/*

 * 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

 * questions.

 */

package jdk.internal.jrtfs;

import java.io.IOException;

import java.nio.file.DirectoryStream;

import java.nio.file.FileSystem;

import java.nio.file.FileSystemException;

import java.nio.file.FileSystems;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.attribute.BasicFileAttributes;

import java.util.ArrayList;

import java.util.Collections;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

/**

 * A jrt file system built on $JAVA_HOME/modules directory ('exploded modules

 * build')

 *

 * @implNote This class needs to maintain JDK 8 source compatibility.

 *

 * It is used internally in the JDK to implement jimage/jrtfs access,

 * but also compiled and delivered as part of the jrtfs.jar to support access

 * to the jimage file provided by the shipped JDK by tools running on JDK 8.

 */

    private static final String MODULES = "/modules/";

    private static final String PACKAGES = "/packages/";

    private static final int PACKAGES_LEN = PACKAGES.length();

    private final FileSystem defaultFS;

    private final String separator;

    private final BasicFileAttributes modulesDirAttrs;

        defaultFS = FileSystems.getDefault();

        String str = defaultFS.getSeparator();

        initNodes();

    }

    // A Node that is backed by actual default file system Path

    private final class PathNode extends Node {

        // Path in underlying default file system

        }

        }

            this.children = children;

        }

        @Override

        }

        @Override

            return children;

        }

    }

    @Override

    }

    @Override

    }

    // find Node for the given Path

        Node node = findModulesNode(str);

        if (node != null) {

            return node;

        }

        // lazily created for paths like /packages/<package>/<module>/xyz

        // For example /packages/java.lang/java.base/java/lang/

        if (str.startsWith(PACKAGES)) {

            // pkgEndIdx marks end of <package> part

            int pkgEndIdx = str.indexOf('/', PACKAGES_LEN);

            if (pkgEndIdx != -1) {

                // modEndIdx marks end of <module> part

                int modEndIdx = str.indexOf('/', pkgEndIdx + 1);

                if (modEndIdx != -1) {

                    // make sure we have such module link!

                    // ie., /packages/<package>/<module> is valid

                    Node linkNode = nodes.get(str.substring(0, modEndIdx));

                    if (linkNode == null || !linkNode.isLink()) {

                    }

                    // map to "/modules/zyz" path and return that node

                    // For example, "/modules/java.base/java/lang" for

                    // "/packages/java.lang/java.base/java/lang".

                    String mod = MODULES + str.substring(pkgEndIdx + 1);

                }

            }

        }

    }

    // find a Node for a path that starts like "/modules/..."

        if (node != null) {

            return node;

        }

        // lazily created "/modules/xyz/abc/" Node

        // This is mapped to default file system path "<JDK_MODULES_DIR>/xyz/abc"

        Path p = underlyingPath(str);

        if (p != null) {

                }

            }

        }

        return null;

    }

    Path underlyingPath(String str) {

        if (str.startsWith(MODULES)) {

            str = frontSlashToNativeSlash(str.substring("/modules".length()));

        }

        return null;

    }

    // convert "/" to platform path separator

    private String frontSlashToNativeSlash(String str) {

        return separator == null ? str : str.replace("/", separator);

    }

    // convert platform path separator to "/"

    private String nativeSlashToFrontSlash(String str) {

        return separator == null ? str : str.replace(separator, "/");

    }

    // convert "/"s to "."s

    private String slashesToDots(String str) {

        return str.replace(separator != null ? separator : "/", ".");

    }

    // initialize file system Nodes

    private void initNodes() throws IOException {

        // same package prefix may exist in mutliple modules. This Map

        // is filled by walking "jdk modules" directory recursively!

        Map<String, List<String>> packageToModules = new HashMap<>();

            for (Path module : stream) {

                if (Files.isDirectory(module)) {

                    String moduleName = module.getFileName().toString();

                    // make sure "/modules/<moduleName>" is created

                    findModulesNode(MODULES + moduleName);

                    Files.walk(module).filter(Files::isDirectory).forEach((p) -> {

                        p = module.relativize(p);

                        String pkgName = slashesToDots(p.toString());

                        // skip META-INFO and empty strings

                        if (!pkgName.isEmpty() && !pkgName.startsWith("META-INF")) {

                            List<String> moduleNames = packageToModules.get(pkgName);

                            if (moduleNames == null) {

                                moduleNames = new ArrayList<>();

                                packageToModules.put(pkgName, moduleNames);

                            }

                            moduleNames.add(moduleName);

                        }

                    });

                }

            }

        }

        // create "/modules" directory

        // "nodes" map contains only /modules/<foo> nodes only so far and so add all as children of /modules

        nodes.put(modulesDir.getName(), modulesDir);

        // create children under "/packages"

        List<Node> packagesChildren = new ArrayList<>(packageToModules.size());

        for (Map.Entry<String, List<String>> entry : packageToModules.entrySet()) {

            String pkgName = entry.getKey();

            List<String> moduleNameList = entry.getValue();

            List<Node> moduleLinkNodes = new ArrayList<>(moduleNameList.size());

            for (String moduleName : moduleNameList) {

                Node moduleNode = findModulesNode(MODULES + moduleName);

                nodes.put(linkNode.getName(), linkNode);

                moduleLinkNodes.add(linkNode);

            }

            nodes.put(pkgDir.getName(), pkgDir);

            packagesChildren.add(pkgDir);

        }

        // "/packages" dir

        nodes.put(packagesDir.getName(), packagesDir);

        // finally "/" dir!

        List<Node> rootChildren = new ArrayList<>();

        rootChildren.add(modulesDir);

        nodes.put(root.getName(), root);

    }

}