// Define Blynk debug print
#define BLYNK_PRINT Serial

// Define Blynk credentials
#define BLYNK_TEMPLATE_ID "TMPL3SIxrAYtx"
#define BLYNK_TEMPLATE_NAME "HealthCare"
#define BLYNK_AUTH_TOKEN "RUlyKMvf28j-Oed9io2WMfHwlZytzO-u"

// Include libraries
#include <DallasTemperature.h>
#include <OneWire.h>
#include <WiFi.h>
#include <BlynkSimpleEsp32.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// WiFi credentials
char ssid[] = "Wokwi-GUEST";
char pass[] = "";

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

// Sensor & output pins
#define PULSE_PIN 35
#define alertLed 5
#define BUZZER_PIN 25

// Thresholds for heart rate and body temperature
int minHeartRate = 50;
int maxHeartRate = 120;
int minBodyTemp = 25;
int maxBodyTemp = 40;

// Temperature sensor setup
const int tempSensor = 13;
OneWire onewire(tempSensor);
DallasTemperature sensor(&onewire);

// Timer for Blynk
BlynkTimer timer;

// Variables to store sensor data
float temp = 0;
int16_t pulse;
float voltage;
int heartRate;

// Spinner characters for loading animation
char spinner[] = {'|', '/', '-'};

// Function to print text on OLED
void printLed(String str1, int c1, int r1, 
              String str2 = " ", int c2=0, int r2=0) {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(c1, r1);
  display.println(str1);
  display.setCursor(c2, r2);
  display.println(str2);
  display.display();
}

// Function to show loading animation
void loading() {
  for (int i = 0; i < 3; i++) {
    printLed(String(spinner[i]), 61, 30);        
    delay(50); 
  }
}

// Function to read sensors and send data to Blynk
void dataToBlynk() {
    sensor.requestTemperatures();
    temp = sensor.getTempCByIndex(0);

    // Read pulse value
    pulse = analogRead(PULSE_PIN);
  
    // Convert analog reading to voltage
    voltage = pulse * (5 / 4095.0);
  
    // Calculate heart rate based on voltage
    heartRate = (voltage / 3.3) * 675;

    // Check for invalid temperature reading
    if(isnan(temp)){
      Serial.println("Failed to fetch data from Temp Sensor");
      printLed("Failed to fetch data", 0, 28, "from Temp-Sensor", 0, 34);
      display.clearDisplay();
      return;
    }

    // Check for invalid pulse reading
    if(isnan(pulse)){
      Serial.println("Failed to fetch data from Pulse Sensor");
      printLed("Failed to fetch data", 0, 28, "from Pulse-Sensor", 0, 34);
      display.clearDisplay();
      return;
    }

    // Display temperature and heart rate on OLED
    display.clearDisplay();
    display.setTextSize(1.05);
    display.setTextColor(SSD1306_WHITE);
    display.setCursor(0, 20);
    display.print("Temperature: ");
    display.print(temp);
    display.println(" C");
    Serial.print("Temperature : ");
    Serial.print(temp);
    Serial.println(" C");

    display.setCursor(0, 40);
    display.print("Heart P/R : ");
    display.print(heartRate);
    display.println(" BPM");
    Serial.print("Heart Pulse Rate : ");
    Serial.print(heartRate);
    Serial.println(" BPM");

    display.display();    

    // Send data to Blynk virtual pins
    Blynk.virtualWrite(V0, heartRate);
    Blynk.virtualWrite(V1, temp);

    Serial.println("Data successfully sent to Blynk");
}

// Function to handle alert conditions
void adverseSituation() {

  if (heartRate < minHeartRate) {
    // Heart rate too low
    display.clearDisplay();
    display.setCursor(0, 0);
    display.println("Heart Rate is LOW");
    display.setCursor(20, 30);
    display.print(String(heartRate) + " bpm");
    display.setCursor(10, 50);
    display.print("ALERT TRIGGERED");
    display.display();

    digitalWrite(alertLed, HIGH);
    digitalWrite(BUZZER_PIN, HIGH);
    Blynk.virtualWrite(V2, 255); // Alert ON in Blynk
  } 
  else if (heartRate > maxHeartRate) {
    // Heart rate too high
    display.clearDisplay();
    display.setCursor(0, 0);
    display.println("Heart Rate HIGH!");
    display.setCursor(20, 30);
    display.print(String(heartRate) + " bpm");
    display.setCursor(10, 50);
    display.print("ALERT TRIGGERED");
    display.display();

    digitalWrite(alertLed, HIGH);
    digitalWrite(BUZZER_PIN, HIGH);
    Blynk.virtualWrite(V2, 255); // Alert ON in Blynk
  }
  else if (temp > maxBodyTemp) {
    // Body temperature too high
    display.clearDisplay();
    display.setCursor(0, 0);
    display.println("Body Temperature HIGH!");
    display.setCursor(20, 30);
    display.print(String(temp) + " C");
    display.setCursor(10, 50);
    display.print("ALERT TRIGGERED");
    display.display();

    digitalWrite(alertLed, HIGH);
    digitalWrite(BUZZER_PIN, HIGH);
    Blynk.virtualWrite(V2, 255); // Alert ON in Blynk
  } 
  else if (temp < minBodyTemp) {
    // Body temperature too low
    display.clearDisplay();
    display.setCursor(0, 0);
    display.println("Body Temperature LOW");
    display.setCursor(20, 30);
    display.print(String(temp) + " C");
    display.setCursor(10, 50);
    display.print("ALERT TRIGGERED");
    display.display();

    digitalWrite(alertLed, HIGH);
    digitalWrite(BUZZER_PIN, HIGH);
    Blynk.virtualWrite(V2, 255); // Alert ON in Blynk
  } 
  else {
    // Normal condition
    digitalWrite(alertLed, LOW);
    digitalWrite(BUZZER_PIN, LOW);
    Blynk.virtualWrite(V2, 0); // Alert OFF in Blynk
  }

  delay(2000);
}

// Setup function
void setup() {
    Serial.begin(9600);

    sensor.begin(); // Start temperature sensor
    Wire.begin(21, 22); // Initialize I2C

    pinMode(alertLed, OUTPUT);
    pinMode(BUZZER_PIN, OUTPUT);

    // Start OLED display
    if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
      Serial.println(F("OLED init failed"));
      while (1);
    }

    // Connect to WiFi
    WiFi.begin(ssid, pass);
    while(WiFi.status() != WL_CONNECTED)
    {
      printLed("Connecting...", 20, 29);
      delay(100);
      loading();
      loading();
      loading();
    }

    Serial.println("WiFi Connected Successfully !");
    printLed("WiFi Connected", 20, 24, "Successfully!", 23, 34);
    delay(1000);

    // Connect to Blynk
    Blynk.begin(BLYNK_AUTH_TOKEN, ssid, pass);
    Serial.println("Blynk ready to use !");
    printLed("Blynk Ready to Use", 9, 31);
    delay(1000);

    // Clear display
    printLed(" ", 0, 0);

    // Set a timer to send sensor data every 2 seconds
    timer.setInterval(2000L, dataToBlynk);    
}

// Loop function
void loop() {
    Blynk.run(); // Run Blynk
    timer.run(); // Run timer
    adverseSituation(); // Check for abnormal conditions
}