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

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

DHTesp dhtSensor;
TempAndHumidity data;
const int DHT_PIN = 15; // always use GPIO15 for DHT sensor
char ssid[] = "Wokwi-GUEST";
char pass[] = "";
WiFiClient client;
unsigned long myChannelNumber = 2481856;
const char * myWriteAPIKey = "55BC630J2V9JAMI5";
int statusCode;

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

  // Initialize OLED display
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  delay(2000);  // Pause for 2 seconds

  WiFi.mode(WIFI_STA);
  ThingSpeak.begin(client);
  dhtSensor.setup(DHT_PIN, DHTesp::DHT22);
}

void loop() {
  data = dhtSensor.getTempAndHumidity();

  if(WiFi.status() != WL_CONNECTED) {
    Serial.print("Attempting to connect");
    while(WiFi.status() != WL_CONNECTED) {
      WiFi.begin(ssid, pass); 
      Serial.print(".");
      delay(5000);
    }
    Serial.println("\nConnected.");
  }

  // Clear display
  display.clearDisplay();

  // Display humidity and temperature
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.print("Humidity: ");
  display.println(String(data.humidity, 1) + " %");
  display.print("Temperature: ");
  display.println(String(data.temperature, 2) + " °C");

  // Display update
  display.display();

  // Update ThingSpeak fields
  ThingSpeak.setField(1, data.humidity);
  ThingSpeak.setField(2, data.temperature);

  statusCode = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);

  if(statusCode == 200) { // Successful writing code
    Serial.println("Channel update successful.");
  } else {
    Serial.println("Problem Writing data. HTTP error code :" + String(statusCode));
  }

  delay(15000); // Delay between updates in milliseconds
}