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

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

#define DHTPIN 15
#define DHTTYPE DHT22
#define MQ2_GAS_PIN 34
#define BUZZER_PIN 27
#define LED_HIJAU 25
#define LED_KUNING 19
#define LED_MERAH 26

DHT dht(DHTPIN, DHTTYPE);

const char* ssid = "Wokwi-GUEST";
const char* password = "";
String apiKey = "KJ4WOEVXO7A8E7S3";
String serverName = "http://api.thingspeak.com/update";

unsigned long lastCloudTime = 0;
unsigned long lastDisplayTime = 0;
const long cloudInterval = 15000; 
const long displayInterval = 1000;

void setup() {
  Serial.begin(115200);
  pinMode(MQ2_GAS_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_HIJAU, OUTPUT);
  pinMode(LED_KUNING, OUTPUT);
  pinMode(LED_MERAH, OUTPUT);
  
  dht.begin();
  
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("Gagal inisialisasi OLED SSD1306"));
    for (;;);
  }
  
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(10, 20);
  display.println("SAFETY SYSTEM");
  display.setCursor(10, 35);
  display.println("Connecting WiFi...");
  display.display();
  
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  
  display.clearDisplay();
  display.setCursor(10, 25);
  display.println("WiFi Terhubung!");
  display.display();
  delay(1000);
}

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

  // Update sensors and display every 1 second without blocking
  if (currentMillis - lastDisplayTime >= displayInterval) {
    lastDisplayTime = currentMillis;

    float suhu = dht.readTemperature();
    float kelembapan = dht.readHumidity();
    int rawGas = analogRead(MQ2_GAS_PIN);
    int gasPercent = map(rawGas, 0, 4095, 0, 100);

    if (isnan(suhu) || isnan(kelembapan)) {
      Serial.println("Gagal membaca dari sensor DHT22!");
      return;
    }

    int hazardLevel = 0;
    if (suhu > 50.0 || gasPercent > 60) {
      hazardLevel = 2;
    } else if ((suhu >= 40.0 && suhu <= 50.0) || (gasPercent >= 30 && gasPercent <= 60)) {
      hazardLevel = 1;
    } else {
      hazardLevel = 0;
    }

    display.clearDisplay();
    display.setTextSize(1);
    display.setCursor(0, 0);
    display.print("Suhu : "); display.print(suhu, 1); display.println(" C");
    display.print("Gas  : "); display.print(gasPercent); display.println(" %");
    display.println("---------------------");

    if (hazardLevel == 2) {
      digitalWrite(LED_MERAH, HIGH); digitalWrite(LED_KUNING, LOW); digitalWrite(LED_HIJAU, LOW);
      tone(BUZZER_PIN, 2000);
      display.setTextSize(2); display.setCursor(0, 35); display.println("DANGER!!!");
      display.setTextSize(1); display.setCursor(0, 55); display.println("EVAKUASI SEGERA!");
    } else if (hazardLevel == 1) {
      digitalWrite(LED_MERAH, LOW); digitalWrite(LED_KUNING, HIGH); digitalWrite(LED_HIJAU, LOW);
      tone(BUZZER_PIN, 1000, 200);
      display.setTextSize(2); display.setCursor(0, 35); display.println("WARNING!");
      display.setTextSize(1); display.setCursor(0, 55); display.println("Cek Area Kerja");
    } else {
      digitalWrite(LED_MERAH, LOW); digitalWrite(LED_KUNING, LOW); digitalWrite(LED_HIJAU, HIGH);
      noTone(BUZZER_PIN);
      display.setTextSize(2); display.setCursor(0, 35); display.println("NORMAL");
      display.setTextSize(1); display.setCursor(0, 55); display.println("Kondisi Aman");
    }
    display.display();
  }

  // Cloud telemetry update every 15 seconds
  if (currentMillis - lastCloudTime >= cloudInterval) {
    lastCloudTime = currentMillis;
    if (WiFi.status() == WL_CONNECTED) {
      HTTPClient http;
      float suhu = dht.readTemperature();
      int rawGas = analogRead(MQ2_GAS_PIN);
      int gasPercent = map(rawGas, 0, 4095, 0, 100);
      int hazardLevel = (suhu > 50.0 || gasPercent > 60) ? 2 : ((suhu >= 40.0 && suhu <= 50.0) || (gasPercent >= 30 && gasPercent <= 60)) ? 1 : 0;

      String url = serverName + "?api_key=" + apiKey + "&field1=" + String(suhu) + "&field2=" + String(gasPercent) + "&field3=" + String(hazardLevel);
      http.begin(url);
      int httpCode = http.GET();
      if (httpCode > 0) {
        Serial.print("Data Terkirim! HTTP Response: ");
        Serial.println(httpCode);
      } else {
        Serial.println("Gagal mengirim data");
      }
      http.end();
    }
  }
}