NTPClient.cpp

/**
 * The MIT License (MIT)
 * Copyright (c) 2015 by Fabrice Weinberg
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "NTPClient.h"

NTPClient::NTPClient(UDP& udp) {
  this->_udp            = &udp;
}

NTPClient::NTPClient(UDP& udp, long timeOffset) {
  this->_udp            = &udp;
  this->_timeOffset     = timeOffset;
}

NTPClient::NTPClient(UDP& udp, const char* poolServerName) {
  this->_udp            = &udp;
  this->_poolServerName = poolServerName;
}

NTPClient::NTPClient(UDP& udp, IPAddress poolServerIP) {
  this->_udp            = &udp;
  this->_poolServerIP   = poolServerIP;
  this->_poolServerName = NULL;
}

NTPClient::NTPClient(UDP& udp, const char* poolServerName, long timeOffset) {
  this->_udp            = &udp;
  this->_timeOffset     = timeOffset;
  this->_poolServerName = poolServerName;
}

NTPClient::NTPClient(UDP& udp, IPAddress poolServerIP, long timeOffset){
  this->_udp            = &udp;
  this->_timeOffset     = timeOffset;
  this->_poolServerIP   = poolServerIP;
  this->_poolServerName = NULL;
}

NTPClient::NTPClient(UDP& udp, const char* poolServerName, long timeOffset, unsigned long updateInterval) {
  this->_udp            = &udp;
  this->_timeOffset     = timeOffset;
  this->_poolServerName = poolServerName;
  this->_updateInterval = updateInterval;
}

NTPClient::NTPClient(UDP& udp, IPAddress poolServerIP, long timeOffset, unsigned long updateInterval) {
  this->_udp            = &udp;
  this->_timeOffset     = timeOffset;
  this->_poolServerIP   = poolServerIP;
  this->_poolServerName = NULL;
  this->_updateInterval = updateInterval;
}

void NTPClient::begin() {
  this->begin(NTP_DEFAULT_LOCAL_PORT);
}

void NTPClient::begin(unsigned int port) {
  this->_port = port;
  this->_state = State::uninitialized;
}

bool NTPClient::update() {
  switch (this->_state) {
    case State::uninitialized:
      this->_udp->begin(this->_port);
      this->_state = State::idle;

      // fall through -- we're all initialized now

    case State::idle:
      if ((millis() - this->_lastUpdate < this->_updateInterval)     // Update after _updateInterval
          && this->_lastUpdate != 0)                                 // Update if there was no update yet.
        return false;

      this->_state = State::send_request;

      // fall through -- ready to send request now

    case State::send_request:
#ifdef DEBUG_NTPClient
      Serial.println(F("Sending NTP request"));
#endif

      // flush any existing packets
      while(this->_udp->parsePacket() != 0)
        this->_udp->flush();

      this->sendNTPPacket();

      this->_lastRequest = millis();
      this->_state = State::wait_response;

      // fall through -- if we're lucky we may already receive a response

    case State::wait_response:
      if (!this->_udp->parsePacket()) {
        // no reply yet
        if (millis() - this->_lastRequest >= 1000) {
          // time out
#ifdef DEBUG_NTPClient
          Serial.println(F("NTP reply timeout"));
#endif
          this->_state = State::idle;
        }
        return false;
      }

#ifdef DEBUG_NTPClient
      Serial.println(F("NTP reply received"));
#endif

      // got a reply!
      this->_lastUpdate = this->_lastRequest;
      this->_udp->read(this->_packetBuffer, NTP_PACKET_SIZE);

      {
        unsigned long highWord = word(this->_packetBuffer[40], this->_packetBuffer[41]);
        unsigned long lowWord = word(this->_packetBuffer[42], this->_packetBuffer[43]);
        // combine the four bytes (two words) into a long integer
        // this is NTP time (seconds since Jan 1 1900):
        unsigned long secsSince1900 = highWord << 16 | lowWord;
        this->_currentEpoc = secsSince1900 - SEVENZYYEARS;
      }

      return true;  // return true after successful update

    default:
      this->_state = State::uninitialized;
  }

  return false;
}

bool NTPClient::forceUpdate() {
  // In contrast to NTPClient::update(), this function always sends a NTP
  // request and only returns when the whole operation completes (no matter
  // if it's a success or a failure because of a timeout).  In other words
  // this function is fully synchronous.  It will block until the whole
  // NTP operation completes.
  //
  // We could only make this function switch the state to State::send_request
  // to ensure a NTP request would happen with the next call to
  // NTPClient::update().  However, this would be an API change, users could
  // expect synchronous behaviour and even skip the calls to NTPClient::update()
  // completely relying only on this function for time updates.

  // ensure we're initialized
  if (this->_state == State::uninitialized) {
    this->_udp->begin(this->_port);
  }

  // At this point we can be in any state except for State::uninitialized.
  // Let's ignore that and switch right to State::send_request to send a
  // fresh NTP request.
  this->_state = State::send_request;

  while (true) {
    if (this->update()) {
      // time updated
      return true;
    } else if (this->_state != State::idle) {
      // still waiting for response
      delay(10);
    } else {
      // failure
      return false;
    }
  }
}

bool NTPClient::isTimeSet() const {
  return (this->_lastUpdate != 0); // returns true if the time has been set, else false
}

unsigned long NTPClient::getEpochTime() const {
  return this->_timeOffset + // User offset
         this->_currentEpoc + // Epoch returned by the NTP server
         ((millis() - this->_lastUpdate) / 1000); // Time since last update
}

int NTPClient::getDay() const {
  return (((this->getEpochTime()  / 86400L) + 4 ) % 7); //0 is Sunday
}
int NTPClient::getHours() const {
  return ((this->getEpochTime()  % 86400L) / 3600);
}
int NTPClient::getMinutes() const {
  return ((this->getEpochTime() % 3600) / 60);
}
int NTPClient::getSeconds() const {
  return (this->getEpochTime() % 60);
}

String NTPClient::getFormattedTime() const {
  unsigned long rawTime = this->getEpochTime();
  unsigned long hours = (rawTime % 86400L) / 3600;
  String hoursStr = hours < 10 ? "0" + String(hours) : String(hours);

  unsigned long minutes = (rawTime % 3600) / 60;
  String minuteStr = minutes < 10 ? "0" + String(minutes) : String(minutes);

  unsigned long seconds = rawTime % 60;
  String secondStr = seconds < 10 ? "0" + String(seconds) : String(seconds);

  return hoursStr + ":" + minuteStr + ":" + secondStr;
}

void NTPClient::end() {
  this->_udp->stop();
  this->_state = State::uninitialized;
}

void NTPClient::setTimeOffset(int timeOffset) {
  this->_timeOffset     = timeOffset;
}

void NTPClient::setUpdateInterval(unsigned long updateInterval) {
  this->_updateInterval = updateInterval;
}

void NTPClient::setPoolServerName(const char* poolServerName) {
    this->_poolServerName = poolServerName;
}

void NTPClient::sendNTPPacket() {
  // set all bytes in the buffer to 0
  memset(this->_packetBuffer, 0, NTP_PACKET_SIZE);
  // Initialize values needed to form NTP request
  this->_packetBuffer[0] = 0b11100011;   // LI, Version, Mode
  this->_packetBuffer[1] = 0;     // Stratum, or type of clock
  this->_packetBuffer[2] = 6;     // Polling Interval
  this->_packetBuffer[3] = 0xEC;  // Peer Clock Precision
  // 8 bytes of zero for Root Delay & Root Dispersion
  this->_packetBuffer[12]  = 49;
  this->_packetBuffer[13]  = 0x4E;
  this->_packetBuffer[14]  = 49;
  this->_packetBuffer[15]  = 52;

  // all NTP fields have been given values, now
  // you can send a packet requesting a timestamp:
  if  (this->_poolServerName) {
    this->_udp->beginPacket(this->_poolServerName, 123);
  } else {
    this->_udp->beginPacket(this->_poolServerIP, 123);
  }
  this->_udp->write(this->_packetBuffer, NTP_PACKET_SIZE);
  this->_udp->endPacket();
}

void NTPClient::setRandomPort(unsigned int minValue, unsigned int maxValue) {
  randomSeed(analogRead(0));
  this->_port = random(minValue, maxValue);

  // we've set a new port, remember to reinitialize UDP next time
  this->_state = State::uninitialized;
}