#include <WiFi.h>           // Library for WiFi connectivity
#include "DHTesp.h"        // Library for the DHT sensor
#include "ThingSpeak.h"    // Library for ThingSpeak communication

// Define the pins for sensors and LED
const int DHT_PIN = 15;    // Pin connected to the DHT22 sensor
const int LED_PIN = 13;    // Pin connected to the LED
const int MQ2_PIN = 34;    // Analog pin connected to the MQ2 gas sensor

// WiFi and ThingSpeak settings
const char* WIFI_NAME = "Wokwi-GUEST";  // WiFi network name
const char* WIFI_PASSWORD = "";        // WiFi password
const int myChannelNumber = 2780341;   // ThingSpeak channel number
const char* myApiKey = "7L60HZYCQQSBWG4K";  // ThingSpeak API key

// Global variables
DHTesp dhtSensor;          // Instance of the DHT sensor
WiFiClient client;         // WiFi client for ThingSpeak

void setup() {
  Serial.begin(115200);    // Initialize the serial communication

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

  // Initialize the pins for LED and MQ2
  pinMode(LED_PIN, OUTPUT);
  pinMode(MQ2_PIN, INPUT);

  // Connect to WiFi network
  WiFi.begin(WIFI_NAME, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);  // Wait 1 second between connection attempts
    Serial.println("Wifi not connected");
  }
  Serial.println("Wifi connected!");

  // Initialize ThingSpeak
  ThingSpeak.begin(client);
}

// Function to read the gas level percentage from the MQ2 sensor
float readMQ2Percentage() {
  int sensorValue = analogRead(MQ2_PIN);   // Read the analog value from MQ2
  // Convert the analog reading (0-4095) to a percentage (0-100)
  float percentage = (sensorValue * 100.0) / 4095.0;
  return percentage;
}

void loop() {
  // Read temperature and humidity from the DHT22 sensor
  TempAndHumidity data = dhtSensor.getTempAndHumidity();

  // Read the gas level percentage from the MQ2 sensor
  float gasPercentage = readMQ2Percentage();

  // Update ThingSpeak fields with sensor data
  ThingSpeak.setField(1, data.temperature);  // Field 1: Temperature
  ThingSpeak.setField(2, data.humidity);     // Field 2: Humidity
  ThingSpeak.setField(3, gasPercentage);     // Field 3: Gas level

  // Determine if an alert is needed based on threshold values
  bool alert = (data.temperature > 35 ||   // High temperature
                data.temperature < 12 ||   // Low temperature
                data.humidity > 70 ||      // High humidity
                data.humidity < 40 ||      // Low humidity
                gasPercentage > 40);       // High gas level

  // Turn the LED on if alert conditions are met
  digitalWrite(LED_PIN, alert);

  // Send data to ThingSpeak
  int response = ThingSpeak.writeFields(myChannelNumber, myApiKey);

  // Print sensor readings and response status to the serial monitor
  Serial.println("Temperature: " + String(data.temperature, 1) + "°C");
  Serial.println("Humidity: " + String(data.humidity, 1) + "%");
  Serial.println("Gas Level: " + String(gasPercentage, 1) + "%");
  Serial.println(response == 200 ? "Data sent successfully" : "Error: " + String(response));
  Serial.println("---");

  // Wait for 10 seconds before the next loop iteration
  delay(10000);
}