#include <LiquidCrystal.h>
#include <SoftwareSerial.h>

LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
SoftwareSerial smsSerial(2, 3); // RX, TX

const int flowSensorPin = 2; // Pin for flow sensor
const int relayPin = 4;      // Pin for controlling water gate
const int buzzerPin = 5;     // Pin for buzzer

volatile int pulseCount = 0;
float flowRate = 0.0;
float totalLiters = 0.0;
float remainingTokens = 100.0; // Initial tokens

unsigned long oldTime = 0;

void setup() {
  lcd.begin(16, 2);
  pinMode(flowSensorPin, INPUT);
  pinMode(relayPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  digitalWrite(relayPin, HIGH); // Open the gate
  attachInterrupt(digitalPinToInterrupt(flowSensorPin), pulseCounter, FALLING);
  smsSerial.begin(9600);
  Serial.begin(9600);
  lcd.print("Water Dispenser");
  delay(2000);
  lcd.clear();
}

void loop() {
  if ((millis() - oldTime) > 1000) {  // Process every second
    detachInterrupt(digitalPinToInterrupt(flowSensorPin));
    flowRate = ((1000.0 / (millis() - oldTime)) * pulseCount) / 7.5;
    oldTime = millis();
    totalLiters += (flowRate / 60);
    pulseCount = 0;
    remainingTokens -= (flowRate / 60); // Decrease tokens based on flow

    lcd.setCursor(0, 0);
    lcd.print("Tokens: ");
    lcd.print(remainingTokens, 2);
    lcd.setCursor(0, 1);
    lcd.print("Flow: ");
    lcd.print(flowRate);
    lcd.print(" L/min");

    if (remainingTokens <= 10) {
      digitalWrite(buzzerPin, HIGH); // Alert user when tokens are low
      sendSMS("Warning: Low water tokens!");
    }

    if (remainingTokens <= 0) {
      digitalWrite(relayPin, LOW); // Close the gate
      sendSMS("Water supply stopped. Recharge tokens.");
      lcd.clear();
      lcd.print("No water left!");
      while (remainingTokens <= 0) {
        // Wait until tokens are recharged
      }
      digitalWrite(relayPin, HIGH); // Open the gate
      lcd.clear();
    }
    
    attachInterrupt(digitalPinToInterrupt(flowSensorPin), pulseCounter, FALLING);
  }
}

void pulseCounter() {
  pulseCount++;
}

void sendSMS(String message) {
  smsSerial.print("AT+CMGF=1\r");
  delay(100);
  smsSerial.print("AT+CMGS=\"+1234567890\"\r"); // Replace with the user's phone number
  delay(100);
  smsSerial.print(message);
  delay(100);
  smsSerial.write(26);
}