/*
 * 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 _LOG4CXX_HELPERS_FILEWATCHDOG_H
#define _LOG4CXX_HELPERS_FILEWATCHDOG_H

#include <log4cxx/logstring.h>
#include <time.h>
#include <log4cxx/helpers/pool.h>
#include <log4cxx/file.h>
#include <thread>
#include <condition_variable>
#include <atomic>

namespace log4cxx
{
namespace helpers
{

/**
Check every now and then that a certain file has not changed. If it
has, then call the #doOnChange method.
*/
class LOG4CXX_EXPORT FileWatchdog
{
	public:
		virtual ~FileWatchdog();
		/**
		The default delay between every file modification check, set to 60
		seconds.  */
		static long DEFAULT_DELAY /*= 60000*/;

	protected:
		/**
		The name of the file to observe  for changes.
		*/
		File file;

		/**
		The delay to observe between every check.
		By default set DEFAULT_DELAY.*/
		long delay;
		log4cxx_time_t lastModif;
		bool warnedAlready;
		std::atomic<int> interrupted;

	protected:
		FileWatchdog(const File& filename);
		virtual void doOnChange() = 0;
		void checkAndConfigure();

	public:
		/**
		Set the delay to observe between each check of the file changes.
		*/
		void setDelay(long delay1)
		{
			this->delay = delay1;
		}

		void start();

	private:
		void run();
		bool is_interrupted();
		Pool pool;
		std::thread thread;
		std::condition_variable interrupt;
		std::mutex interrupt_mutex;

		FileWatchdog(const FileWatchdog&);
		FileWatchdog& operator=(const FileWatchdog&);

};
}  // namespace helpers
} // namespace log4cxx


#endif // _LOG4CXX_HELPERS_FILEWATCHDOG_H