#include <WiFi.h>
#include <ThingSpeak.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

const char* ssid = "Wokwi-GUEST";
const char* password = "";

unsigned long myChannelNumber = 2825643;
const char* myWriteAPIKey = "N6V8J4FS51ZOP1OG";

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

WiFiClient client;

const int mq135Pin = 36; // 

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

  
  if (!display.begin(SSD1306_PAGEADDR, 21, 22)) { 
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Air Quality Monitor");
  display.display();
  delay(2000);

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi");
 
  ThingSpeak.begin(client);
}

void loop() {
  
  int sensorValue = analogRead(mq135Pin);
  Serial.print("Air Quality Sensor Value: ");
  Serial.println(sensorValue);

  display.clearDisplay();
  display.setCursor(0, 0);
  display.println("Air Quality Monitor");
  display.setCursor(0, 20);
  display.print("Sensor Value: ");
  display.println(sensorValue);
  display.display();

  ThingSpeak.setField(1, sensorValue); 
  int status = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);

  if (status == 200) {
    Serial.println("Data sent to ThingSpeak successfully!");
  } else {
    Serial.println("Problem sending data to ThingSpeak. HTTP error code: " + String(status));
  }
  delay(20000);
}