet = new HashSet<>();

        graalModuleSet.add(graalModule.getName());

        for (Module module : graalModule.getLayer().modules()) {

            if (requires(module, graalModule)) {

                graalModuleSet.add(module.getName());

            }

        }

        Path top = fs.getPath("/modules/");

        Files.find(top, Integer.MAX_VALUE,

                        (path, attrs) -> attrs.isRegularFile()).forEach(p -> {

                            int nameCount = p.getNameCount();

                            if (nameCount > 2) {

                                String base = p.getName(nameCount - 1).toString();

                                if (base.endsWith(".class") && !base.equals("module-info.class")) {

                                    String module = p.getName(1).toString();

                                    if (graalModuleSet.contains(module)) {

                                        // Strip module prefix and convert to dotted

                                        // form

                                        String className = p.subpath(2, nameCount).toString().replace('/', '.');

                                        // Strip ".class" suffix

                                        className = className.replace('/', '.').substring(0, className.length() - ".class".length());

                                        classNames.add(className);

                                    }

                                }

                            }

                        });

        return classNames;

    }

    private static boolean requires(Module module, Module graalModule) {

        ModuleLayer graalLayer = graalModule.getLayer();

        for (Requires r : module.getDescriptor().requires()) {

            if (r.name().equals(graalModule.getName())) {

                return true;

            }

            Module dep = graalLayer.findModule(r.name()).get();

            if (requires(dep, graalModule)) {

                return true;

            }

        }

        return false;

    }

}