/*

 * 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.javac.file;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.io.OutputStreamWriter;

import java.io.Reader;

import java.io.Writer;

import java.net.URI;

import java.nio.ByteBuffer;

import java.nio.CharBuffer;

import java.nio.charset.CharsetDecoder;

import java.nio.file.Files;

import java.nio.file.LinkOption;

import java.nio.file.Path;

import java.util.Objects;

import javax.lang.model.element.Modifier;

import javax.lang.model.element.NestingKind;

import javax.tools.JavaFileObject;

import com.sun.tools.javac.util.DefinedBy;

import com.sun.tools.javac.util.DefinedBy.Api;

/**

 *  Implementation of JavaFileObject using java.nio.file API.

 *

 *  <p>PathFileObjects are, for the most part, straightforward wrappers around

 *  Path objects. The primary complexity is the support for "inferBinaryName".

 *  This is left as an abstract method, implemented by each of a number of

 *  different factory methods, which compute the binary name based on

 *  information available at the time the file object is created.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 */

public abstract class PathFileObject implements JavaFileObject {

    private final BaseFileManager fileManager;

    private final Path path;

    /**

     * Create a PathFileObject within a directory, such that the binary name

     * can be inferred from the relationship to the parent directory.

     */

    static PathFileObject createDirectoryPathFileObject(BaseFileManager fileManager,

            final Path path, final Path dir) {

        return new PathFileObject(fileManager, path) {

            @Override

            public String inferBinaryName(Iterable<? extends Path> paths) {

                return toBinaryName(dir.relativize(path));

            }

        };

    }

    /**

     * Create a PathFileObject in a file system such as a jar file, such that

     * the binary name can be inferred from its position within the filesystem.

     */

    public static PathFileObject createJarPathFileObject(BaseFileManager fileManager,

            final Path path) {

        return new PathFileObject(fileManager, path) {

            @Override

            public String inferBinaryName(Iterable<? extends Path> paths) {

                return toBinaryName(path);

            }

        };

    }

    /**

     * Create a PathFileObject in a modular file system, such as jrt:, such that

     * the binary name can be inferred from its position within the filesystem.

     */

    public static PathFileObject createJRTPathFileObject(BaseFileManager fileManager,

            final Path path) {

        return new PathFileObject(fileManager, path) {

            @Override

            public String inferBinaryName(Iterable<? extends Path> paths) {

            }

        };

    }

    /**

     * Create a PathFileObject whose binary name can be inferred from the

     * relative path to a sibling.

     */

    static PathFileObject createSiblingPathFileObject(BaseFileManager fileManager,

            final Path path, final String relativePath) {

        return new PathFileObject(fileManager, path) {

            @Override

            public String inferBinaryName(Iterable<? extends Path> paths) {

                return toBinaryName(relativePath, "/");

            }

        };

    }

    /**

     * Create a PathFileObject whose binary name might be inferred from its

     * position on a search path.

     */

    static PathFileObject createSimplePathFileObject(BaseFileManager fileManager,

            final Path path) {

        return new PathFileObject(fileManager, path) {

            @Override

            public String inferBinaryName(Iterable<? extends Path> paths) {

                Path absPath = path.toAbsolutePath();

                for (Path p: paths) {

                    Path ap = p.toAbsolutePath();

                    if (absPath.startsWith(ap)) {

                        try {

                            Path rp = ap.relativize(absPath);

                            if (rp != null) // maybe null if absPath same as ap

                                return toBinaryName(rp);

                        } catch (IllegalArgumentException e) {

                            // ignore this p if cannot relativize path to p

                        }

                    }

                }

                return null;

            }

        };

    }

    protected PathFileObject(BaseFileManager fileManager, Path path) {

        this.fileManager = Objects.requireNonNull(fileManager);

        this.path = Objects.requireNonNull(path);

    }

    public abstract String inferBinaryName(Iterable<? extends Path> paths);

    /**

     * Return the Path for this object.

     * @return the Path for this object.

     */

    public Path getPath() {

        return path;

    }

    @Override @DefinedBy(Api.COMPILER)

    public Kind getKind() {

        return BaseFileManager.getKind(path.getFileName().toString());

    }

    @Override @DefinedBy(Api.COMPILER)

    public boolean isNameCompatible(String simpleName, Kind kind) {

        Objects.requireNonNull(simpleName);

        // null check

        if (kind == Kind.OTHER && getKind() != kind) {

            return false;

        }

        String sn = simpleName + kind.extension;

        String pn = path.getFileName().toString();

        if (pn.equals(sn)) {

            return true;

        }

        if (pn.equalsIgnoreCase(sn)) {

            try {

                // allow for Windows

                return path.toRealPath(LinkOption.NOFOLLOW_LINKS).getFileName().toString().equals(sn);

            } catch (IOException e) {

            }

        }

        return false;

    }

    @Override @DefinedBy(Api.COMPILER)

    public NestingKind getNestingKind() {

        return null;

    }

    @Override @DefinedBy(Api.COMPILER)

    public Modifier getAccessLevel() {

        return null;

    }

    @Override @DefinedBy(Api.COMPILER)

    public URI toUri() {

        return path.toUri();

    }

    @Override @DefinedBy(Api.COMPILER)

    public String getName() {

        return path.toString();

    }

    @Override @DefinedBy(Api.COMPILER)

    public InputStream openInputStream() throws IOException {

        return Files.newInputStream(path);

    }

    @Override @DefinedBy(Api.COMPILER)

    public OutputStream openOutputStream() throws IOException {

        fileManager.flushCache(this);

        ensureParentDirectoriesExist();

        return Files.newOutputStream(path);

    }

    @Override @DefinedBy(Api.COMPILER)

    public Reader openReader(boolean ignoreEncodingErrors) throws IOException {

        CharsetDecoder decoder = fileManager.getDecoder(fileManager.getEncodingName(), ignoreEncodingErrors);

        return new InputStreamReader(openInputStream(), decoder);

    }

    @Override @DefinedBy(Api.COMPILER)

    public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {

        CharBuffer cb = fileManager.getCachedContent(this);

        if (cb == null) {

            try (InputStream in = openInputStream()) {

                ByteBuffer bb = fileManager.makeByteBuffer(in);

                JavaFileObject prev = fileManager.log.useSource(this);

                try {

                    cb = fileManager.decode(bb, ignoreEncodingErrors);

                } finally {

                    fileManager.log.useSource(prev);

                }

                fileManager.recycleByteBuffer(bb);

                if (!ignoreEncodingErrors) {

                    fileManager.cache(this, cb);

                }

            }

        }

        return cb;

    }

    @Override @DefinedBy(Api.COMPILER)

    public Writer openWriter() throws IOException {

        fileManager.flushCache(this);

        ensureParentDirectoriesExist();

        return new OutputStreamWriter(Files.newOutputStream(path), fileManager.getEncodingName());

    }

    @Override @DefinedBy(Api.COMPILER)

    public long getLastModified() {

        try {

            return Files.getLastModifiedTime(path).toMillis();

        } catch (IOException e) {

            return -1;

        }

    }

    @Override @DefinedBy(Api.COMPILER)

    public boolean delete() {

        try {

            Files.delete(path);

            return true;

        } catch (IOException e) {

            return false;

        }

    }

    public boolean isSameFile(PathFileObject other) {

        try {

            return Files.isSameFile(path, other.path);

        } catch (IOException e) {

            return false;

        }

    }

    @Override

    public boolean equals(Object other) {

        return (other instanceof PathFileObject && path.equals(((PathFileObject) other).path));

    }

    @Override

    public int hashCode() {

        return path.hashCode();

    }

    @Override

    public String toString() {

        return getClass().getSimpleName() + "[" + path + "]";

    }

    private void ensureParentDirectoriesExist() throws IOException {

        Path parent = path.getParent();

        if (parent != null)

            Files.createDirectories(parent);

    }

    private long size() {

        try {

            return Files.size(path);

        } catch (IOException e) {

            return -1;

        }

    }

    protected static String toBinaryName(Path relativePath) {

        return toBinaryName(relativePath.toString(),

                relativePath.getFileSystem().getSeparator());

    }

    protected static String toBinaryName(String relativePath, String sep) {

        return removeExtension(relativePath).replace(sep, ".");

    }

    protected static String removeExtension(String fileName) {

        int lastDot = fileName.lastIndexOf(".");

        return (lastDot == -1 ? fileName : fileName.substring(0, lastDot));

    }

}