#include <DHT.h>
#include <Wire.h>
#include <Adafruit_SSD1306.h>
#include <WiFi.h>
#include <PubSubClient.h>

#define DHTPIN 4                // DHT22 sensor pin
#define DHTTYPE DHT22           // DHT 22 (AM2302)
#define SCREEN_WIDTH 128        // OLED display width
#define SCREEN_HEIGHT 64        // OLED display height

const char* ssid = "Wokwi-GUEST";               // Wi-Fi SSID
const char* password = "";                      // Wi-Fi password
const char* mqtt_server = "mqtt.thingsboard.cloud"; // ThingsBoard MQTT server
const char* access_token = "p0vviIl3VrJV2CebNEaw";  // ThingsBoard device access token

WiFiClient espClient;                // Wi-Fi client
PubSubClient client(espClient);      // MQTT client
DHT dht(DHTPIN, DHTTYPE);            // DHT22 sensor instance
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1); // OLED display instance

void setup() {
  Serial.begin(115200);      // Initialize serial communication
  dht.begin();               // Initialize the DHT22 sensor

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Initialize the OLED display
    Serial.println(F("SSD1306 allocation failed"));
    for (;;); // Loop forever if OLED initialization fails
  }
  display.display();
  delay(2000);
  display.clearDisplay();

  setup_wifi();               // Connect to Wi-Fi
  client.setServer(mqtt_server, 1883); // Set MQTT server and port
  client.setCallback(callback);        // Set MQTT callback function
}

void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    if (client.connect("ESP32Client", access_token, "")) {
      Serial.println("connected");
      client.subscribe("v1/devices/me/rpc/request/+");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  float h = dht.readHumidity();          // Read humidity
  float t = dht.readTemperature();       // Read temperature
  int rawHeartRate = analogRead(34);     // Simulate heart rate using potentiometer
  int rawBP = analogRead(35);            // Simulate blood pressure using potentiometer

  Serial.print("Raw Heart Rate: "); Serial.println(rawHeartRate);
  Serial.print("Raw BP: "); Serial.println(rawBP);

  float heartRate = map(rawHeartRate, 0, 4095, 60, 100); // Map heart rate value
  float bp = map(rawBP, 0, 4095, 80, 120);               // Map blood pressure value

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

  Serial.print("Temp: "); Serial.print(t); Serial.println(" *C");
  Serial.print("Humidity: "); Serial.print(h); Serial.println(" %");
  Serial.print("Heart Rate: "); Serial.print(heartRate); Serial.println(" bpm");
  Serial.print("BP: "); Serial.print(bp); Serial.println(" mmHg");

  display.clearDisplay();                 // Clear the OLED display
  display.setTextSize(1);                 // Set text size
  display.setTextColor(SSD1306_WHITE);    // Set text color
  display.setCursor(0, 0);                // Set cursor position
  display.print("Temp: "); display.print(t); display.println(" *C");
  display.print("Humidity: "); display.print(h); display.println(" %");
  display.print("Heart Rate: "); display.print(heartRate); display.println(" bpm");
  display.print("BP: "); display.print(bp); display.println(" mmHg");
  display.display();                      // Display updated data

  char payload[128];
  snprintf(payload, sizeof(payload), "{\"temperature\":%.2f,\"humidity\":%.2f,\"heartRate\":%.2f,\"bp\":%.2f}", t, h, heartRate, bp);
  client.publish("v1/devices/me/telemetry", payload); // Publish sensor data to ThingsBoard

  delay(2000); // Wait for 2 seconds before next reading
}