#include <IRremote.hpp>
#include <DHTesp.h>
#include <HardwareSerial.h> // For GSM serial

#define DHT_PIN 15
#define IR_RECEIVE_PIN 23
#define SMOKE_PIN 34
#define METHANE_PIN 35
#define CO_PIN 32
#define LDR_PIN 36
#define BUTTON_PIN 5

// GSM module pins
#define GSM_TX 17
#define GSM_RX 16
HardwareSerial GSM_serial(2); // UART2 for GSM

DHTesp dhtSensor;

enum HazardLevel { SAFE, ALERT };
HazardLevel currentHazard = SAFE;
volatile bool isAlarmMuted = false;

const int SMOKE_THRESHOLD = 1500;
const int METHANE_THRESHOLD = 1800;
const int CO_THRESHOLD = 1600;

unsigned long previousSensorReadMillis = 0;
const long sensorReadInterval = 2000;

unsigned long lastButtonPressMillis = 0;
const long debounceDelay = 50;

void setup() {
  Serial.begin(115200);

  // DHT sensor
  dhtSensor.setup(DHT_PIN, DHTesp::DHT22);

  // IR Receiver
  IrReceiver.begin(IR_RECEIVE_PIN, ENABLE_LED_FEEDBACK);

  // Pins
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  pinMode(SMOKE_PIN, INPUT);
  pinMode(METHANE_PIN, INPUT);
  pinMode(CO_PIN, INPUT);
  pinMode(LDR_PIN, INPUT);

  // GSM setup
  GSM_serial.begin(115200, SERIAL_8N1, GSM_RX, GSM_TX);
  delay(1000);
  Serial.println("GSM Serial initialized");
}

void loop() {
  unsigned long currentMillis = millis();

  handleButton();
  handleIR();
  handleGSMResponse();

  if (currentMillis - previousSensorReadMillis >= sensorReadInterval) {
    previousSensorReadMillis = currentMillis;

    TempAndHumidity data = dhtSensor.getTempAndHumidity();
    float humidity = data.humidity;
    float temperature = data.temperature;

    int smokeVal = analogRead(SMOKE_PIN);
    int methaneVal = analogRead(METHANE_PIN);
    int coVal = analogRead(CO_PIN);
    int ldrVal = analogRead(LDR_PIN);

    currentHazard = (smokeVal > SMOKE_THRESHOLD || methaneVal > METHANE_THRESHOLD || coVal > CO_THRESHOLD) ? ALERT : SAFE;

    printStatus(temperature, humidity, smokeVal, methaneVal, coVal, ldrVal);
    triggerAlarm();
  }
}

void handleButton() {
  if (millis() - lastButtonPressMillis > debounceDelay) {
    if (digitalRead(BUTTON_PIN) == LOW) {
      toggleMute();
      lastButtonPressMillis = millis();
    }
  }
}

void handleIR() {
  if (IrReceiver.decode()) {
    Serial.print("IR Code Received: 0x");
    Serial.println(IrReceiver.decodedIRData.decodedRawData, HEX);
    toggleMute();
    IrReceiver.resume();
  }
}

void handleGSMResponse() {
  while (GSM_serial.available()) {
    Serial.write(GSM_serial.read());
  }
}

void toggleMute() {
  isAlarmMuted = !isAlarmMuted;
  Serial.println(isAlarmMuted ? ">>>> ALARM MUTED <<<<" : ">>>> ALARM UNMUTED <<<<");
}

void triggerAlarm() {
  if (currentHazard == ALERT && !isAlarmMuted) {
    Serial.println("!!! HAZARD DETECTED - ALARM ACTIVE !!!");
    sendSMS("ShieldSense Alert: Hazard Detected!", "+911234567890"); // Replace with your number
  }
}

void sendSMS(const String &message, const String &number) {
  Serial.println("Sending SMS...");
  GSM_serial.println("AT+CMGF=1"); // Text mode
  delay(500);
  GSM_serial.println("AT+CMGS=\"" + number + "\"");
  delay(500);
  GSM_serial.print(message);
  GSM_serial.write(26); // Ctrl+Z
  delay(3000);
  Serial.println("SMS: " + message);
  Serial.println("SMS sent.");
}

void printStatus(float temp, float hum, int smoke, int methane, int co, int ldr) {
  Serial.print("Temp: "); Serial.print(temp, 1); Serial.print("°C | ");
  Serial.print("Hum: "); Serial.print(hum, 1); Serial.print("% | ");
  Serial.print("Smoke: "); Serial.print(smoke); Serial.print(" | ");
  Serial.print("Methane: "); Serial.print(methane); Serial.print(" | ");
  Serial.print("CO: "); Serial.print(co); Serial.print(" | ");
  Serial.print("LDR: "); Serial.print(ldr);
  Serial.print(currentHazard == ALERT ? " -> [ALERT]" : " -> [SAFE]");
  Serial.println();
}