/*
 * Server.h
 *
 *  Created on: Apr 24, 2015
 *      Author: rheijden
 */

#ifndef INCLUDE_SERVER_TCPCONNECTIONDIRECTOR_H_
#define INCLUDE_SERVER_TCPCONNECTIONDIRECTOR_H_

#include <vector>
#include <memory>
#include <mutex>
#include <atomic>
#include <di/Configuration.h>
#include <di/Mailbox.h>

#define DESIRED_WORKERS(ncon) static_cast<ssize_t>(MAX(10, (ncon / 5)))

class DeviceFacade;
class TCPConnection;
class ProtocolFacade;
struct Message;

class TCPConnectionDirector {
 public:
	const int kWorkerMailboxTimeoutMs = 50;
	const size_t kWorkerSelectTimeoutMs = 10;

	const float kMinimumWorkers = 10;
	const float kMaximumWorkers = 100;
	const float kConnectionsPerWorker = 5;
	const float kWorkerMovingAverageFactor = 30;
	const float kWorkerFastScalingThreshold = 2;

	/**
	 * constructor of the connection director
	 * @param c	pointer to config
	 * @param d	pointer to device facade
	 */
	TCPConnectionDirector(const std::shared_ptr<Di::Configuration> &c, const std::shared_ptr<DeviceFacade> &d);
	~TCPConnectionDirector();

	/**
	 * create a new connection
	 * @param fd	socket
	 * @param info
	 * @return	true if .. false if ..
	 */
	bool newConnection(int fd, const struct sockaddr_in &info);

 private:
	struct Worker {
		std::shared_ptr<std::thread> workerThread;
		std::atomic_bool running;
	};

	std::atomic_bool __running;
	uint64_t __connectionTimeoutMs;
	std::mutex __workerMutex;
	std::shared_ptr<Di::Configuration> __cfg;
	std::vector<std::shared_ptr<struct Worker>> __workerList;
	std::shared_ptr<Di::Mailbox<TCPConnection>> __mailbox;
	std::shared_ptr<ProtocolFacade> __protoFacade;
	std::shared_ptr<DeviceFacade> __deviceFacade;
	std::atomic_size_t __nConnections;
	std::shared_ptr<std::thread> workerScaler;
	float __workerCountAverage;

	/**
	 * thread function which adjusts the number of workers to
	 *  the desired amount (based on number of connections)
	 */
	void __scaleWorkers(void);

	/**
	 * Calculates how many workers are desired
	 */
	size_t __workerCount(void);

	/**
	 * stop inactive worker
	 */
	void __terminateWorkers(ssize_t);

	/**
	* create new worker
	*/
	void __spawnWorkers(ssize_t);

	void __encodeAndWrite(const std::shared_ptr<TCPConnection> &conn, const std::shared_ptr<struct Message> &msg);

	void __worker(std::shared_ptr<struct Worker> worker);
	void __workerRead(const std::shared_ptr<TCPConnection> &conn);
	void __workerMessage(const std::shared_ptr<TCPConnection> &conn, const std::shared_ptr<struct Message> &msg);
};

#endif  // INCLUDE_SERVER_TCPCONNECTIONDIRECTOR_H_