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

#define DHT_PIN 12
// Define PULSE_PIN
#define PULSE_PIN 35

#define MQTT_SERVER "broker.emqx.io"
#define MQTT_PORT 1883

const char *ssid = "Wokwi-GUEST";
const char *password = "";

#define MQTT_TOPIC_HR "/heartRate"
#define MQTT_TOPIC_TEMP "/tempValue"
#define MQTT_TOPIC_HUM "/humValue"

#define OLED_RESET -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(128, 64, &Wire, OLED_RESET);

WiFiClient espClient;
PubSubClient client(espClient);
DHT dht(DHT_PIN, DHT22);

void setup() {
  Wire.begin(23, 22);
  Serial.begin(115200);

  Serial.println("Starting...");

  dht.begin();

  pinMode(PULSE_PIN, INPUT);

  connectToWiFi();

  client.setServer(MQTT_SERVER, MQTT_PORT);

  // Initialize OLED display
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3C for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  display.display();
  delay(2000); // Pause for 2 seconds
  display.clearDisplay();
}

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

  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  // Read pulseValue from PULSE_PIN
  int16_t pulseValue = analogRead(PULSE_PIN);

  // Convert pulseValue to voltage
  float voltage = pulseValue * (5.0 / 4095.0);

  // calculate heartRate from voltage
  int heartRate = (voltage / 3.3) * 675;

  display.clearDisplay();
  display.setTextSize(1); // Normal 1:1 pixel scale
  display.setTextColor(SSD1306_WHITE); // Draw white text
  display.setCursor(0,0); // Start at top-left corner
  display.print("Heart Rate: ");
  display.println(heartRate);
  display.print("Temp: ");
  display.println(temperature);
  display.print("Humidity: ");
  display.println(humidity);
  display.display();

  Serial.print("Heart Rate: ");
  Serial.print(heartRate);
  Serial.print(", Temp: ");
  Serial.print(temperature);
  Serial.print(", Humidity: ");
  Serial.println(humidity);

  delay(100);

  client.publish(MQTT_TOPIC_HR, String(heartRate).c_str());
  client.publish(MQTT_TOPIC_TEMP, String(temperature).c_str());
  client.publish(MQTT_TOPIC_HUM, String(humidity).c_str());

  Serial.println("Sent MQTT data");
  delay(10);
}

void connectToWiFi() {
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi");
}

void reconnect() {
  while (!client.connected()) {
    if (client.connect("esp32_neopixel_controller")) {
      Serial.println("Connected to MQTT");
      // Subscribe to MQTT topics here if needed
      // client.subscribe("topic_name");
    } else {
      Serial.print("Failed, rc=");
      Serial.print(client.state());
      Serial.println(" Retrying in 5 seconds...");
      delay(5000);
    }
  }
}