/*

 * Copyright (c) 2012, 2014, 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 com.sun.tools.jdeps;

import com.sun.tools.classfile.ClassFile;

import com.sun.tools.jdeps.ClassFileReader.ModuleClassReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.BufferedInputStream;

import java.net.URI;

import java.nio.file.*;

import java.nio.file.attribute.BasicFileAttributes;

import java.util.*;

import java.util.stream.Collectors;

/**

 * ClassPath for Java SE and JDK

 */

class PlatformClassPath {

    private static List<Archive> modules;

    static synchronized List<Archive> getModules(Path mpath) throws IOException {

        if (modules == null) {

            initPlatformModules(mpath);

        }

        return modules;

    }

    private static void initPlatformModules(Path mpath) throws IOException {

        ImageHelper helper = ImageHelper.getInstance(mpath);

        String fn = System.getProperty("jdeps.modules.xml");

        if (fn != null) {

            Path p = Paths.get(fn);

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

                modules = new ArrayList<>(ModulesXmlReader.load(helper, in));

            }

        } else {

            try (InputStream in = PlatformClassPath.class

                    .getResourceAsStream("resources/jdeps-modules.xml")) {

                modules = new ArrayList<>(ModulesXmlReader.load(helper, in));

            }

        }

        if (findModule("java.base") != null) {

            Profile.initProfiles(modules);

        }

    }

    /**

     * Finds the module with the given name. Returns null

     * if such module doesn't exist.

     *

     * @param mn module name

     */

    static Module findModule(String mn) {

        for (Archive a : modules) {

            if (Module.class.isInstance(a)) {

                Module m = (Module)a;

                if (mn.equals(m.name())) {

                    return m;

                }

            }

        }

        return null;

    }

    /**

     * Returns JAR files in $java.home/lib.  This is for transition until

     * all components are linked into jimage.

     */

    static List<Archive> getJarFiles() throws IOException {

        Path home = Paths.get(System.getProperty("java.home"), "lib");

        return Files.find(home, 1, (Path p, BasicFileAttributes attr)

                -> p.getFileName().toString().endsWith(".jar"))

                .map(Archive::getInstance)

                .collect(Collectors.toList());

    }

    static class ImageHelper {

        private static boolean isJrtAvailable() {

            try {

                FileSystems.getFileSystem(URI.create("jrt:/"));

                return true;

            } catch (ProviderNotFoundException | FileSystemNotFoundException e) {

                return false;

            }

        }

        static ImageHelper getInstance(Path mpath) throws IOException {

            if (mpath != null) {

                return new ImageHelper(mpath);

            }

            if (isJrtAvailable()) {

                // jrt file system

                FileSystem fs = FileSystems.getFileSystem(URI.create("jrt:/"));

                return new ImageHelper(fs, fs.getPath("/modules"));

            } else {

                // exploded modules

                String home = System.getProperty("java.home");

                Path exploded = Paths.get(home, "modules");

                if (!Files.isDirectory(exploded)) {

                     throw new InternalError(home + " not a modular image");

                }

                return new ImageHelper(exploded);

            }

        }

        private final FileSystem fs;

        private final Path mpath;

        ImageHelper(Path path) throws IOException {

            this(FileSystems.getDefault(), path);

        }

        ImageHelper(FileSystem fs, Path path) throws IOException {

            this.fs = fs;

            this.mpath = path;

        }

        /**

         * Returns a ModuleClassReader that only reads classes for the given modulename.

         */

        public ModuleClassReader getModuleClassReader(String modulename)

            throws IOException

        {

            Path mp = mpath.resolve(modulename);

            if (Files.exists(mp) && Files.isDirectory(mp)) {

                return new ModuleClassReader(fs, modulename, mp);

            } else {

                // aggregator module or os-specific module in jdeps-modules.xml

                // mdir not exist

                return new NonExistModuleReader(fs, modulename, mp);

            }

        }

        static class NonExistModuleReader extends ModuleClassReader {

            private final List<ClassFile> classes = Collections.emptyList();

            private NonExistModuleReader(FileSystem fs, String mn, Path mpath)

                throws IOException

            {

                super(fs, mn, mpath);

            }

            public ClassFile getClassFile(String name) throws IOException {

                return null;

            }

            public Iterable<ClassFile> getClassFiles() throws IOException {

                return classes;

            }

            public Set<String> packages() {

                return Collections.emptySet();

            }

        }

    }

}