#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// LCD setup
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Pin definitions
const int potPin = A0;   // Potentiometer simulates TDS sensor
//const int ledA   = 5;    // Pump A LED
//const int ledB   = 4;    // Pump B LED
const int relayA = 5;    // Relay A (active LOW)
const int relayB = 4;    // Relay B (active LOW)

const int tdsThreshold = 100; // ppm threshold

void setup() {
  lcd.init();
  lcd.backlight();

  //pinMode(ledA, OUTPUT);
  //pinMode(ledB, OUTPUT);
  pinMode(relayA, OUTPUT);
  pinMode(relayB, OUTPUT);

  // Start OFF (LEDs and Relays OFF)
  //digitalWrite(ledA, LOW);
  //digitalWrite(ledB, LOW);
  digitalWrite(relayA, !HIGH);  // OFF (active LOW)
  digitalWrite(relayB, !HIGH);  // OFF (active LOW)
}

void loop() {
  int sensorValue = analogRead(potPin);
  int tdsValue = map(sensorValue, 0, 1023, 0, 1000);

  lcd.setCursor(0, 0);
  lcd.print("TDS: ");
  lcd.print(tdsValue);
  lcd.print(" ppm   ");

  if (tdsValue >= tdsThreshold) {
    // Both pumps ON
    //digitalWrite(ledA, HIGH);
    //digitalWrite(ledB, HIGH);
    digitalWrite(relayA, !LOW);   // ON (active LOW)
    digitalWrite(relayB, !LOW);   // ON (active LOW)

    lcd.setCursor(0, 1);
    lcd.print("Pumps ON        ");
  } else {
    // Pump A stops immediately
    //digitalWrite(ledA, LOW);
    digitalWrite(relayA, !HIGH);  // OFF

    // Countdown for Pump B
    for (int i = 6; i > 0; i--) {
      lcd.setCursor(0, 1);
      lcd.print("PumpB off in ");
      lcd.print(i);
      lcd.print("s   ");
      delay(1000);
    }

    // After countdown, Pump B stops
    //digitalWrite(ledB, LOW);
    digitalWrite(relayB, !HIGH);  // OFF

    lcd.setCursor(0, 1);
    lcd.print("Pumps OFF       ");
  }

  delay(500);
}