NTPClient.h

#pragma once

#include "Arduino.h"

#include <Udp.h>

#define SEVENZYYEARS 2208988800UL
#define NTP_PACKET_SIZE 48
#define NTP_DEFAULT_LOCAL_PORT 1337

class NTPClient {
	private:
		UDP*					_udp;
		bool					_udpSetup				= false;

		const char*		_poolServerName = "pool.ntp.org"; // Default time server
		int						_port						= NTP_DEFAULT_LOCAL_PORT;
		long					_timeOffset			= 0;

		unsigned long _updateInterval = 60000;	// In ms

		unsigned long _currentEpoc		= 0;			// In s
		unsigned long _lastUpdate			= 0;			// In ms

		byte					_packetBuffer[NTP_PACKET_SIZE];

		void					sendNTPPacket();

	public:
		NTPClient(UDP& udp);
		NTPClient(UDP& udp, long timeOffset);
		NTPClient(UDP& udp, const char* poolServerName);
		NTPClient(UDP& udp, const char* poolServerName, long timeOffset);
		NTPClient(UDP& udp, const char* poolServerName, long timeOffset, unsigned long updateInterval);

		/**
		 * Set time server name
		 *
		 * @param poolServerName
		 */
		void setPoolServerName(const char* poolServerName);

		/**
		 * Starts the underlying UDP client with the default local port
		 */
		void begin();

		/**
		 * Starts the underlying UDP client with the specified local port
		 */
		void begin(int port);

		/**
		 * This should be called in the main loop of your application. By default an update from the NTP Server is only
		 * made every 60 seconds. This can be configured in the NTPClient constructor.
		 *
		 * @return true on success, false on failure
		 */
		bool update();

		/**
		 * This will force the update from the NTP Server.
		 *
		 * @return true on success, false on failure
		 */
		bool forceUpdate();

		int getDay() const;
		int getHours() const;
		int getMinutes() const;
		int getSeconds() const;

		/**
		 * Changes the time offset. Useful for changing timezones dynamically
		 */
		void setTimeOffset(int timeOffset);

		/**
		 * Set the update interval to another frequency. E.g. useful when the
		 * timeOffset should not be set in the constructor
		 */
		void setUpdateInterval(unsigned long updateInterval);

		/**
		 * @return time formatted like `hh:mm:ss`
		 */
		String getFormattedTime() const;

		/**
		 * @return time in seconds since Jan. 1, 1970
		 */
		unsigned long getEpochTime() const;

		/**
		 * Stops the underlying UDP client
		 */
		void end();
};