/****************************************************************************************************************************
  UDPSendReceive.ino - Simple Arduino web server sample for ESP8266/ESP32 AT-command shield

  For Ethernet shields using ESP32_W5500 (ESP32 + W5500)

  WebServer_ESP32_W5500 is a library for the ESP32 with Ethernet W5500 to run WebServer

  Based on and modified from ESP32-IDF https://github.com/espressif/esp-idf
  Built by Khoi Hoang https://github.com/khoih-prog/WebServer_ESP32_W5500
  Licensed under GPLv3 license
 *****************************************************************************************************************************/

#if !( defined(ESP32) )
  #error This code is designed for (ESP32 + W5500) to run on ESP32 platform! Please check your Tools->Board setting.
#endif

#define DEBUG_ETHERNET_WEBSERVER_PORT       Serial

// Debug Level from 0 to 4
#define _ETHERNET_WEBSERVER_LOGLEVEL_       3

//////////////////////////////////////////////////////////

// Optional values to override default settings
// Don't change unless you know what you're doing
//#define ETH_SPI_HOST        SPI3_HOST
//#define SPI_CLOCK_MHZ       25

// Must connect INT to GPIOxx or not working
//#define INT_GPIO            4

//#define MISO_GPIO           19
//#define MOSI_GPIO           23
//#define SCK_GPIO            18
//#define CS_GPIO             5

//////////////////////////////////////////////////////////

#include <WebServer_ESP32_W5500.h>

// Enter a MAC address and IP address for your controller below.
#define NUMBER_OF_MAC      20

byte mac[][NUMBER_OF_MAC] =
{
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x01 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x02 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x03 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x04 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x05 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x06 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x07 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x08 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x09 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x0A },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x0B },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x0C },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x0D },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x0E },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x0F },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x10 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x11 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x12 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x13 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x14 },
};

// Select the IP address according to your local network
IPAddress myIP(192, 168, 2, 232);
IPAddress myGW(192, 168, 2, 1);
IPAddress mySN(255, 255, 255, 0);

// Google DNS Server IP
IPAddress myDNS(8, 8, 8, 8);

char timeServer[]         = "time.nist.gov";  // NTP server
unsigned int localPort    = 2390;             // local port to listen for UDP packets

const int NTP_PACKET_SIZE = 48;       // NTP timestamp is in the first 48 bytes of the message
const int UDP_TIMEOUT     = 2000;     // timeout in milliseconds to wait for an UDP packet to arrive

byte packetBuffer[NTP_PACKET_SIZE];          // buffer to hold incoming packet
byte ReplyBuffer[] = "ACK";      // a string to send back

// A UDP instance to let us send and receive packets over UDP
WiFiUDP Udp;

// send an NTP request to the time server at the given address
void sendNTPpacket(char *ntpSrv)
{
  // set all bytes in the buffer to 0
  memset(packetBuffer, 0, NTP_PACKET_SIZE);
  // Initialize values needed to form NTP request
  // (see URL above for details on the packets)

  packetBuffer[0] = 0b11100011;   // LI, Version, Mode
  packetBuffer[1] = 0;     // Stratum, or type of clock
  packetBuffer[2] = 6;     // Polling Interval
  packetBuffer[3] = 0xEC;  // Peer Clock Precision
  // 8 bytes of zero for Root Delay & Root Dispersion
  packetBuffer[12]  = 49;
  packetBuffer[13]  = 0x4E;
  packetBuffer[14]  = 49;
  packetBuffer[15]  = 52;

  // all NTP fields have been given values, now
  // you can send a packet requesting a timestamp:
  Udp.beginPacket(ntpSrv, 123); //NTP requests are to port 123

  Udp.write(packetBuffer, NTP_PACKET_SIZE);

  Udp.endPacket();
}

void setup()
{
  Serial.begin(115200);

  while (!Serial && (millis() < 5000));

  Serial.print(F("\nStart UDPSendReceive on "));
  Serial.print(ARDUINO_BOARD);
  Serial.print(F(" with "));
  Serial.println(SHIELD_TYPE);
  Serial.println(WEBSERVER_ESP32_W5500_VERSION);

  ET_LOGWARN(F("Default SPI pinout:"));
  ET_LOGWARN1(F("SPI_HOST:"), ETH_SPI_HOST);
  ET_LOGWARN1(F("MOSI:"), MOSI_GPIO);
  ET_LOGWARN1(F("MISO:"), MISO_GPIO);
  ET_LOGWARN1(F("SCK:"),  SCK_GPIO);
  ET_LOGWARN1(F("CS:"),   CS_GPIO);
  ET_LOGWARN1(F("INT:"),  INT_GPIO);
  ET_LOGWARN1(F("SPI Clock (MHz):"), SPI_CLOCK_MHZ);
  ET_LOGWARN(F("========================="));

  ///////////////////////////////////

  // To be called before ETH.begin()
  ESP32_W5500_onEvent();

  // start the ethernet connection and the server:
  // Use DHCP dynamic IP and random mac
  //bool begin(int MISO_GPIO, int MOSI_GPIO, int SCLK_GPIO, int CS_GPIO, int INT_GPIO, int SPI_CLOCK_MHZ,
  //           int SPI_HOST, uint8_t *W6100_Mac = W6100_Default_Mac);
  ETH.begin( MISO_GPIO, MOSI_GPIO, SCK_GPIO, CS_GPIO, INT_GPIO, SPI_CLOCK_MHZ, ETH_SPI_HOST );
  //ETH.begin( MISO_GPIO, MOSI_GPIO, SCK_GPIO, CS_GPIO, INT_GPIO, SPI_CLOCK_MHZ, ETH_SPI_HOST, mac[millis() % NUMBER_OF_MAC] );

  // Static IP, leave without this line to get IP via DHCP
  //bool config(IPAddress local_ip, IPAddress gateway, IPAddress subnet, IPAddress dns1 = 0, IPAddress dns2 = 0);
  //ETH.config(myIP, myGW, mySN, myDNS);

  ESP32_W5500_waitForConnect();

  ///////////////////////////////////

  Serial.println(F("\nStarting connection to server..."));
  // if you get a connection, report back via serial:
  Udp.begin(localPort);

  Serial.print(F("Listening on port "));
  Serial.println(localPort);
}

void loop()
{
  sendNTPpacket(timeServer); // send an NTP packet to a time server

  // wait for a reply for UDP_TIMEOUT milliseconds
  unsigned long startMs = millis();

  while (!Udp.available() && (millis() - startMs) < UDP_TIMEOUT) {}

  // if there's data available, read a packet
  int packetSize = Udp.parsePacket();

  if (packetSize)
  {
    Serial.print(F("UDP Packet received, size "));
    Serial.println(packetSize);
    Serial.print(F("From "));
    IPAddress remoteIp = Udp.remoteIP();
    Serial.print(remoteIp);
    Serial.print(F(", port "));
    Serial.println(Udp.remotePort());

    // We've received a packet, read the data from it into the buffer
    Udp.read(packetBuffer, NTP_PACKET_SIZE);

    // the timestamp starts at byte 40 of the received packet and is four bytes,
    // or two words, long. First, esxtract the two words:

    unsigned long highWord = word(packetBuffer[40], packetBuffer[41]);
    unsigned long lowWord = word(packetBuffer[42], 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;

    Serial.print(F("Seconds since Jan 1 1900 = "));
    Serial.println(secsSince1900);

    // now convert NTP time into )everyday time:
    Serial.print(F("Unix time = "));
    // Unix time starts on Jan 1 1970. In seconds, that's 2208988800:
    const unsigned long seventyYears = 2208988800UL;
    // subtract seventy years:
    unsigned long epoch = secsSince1900 - seventyYears;
    // print Unix time:
    Serial.println(epoch);

    // print the hour, minute and second:
    Serial.print(F("The UTC time is "));       // UTC is the time at Greenwich Meridian (GMT)
    Serial.print((epoch  % 86400L) / 3600); // print the hour (86400 equals secs per day)
    Serial.print(F(":"));

    if (((epoch % 3600) / 60) < 10)
    {
      // In the first 10 minutes of each hour, we'll want a leading '0'
      Serial.print(F("0"));
    }

    Serial.print((epoch  % 3600) / 60); // print the minute (3600 equals secs per minute)
    Serial.print(F(":"));

    if ((epoch % 60) < 10)
    {
      // In the first 10 seconds of each minute, we'll want a leading '0'
      Serial.print(F("0"));
    }

    Serial.println(epoch % 60); // print the second
  }

  // wait ten seconds before asking for the time again
  delay(10000);
}