package jp.ac.u_ryukyu.treevnc;

import java.io.*;
import java.net.*;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import com.glavsoft.rfb.protocol.ProtocolContext.TreeCommand;

public class TreeVncProtocol {
    private BufferedReader is = null;
    private DataOutputStream os = null;
    private Socket echoSocket = null;
    private int rootPort;
    private String rootAddress;
    private int singleWidth;
    private int singleHeight;

    public TreeVncProtocol(String name, int echoPort) {
        this.rootPort = echoPort;
        this.rootAddress = name;
    }

    public void setSingleSize(int singleWidth, int singleHeight) {
        this.singleWidth = singleWidth;
        this.singleHeight = singleHeight;
    }

    public void openport() throws IOException {
        echoSocket = new Socket(rootAddress, rootPort);
        // echoSocket.setReuseAddress(true);
        os = new DataOutputStream(echoSocket.getOutputStream());
        is = new BufferedReader(new InputStreamReader(
                echoSocket.getInputStream()));
    }

    public void findRootReply(int port) throws IOException {
        sendWithHostAndPort(TreeCommand.FIND_ROOT_REPLY, null, port, (short) 0);
    }

    public void whereToConnect(String hostname, int port) throws IOException {
        sendWithHostAndPort(TreeCommand.WHERE_TO_CONNECT, hostname, port, (short) 0);
    }

    public void connectTo(String hostname, int port,int leaderFlag, short yourId) throws IOException{
        TreeCommand command = leaderFlag == 1 ? TreeCommand.CONNECT_TO_AS_LEADER : TreeCommand.CONNECT_TO;
        sendWithHostAndPort(command , hostname, port, yourId);
    }

    public void lostParent(String hostname, int port) throws IOException {
        sendWithHostAndPort(TreeCommand.LOST_PARENT, hostname, port, (short) 0);
    }

    public void sendWithHostAndPort(TreeCommand command, String hostname, int port, short value) {
        try {
            openport();
            if (hostname == null) {
                // in case of root finder, we can't get localaddress from datagram packet.
                // so use local part of TCP socket.
                hostname = echoSocket.getLocalAddress().getHostAddress();
            }
            int cmdlen = 4 + 4 + 4 + hostname.length();
            if (cmdlen < 12) cmdlen = 12;
            ByteBuffer buf = ByteBuffer.allocate(cmdlen);
            buf.order(ByteOrder.BIG_ENDIAN);
            buf.put((byte) command.cmd);
            buf.put((byte) 0);
            buf.putShort(value);
            buf.putInt(4 + hostname.length()); // length
            buf.putInt(port);
            buf.put(hostname.getBytes(), 0, hostname.length());
            while (buf.hasRemaining()) buf.put((byte) 0);
            buf.flip();
            sendCommandToTheRoot(buf);
        } catch (IOException e) {
            System.out.println("cannot send command to the root.");
            streamClose();
        }
    }

    public void sendCommandToTheRoot(ByteBuffer buf) throws IOException {
        char[] charBuf = new char[12];
            is.read(charBuf, 0, 12);                       // skip root's version header
            os.write(buf.array(), 0, buf.limit());         // send our command
    }

    void streamClose() {
        try {
            os.close();
            is.close();
            echoSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("cannot close stream.");
        }
    }

}