/**
 * @file ListenSyslog.h
 * ListenSyslog class declaration
 *
 * 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.
 */
#ifndef __LISTEN_SYSLOG_H__
#define __LISTEN_SYSLOG_H__

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/types.h>
#include <chrono>
#include <thread>
#include "FlowFileRecord.h"
#include "Processor.h"
#include "ProcessSession.h"

//! SyslogEvent
typedef struct {
	uint8_t *payload;
	uint64_t len;
} SysLogEvent;

//! ListenSyslog Class
class ListenSyslog : public Processor
{
public:
	//! Constructor
	/*!
	 * Create a new processor
	 */
	ListenSyslog(std::string name, uuid_t uuid = NULL)
	: Processor(name, uuid)
	{
		_logger = Logger::getLogger();
		_eventQueueByteSize = 0;
		_serverSocket = 0;
		_recvBufSize = 65507;
		_maxSocketBufSize = 1024*1024;
		_maxConnections = 2;
		_maxBatchSize = 1;
		_messageDelimiter = "\n";
		_protocol = "UDP";
		_port = 514;
		_parseMessages = false;
		_serverSocket = 0;
		_maxFds = 0;
		FD_ZERO(&_readfds);
		_thread = NULL;
		_resetServerSocket = false;
		_serverTheadRunning = false;
	}
	//! Destructor
	virtual ~ListenSyslog()
	{
		_serverTheadRunning = false;
		if (this->_thread)
			delete this->_thread;
		// need to reset the socket
		std::vector<int>::iterator it;
		for (it = _clientSockets.begin(); it != _clientSockets.end(); ++it)
		{
			int clientSocket = *it;
			close(clientSocket);
		}
		_clientSockets.clear();
		if (_serverSocket > 0)
		{
			_logger->log_info("ListenSysLog Server socket %d close", _serverSocket);
			close(_serverSocket);
			_serverSocket = 0;
		}
	}
	//! Processor Name
	static const std::string ProcessorName;
	//! Supported Properties
	static Property RecvBufSize;
	static Property MaxSocketBufSize;
	static Property MaxConnections;
	static Property MaxBatchSize;
	static Property MessageDelimiter;
	static Property ParseMessages;
	static Property Protocol;
	static Property Port;
	//! Supported Relationships
	static Relationship Success;
	static Relationship Invalid;
	//! Nest Callback Class for write stream
	class WriteCallback : public OutputStreamCallback
	{
		public:
		WriteCallback(char *data, uint64_t size)
		: _data(data), _dataSize(size) {}
		char *_data;
		uint64_t _dataSize;
		void process(std::ofstream *stream) {
			if (_data && _dataSize > 0)
				stream->write(_data, _dataSize);
		}
	};

public:
	//! OnTrigger method, implemented by NiFi ListenSyslog
	virtual void onTrigger(ProcessContext *context, ProcessSession *session);
	//! Initialize, over write by NiFi ListenSyslog
	virtual void initialize(void);

protected:

private:
	//! Logger
	Logger *_logger;
	//! Run function for the thread
	static void run(ListenSyslog *process);
	//! Run Thread
	void runThread();
	//! Queue for store syslog event
	std::queue<SysLogEvent> _eventQueue;
	//! Size of Event queue in bytes
	uint64_t _eventQueueByteSize;
	//! Get event queue size
	uint64_t getEventQueueSize() {
		std::lock_guard<std::mutex> lock(_mtx);
		return _eventQueue.size();
	}
	//! Get event queue byte size
	uint64_t getEventQueueByteSize() {
		std::lock_guard<std::mutex> lock(_mtx);
		return _eventQueueByteSize;
	}
	//! Whether the event queue  is empty
	bool isEventQueueEmpty()
	{
		std::lock_guard<std::mutex> lock(_mtx);
		return _eventQueue.empty();
	}
	//! Put event into directory listing
	void putEvent(uint8_t *payload, uint64_t len)
	{
		std::lock_guard<std::mutex> lock(_mtx);
		SysLogEvent event;
		event.payload = payload;
		event.len = len;
		_eventQueue.push(event);
		_eventQueueByteSize += len;
	}
	//! Read \n terminated line from TCP socket
	int readline( int fd, char *bufptr, size_t len );
	//! start server socket and handling client socket
	void startSocketThread();
	//! Poll event
	void pollEvent(std::queue<SysLogEvent> &list, int maxSize)
	{
		std::lock_guard<std::mutex> lock(_mtx);

		while (!_eventQueue.empty() && (maxSize == 0 || list.size() < maxSize))
		{
			SysLogEvent event = _eventQueue.front();
			_eventQueue.pop();
			_eventQueueByteSize -= event.len;
			list.push(event);
		}
		return;
	}
	//! Mutex for protection of the directory listing
	std::mutex _mtx;
	int64_t _recvBufSize;
	int64_t _maxSocketBufSize;
	int64_t _maxConnections;
	int64_t _maxBatchSize;
	std::string _messageDelimiter;
	std::string _protocol;
	int64_t _port;
	bool _parseMessages;
	int _serverSocket;
	std::vector<int> _clientSockets;
	int _maxFds;
	fd_set _readfds;
	//! thread
	std::thread *_thread;
	//! whether to reset the server socket
	bool _resetServerSocket;
	bool _serverTheadRunning;
	//! buffer for read socket
	uint8_t _buffer[2048];
};

#endif