#include <Wire.h> //allows communication over i2c devices
#include <EEPROM.h> //Electronically erasable programmable memory library
#include <LiquidCrystal_I2C.h> //allows interfacing with LCD screens
#include <Bounce2.h> //Button debouncing library

//Inputs
int pressureInput = A7; //sets the analog input pin for the pressure transducer
int RedEnd = 10; //sets address of end loop button on Nano digital pins

//Digital Outputs
int ConcRelay1 = 2; //sets address of concentrator1 relay on digital pins found on Nano
int ConcRelay2 = 3; //sets address of concentrator2 relay on digital pins found on Nano
int CompRelay3 = 4; //sets address of compressor relay on digital pins found on Nano
int ValveRelay4 = 5; //sets address of unloader valve relay on digital pins found on Nano

//Start and stop pressure values
const int Start = 40; //concentrators and compressor start at 40 PSI
const int Stop = 85; //concentrators and compressor stop at 85 PSI

const long solenoidInterval = 30000;  // 30 sec
const long warmInterval     = 15000;  // 15 sec

//GERRY MOD
bool prevPsiWasStart;
unsigned long prevPsiTime;
bool inStartTransition;
bool inStopTransition;

LiquidCrystal_I2C lcd (0x27, 16, 2); //sets the LCD I2C communication address; format (address, columns, rows)
Bounce debouncer = Bounce (); //instantiates a bounce object

// -----------------------------------------------------------------------------

// this is the EEPROM section
int eeAddress1 = 10;                // this sets the eeAddress1 tag and sets the address to 10, eeprom
int eeAddress2 = 20;                // this sets the eeAddress2 tag and sets the address to 20, eeprom

//Debounce section
byte butState;

// -----------------------------------------------------------------------------
void setup () //setup routine, runs once when system turned on or reset
{
  //  this section assigns the inputs and outputs

  // inputs
  pinMode (RedEnd, INPUT_PULLUP);             // End loop button
  butState = digitalRead (RedEnd);

  // outputs
  pinMode      (ConcRelay1, OUTPUT);            // concentrator1 relay
  digitalWrite (ConcRelay1, LOW);        // initially sets output tag "ConcRelay1" low
  pinMode      (ConcRelay2, OUTPUT);          // concentrator2 relay
  digitalWrite (ConcRelay2, LOW);       // initially sets output tag "ConcRelay2" low
  pinMode      (CompRelay3, OUTPUT);            // comperssor relay
  digitalWrite (CompRelay3, LOW);         // initially sets output tag "CompRelay3" low
  pinMode      (ValveRelay4, OUTPUT);         // unloader valve relay
  digitalWrite (ValveRelay4, LOW);      // initially sets output tag "ValveRelay4" low
  //GERRY MOD
  prevPsiWasStart = false;
  inStartTransition = false;
  inStopTransition = false;

  // Retrieves the setpoints from the arduino eeprom so the unit can start up after a power fail
  EEPROM.get (eeAddress1, Start);         // retrieves the start psi from eeprom
  EEPROM.get (eeAddress2, Stop);          // retrieves the stop psi from eeprom

  //  Starts up the different libraries
  Serial.begin (9600); // start the serial monitor at 9600 baud
  lcd.init ();         // start the lcd library
  lcd.backlight ();    // turn on the lcd backlight
  lcd.clear ();        // clear the cld screen
  Wire.begin ();       // start the I2C library

  //Start up messge
  lcd.setCursor (2, 0); //sets cursor to column 2, row 0
  lcd.print ("Hello There!"); //prints label
  lcd.setCursor (0, 1); //sets cursor to column 0, row 1
  lcd.print ("Press Red Button");

  lcd.clear ();
}

// -----------------------------------------------------------------------------
void monitor ()
{
  // measure pressure
  int psi = analogRead (pressureInput);
  psi = map (psi, 102, 922, 0, 150);

  // This section prints the PSI value caluculated from transducer to the LCD screeen
  lcd.clear ();
  //  Serial.print(psi, 1); //prints value from previous line to serial
  //  Serial.println("psi"); //prints label to serial

  lcd.setCursor(0, 0); //sets cursor to column 0, row 0
  lcd.print("Current= "); //prints label
  lcd.setCursor(10, 0); //sets cursor to column 10, row 0
  lcd.print(psi); //prints pressure value to lcd screen
  lcd.setCursor(12, 0); //sets cursor to column 12, row 0
  lcd.print("PSI"); //prints label after value
  lcd.print("   "); //to clear the display after large values or negatives

  lcd.setCursor(0, 1); //sets cursor to column 0, row 1
  lcd.print ("Min=40 ; Max=85"); //prints Start and Stop pressure values

  // check for stop condition
  if (psi >= Stop )  {
    digitalWrite (ConcRelay1 ,  LOW);
    digitalWrite (ConcRelay2 ,  LOW);
    digitalWrite (CompRelay3 ,  LOW);
									  

    /*GERRY MOD
      digitalWrite (ValveRelay4 , HIGH);

      delay (solenoidInterval);
      digitalWrite (ValveRelay4 , LOW);
    */
    if (prevPsiWasStart == true) { //First time
      prevPsiTime = millis();
      prevPsiWasStart = false;
      inStopTransition = true;
      inStartTransition = false;
    }


  }

  else if (psi <= Start) {
    digitalWrite (ConcRelay1 , HIGH);
    digitalWrite (ConcRelay2 , HIGH);


    /*GERRY MOD
      digitalWrite (ValveRelay4 , HIGH);
      delay (warmInterval);
      digitalWrite (ValveRelay4 , LOW);
      digitalWrite (CompRelay3 , HIGH);
    */
    if (prevPsiWasStart == false) { //First time
      prevPsiTime = millis();
      prevPsiWasStart = true;
      inStartTransition = true;
      inStopTransition = false;
    }
  }

  if (inStopTransition == true) {
    if (millis() - prevPsiTime < solenoidInterval) {
      digitalWrite (ValveRelay4 , HIGH);
      Serial.print("Stop in: ");
      Serial.println(1 + (solenoidInterval - millis() + prevPsiTime) / 1000);
    } else {
      digitalWrite (ValveRelay4 , LOW);
      inStopTransition = false;
      Serial.println("Stop done");
    }
  }
  if (inStartTransition == true) {
    if ((millis() - prevPsiTime < warmInterval)) {
      digitalWrite (ValveRelay4 , HIGH);
      Serial.print("Start in ");
      Serial.println(1 + (- millis() + prevPsiTime + warmInterval) / 1000);
    } else {
      digitalWrite (ValveRelay4 , LOW);
      digitalWrite (CompRelay3 , HIGH);
      inStartTransition = false;
      Serial.println("Start done");
    }
  }


}

// -----------------------------------------------------------------------------
void loop ()
{
  enum { ST_IDLE, ST_RUN, ST_SHUTDOWN };
  static int state = ST_IDLE;

  switch (state)  {
    case ST_RUN:
      monitor ();
      break;

    case ST_SHUTDOWN:
      digitalWrite (ConcRelay1 ,  LOW);
      digitalWrite (ConcRelay2 ,  LOW);
      digitalWrite (CompRelay3 ,  LOW);
      digitalWrite (ValveRelay4 , HIGH);

      lcd.clear ();
      lcd.setCursor (1, 0); //sets cursor to column 1, row 0
      lcd.print ("Program Ended!"); //prints label
      delay(45000);
      //GERRY MOD
      prevPsiWasStart = false;
      inStartTransition = false;
      inStopTransition = false;
      lcd.clear ();

      state = ST_IDLE;
      break;

    case ST_IDLE:

      lcd.setCursor (2, 0); //sets cursor to column 2, row 0
      lcd.print ("Hello There!"); //prints label
      lcd.setCursor (0, 1); //sets cursor to column 0, row 1
      lcd.print ("Press Red Button");

      break;
  }

  byte but = digitalRead (RedEnd);
  if (butState != but)  {
    butState = but;
    delay (10);         // debounce

    if (LOW == but)  {  // press
      if (ST_IDLE == state)
        state = ST_RUN;
      else
        state = ST_SHUTDOWN;
    }
  }
}