#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <ZMPT101B.h>
#include <SoftwareSerial.h>

ZMPT101B zmpt(A0);

LiquidCrystal_I2C lcd(0x27, 16, 2);

SoftwareSerial SIM800L(10, 11); // RX, TX for SIM800L

int relay = 8;
int yellow = 4;
int green = 5;

unsigned long printPeriod = 1000;
unsigned long previousMillis = 0;
bool isNormalVoltage = true;

void setup() {
  Serial.begin(9600);
  lcd.init();
  lcd.init();
  lcd.backlight();
  lcd.begin(16, 2);
  pinMode(relay, OUTPUT);
  pinMode(yellow, OUTPUT);
  pinMode(green, OUTPUT);
  lcd.print("Voltage:");
  delay(1000);
  SIM800L.begin(9600);
}

void sendSMS(const char* message) {
  SIM800L.println("AT+CMGF=1"); // Set the GSM Module in text mode
  delay(1000);
  SIM800L.println("AT+CMGS=\"+2349014028334\""); // Replace with your mobile number
  delay(1000);
  SIM800L.print(message);
  delay(100);
  SIM800L.println((char)26); // End the SMS by sending Ctrl+Z
  delay(1000);
}

void loop() {
  float current_Volts = zmpt.getRmsVoltage();

  if ((unsigned long)(millis() - previousMillis) >= printPeriod) {
    previousMillis = millis();
    lcd.setCursor(9, 0);
    lcd.print(current_Volts);
    lcd.print("V");
  }

  if (current_Volts < 150 || current_Volts > 260) {
    if (!isNormalVoltage) {
      if (current_Volts < 150) {
        lcd.setCursor(0, 1);
        lcd.print("Under Voltage");
        digitalWrite(relay, LOW);
        digitalWrite(yellow, HIGH);
        digitalWrite(green, LOW);
        sendSMS("Under Voltage detected!");
        delay(5000);
      } else if (current_Volts > 260) {
        lcd.setCursor(0, 1);
        lcd.print("Over Voltage");
        digitalWrite(relay, LOW);
        digitalWrite(yellow, HIGH);
        digitalWrite(green, LOW);
        sendSMS("Over Voltage detected!");
        delay(5000);
      }
      isNormalVoltage = true;
    }
  } else {
    if (isNormalVoltage) {
      lcd.setCursor(0, 1);
      lcd.print("Normal Voltage");
      digitalWrite(relay, HIGH);
      digitalWrite(yellow, LOW);
      digitalWrite(green, HIGH);
      sendSMS("Normal Voltage!");
      delay(5000);
      isNormalVoltage = false;
    }
  }
}