/*

 * 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.  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

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package build.tools.symbolgenerator;

import java.io.IOException;

import java.util.Arrays;

import java.util.HashSet;

import java.util.LinkedList;

import java.util.List;

import java.util.Set;

import java.util.stream.Collectors;

import javax.lang.model.element.ModuleElement.RequiresDirective;

import javax.lang.model.util.Elements;

import javax.tools.JavaCompiler;

import javax.tools.ToolProvider;

import com.sun.tools.javac.api.JavacTaskImpl;

import com.sun.tools.javac.code.Symbol.ModuleSymbol;

/**

 * Print reflexive transitive closure of the given modules along their requires transitive edges.

 */

public class TransitiveDependencies {

    private static void help() {

        System.err.println("java TransitiveDependencies <module-source-path> <root-modules>");

    }

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

        if (args.length < 1) {

            help();

            return ;

        }

        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();

        List<String> options = Arrays.asList("-source", "9",

                                             "-target", "9",

                                             "-proc:only",

                                             "--system", "none",

                                             "--module-source-path", args[0],

                                             "--add-modules", Arrays.stream(args)

                                                                    .skip(1)

                                                                    .collect(Collectors.joining(",")));

        List<String> jlObjectList = Arrays.asList("java.lang.Object");

        JavacTaskImpl task = (JavacTaskImpl) compiler.getTask(null, null, null, options, jlObjectList, null);

        task.enter();

        Elements elements = task.getElements();

        List<String> todo = new LinkedList<>();

        Arrays.stream(args).skip(1).forEach(todo::add);

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

        while (!todo.isEmpty()) {

            String current = todo.remove(0);

            if (!allModules.add(current))

                continue;

            ModuleSymbol mod = (ModuleSymbol) elements.getModuleElement(current);

            if (mod == null) {

                throw new IllegalStateException("Missing: " + current);

            }

             //use the internal structure to avoid unnecesarily completing the symbol using the UsesProvidesVisitor:

            for (RequiresDirective rd : mod.requires) {

                if (rd.isTransitive()) {

                    todo.add(rd.getDependency().getQualifiedName().toString());

                }

            }

        }

        allModules.add("java.base");

        allModules.add("jdk.unsupported");

        allModules.stream()

                  .sorted()

                  .forEach(System.out::println);

    }

}