/*
 * Copyright 2013 Eediom Inc.
 * 
 * Licensed 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.araqne.logdb.client.http.impl;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringReader;
import java.net.ConnectException;
import java.net.HttpURLConnection;
import java.net.SocketException;
import java.net.SocketTimeoutException;
import java.net.URL;
import java.util.concurrent.CopyOnWriteArraySet;

import org.araqne.logdb.client.Message;
import org.json.JSONArray;
import org.json.JSONTokener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 로그프레소 서버에서 전송되는 비동기적 트랩 전문을 수신합니다.
 * 
 * @author xeraph@eediom.com
 * 
 */
public class TrapReceiver extends Thread {
	private final Logger logger = LoggerFactory.getLogger(TrapReceiver.class);
	private boolean doStop;
	private String host;
	private int port;
	private String cookie;
	private CopyOnWriteArraySet<TrapListener> listeners;
	private HttpURLConnection con;

	public TrapReceiver(String host, String cookie) {
		this(host, 80, cookie);
	}

	public TrapReceiver(String host, int port, String cookie) {
		this.host = host;
		this.port = port;
		this.cookie = cookie;
		this.listeners = new CopyOnWriteArraySet<TrapListener>();
	}

	@Override
	public void run() {
		try {
			logger.trace("logdb client: trap thread started");
			while (!doStop) {
				receiveTrap();
			}
		} catch (SocketException e) {
			if (e.getMessage().equalsIgnoreCase("socket closed"))
				return;
		} catch (Throwable t) {
			logger.error("logdb client: trap receiver error", t);
		} finally {
			logger.trace("logdb client: trap thread stopped");
		}
	}

	private void receiveTrap() throws SocketException {
		InputStream is = null;
		try {
			con = (HttpURLConnection) new URL("http://" + host + ":" + port + "/msgbus/trap").openConnection();
			con.setRequestProperty("Content-Type", "text/json");
			con.setRequestProperty("Cookie", cookie);
			con.setConnectTimeout(5000);
			con.setReadTimeout(5000);

			is = con.getInputStream();

			ByteArrayOutputStream bos = null;
			if (con.getContentLength() > 0)
				bos = new ByteArrayOutputStream(con.getContentLength());
			else
				bos = new ByteArrayOutputStream();

			byte[] b = new byte[8096];

			while (true) {
				int read = is.read(b);
				if (read < 0)
					break;

				bos.write(b, 0, read);
			}

			String text = new String(bos.toByteArray(), "utf-8");
			if (text.isEmpty())
				return;

			JSONTokener tokenizer = new JSONTokener(new StringReader(text));
			JSONArray container = (JSONArray) tokenizer.nextValue();
			for (int i = 0; i < container.length(); i++) {
				JSONArray obj = container.getJSONArray(i);
				Message msg = MessageCodec.decode(obj.toString());
				invokeTrapCallbacks(msg);
			}
		} catch (SocketTimeoutException e) {
			logger.debug("logdb client: socket timeout");
		} catch (ConnectException e) {
			throw e;
		} catch (SocketException e) {
			if (e.getMessage().equalsIgnoreCase("socket closed"))
				throw e;
			logger.error("logdb client: cannot fetch trap", e);
		} catch (Throwable t) {
			logger.error("logdb client: cannot fetch trap", t);
		} finally {
			if (is != null) {
				try {
					is.close();
				} catch (IOException e) {
				}
			}

			if (con != null) {
				con.disconnect();
				con = null;
			}
		}

	}

	private void invokeTrapCallbacks(Message msg) {
		for (TrapListener listener : listeners) {
			try {
				listener.onTrap(msg);
			} catch (Throwable t) {
				logger.error("logdb client: listener should not throw any exception", t);
			}
		}
	}

	public void addListener(TrapListener listener) {
		listeners.add(listener);
	}

	public void removeListener(TrapListener listener) {
		listeners.remove(listener);
	}

	public void close() {
		try {
			doStop = true;
			if (con != null)
				con.disconnect();
			interrupt();
			join();
		} catch (InterruptedException e) {
		}
	}
}