/*

 * Copyright (c) 2015, 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.

 *

 * 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.

 */

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

import java.io.DataInputStream;

import java.io.DataOutputStream;

import java.io.IOException;

import java.io.StringWriter;

import java.net.Socket;

import java.nio.charset.StandardCharsets;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.Collections;

public class CustomEditor implements AutoCloseable {

    public static final int SOURCE_CODE = 0;

    public static final int GET_SOURCE_CODE = 1;

    public static final int REMOVE_CODE = 2;

    public static final int GET_FILENAME = 3;

    public static final int EXIT_CODE = -1;

    public static final int ACCEPT_CODE = -2;

    public static final int CANCEL_CODE = -3;

    private final Socket socket;

    private final Path path;

    private final StringWriter writer;

    private final String source;

    public CustomEditor(int port, String fileName) throws IOException {

        this.socket = new Socket((String) null, port);

        this.path = Paths.get(fileName);

        this.writer = new StringWriter();

        this.source = new String(Files.readAllBytes(path), StandardCharsets.UTF_8);

    }

    public void loop() throws IOException {

        DataInputStream input = new DataInputStream(new BufferedInputStream(socket.getInputStream()));

        DataOutputStream output = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));

        while (true) {

            int cmd = input.readInt();

            switch (cmd) {

                case EXIT_CODE: {

                    Files.write(path, Collections.singletonList(writer.toString()));

                    return;

                }

                case GET_SOURCE_CODE: {

                    writeString(output, source);

                    break;

                }

                case REMOVE_CODE: {

                    // only for external editor

                    Files.delete(path);

                    break;

                }

                case GET_FILENAME: {

                    writeString(output, path.toString());

                    break;

                }

                case CANCEL_CODE: {

                    return;

                }

                case ACCEPT_CODE: {

                    Files.write(path, Collections.singletonList(writer.toString()));

                    break;

                }

                case SOURCE_CODE: {

                    int length = input.readInt();

                    byte[] bytes = new byte[length];

                    input.readFully(bytes);

                    writer.write(new String(bytes, StandardCharsets.UTF_8));

                    break;

                }

            }

        }

    }

    private void writeString(DataOutputStream output, String s) throws IOException {

        byte[] bytes = s.getBytes(StandardCharsets.UTF_8);

        output.writeInt(bytes.length);

        output.write(bytes);

        output.flush();

    }

    public static void main(String[] args) throws IOException {

        if (args.length != 2) {

            System.err.println("Usage: port file");

            System.exit(1);

        }

        try (CustomEditor editor = new CustomEditor(Integer.parseInt(args[0]), args[1])) {

            editor.loop();

        }

    }

    @Override

    public void close() throws IOException {

        socket.close();

    }

}