/*

 * Copyright (c) 2015, 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

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 */

package jdk.tools.jlink.internal;

import java.lang.module.ModuleDescriptor;

import java.nio.ByteBuffer;

import java.nio.ByteOrder;

import java.util.HashSet;

import java.util.LinkedHashMap;

import java.util.Map;

import java.util.Objects;

import java.util.Optional;

import java.util.Set;

import java.util.stream.Stream;

import jdk.internal.jimage.decompressor.CompressedResourceHeader;

import jdk.tools.jlink.plugin.ResourcePool;

import jdk.tools.jlink.plugin.ResourcePoolBuilder;

import jdk.tools.jlink.plugin.ResourcePoolEntry;

import jdk.tools.jlink.plugin.ResourcePoolModule;

import jdk.tools.jlink.plugin.ResourcePoolModuleView;

import jdk.tools.jlink.plugin.PluginException;

/**

 * A manager for pool of resources.

 */

public class ResourcePoolManager {

    // utility to read ModuleDescriptor of the given ResourcePoolModule

    static ModuleDescriptor readModuleDescriptor(ResourcePoolModule mod) {

        String p = "/" + mod.name() + "/module-info.class";

        Optional<ResourcePoolEntry> content = mod.findEntry(p);

        if (!content.isPresent()) {

              throw new PluginException("No module-info for " + mod.name()

                      + " module");

        }

        ByteBuffer bb = ByteBuffer.wrap(content.get().contentBytes());

        return ModuleDescriptor.read(bb);

    }

    class ResourcePoolModuleImpl implements ResourcePoolModule {

        final Map<String, ResourcePoolEntry> moduleContent = new LinkedHashMap<>();

        // lazily initialized

        private ModuleDescriptor descriptor;

        final String name;

        private ResourcePoolModuleImpl(String name) {

            this.name = name;

        }

        @Override

        public String name() {

            return name;

        }

        @Override

        public Optional<ResourcePoolEntry> findEntry(String path) {

            if (!path.startsWith("/")) {

                path = "/" + path;

            }

            if (!path.startsWith("/" + name + "/")) {

                path = "/" + name + path; // path already starts with '/'

            }

            return Optional.ofNullable(moduleContent.get(path));

        }

        @Override

        public ModuleDescriptor descriptor() {

            if (descriptor == null) {

                descriptor = readModuleDescriptor(this);

            }

            return descriptor;

        }

        @Override

        public Set<String> packages() {

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

            moduleContent.values().stream()

                .filter(m -> m.type() == ResourcePoolEntry.Type.CLASS_OR_RESOURCE)

                .forEach(res -> {

                    String name = ImageFileCreator.resourceName(res.path());

                        String pkg = ImageFileCreator.toPackage(name);

                        if (!pkg.isEmpty()) {

                            pkgs.add(pkg);

                        }

                    }

                });

            return pkgs;

        }

        @Override

        public String toString() {

            return name();

        }

        @Override

        public Stream<ResourcePoolEntry> entries() {

            return moduleContent.values().stream();

        }

        @Override

        public int entryCount() {

            return moduleContent.values().size();

        }

    }

    public class ResourcePoolImpl implements ResourcePool {

        @Override

        public ResourcePoolModuleView moduleView() {

            return ResourcePoolManager.this.moduleView();

        }

        @Override

        public Stream<ResourcePoolEntry> entries() {

            return ResourcePoolManager.this.entries();

        }

        @Override

        public int entryCount() {

            return ResourcePoolManager.this.entryCount();

        }

        @Override

        public Optional<ResourcePoolEntry> findEntry(String path) {

            return ResourcePoolManager.this.findEntry(path);

        }

        @Override

        public Optional<ResourcePoolEntry> findEntryInContext(String path, ResourcePoolEntry context) {

            return ResourcePoolManager.this.findEntryInContext(path, context);

        }

        @Override

        public boolean contains(ResourcePoolEntry data) {

            return ResourcePoolManager.this.contains(data);

        }

        @Override

        public boolean isEmpty() {

            return ResourcePoolManager.this.isEmpty();

        }

        @Override

        public ByteOrder byteOrder() {

            return ResourcePoolManager.this.byteOrder();

        }

        public StringTable getStringTable() {

            return ResourcePoolManager.this.getStringTable();

        }

    }

    class ResourcePoolBuilderImpl implements ResourcePoolBuilder {

        private boolean built;

        @Override

        public void add(ResourcePoolEntry data) {

            if (built) {

                throw new IllegalStateException("resource pool already built!");

            }

            ResourcePoolManager.this.add(data);

        }

        @Override

        public ResourcePool build() {

            built = true;

            return ResourcePoolManager.this.resourcePool();

        }

    }

    class ResourcePoolModuleViewImpl implements ResourcePoolModuleView {

        @Override

        public Optional<ResourcePoolModule> findModule(String name) {

            return ResourcePoolManager.this.findModule(name);

        }

        @Override

        public Stream<ResourcePoolModule> modules() {

            return ResourcePoolManager.this.modules();

        }

        @Override

        public int moduleCount() {

            return ResourcePoolManager.this.moduleCount();

        }

    }

    private final Map<String, ResourcePoolEntry> resources = new LinkedHashMap<>();

    private final Map<String, ResourcePoolModule> modules = new LinkedHashMap<>();

    private final ByteOrder order;

    private final StringTable table;

    private final ResourcePool poolImpl;

    private final ResourcePoolBuilder poolBuilderImpl;

    private final ResourcePoolModuleView moduleViewImpl;

    public ResourcePoolManager() {

        this(ByteOrder.nativeOrder());

    }

    public ResourcePoolManager(ByteOrder order) {

        this(order, new StringTable() {

            @Override

            public int addString(String str) {

                return -1;

            }

            @Override

            public String getString(int id) {

                return null;

            }

        });

    }

    public ResourcePoolManager(ByteOrder order, StringTable table) {

        this.order = Objects.requireNonNull(order);

        this.table = Objects.requireNonNull(table);

        this.poolImpl = new ResourcePoolImpl();

        this.poolBuilderImpl = new ResourcePoolBuilderImpl();

        this.moduleViewImpl = new ResourcePoolModuleViewImpl();

    }

    public ResourcePool resourcePool() {

        return poolImpl;

    }

    public ResourcePoolBuilder resourcePoolBuilder() {

        return poolBuilderImpl;

    }

    public ResourcePoolModuleView moduleView() {

        return moduleViewImpl;

    }

    /**

     * Add a ResourcePoolEntry.

     *

     * @param data The ResourcePoolEntry to add.

     */

    public void add(ResourcePoolEntry data) {

        Objects.requireNonNull(data);

        if (resources.get(data.path()) != null) {

            throw new PluginException("Resource " + data.path()

                    + " already present");

        }

        String modulename = data.moduleName();

        ResourcePoolModuleImpl m = (ResourcePoolModuleImpl)modules.get(modulename);

        if (m == null) {

            m = new ResourcePoolModuleImpl(modulename);

            modules.put(modulename, m);

        }

        resources.put(data.path(), data);

        m.moduleContent.put(data.path(), data);

    }

    /**

     * Retrieves the module for the provided name.

     *

     * @param name The module name

     * @return the module of matching name, if found

     */

    public Optional<ResourcePoolModule> findModule(String name) {

        Objects.requireNonNull(name);

        return Optional.ofNullable(modules.get(name));

    }

    /**

     * The stream of modules contained in this ResourcePool.

     *

     * @return The stream of modules.

     */

    public Stream<ResourcePoolModule> modules() {

        return modules.values().stream();

    }

    /**

     * Return the number of ResourcePoolModule count in this ResourcePool.

     *

     * @return the module count.

     */

    public int moduleCount() {

        return modules.size();

    }

    /**

     * Get all ResourcePoolEntry contained in this ResourcePool instance.

     *

     * @return The stream of ResourcePoolModuleEntries.

     */

    public Stream<ResourcePoolEntry> entries() {

        return resources.values().stream();

    }

    /**

     * Return the number of ResourcePoolEntry count in this ResourcePool.

     *

     * @return the entry count.

     */

    public int entryCount() {

        return resources.values().size();

    }

    /**

     * Get the ResourcePoolEntry for the passed path.

     *

     * @param path A data path

     * @return A ResourcePoolEntry instance or null if the data is not found

     */

    public Optional<ResourcePoolEntry> findEntry(String path) {

        Objects.requireNonNull(path);

        return Optional.ofNullable(resources.get(path));

    }

    /**

     * Get the ResourcePoolEntry for the passed path restricted to supplied context.

     *

     * @param path A data path

     * @param context A context of the search

     * @return A ResourcePoolEntry instance or null if the data is not found

     */

    public Optional<ResourcePoolEntry> findEntryInContext(String path, ResourcePoolEntry context) {

        Objects.requireNonNull(path);

        Objects.requireNonNull(context);

        ResourcePoolModule module = modules.get(context.moduleName());

        Objects.requireNonNull(module);

        Optional<ResourcePoolEntry> entry = module.findEntry(path);

        // Navigating other modules via requires and exports is problematic

        // since we cannot construct the runtime model of loaders and layers.

        return entry;

     }

    /**

     * Check if the ResourcePool contains the given ResourcePoolEntry.

     *

     * @param data The module data to check existence for.

     * @return The module data or null if not found.

     */

    public boolean contains(ResourcePoolEntry data) {

        Objects.requireNonNull(data);

        return findEntry(data.path()).isPresent();

    }

    /**

     * Check if the ResourcePool contains some content at all.

     *

     * @return True, no content, false otherwise.

     */

    public boolean isEmpty() {

        return resources.isEmpty();

    }

    /**

     * The ByteOrder currently in use when generating the jimage file.

     *

     * @return The ByteOrder.

     */

    public ByteOrder byteOrder() {

        return order;

    }

    public StringTable getStringTable() {

        return table;

    }

    /**

     * A resource that has been compressed.

     */

    public static final class CompressedModuleData extends ByteArrayResourcePoolEntry {

        final long uncompressed_size;

        private CompressedModuleData(String module, String path,

                byte[] content, long uncompressed_size) {

            super(module, path, ResourcePoolEntry.Type.CLASS_OR_RESOURCE, content);

            this.uncompressed_size = uncompressed_size;

        }

        public long getUncompressedSize() {

            return uncompressed_size;

        }

        @Override

        public boolean equals(Object other) {

            if (!(other instanceof CompressedModuleData)) {

                return false;

            }

            CompressedModuleData f = (CompressedModuleData) other;

            return f.path().equals(path());

        }

        @Override

        public int hashCode() {

            return super.hashCode();

        }

    }

    public static CompressedModuleData newCompressedResource(ResourcePoolEntry original,

            ByteBuffer compressed,

            String plugin, String pluginConfig, StringTable strings,

            ByteOrder order) {

        Objects.requireNonNull(original);

        Objects.requireNonNull(compressed);

        Objects.requireNonNull(plugin);

        boolean isTerminal = !(original instanceof CompressedModuleData);

        long uncompressed_size = original.contentLength();

        if (original instanceof CompressedModuleData) {

            CompressedModuleData comp = (CompressedModuleData) original;

            uncompressed_size = comp.getUncompressedSize();

        }

        int nameOffset = strings.addString(plugin);

        int configOffset = -1;

        if (pluginConfig != null) {

            configOffset = strings.addString(plugin);

        }

        CompressedResourceHeader rh

                = new CompressedResourceHeader(compressed.limit(), original.contentLength(),

                        nameOffset, configOffset, isTerminal);

        // Merge header with content;

        byte[] h = rh.getBytes(order);

        ByteBuffer bb = ByteBuffer.allocate(compressed.limit() + h.length);

        bb.order(order);

        bb.put(h);

        bb.put(compressed);

        byte[] contentWithHeader = bb.array();

        CompressedModuleData compressedResource

                = new CompressedModuleData(original.moduleName(), original.path(),

                        contentWithHeader, uncompressed_size);

        return compressedResource;

    }

}