/*

 * 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 sun.nio.fs;

import java.nio.file.*;

import java.nio.file.attribute.*;

import java.nio.file.spi.*;

import java.util.*;

import java.util.regex.Pattern;

import java.io.IOException;

import java.security.AccessController;

import java.security.PrivilegedAction;

import sun.security.action.GetPropertyAction;

class WindowsFileSystem

    extends FileSystem

{

    private final WindowsFileSystemProvider provider;

    // default directory (is absolute), and default root

    private final String defaultDirectory;

    private final String defaultRoot;

    private final boolean supportsLinks;

    private final boolean supportsStreamEnumeration;

    // package-private

    WindowsFileSystem(WindowsFileSystemProvider provider,

                      String dir)

    {

        this.provider = provider;

        // parse default directory and check it is absolute

        WindowsPathParser.Result result = WindowsPathParser.parse(dir);

        if (result.type() != WindowsPathType.ABSOLUTE)

            throw new AssertionError("Default directory must be absolute/non-UNC");

        this.defaultDirectory = result.path();

        this.defaultRoot = result.root();

        PrivilegedAction<String> pa = new GetPropertyAction("os.version");

        String osversion = AccessController.doPrivileged(pa);

        String[] vers = Util.split(osversion, '.');

        int major = Integer.parseInt(vers[0]);

        int minor = Integer.parseInt(vers[1]);

        // symbolic links available on Vista and newer

        supportsLinks = (major >= 6);

        // enumeration of data streams available on Windows Server 2003 and newer

        supportsStreamEnumeration = (major >= 6) || (major == 5 && minor >= 2);

    }

    // package-private

    String defaultDirectory() {

        return defaultDirectory;

    }

    String defaultRoot() {

        return defaultRoot;

    }

    boolean supportsLinks() {

        return supportsLinks;

    }

    boolean supportsStreamEnumeration() {

        return supportsStreamEnumeration;

    }

    @Override

    public FileSystemProvider provider() {

        return provider;

    }

    @Override

    public String getSeparator() {

        return "\\";

    }

    @Override

    public boolean isOpen() {

        return true;

    }

    @Override

    public boolean isReadOnly() {

        return false;

    }

    @Override

    public void close() throws IOException {

        throw new UnsupportedOperationException();

    }

    @Override

    public Iterable<Path> getRootDirectories() {

        int drives = 0;

        try {

            drives = WindowsNativeDispatcher.GetLogicalDrives();

        } catch (WindowsException x) {

            // shouldn't happen

            throw new AssertionError(x.getMessage());

        }

        // iterate over roots, ignoring those that the security manager denies

        ArrayList<Path> result = new ArrayList<>();

        SecurityManager sm = System.getSecurityManager();

        for (int i = 0; i <= 25; i++) {  // 0->A, 1->B, 2->C...

            if ((drives & (1 << i)) != 0) {

                StringBuilder sb = new StringBuilder(3);

                sb.append((char)('A' + i));

                sb.append(":\\");

                String root = sb.toString();

                if (sm != null) {

                    try {

                        sm.checkRead(root);

                    } catch (SecurityException x) {

                        continue;

                    }

                }

                result.add(WindowsPath.createFromNormalizedPath(this, root));

            }

        }

        return Collections.unmodifiableList(result);

    }

    /**

     * Iterator returned by getFileStores method.

     */

    private class FileStoreIterator implements Iterator<FileStore> {

        private final Iterator<Path> roots;

        private FileStore next;

        FileStoreIterator() {

            this.roots = getRootDirectories().iterator();

        }

        private FileStore readNext() {

            assert Thread.holdsLock(this);

            for (;;) {

                if (!roots.hasNext())

                    return null;

                WindowsPath root = (WindowsPath)roots.next();

                // ignore if security manager denies access

                try {

                    root.checkRead();

                } catch (SecurityException x) {

                    continue;

                }

                try {

                    FileStore fs = WindowsFileStore.create(root.toString(), true);

                    if (fs != null)

                        return fs;

                } catch (IOException ioe) {

                    // skip it

                }

            }

        }

        @Override

        public synchronized boolean hasNext() {

            if (next != null)

                return true;

            next = readNext();

            return next != null;

        }

        @Override

        public synchronized FileStore next() {

            if (next == null)

                next = readNext();

            if (next == null) {

                throw new NoSuchElementException();

            } else {

                FileStore result = next;

                next = null;

                return result;

            }

        }

        @Override

        public void remove() {

            throw new UnsupportedOperationException();

        }

    }

    @Override

    public Iterable<FileStore> getFileStores() {

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            try {

                sm.checkPermission(new RuntimePermission("getFileStoreAttributes"));

            } catch (SecurityException se) {

                return Collections.emptyList();

            }

        }

        return new Iterable<FileStore>() {

            public Iterator<FileStore> iterator() {

                return new FileStoreIterator();

            }

        };

    }

    // supported views

    private static final Set<String> supportedFileAttributeViews = Collections

        .unmodifiableSet(new HashSet<String>(Arrays.asList("basic", "dos", "acl", "owner", "user")));

    @Override

    public Set<String> supportedFileAttributeViews() {

        return supportedFileAttributeViews;

    }

    @Override

    public final Path getPath(String first, String... more) {

        String path;

        if (more.length == 0) {

            path = first;

        } else {

            StringBuilder sb = new StringBuilder();

            sb.append(first);

            for (String segment: more) {

                if (segment.length() > 0) {

                    if (sb.length() > 0)

                        sb.append('\\');

                    sb.append(segment);

                }

            }

            path = sb.toString();

        }

        return WindowsPath.parse(this, path);

    }

    @Override

    public UserPrincipalLookupService getUserPrincipalLookupService() {

        return LookupService.instance;

    }

    private static class LookupService {

        static final UserPrincipalLookupService instance =

            new UserPrincipalLookupService() {

                @Override

                public UserPrincipal lookupPrincipalByName(String name)

                    throws IOException

                {

                    return WindowsUserPrincipals.lookup(name);

                }

                @Override

                public GroupPrincipal lookupPrincipalByGroupName(String group)

                    throws IOException

                {

                    UserPrincipal user = WindowsUserPrincipals.lookup(group);

                    if (!(user instanceof GroupPrincipal))

                        throw new UserPrincipalNotFoundException(group);

                    return (GroupPrincipal)user;

                }

            };

    }

    @Override

    public PathMatcher getPathMatcher(String syntaxAndInput) {

        int pos = syntaxAndInput.indexOf(':');

        if (pos <= 0 || pos == syntaxAndInput.length())

            throw new IllegalArgumentException();

        String syntax = syntaxAndInput.substring(0, pos);

        String input = syntaxAndInput.substring(pos+1);

        String expr;

        if (syntax.equals(GLOB_SYNTAX)) {

            expr = Globs.toWindowsRegexPattern(input);

        } else {

            if (syntax.equals(REGEX_SYNTAX)) {

                expr = input;

            } else {

                throw new UnsupportedOperationException("Syntax '" + syntax +

                    "' not recognized");

            }

        }

        // match in unicode_case_insensitive

        final Pattern pattern = Pattern.compile(expr,

            Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);

        // return matcher

        return new PathMatcher() {

            @Override

            public boolean matches(Path path) {

                return pattern.matcher(path.toString()).matches();

            }

        };

    }

    private static final String GLOB_SYNTAX = "glob";

    private static final String REGEX_SYNTAX = "regex";

    @Override

    public WatchService newWatchService()

        throws IOException

    {

        return new WindowsWatchService(this);

    }

}