/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.activemq.transport.stomp;

import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.HashMap;

public class StompConnection {

    public static final long RECEIVE_TIMEOUT = 10000;

    private Socket stompSocket;
    private ByteArrayOutputStream inputBuffer = new ByteArrayOutputStream();
    
    public void open(String host, int port) throws IOException, UnknownHostException {
        open(new Socket(host, port));
    }
    
    public void open(Socket socket) {
    	stompSocket = socket;
    }

    public void close() throws IOException {
        if (stompSocket != null) {
            stompSocket.close();
            stompSocket = null;
        }
    }

    public void sendFrame(String data) throws Exception {
        byte[] bytes = data.getBytes("UTF-8");
        OutputStream outputStream = stompSocket.getOutputStream();
        outputStream.write(bytes);
        outputStream.write(0);
        outputStream.flush();
    }
    
    public void sendFrame(String frame, byte[] data) throws Exception {
        byte[] bytes = frame.getBytes("UTF-8");
        OutputStream outputStream = stompSocket.getOutputStream();
        outputStream.write(bytes);
        outputStream.write(data);
        outputStream.write(0);
        outputStream.flush();        
    }
    
    public StompFrame receive() throws Exception {
        return receive(RECEIVE_TIMEOUT);
    }    
    
    public StompFrame receive(long timeOut) throws Exception {
    	stompSocket.setSoTimeout((int)timeOut);
    	InputStream is = stompSocket.getInputStream();
        StompWireFormat wf = new StompWireFormat();
        DataInputStream dis = new DataInputStream(is);
        return (StompFrame)wf.unmarshal(dis);
    }

    public String receiveFrame() throws Exception {
        return receiveFrame(RECEIVE_TIMEOUT);
    }

    public String receiveFrame(long timeOut) throws Exception {
        stompSocket.setSoTimeout((int)timeOut);
        InputStream is = stompSocket.getInputStream();
        int c = 0;
        for (;;) {
            c = is.read();
            if (c < 0) {
                throw new IOException("socket closed.");
            } else if (c == 0) {
                c = is.read();
                if (c == '\n') {
                    // end of frame
                    return stringFromBuffer(inputBuffer);
                } else {
                    inputBuffer.write(0);
                    inputBuffer.write(c);
                }
            } else {
                inputBuffer.write(c);
            }
        }
    }

	private String stringFromBuffer(ByteArrayOutputStream inputBuffer) throws Exception {
	    byte[] ba = inputBuffer.toByteArray();
        inputBuffer.reset();
        return new String(ba, "UTF-8");
    }

    public Socket getStompSocket() {
		return stompSocket;
	}

	public void setStompSocket(Socket stompSocket) {
		this.stompSocket = stompSocket;
	}
	
    public void connect(String username, String password) throws Exception {
        connect(username, password, null);
    }
	
    public void connect(String username, String password, String client) throws Exception {
    	HashMap<String, String> headers = new HashMap();
    	headers.put("login", username);
    	headers.put("passcode", password);
    	if (client != null) {
    		headers.put("client-id", client);
    	}
    	StompFrame frame = new StompFrame("CONNECT", headers);
        sendFrame(frame.toString());
        
        StompFrame connect = receive();
        if (!connect.getAction().equals(Stomp.Responses.CONNECTED)) {
        	throw new Exception ("Not connected: " + connect.getBody());
        }
    }
    
    public void disconnect() throws Exception {
    	StompFrame frame = new StompFrame("DISCONNECT");
        sendFrame(frame.toString());    	
    }
    
    public void send(String destination, String message) throws Exception {
    	send(destination, message, null, null);
    }
    
    public void send(String destination, String message, String transaction, HashMap<String, String> headers) throws Exception {
    	if (headers == null) {
    		headers = new HashMap<String, String>();
    	}
    	headers.put("destination", destination);
    	if (transaction != null) {
    		headers.put("transaction", transaction);
    	}
    	StompFrame frame = new StompFrame("SEND", headers, message.getBytes());
        sendFrame(frame.toString());    	
    }
    
    public void subscribe(String destination) throws Exception {
    	subscribe(destination, null, null);
    }
    
    public void subscribe(String destination, String ack) throws Exception {
    	subscribe(destination, ack, new HashMap<String, String>());
    }
    
    public void subscribe(String destination, String ack, HashMap<String, String> headers) throws Exception {
		if (headers == null) {
			headers = new HashMap<String, String>();
		}
		headers.put("destination", destination);
    	if (ack != null) {
    		headers.put("ack", ack);
    	}
    	StompFrame frame = new StompFrame("SUBSCRIBE", headers);
        sendFrame(frame.toString());    	
    }
    
    public void unsubscribe(String destination) throws Exception {
    	unsubscribe(destination, null);
    }
    
    public void unsubscribe(String destination, HashMap<String, String> headers) throws Exception {
		if (headers == null) {
			headers = new HashMap<String, String>();
		}
		headers.put("destination", destination);
    	StompFrame frame = new StompFrame("UNSUBSCRIBE", headers);
        sendFrame(frame.toString());    	
    }    
    
    public void begin(String transaction) throws Exception {
    	HashMap<String, String> headers = new HashMap<String, String>();
    	headers.put("transaction", transaction);
    	StompFrame frame = new StompFrame("BEGIN", headers);
    	sendFrame(frame.toString());
    }
    
    public void abort(String transaction) throws Exception {
    	HashMap<String, String> headers = new HashMap<String, String>();
    	headers.put("transaction", transaction);
    	StompFrame frame = new StompFrame("ABORT", headers);
    	sendFrame(frame.toString());
    }
    
    public void commit(String transaction) throws Exception {
    	HashMap<String, String> headers = new HashMap<String, String>();
    	headers.put("transaction", transaction);
    	StompFrame frame = new StompFrame("COMMIT", headers);
    	sendFrame(frame.toString());
    }
    
    public void ack(StompFrame frame) throws Exception {
    	ack(frame.getHeaders().get("message-id"), null);
    }    
    
    public void ack(StompFrame frame, String transaction) throws Exception {
    	ack(frame.getHeaders().get("message-id"), transaction);
    }
    
    public void ack(String messageId) throws Exception {
    	ack(messageId, null);
    }
    
    public void ack(String messageId, String transaction) throws Exception {
    	HashMap<String, String> headers = new HashMap<String, String>();
    	headers.put("message-id", messageId);
    	if (transaction != null)
    		headers.put("transaction", transaction);
    	StompFrame frame = new StompFrame("ACK", headers);
    	sendFrame(frame.toString());	
    }
    
    protected String appendHeaders(HashMap<String, Object> headers) {
    	StringBuffer result = new StringBuffer();
    	for (String key : headers.keySet()) {
    		result.append(key + ":" + headers.get(key) + "\n");
    	}
    	result.append("\n");
    	return result.toString();
    }

}
