//SketchRF.ino 06/05/2022 09:55:18
//https://www.deviceplus.com/arduino/nrf24l01-rf-module-tutorial/
//Arduino Mega 2560

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

#define CE_PIN   9
#define CSN_PIN 10

byte addresses[][6] = {"Addr0", "Addr1"};

RF24 radio(CE_PIN, CSN_PIN);

String sgUsername = "";
String sgDataInput = "";;
char cgDataToSend[32];
char cgDataReceived[32];
unsigned long lgUpdateTime;
int iFirstRun = 1; // 1 = First run
int iAck = 0;      // 1 = App is ready

void setup()
{
          Serial.begin(9600);

          radio.begin();
          radio.setPALevel(RF24_PA_MAX);
          radio.setDataRate(RF24_1MBPS);
          radio.setRetries(3, 5);
          radio.openWritingPipe(addresses[0]);
          radio.openReadingPipe(1, addresses[1]);
          radio.startListening();

          lgUpdateTime = millis();
}

void loop()
{
          if((iFirstRun == 1) && (iAck == 0))
          {
                if ( Serial.available() ) //Get Acknowledgment from App (App is ready)
                {
                          iAck = Serial.read();
                      if (iAck == 1)
                      {
                            iFirstRun = 0;
                            Serial.print("Enter User Name");
                            Serial.println();

                            //Set User Name
                            while (sgUsername == "")
                            {
                                  if ( Serial.available() )
                                  {
                                        sgUsername = Serial.readStringUntil('\n');
                                        Serial.print("Welcome ");
                                        Serial.print(sgUsername);
                                        Serial.println();
                                  }
                            }
                      }
                }
          }
          else
          {
                //Loop radio
	            if(millis() - lgUpdateTime > 500) //Loop approx every 0.5 seconds
                {
                      lgUpdateTime = millis();

                      //Listen for radio data
                      radio.startListening();

                      if (radio.available())
                      {
                            //Read data from radio
                            radio.read(&cgDataReceived, sizeof(cgDataReceived));

                            if(Serial.available())
                            {
                                  Serial.print(cgDataReceived);
                                  Serial.println();
                            }
                      }

                      if(Serial.available())
                      {
                            //Stop listening on radio
                            radio.stopListening();

                            //Get serial input
                                         sgDataInput = "[" + sgUsername + "] " + Serial.readStringUntil('\n');
                            Serial.print(sgDataInput);
                            Serial.println();

                            //Send data
                            sgDataInput.toCharArray(cgDataToSend, 32);
                                  radio.write(&cgDataToSend, sizeof(cgDataToSend));
                      }
                }
          }
}