/***** ESP32-S3 + DHT22 + MQ2 + POT + DS18B20 + MPU6050 + OLED + Firebase *****/

#include <WiFi.h>
#include <WiFiClientSecure.h>
#include <HTTPClient.h>

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

#include "DHTesp.h"
#include <OneWire.h>
#include <DallasTemperature.h>
#include <MPU6050.h>

// ---------------- WIFI DETAILS ----------------
const char* WIFI_SSID     = "Wokwi-GUEST";
const char* WIFI_PASSWORD = "";

// ------------- FIREBASE REALTIME DB ------------
// Example DB URL: https://your-project-id-default-rtdb.firebaseio.com/
const char* FIREBASE_HOST =  "https://aurasensehack-default-rtdb.firebaseio.com/"; // no https://
const char* FIREBASE_AUTH = "YOUR_DB_SECRET_OR_ID_TOKEN";                  // ?auth= value
const char* FIREBASE_PATH = "/multiSensorHub.json";

// ----------------- PIN CONFIG ------------------
#define DHT_PIN      15     // DHT22 data
#define MQ2_PIN      2      // MQ2 analog out
#define POT_PIN      1      // potentiometer analog
#define DS18B20_PIN  14     // one-wire
#define I2C_SDA_PIN  11     // OLED + MPU6050
#define I2C_SCL_PIN  12

// ----------- OBJECTS ---------------------------
// DHT22
DHTesp dht;

// DS18B20
OneWire oneWire(DS18B20_PIN);
DallasTemperature ds18b20(&oneWire);

// MPU6050
MPU6050 mpu;

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

// --------------- WIFI CONNECT ------------------
void connectWiFi() {
  Serial.print("Connecting to WiFi");
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi connected!");
  Serial.print("IP: ");
  Serial.println(WiFi.localIP());
}

// ------------- SEND TO FIREBASE ----------------
bool sendToFirebase(const String& json) {
  WiFiClientSecure *client = new WiFiClientSecure;
  client->setInsecure(); // ignore cert

  HTTPClient https;
  String url = "https://" + String(FIREBASE_HOST) + String(FIREBASE_PATH) +
               "?auth=" + String(FIREBASE_AUTH);

  Serial.print("Firebase URL: ");
  Serial.println(url);

  if (!https.begin(*client, url)) {
    Serial.println("HTTPS begin failed");
    delete client;
    return false;
  }

  https.addHeader("Content-Type", "application/json");
  int httpCode = https.PUT(json);   // overwrite node

  if (httpCode > 0) {
    Serial.print("HTTP code: ");
    Serial.println(httpCode);
  } else {
    Serial.print("Firebase error: ");
    Serial.println(https.errorToString(httpCode));
  }

  https.end();
  delete client;
  return (httpCode == 200 || httpCode == 201);
}

// -------------- OLED DISPLAY -------------------
void showOnOLED(float t_dht, float h_dht,
                float mq2, float pot,
                float t_ds,
                int16_t gx, int16_t gy, int16_t gz) {

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);

  display.setCursor(0, 0);
  display.println("Multi Sensor Hub");

  display.setCursor(0, 12);
  display.printf("DHT: %.1fC  %.1f%%", t_dht, h_dht);

  display.setCursor(0, 24);
  display.printf("MQ2 : %.0f   POT: %.0f", mq2, pot);

  display.setCursor(0, 36);
  display.printf("DS18B20: %.1fC", t_ds);

  display.setCursor(0, 48);
  display.printf("Gx:%d Gy:%d Gz:%d", gx, gy, gz);

  display.display();
}

// -------------------- SETUP --------------------
void setup() {
  Serial.begin(115200);

  // I2C
  Wire.begin(I2C_SDA_PIN, I2C_SCL_PIN);

  // DHT
  dht.setup(DHT_PIN, DHTesp::DHT22);

  // DS18B20
  ds18b20.begin();

  // MPU6050
  Serial.println("Init MPU6050...");
  mpu.initialize();
  if (mpu.testConnection()) {
    Serial.println("MPU6050 OK");
  } else {
    Serial.println("MPU6050 FAIL");
  }

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

  // WiFi
  connectWiFi();
}

// --------------------- LOOP --------------------
void loop() {
  // --- DHT22 ---
  TempAndHumidity dhtData = dht.getTempAndHumidity();
  float t_dht = dhtData.temperature;
  float h_dht = dhtData.humidity;

  // --- MQ2 & POT (raw ADC values 0-4095) ---
  float mq2Val = analogRead(MQ2_PIN);
  float potVal = analogRead(POT_PIN);

  // --- DS18B20 temperature ---
  ds18b20.requestTemperatures();
  float t_ds = ds18b20.getTempCByIndex(0);

  // --- MPU6050 motion data ---
  int16_t ax, ay, az, gx, gy, gz;
  mpu.getMotion6(&ax, &ay, &az, &gx, &gy, &gz);

  // Serial debug
  Serial.printf("DHT: %.1fC %.1f%% | MQ2: %.0f | POT: %.0f | DS: %.1fC\n",
                t_dht, h_dht, mq2Val, potVal, t_ds);
  Serial.printf("MPU6050 Acc: %d,%d,%d Gyro: %d,%d,%d\n",
                ax, ay, az, gx, gy, gz);

  // --- Create JSON payload for Firebase ---
  String json = "{";
  json += "\"dht\":{";
  json += "\"temperature\":" + String(t_dht, 2) + ",";
  json += "\"humidity\":"    + String(h_dht, 2) + "},";

  json += "\"mq2\":" + String(mq2Val, 0) + ",";
  json += "\"pot\":" + String(potVal, 0) + ",";
  json += "\"ds18b20_temp\":" + String(t_ds, 2) + ",";

  json += "\"mpu6050\":{";
  json += "\"ax\":" + String(ax) + ",";
  json += "\"ay\":" + String(ay) + ",";
  json += "\"az\":" + String(az) + ",";
  json += "\"gx\":" + String(gx) + ",";
  json += "\"gy\":" + String(gy) + ",";
  json += "\"gz\":" + String(gz) + "}";

  json += "}";

  // --- send to Firebase ---
  if (WiFi.status() != WL_CONNECTED) {
    connectWiFi();
  }
  bool ok = sendToFirebase(json);

  // --- show on OLED ---
  showOnOLED(t_dht, h_dht, mq2Val, potVal, t_ds, gx, gy, gz);

  if (ok) {
    Serial.println("Firebase update OK");
  } else {
    Serial.println("Firebase update FAILED");
  }

  delay(5000); // every 5 seconds
}