// 1-channel LoRa Gateway for ESP8266
// Copyright (c) 2016, 2017, 2018, 2019 Maarten Westenberg
// Version 6.1.5
// Date: 2019-12-20
// Author: Maarten Westenberg (mw12554@hotmail.com)
//
// Based on work done by Thomas Telkamp for Raspberry PI 1-ch gateway and many others.
//
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the MIT License
// which accompanies this distribution, and is available at
// https://opensource.org/licenses/mit-license.php
//
// NO WARRANTY OF ANY KIND IS PROVIDED
//
// The protocols and specifications used for this 1ch gateway: 
// 1. LoRA Specification version V1.0 and V1.1 for Gateway-Node communication
//	
// 2. Semtech Basic communication protocol between Lora gateway and server version 3.0.0
//	https://github.com/Lora-net/packet_forwarder/blob/master/PROTOCOL.TXT
//
// Notes: 
// - Once call hostbyname() to get IP for services, after that only use IP
//	 addresses (too many gethost name makes the ESP unstable)
// - Only call yield() in main stream (not for background NTP sync). 
//
// ----------------------------------------------------------------------------------------

// The followion file contains most of the definitions
// used in other files. It should be the first file.
#include "configGway.h"									// This file contains configuration of GWay
#include "configNode.h"									// Contains the AVG data of Wifi etc.

#if defined (ARDUINO_ARCH_ESP32) || defined(ESP32)
#define ESP32_ARCH 1
#endif

#include <Esp.h>											// ESP8266 specific IDE functions
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <cstdlib>
#include <sys/time.h>
#include <cstring>
#include <string>											// C++ specific string functions

#include <SPI.h>											// For the RFM95 bus
#include <TimeLib.h>										// http://playground.arduino.cc/code/time
#include <DNSServer.h>										// Local DNSserver
#include <ArduinoJson.h>
#include <FS.h>												// ESP8266 Specific
#include <WiFiUdp.h>
#include <pins_arduino.h>
#include <gBase64.h>										// https://github.com/adamvr/arduino-base64 (changed the name)

// Local include files
#include "loraModem.h"
#include "loraFiles.h"
#include "oLED.h"

extern "C" {
#include "lwip/err.h"
#include "lwip/dns.h"
}

#if _WIFIMANAGER==1
#include <WiFiManager.h>									// Library for ESP WiFi config through an AP
#endif

#if (GATEWAYNODE==1) || (_LOCALSERVER==1)
#include "AES-128_V10.h"
#endif


// ----------- Specific ESP32 stuff --------------
#if ESP32_ARCH==1											// IF ESP32

#include "WiFi.h"
#include <ESPmDNS.h>
#include <SPIFFS.h>
#if A_SERVER==1
#include <ESP32WebServer.h>									// Dedicated Webserver for ESP32
#include <Streaming.h>          							// http://arduiniana.org/libraries/streaming/
#endif
#if A_OTA==1
#include <ESP32httpUpdate.h>								// Not yet available
#include <ArduinoOTA.h>
#endif//OTA

// ----------- Specific ESP8266 stuff --------------
#else

#include <ESP8266WiFi.h>									// Which is specific for ESP8266
#include <ESP8266mDNS.h>
extern "C" {
#include "user_interface.h"
#include "c_types.h"
}
#if A_SERVER==1
#include <ESP8266WebServer.h>
#include <Streaming.h>          							// http://arduiniana.org/libraries/streaming/
#endif //A_SERVER

#if A_OTA==1
#include <ESP8266httpUpdate.h>
#include <ArduinoOTA.h>
#endif//OTA

#endif//ESP_ARCH

// ----------- Declaration of vars --------------
uint8_t debug=1;											// Debug level! 0 is no msgs, 1 normal, 2 extensive
uint8_t pdebug=0xFF;										// Allow all patterns for debugging

#if GATEWAYNODE==1

#if _GPS==1
#include <TinyGPS++.h>
TinyGPSPlus gps;
HardwareSerial sGps(1);
#endif //_GPS
#endif //GATEWAYNODE

// You can switch webserver off if not necessary but probably better to leave it in.
#if A_SERVER==1
#if ESP32_ARCH==1
	ESP32WebServer server(A_SERVERPORT);
#else
	ESP8266WebServer server(A_SERVERPORT);
#endif
#endif

using namespace std;

byte currentMode = 0x81;

bool sx1272 = true;											// Actually we use sx1276/RFM95

uint8_t	 ifreq = 0;											// Channel Index
//unsigned long freq = 0;

uint8_t MAC_array[6];

// ----------------------------------------------------------------------------
//
// Configure these values only if necessary!
//
// ----------------------------------------------------------------------------

// Set spreading factor (SF7 - SF12)
sf_t sf 			= _SPREADING;
sf_t sfi 			= _SPREADING;							// Initial value of SF

// Set location, description and other configuration parameters
// Defined in ESP-sc_gway.h
//
float lat			= _LAT;									// Configuration specific info...
float lon			= _LON;
int   alt			= _ALT;
char platform[24]	= _PLATFORM; 							// platform definition
char email[40]		= _EMAIL;    							// used for contact email
char description[64]= _DESCRIPTION;							// used for free form description 

// define servers

IPAddress ntpServer;										// IP address of NTP_TIMESERVER
IPAddress ttnServer;										// IP Address of thethingsnetwork server
IPAddress thingServer;

WiFiUDP Udp;

time_t startTime = 0;										// The time in seconds since 1970 that the server started
															// be aware that UTP time has to succeed for meaningful values.
															// We use this variable since millis() is reset every 50 days...
uint32_t eventTime = 0;										// Timing of _event to change value (or not).
uint32_t sendTime = 0;										// Time that the last message transmitted
uint32_t doneTime = 0;										// Time to expire when CDDONE takes too long
uint32_t statTime = 0;										// last time we sent a stat message to server
uint32_t pulltime = 0;										// last time we sent a pull_data request to server
//uint32_t lastTmst = 0;									// Last activity Timer

#if A_SERVER==1
uint32_t wwwtime = 0;
#endif
#if NTP_INTR==0
uint32_t ntptimer = 0;
#endif

#define TX_BUFF_SIZE  1024									// Upstream buffer to send to MQTT
#define RX_BUFF_SIZE  1024									// Downstream received from MQTT
#define STATUS_SIZE	  512									// Should(!) be enough based on the static text .. was 1024

#if GATEWAYNODE==1
uint16_t frameCount=0;										// We write this to SPIFF file
#endif

// volatile bool inSPI This initial value of mutex is to be free,
// which means that its value is 1 (!)
// 
int mutexSPI = 1;

// ----------------------------------------------------------------------------
// FORWARD DECLARATIONS
// These forward declarations are done since other .ino fils are linked by the
// compiler/linker AFTER the main ESP-sc-gway.ino file. 
// And espcecially when calling functions with ICACHE_RAM_ATTR the complier 
// does not want this.
// Solution can also be to specify less STRICT compile options in Makefile
// ----------------------------------------------------------------------------

void ICACHE_RAM_ATTR Interrupt_0();
void ICACHE_RAM_ATTR Interrupt_1();

int sendPacket(uint8_t *buf, uint8_t length);				// _txRx.ino forward

static void printIP(IPAddress ipa, const char sep, String& response);	// _wwwServer.ino
void setupWWW();											// _wwwServer.ino forward

void SerialTime();											// _utils.ino forward
static void mPrint(String txt);								// _utils.ino (static void)
int mStat(uint8_t intr, String & response);					// _utils.ini
void SerialStat(uint8_t intr);								// _utils.ino
void printHexDigit(uint8_t digit);							// _utils.ino
int inDecodes(char * id);									// _utils.ino

int initMonitor(struct moniLine *monitor);					// _loraFiles.ino

void init_oLED();											// _oLED.ino
void acti_oLED();											// _oLED.ino
void addr_oLED();											// _oLED.ino

void setupOta(char *hostname);								// _otaServer.ino

void initLoraModem();										// _loraModem.ino
void rxLoraModem();											// _loraModem.ino
void writeRegister(uint8_t addr, uint8_t value);			// _loraModem.ino
void cadScanner();											// _loraModem.ino

void stateMachine();										// _stateMachine.ino

bool connectUdp();											// _udpSemtech.ino
int readUdp(int packetSize);								// _udpSemtech.ino
int sendUdp(IPAddress server, int port, uint8_t *msg, int length);	// _udpSemtech.ino
void sendstat();											// _udpSemtech.ino
void pullData();											// _udpSemtech.ino

#if MUTEX==1
// Forward declarations
void ICACHE_FLASH_ATTR CreateMutux(int *mutex);
bool ICACHE_FLASH_ATTR GetMutex(int *mutex);
void ICACHE_FLASH_ATTR ReleaseMutex(int *mutex);
#endif

// ----------------------------------------------------------------------------
// DIE is not used actively in the source code apart from resolveHost().
// It is replaced by a Serial.print command so we know that we have a problem
// somewhere.
// There are at least 3 other ways to restart the ESP. Pick one if you want.
// ----------------------------------------------------------------------------
void die(String s)
{
#	if _MONITOR>=1
	mPrint(s);
#	endif

#	if _DUSB>=1
	Serial.println(s);
	if (debug>=2) Serial.flush();
#	endif //_DUSB _MONITOR

	delay(50);
	// system_restart();									// SDK function
	// ESP.reset();				
	abort();												// Within a second
}

// ----------------------------------------------------------------------------
// gway_failed is a function called by ASSERT in configGway.h
//
// ----------------------------------------------------------------------------
void gway_failed(const char *file, uint16_t line) {
#if _DUSB>=1 || _MONITOR>=1
	String response="";
	response += "Program failed in file: ";
	response += String(file);
	response += ", line: ";
	response += String(line);
	mPrint(response);
#endif //_DUSB||_MONITOR
}



// ----------------------------------------------------------------------------
// Convert a float to string for printing
// Parameters:
//	f is float value to convert
//	p is precision in decimal digits
//	val is character array for results
// ----------------------------------------------------------------------------
void ftoa(float f, char *val, int p) {
	int j=1;
	int ival, fval;
	char b[7] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
	
	for (int i=0; i< p; i++) { j= j*10; }

	ival = (int) f;											// Make integer part
	fval = (int) ((f- ival)*j);								// Make fraction. Has same sign as integer part
	if (fval<0) fval = -fval;								// So if it is negative make fraction positive again.
															// sprintf does NOT fit in memory
	if ((f<0) && (ival == 0)) strcat(val, "-");
	strcat(val,itoa(ival,b,10));							// Copy integer part first, base 10, null terminated
	strcat(val,".");										// Copy decimal point
	
	itoa(fval,b,10);										// Copy fraction part base 10
	for (int i=0; i<(p-strlen(b)); i++) {
		strcat(val,"0");									// first number of 0 of faction?
	}
	
	// Fraction can be anything from 0 to 10^p , so can have less digits
	strcat(val,b);
}

// ============================================================================
// NTP TIME functions

// ----------------------------------------------------------------------------
// Send the request packet to the NTP server.
//
// ----------------------------------------------------------------------------
int sendNtpRequest(IPAddress timeServerIP) {
	const int NTP_PACKET_SIZE = 48;							// Fixed size of NTP record
	byte packetBuffer[NTP_PACKET_SIZE];

	memset(packetBuffer, 0, NTP_PACKET_SIZE);				// Zero the buffer.
	
	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;	

	
	if (!sendUdp( (IPAddress) timeServerIP, (int) 123, packetBuffer, NTP_PACKET_SIZE)) {
		gwayConfig.ntpErr++;
		gwayConfig.ntpErrTime = now();
		return(0);	
	}
	return(1);
}


// ----------------------------------------------------------------------------
// Get the NTP time from one of the time servers
// Note: As this function is called from SyncINterval in the background
//	make sure we have no blocking calls in this function
// ----------------------------------------------------------------------------
time_t getNtpTime()
{
	gwayConfig.ntps++;
	
    if (!sendNtpRequest(ntpServer))							// Send the request for new time
	{
		if (pdebug & P_MAIN) {
			mPrint("M sendNtpRequest failed");
		}
		return(0);
	}
	
	const int NTP_PACKET_SIZE = 48;							// Fixed size of NTP record
	byte packetBuffer[NTP_PACKET_SIZE];
	memset(packetBuffer, 0, NTP_PACKET_SIZE);				// Set buffer cntents to zero

    uint32_t beginWait = millis();
	delay(10);
    while (millis() - beginWait < 1500) 
	{
		int size = Udp.parsePacket();
		if ( size >= NTP_PACKET_SIZE ) {
		
			if (Udp.read(packetBuffer, NTP_PACKET_SIZE) < NTP_PACKET_SIZE) {
				break;
			}
			else {
				// Extract seconds portion.
				unsigned long secs;
				secs  = packetBuffer[40] << 24;
				secs |= packetBuffer[41] << 16;
				secs |= packetBuffer[42] <<  8;
				secs |= packetBuffer[43];
				// UTC is 1 TimeZone correction when no daylight saving time
				return(secs - 2208988800UL + NTP_TIMEZONES * SECS_IN_HOUR);
			}
			Udp.flush();	
		}
		delay(100);											// Wait 100 millisecs, allow kernel to act when necessary
    }

	Udp.flush();
	
	// If we are here, we could not read the time from internet
	// So increase the counter
	gwayConfig.ntpErr++;
	gwayConfig.ntpErrTime = now();

#	if _MONITOR>=1
	if (pdebug & P_MAIN) {
		mPrint("getNtpTime:: read failed");
	}
#	endif //_MONITOR
	return(0); 												// return 0 if unable to get the time
}

// ----------------------------------------------------------------------------
// Set up regular synchronization of NTP server and the local time.
// ----------------------------------------------------------------------------
#if NTP_INTR==1
void setupTime() {
  setSyncProvider(getNtpTime);
  setSyncInterval(_NTP_INTERVAL);
}
#endif



// ============================================================================
// MAIN PROGRAM CODE (SETUP AND LOOP)


// ----------------------------------------------------------------------------
// Setup code (one time)
// _state is S_INIT
// ----------------------------------------------------------------------------
void setup() {

	char MAC_char[19];										// XXX Unbelievable
	MAC_char[18] = 0;

#	if _DUSB>=1
		Serial.begin(_BAUDRATE);							// As fast as possible for bus
#	endif
	delay(500);	

#if _MONITOR>=1
	initMonitor(monitor);
#endif


#if _GPS==1
	// Pins are define in LoRaModem.h together with other pins
	sGps.begin(9600, SERIAL_8N1, GPS_TX, GPS_RX);// PIN 12-TX 15-RX
#endif //_GPS

#ifdef ESP32
#	if _MONITOR>=1
		mPrint("ESP32 defined, freq=" + String(freqs[0].upFreq));
#	endif //_MONITOR
#endif //ESP32

#ifdef ARDUINO_ARCH_ESP32
#	if _MONITOR>=1
		mPrint("ARDUINO_ARCH_ESP32 defined");
#	endif //_MONITOR
#endif //ARDUINO_ARCH_ESP32


#	if _DUSB>=1
		Serial.flush();
#	endif //_DUSB
	delay(500);

	if (SPIFFS.begin()) {
#		if _MONITOR>=1
			mPrint("SPIFFS init success");
#		endif //_MONITOR
	}
	else {
		if (pdebug & P_MAIN) {
			mPrint("SPIFFS not found");
		}
	}
	
#	if _SPIFF_FORMAT>=1
	SPIFFS.format();										// Normally disabled. Enable only when SPIFFS corrupt
	if ((debug>=1) && (pdebug & P_MAIN)) {
		mPrint("Format SPIFFS Filesystem Done");
	}
#	endif //_SPIFF_FORMAT>=1

	delay(500);
	
	// Read the config file for all parameters not set in the setup() or configGway.h file
	// This file should be read just after SPIFFS is initializen and before
	// other configuration parameters are used.
	//
	readConfig(CONFIGFILE, &gwayConfig);
	readSeen(_SEENFILE, listSeen);							// read the seenFile records

#	if _MONITOR>=1
		mPrint("Assert=");
#		if defined CFG_noassert
			mPrint("No Asserts");
#		else
			mPrint("Do Asserts");
#		endif //CFG_noassert
#	endif //_MONITOR

#if OLED>=1
	init_oLED();											// When done display "STARTING" on OLED
#endif //OLED

	delay(500);
	yield();

	WiFi.mode(WIFI_STA);
	WiFi.setAutoConnect(true);
	//WiFi.begin();
	
	WlanReadWpa();											// Read the last Wifi settings from SPIFFS into memory

	WiFi.macAddress(MAC_array);
	
    sprintf(MAC_char,"%02x:%02x:%02x:%02x:%02x:%02x",
		MAC_array[0],MAC_array[1],MAC_array[2],MAC_array[3],MAC_array[4],MAC_array[5]);
	Serial.print("MAC: ");
    Serial.print(MAC_char);
	Serial.print(F(", len="));
	Serial.println(strlen(MAC_char));

	// We start by connecting to a WiFi network, set hostname
	char hostname[12];

	// Setup WiFi UDP connection. Give it some time and retry x times..
	while (WlanConnect(0) <= 0) {
		Serial.print(F("Error Wifi network connect "));
		Serial.println();
		yield();
	}	
	
	// After there is a WiFi router connection, we can also set the hostname.
#if ESP32_ARCH==1
	sprintf(hostname, "%s%02x%02x%02x", "esp32-", MAC_array[3], MAC_array[4], MAC_array[5]);
	WiFi.setHostname( hostname );
	MDNS.begin(hostname);
#else
	sprintf(hostname, "%s%02x%02x%02x", "esp8266-", MAC_array[3], MAC_array[4], MAC_array[5]);
	wifi_station_set_hostname( hostname );
#endif	//ESP32_ARCH

#	if _DUSB>=1
		Serial.print(F("Host "));
#if ESP32_ARCH==1
		Serial.print(WiFi.getHostname());
#else
		Serial.print(wifi_station_get_hostname());
#endif //ESP32_ARCH

		Serial.print(F(" WiFi Connected to "));
		Serial.print(WiFi.SSID());
		Serial.print(F(" on IP="));
		Serial.print(WiFi.localIP());
		Serial.println();
#	endif //_DUSB	

	delay(500);
	// If we are here we are connected to WLAN
	
#if defined(_UDPROUTER)
	// So now test the UDP function
	if (!connectUdp()) {
		Serial.println(F("Error connectUdp"));
	}
#elif defined(_TTNROUTER)
	if (!connectTtn()) {
#	if _DUSB>=1
		Serial.println(F("Error connectTtn"));
#	endif //_DUSB
	}
#else
#	if _MONITOR>=1
		mPrint(F("Setup:: ERROR, No UDP or TCP Connection defined"));
#	endif //_MONITOR	
#endif //_UDPROUTER
	delay(200);
	
	// Pins are defined and set in loraModem.h
    pinMode(pins.ss, OUTPUT);
	pinMode(pins.rst, OUTPUT);
    pinMode(pins.dio0, INPUT);								// This pin is interrupt
	pinMode(pins.dio1, INPUT);								// This pin is interrupt
	//pinMode(pins.dio2, INPUT);							// XXX

	// Init the SPI pins
#if ESP32_ARCH==1
	SPI.begin(SCK, MISO, MOSI, SS);
#else
	SPI.begin();
#endif //ESP32_ARCH==1

	delay(500);
	
	// We choose the Gateway ID to be the Ethernet Address of our Gateway card
    // display results of getting hardware address
	//
#	if _DUSB>=1
		Serial.print(F("Gateway ID: "));
		printHexDigit(MAC_array[0]);
		printHexDigit(MAC_array[1]);
		printHexDigit(MAC_array[2]);
		printHexDigit(0xFF);
		printHexDigit(0xFF);
		printHexDigit(MAC_array[3]);
		printHexDigit(MAC_array[4]);
		printHexDigit(MAC_array[5]);

		Serial.print(F(", Listening at SF"));
		Serial.print(sf);
		Serial.print(F(" on "));
		Serial.print((double)freqs[ifreq].upFreq/1000000);
		Serial.println(" MHz.");
#	endif //_DUSB

	ntpServer = resolveHost(NTP_TIMESERVER);
#	if _MONITOR>=1
		if (debug>=1) mPrint("NTP Server found and contacted");
#	endif
	delay(100);
	
#ifdef _TTNSERVER
	ttnServer = resolveHost(_TTNSERVER);					// Use DNS to get server IP
	delay(100);
#endif //_TTNSERVER

#ifdef _THINGSERVER
	thingServer = resolveHost(_THINGSERVER);					// Use DNS to get server IP
	delay(100);
#endif //_THINGSERVER

	// The Over the Air updates are supported when we have a WiFi connection.
	// The NTP time setting does not have to be precise for this function to work.
#if A_OTA==1
	setupOta(hostname);										// Uses wwwServer 
#endif //A_OTA

	// Set the NTP Time
	// As long as the time has not been set we try to set the time.
#if NTP_INTR==1
	setupTime();											// Set NTP time host and interval
#else //NTP_INTR
	// If not using the standard libraries, do a manual setting
	// of the time. This method works more reliable than the 
	// interrupt driven method.
	
	//setTime((time_t)getNtpTime());
	while (timeStatus() == timeNotSet) {
#		if _DUSB>=1 || _MONITOR>=1
		if (( debug>=0 ) && ( pdebug & P_MAIN )) 
			mPrint("setupTime:: Time not set (yet)");
#		endif //_DUSB
		delay(500);
		time_t newTime;
		newTime = (time_t)getNtpTime();
		if (newTime != 0) setTime(newTime);
	}
	// When we are here we succeeded in getting the time
	startTime = now();										// Time in seconds
#	if _DUSB>=1
		Serial.print("writeGwayCfg: "); printTime();
		Serial.println();
	#endif //_DUSB
	writeGwayCfg(CONFIGFILE );
#endif //NTP_INTR

#if A_SERVER==1	
	// Setup the webserver
	setupWWW();
#endif //A_SERVER

	delay(100);												// Wait after setup
	
	// Setup and initialise LoRa state machine of _loraModem.ino
	_state = S_INIT;
	initLoraModem();
	
	if (_cad) {
		_state = S_SCAN;
		sf = SF7;
		cadScanner();										// Always start at SF7
	}
	else { 
		_state = S_RX;
		rxLoraModem();
	}
	LoraUp.payLoad[0]= 0;
	LoraUp.payLength = 0;									// Init the length to 0

	// init interrupt handlers, which are shared for GPIO15 / D8, 
	// we switch on HIGH interrupts
	if (pins.dio0 == pins.dio1) {
		//SPI.usingInterrupt(digitalPinToInterrupt(pins.dio0));
		attachInterrupt(pins.dio0, Interrupt_0, RISING);	// Share interrupts
	}
	// Or in the traditional Comresult case
	else {
		//SPI.usingInterrupt(digitalPinToInterrupt(pins.dio0));
		//SPI.usingInterrupt(digitalPinToInterrupt(pins.dio1));
		attachInterrupt(pins.dio0, Interrupt_0, RISING);	// Separate interrupts
		attachInterrupt(pins.dio1, Interrupt_1, RISING);	// Separate interrupts		
	}
	
	writeConfig(CONFIGFILE, &gwayConfig);					// Write config
	writeSeen( _SEENFILE, listSeen);						// Write the last time record  is seen

	// activate OLED display
#if OLED>=1
	acti_oLED();
	addr_oLED();
#endif //OLED

#	if _DUSB>=1
		Serial.println(F("--------------------------------------"));
#	endif //_DUSB

	mPrint("Setup() ended, Starting loop()");
}//setup



// ----------------------------------------------------------------------------
// LOOP
// This is the main program that is executed time and time again.
// We need to give way to the backend WiFi processing that 
// takes place somewhere in the ESP8266 firmware and therefore
// we include yield() statements at important points.
//
// Note: If we spend too much time in user processing functions
// and the backend system cannot do its housekeeping, the watchdog
// function will be executed which means effectively that the 
// program crashes.
// We use yield() a lot to avoid ANY watch dog activity of the program.
//
// NOTE2: For ESP make sure not to do large array declarations in loop();
// ----------------------------------------------------------------------------
void loop ()
{
	uint32_t uSeconds;										// micro seconds
	int packetSize;
	uint32_t nowSeconds = now();
	
	// check for event value, which means that an interrupt has arrived.
	// In this case we handle the interrupt ( e.g. message received)
	// in userspace in loop().
	//
	stateMachine();											// do the state machine
	
	// After a quiet period, make sure we reinit the modem and state machine.
	// The interval is in seconds (about 15 seconds) as this re-init
	// is a heavy operation. 
	// So it will kick in if there are not many messages for the gateway.
	// Note: Be careful that it does not happen too often in normal operation.
	//
	if ( ((nowSeconds - statr[0].tmst) > _MSG_INTERVAL ) &&
		(msgTime <= statr[0].tmst) ) 
	{
#		if _MONITOR>=1
		if (( debug>=2 ) && ( pdebug & P_MAIN )) {
			String response="";
			response += "REINIT:: ";
			response += String( _MSG_INTERVAL );
			response += (" ");
			mStat(0, response);
			mPrint(response);
		}
#		endif //_MONITOR

		yield();											// Allow buffer operations to finish

		if ((_cad) || (_hop)) {
			_state = S_SCAN;
			sf = SF7;
			cadScanner();
		}
		else {
			_state = S_RX;
			rxLoraModem();
		}
		writeRegister(REG_IRQ_FLAGS_MASK, (uint8_t) 0x00);
		writeRegister(REG_IRQ_FLAGS, (uint8_t) 0xFF);		// Reset all interrupt flags
		msgTime = nowSeconds;
	}

#if A_SERVER==1
	// Handle the Web server part of this sketch. Mainly used for administration 
	// and monitoring of the node. This function is important so it is called at the
	// start of the loop() function.
	yield();
	server.handleClient();
#endif //A_SERVER

#if A_OTA==1
	// Perform Over the Air (OTA) update if enabled and requested by user.
	// It is important to put this function early in loop() as it is
	// not called frequently but it should always run when called.
	//
	yield();
	ArduinoOTA.handle();
#endif //A_OTA

	// If event is set, we know that we have a (soft) interrupt.
	// After all necessary web/OTA services are scanned, we will
	// reloop here for timing purposes. 
	// Do as less yield() as possible.
	// XXX 180326
	if (_event == 1) {
		return;
	}
	else yield();

	
	// If we are not connected, try to connect.
	// We will not read Udp in this loop cycle then
	if (WlanConnect(1) < 0) {
#		if _DUSB>=1 || _MONITOR>=1
		if (( debug >= 0 ) && ( pdebug & P_MAIN )) {
			mPrint("M ERROR reconnect WLAN");
		}
#		endif //_DUSB || _MONITOR
		yield();
		return;												// Exit loop if no WLAN connected
	}
	
	// So if we are connected 
	// Receive UDP PUSH_ACK messages from server. (*2, par. 3.3)
	// This is important since the TTN broker will return confirmation
	// messages on UDP for every message sent by the gateway. So we have to consume them.
	// As we do not know when the server will respond, we test in every loop.
	//
	else {
		while( (packetSize = Udp.parsePacket()) > 0) {
#			if _MONITOR>=1
				if (debug>=2) {
					mPrint("loop:: readUdp calling");
				}
#			endif //_MONITOR
			// DOWNSTREAM
			// Packet may be PKT_PUSH_ACK (0x01), PKT_PULL_ACK (0x03) or PKT_PULL_RESP (0x04)
			// This command is found in byte 4 (buffer[3])
			if (readUdp(packetSize) <= 0) {
				#if _MONITOR>=1
				if ( debug>=0 )
					mPrint("readUdp ERROR, retuning <=0");
#				endif //_MONITOR
				break;
			}
			// Now we know we succesfully received message from host
			else {
				//_event=1;									// Could be done double if more messages received
			}
		}
	}
	
	yield();					// on 26/12/2017

	// stat PUSH_DATA message (*2, par. 4)
	//	

    if ((nowSeconds - statTime) >= _STAT_INTERVAL) {		// Wake up every xx seconds
        sendstat();											// Show the status message and send to server
#		if _MONITOR>=1
		if (( debug>=1 ) && ( pdebug & P_MAIN )) {
			mPrint("Send sendstat");
		}
#		endif //_MONITOR

		// If the gateway behaves like a node, we do from time to time
		// send a node message to the backend server.
		// The Gateway node emessage has nothing to do with the STAT_INTERVAL
		// message but we schedule it in the same frequency.
		//
#if GATEWAYNODE==1
		if (gwayConfig.isNode) {
			// Give way to internal some Admin if necessary
			yield();
			
			// If the 1ch gateway is a sensor itself, send the sensor values
			// could be battery but also other status info or sensor info
		
			if (sensorPacket() < 0) {
#			if _MONITOR>=1
				if ((debug>=1) || (pdebug & P_MAIN)) {
					mPrint("sensorPacket: Error");
				}
#			endif// _MONITOR
			}
		}
#endif//GATEWAYNODE
		statTime = nowSeconds;
    }
	
	yield();

	
	// send PULL_DATA message (*2, par. 4)
	//
	nowSeconds = now();
    if ((nowSeconds - pulltime) >= _PULL_INTERVAL) {		// Wake up every xx seconds
#		if _DUSB>=1 || _MONITOR>=1
		if (( debug>=2) && ( pdebug & P_MAIN )) {
			mPrint("M PULL");
		}
#		endif//_DUSB _MONITOR
        pullData();											// Send PULL_DATA message to server
		startReceiver();
	
		pulltime = nowSeconds;
    }

	
	// If we do our own NTP handling (advisable)
	// We do not use the timer interrupt but use the timing
	// of the loop() itself which is better for SPI
#if NTP_INTR==0
	// Set the time in a manual way. Do not use setSyncProvider
	// as this function may collide with SPI and other interrupts
	yield();												// 26/12/2017
	nowSeconds = now();
	if (nowSeconds - ntptimer >= _NTP_INTERVAL) {
		yield();
		time_t newTime;
		newTime = (time_t)getNtpTime();
		if (newTime != 0) setTime(newTime);
		ntptimer = nowSeconds;
	}
#endif//NTP_INTR
	

}//loop