/*

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

import static com.sun.tools.jdeps.Module.trace;

import static java.util.stream.Collectors.*;

import com.sun.tools.classfile.Dependency;

import java.io.BufferedInputStream;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.io.UncheckedIOException;

import java.lang.module.Configuration;

import java.lang.module.ModuleDescriptor;

import java.lang.module.ModuleFinder;

import java.lang.module.ModuleReader;

import java.lang.module.ModuleReference;

import java.lang.module.ResolvedModule;

import java.net.URI;

import java.nio.file.DirectoryStream;

import java.nio.file.FileSystem;

import java.nio.file.FileSystems;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.ArrayList;

import java.util.Collections;

import java.util.HashMap;

import java.util.HashSet;

import java.util.LinkedHashMap;

import java.util.LinkedHashSet;

import java.util.List;

import java.util.Map;

import java.util.Objects;

import java.util.Optional;

import java.util.Set;

import java.util.function.Function;

import java.util.function.Supplier;

import java.util.stream.Stream;

public class JdepsConfiguration implements AutoCloseable {

    // the token for "all modules on the module path"

    public static final String ALL_MODULE_PATH = "ALL-MODULE-PATH";

    public static final String ALL_DEFAULT = "ALL-DEFAULT";

    public static final String ALL_SYSTEM = "ALL-SYSTEM";

    public static final String MODULE_INFO = "module-info.class";

    private final SystemModuleFinder system;

    private final ModuleFinder finder;

    private final Map<String, Module> nameToModule = new LinkedHashMap<>();

    private final Map<String, Module> packageToModule = new HashMap<>();

    private final Map<String, List<Archive>> packageToUnnamedModule = new HashMap<>();

    private final List<Archive> classpathArchives = new ArrayList<>();

    private final List<Archive> initialArchives = new ArrayList<>();

    private final Set<Module> rootModules = new HashSet<>();

    private final Configuration configuration;

    private final Runtime.Version version;

    private JdepsConfiguration(SystemModuleFinder systemModulePath,

                               ModuleFinder finder,

                               Set<String> roots,

                               List<Path> classpaths,

                               List<Archive> initialArchives,

                               Set<String> tokens,

                               Runtime.Version version)

        throws IOException

    {

        trace("root: %s%n", roots);

        this.system = systemModulePath;

        this.finder = finder;

        this.version = version;

        // build root set for resolution

        Set<String> mods = new HashSet<>(roots);

        if (tokens.contains(ALL_SYSTEM)) {

            systemModulePath.findAll().stream()

                .map(mref -> mref.descriptor().name())

                .forEach(mods::add);

        }

        if (tokens.contains(ALL_DEFAULT)) {

            mods.addAll(systemModulePath.defaultSystemRoots());

        }

        this.configuration = Configuration.empty()

                .resolve(finder, ModuleFinder.of(), mods);

        this.configuration.modules().stream()

                .map(ResolvedModule::reference)

                .forEach(this::addModuleReference);

        // packages in unnamed module

        initialArchives.forEach(archive -> {

            addPackagesInUnnamedModule(archive);

            this.initialArchives.add(archive);

        });

        // classpath archives

        for (Path p : classpaths) {

            if (Files.exists(p)) {

                Archive archive = Archive.getInstance(p, version);

                addPackagesInUnnamedModule(archive);

                classpathArchives.add(archive);

            }

        }

        // all roots specified in --add-modules or -m are included

        // as the initial set for analysis.

        roots.stream()

             .map(nameToModule::get)

             .forEach(this.rootModules::add);

        initProfiles();

        trace("resolved modules: %s%n", nameToModule.keySet().stream()

                .sorted().collect(joining("\n", "\n", "")));

    }

    private void initProfiles() {

        // other system modules are not observed and not added in nameToModule map

        Map<String, Module> systemModules =

            system.moduleNames()

                .collect(toMap(Function.identity(), (mn) -> {

                    Module m = nameToModule.get(mn);

                    if (m == null) {

                        ModuleReference mref = finder.find(mn).get();

                        m = toModule(mref);

                    }

                    return m;

                }));

        Profile.init(systemModules);

    }

    private void addModuleReference(ModuleReference mref) {

        Module module = toModule(mref);

        nameToModule.put(mref.descriptor().name(), module);

        mref.descriptor().packages()

            .forEach(pn -> packageToModule.putIfAbsent(pn, module));

    }

    private void addPackagesInUnnamedModule(Archive archive) {

        archive.reader().entries().stream()

               .filter(e -> e.endsWith(".class") && !e.equals(MODULE_INFO))

               .map(this::toPackageName)

               .distinct()

               .forEach(pn -> packageToUnnamedModule

                   .computeIfAbsent(pn, _n -> new ArrayList<>()).add(archive));

    }

    private String toPackageName(String name) {

        int i = name.lastIndexOf('/');

        return i > 0 ? name.replace('/', '.').substring(0, i) : "";

    }

    public Optional<Module> findModule(String name) {

        Objects.requireNonNull(name);

        Module m = nameToModule.get(name);

        return m!= null ? Optional.of(m) : Optional.empty();

    }

    public Optional<ModuleDescriptor> findModuleDescriptor(String name) {

        Objects.requireNonNull(name);

        Module m = nameToModule.get(name);

        return m!= null ? Optional.of(m.descriptor()) : Optional.empty();

    }

    public static boolean isToken(String name) {

        return ALL_MODULE_PATH.equals(name) ||

               ALL_DEFAULT.equals(name) ||

               ALL_SYSTEM.equals(name);

    }

    /**

     * Returns the list of packages that split between resolved module and

     * unnamed module

     */

    public Map<String, Set<String>> splitPackages() {

        Set<String> splitPkgs = packageToModule.keySet().stream()

                                       .filter(packageToUnnamedModule::containsKey)

                                       .collect(toSet());

        if (splitPkgs.isEmpty())

            return Collections.emptyMap();

        return splitPkgs.stream().collect(toMap(Function.identity(), (pn) -> {

            Set<String> sources = new LinkedHashSet<>();

            sources.add(packageToModule.get(pn).getModule().location().toString());

            packageToUnnamedModule.get(pn).stream()

                .map(Archive::getPathName)

                .forEach(sources::add);

            return sources;

        }));

    }

    /**

     * Returns an optional archive containing the given Location

     */

    public Optional<Archive> findClass(Dependency.Location location) {

        String name = location.getName();

        int i = name.lastIndexOf('/');

        String pn = i > 0 ? name.substring(0, i).replace('/', '.') : "";

        Archive archive = packageToModule.get(pn);

        if (archive != null) {

            return archive.contains(name + ".class")

                        ? Optional.of(archive)

                        : Optional.empty();

        }

        if (packageToUnnamedModule.containsKey(pn)) {

            return packageToUnnamedModule.get(pn).stream()

                    .filter(a -> a.contains(name + ".class"))

                    .findFirst();

        }

        return Optional.empty();

    }

    /**

     * Returns the list of Modules that can be found in the specified

     * module paths.

     */

    public Map<String, Module> getModules() {

        return nameToModule;

    }

    /**

     * Returns Configuration with the given roots

     */

    public Configuration resolve(Set<String> roots) {

        if (roots.isEmpty())

            throw new IllegalArgumentException("empty roots");

        return Configuration.empty()

                    .resolve(finder, ModuleFinder.of(), roots);

    }

    public List<Archive> classPathArchives() {

        return classpathArchives;

    }

    public List<Archive> initialArchives() {

        return initialArchives;

    }

    public Set<Module> rootModules() {

        return rootModules;

    }

    public Module toModule(ModuleReference mref) {

        try {

            String mn = mref.descriptor().name();

            URI location = mref.location().orElseThrow(FileNotFoundException::new);

            ModuleDescriptor md = mref.descriptor();

            // is this module from the system module path?

            URI loc = system.find(mn).flatMap(ModuleReference::location).orElse(null);

            boolean isSystem = location.equals(loc);

            final ClassFileReader reader;

            if (location.getScheme().equals("jrt")) {

                reader = system.getClassReader(mn);

            } else {

                reader = ClassFileReader.newInstance(Paths.get(location), version);

            }

            Module.Builder builder = new Module.Builder(md, isSystem);

            builder.classes(reader);

            builder.location(location);

            return builder.build();

        } catch (IOException e) {

            throw new UncheckedIOException(e);

        }

    }

    public Runtime.Version getVersion() {

        return version;

    }

    /*

     * Close all archives e.g. JarFile

     */

    @Override

    public void close() throws IOException {

        for (Archive archive : initialArchives)

            archive.close();

        for (Archive archive : classpathArchives)

            archive.close();

        for (Module module : nameToModule.values())

            module.close();

    }

    static class SystemModuleFinder implements ModuleFinder {

        private static final String JAVA_HOME = System.getProperty("java.home");

        private static final String JAVA_SE = "java.se";

        private final FileSystem fileSystem;

        private final Path root;

        private final Map<String, ModuleReference> systemModules;

        SystemModuleFinder() {

            if (Files.isRegularFile(Paths.get(JAVA_HOME, "lib", "modules"))) {

                // jrt file system

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

                this.root = fileSystem.getPath("/modules");

                this.systemModules = walk(root);

            } else {

                // exploded image

                this.fileSystem = FileSystems.getDefault();

                root = Paths.get(JAVA_HOME, "modules");

                this.systemModules = ModuleFinder.ofSystem().findAll().stream()

                    .collect(toMap(mref -> mref.descriptor().name(), Function.identity()));

            }

        }

        SystemModuleFinder(String javaHome) throws IOException {

            if (javaHome == null) {

                // --system none

                this.fileSystem = null;

                this.root = null;

                this.systemModules = Collections.emptyMap();

            } else {

                if (Files.isRegularFile(Paths.get(javaHome, "lib", "modules")))

                    throw new IllegalArgumentException("Invalid java.home: " + javaHome);

                // alternate java.home

                Map<String, String> env = new HashMap<>();

                env.put("java.home", javaHome);

                // a remote run-time image

                this.fileSystem = FileSystems.newFileSystem(URI.create("jrt:/"), env);

                this.root = fileSystem.getPath("/modules");

                this.systemModules = walk(root);

            }

        }

        private Map<String, ModuleReference> walk(Path root) {

            try (Stream<Path> stream = Files.walk(root, 1)) {

                return stream.filter(path -> !path.equals(root))

                             .map(this::toModuleReference)

                             .collect(toMap(mref -> mref.descriptor().name(),

                                            Function.identity()));

            } catch (IOException e) {

                throw new UncheckedIOException(e);

            }

        }

        private ModuleReference toModuleReference(Path path) {

            Path minfo = path.resolve(MODULE_INFO);

            try (InputStream in = Files.newInputStream(minfo);

                 BufferedInputStream bin = new BufferedInputStream(in)) {

                ModuleDescriptor descriptor = dropHashes(ModuleDescriptor.read(bin));

                String mn = descriptor.name();

                URI uri = URI.create("jrt:/" + path.getFileName().toString());

                Supplier<ModuleReader> readerSupplier = () -> new ModuleReader() {

                    @Override

                    public Optional<URI> find(String name) throws IOException {

                        return name.equals(mn)

                            ? Optional.of(uri) : Optional.empty();

                    }

                    @Override

                    public Stream<String> list() {

                        return Stream.empty();

                    }

                    @Override

                    public void close() {

                    }

                };

                return new ModuleReference(descriptor, uri) {

                    @Override

                    public ModuleReader open() {

                        return readerSupplier.get();

                    }

                };

            } catch (IOException e) {

                throw new UncheckedIOException(e);

            }

        }

        private ModuleDescriptor dropHashes(ModuleDescriptor md) {

            ModuleDescriptor.Builder builder = ModuleDescriptor.newModule(md.name());

            md.requires().forEach(builder::requires);

            md.exports().forEach(builder::exports);

            md.opens().forEach(builder::opens);

            md.provides().stream().forEach(builder::provides);

            md.uses().stream().forEach(builder::uses);

            builder.packages(md.packages());

            return builder.build();

        }

        @Override

        public Set<ModuleReference> findAll() {

            return systemModules.values().stream().collect(toSet());

        }

        @Override

        public Optional<ModuleReference> find(String mn) {

            return systemModules.containsKey(mn)

                    ? Optional.of(systemModules.get(mn)) : Optional.empty();

        }

        public Stream<String> moduleNames() {

            return systemModules.values().stream()

                .map(mref -> mref.descriptor().name());

        }

        public ClassFileReader getClassReader(String modulename) throws IOException {

            Path mp = root.resolve(modulename);

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

                return ClassFileReader.newInstance(fileSystem, mp);

            } else {

                throw new FileNotFoundException(mp.toString());

            }

        }

        public Set<String> defaultSystemRoots() {

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

            boolean hasJava = false;

            if (systemModules.containsKey(JAVA_SE)) {

                // java.se is a system module

                hasJava = true;

                roots.add(JAVA_SE);

            }

            for (ModuleReference mref : systemModules.values()) {

                String mn = mref.descriptor().name();

                if (hasJava && mn.startsWith("java."))

                    continue;

                // add as root if observable and exports at least one package

                ModuleDescriptor descriptor = mref.descriptor();

                for (ModuleDescriptor.Exports e : descriptor.exports()) {

                    if (!e.isQualified()) {

                        roots.add(mn);

                        break;

                    }

                }

            }

            return roots;

        }

    }

    public static class Builder {

        final SystemModuleFinder systemModulePath;

        final Set<String> rootModules = new HashSet<>();

        final List<Archive> initialArchives = new ArrayList<>();

        final List<Path> paths = new ArrayList<>();

        final List<Path> classPaths = new ArrayList<>();

        final Set<String> tokens = new HashSet<>();

        ModuleFinder upgradeModulePath;

        ModuleFinder appModulePath;

        Runtime.Version version;

        public Builder() {

            this.systemModulePath = new SystemModuleFinder();

        }

        public Builder(String javaHome) throws IOException {

            this.systemModulePath = SystemModuleFinder.JAVA_HOME.equals(javaHome)

                ? new SystemModuleFinder()

                : new SystemModuleFinder(javaHome);