#include <WiFi.h>
#include <HTTPClient.h>
#include "DHT.h"
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// ThingSpeak details
String server = "http://api.thingspeak.com/update?api_key=3LJ89VEH95FNGY9G";

// WiFi details
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// DHT setup
#define DHTPIN 15
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

// LED pin
#define LED_PIN 5

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

void setup() {
  Serial.begin(115200);
  pinMode(LED_PIN, OUTPUT);
  dht.begin();

  // OLED init
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);

  // Connect to WiFi
  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nConnected to WiFi");
}

void loop() {
  float temp = dht.readTemperature();
  float hum = dht.readHumidity();

  if (isnan(temp) || isnan(hum)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }

  Serial.print("Temp: ");
  Serial.print(temp);
  Serial.print(" °C, Humidity: ");
  Serial.print(hum);
  Serial.println(" %");

  // OLED display
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Temp: ");
  display.print(temp);
  display.println(" C");
  display.print("Humidity: ");
  display.print(hum);
  display.println(" %");
  display.display();

  // Threshold Action: LED ON if temp > 30
  if (temp > 30) {
    digitalWrite(LED_PIN, HIGH);
  } else {
    digitalWrite(LED_PIN, LOW);
  }

  // Send data to ThingSpeak
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    String url = server + "&field1=" + String(temp) + "&field2=" + String(hum);
    http.begin(url.c_str());
    int httpResponseCode = http.GET();
    if (httpResponseCode > 0) {
      Serial.println("Data sent to ThingSpeak!");
    } else {
      Serial.println("Error sending data");
    }
    http.end();
  }

  delay(20000); // ThingSpeak requires minimum 15s
}