/*Description:  "Heart Rate Monitor"
      This project measures the heart-rate using a custom chip and if it senses high heartrate,
      it sends an alert via SMS to the specified number and gives an alert using alertLed.
      This project also loads the data onto ThingSpeak for analytics;

*/
//channel id:2527670
//channel api key:4GUFVO761V2M6QVY
//Twilio AC574c8ac9da6d95d130a441fdaface639

//Including the dependencies
#include <Wire.h> 
#include <WiFi.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <ThingSpeak.h>
#include <HTTPClient.h>
#include "base64.h"

//ThingSpeak Channel Credentials
const char* WIFI_NAME="Wokwi-GUEST";        
const char* WIFI_PASSWORD = "";               
const int myChannelNumber=2527670;            
const char* myApiKey="4GUFVO761V2M6QVY";
const char* server = "api.thingspeak.com";

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);


#define RELAY 19          //Pin for Relay (To imitate the functioning of a fan)

#define PULSE_PIN 35      //Pin for the pulse sensor

#define alertLed 32       //Pin for the alterLed

WiFiClient client;

//Crenditals for Twilio (Messaging)
const char* accountSid = "AC574c8ac9da6d95d130a441fdaface639";  
const char* authToken = "0c406fcdada6b04db18ce894536ee0c6";
const char* fromPhoneNumber = "+17693009297";
const char* toPhoneNumber = "+919884219859";

int minHeartRate = 50;
int maxHeartRate = 120;

void setup() {
  Wire.begin();
  Wire.begin(16,17);
  Serial.begin(115200);
  
  pinMode(alertLed, OUTPUT);  //Declaration of PinMode
  pinMode(RELAY, OUTPUT);

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    while(1);
  }

  // Clear the buffer
  display.clearDisplay();

  // Initialzing the OLED display
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0,30);
  display.println("Heart Rate Monitor");
  display.display();

  //Connecting with Wifi
  WiFi.begin(WIFI_NAME,WIFI_PASSWORD);
  while (WiFi.status()!=WL_CONNECTED){
    delay(1000);
    Serial.print("Wifi not connected...\n");
  }
  Serial.println("\nWifi connected");
  Serial.println("IP Address: "+String(WiFi.localIP()));
  WiFi.mode(WIFI_STA);
  ThingSpeak.begin(client);   //Connecting with ThingSpeak

  Serial.println("HIGH HEART RATES WILL BE DISPLAYED BELOW:");
}

void loop() {
  int statusCode=0;        //StatusCode for getting input from thingSpeak
  
  // Read pulseValue from PULSE_PIN 
  int16_t pulseValue = analogRead(PULSE_PIN);
  
  // Convert pulseValue to voltage
  float voltage = pulseValue * (5 / 4095.0);
  
  // calculate heartRate from voltage
  int heartRate = (voltage / 3.3) * 675;


  ThingSpeak.setField(1,heartRate);                //Exporting data to thingSpeak
  ThingSpeak.writeFields(myChannelNumber,myApiKey);

  String messageBody = "ALERT: Heart Rate is above threshold.";

  // Encode the Twilio credentials
  String credentials = String(accountSid) + ":" + String(authToken);
  String encodedCredentials = base64::encode(credentials);

  // Create the URL for the Twilio API
  String url = "https://api.twilio.com/2010-04-01/Accounts/" + String(accountSid) + "/Messages.json";

  // Create the POST data
  String postData = "To=" + String(toPhoneNumber) + "&From=" + String(fromPhoneNumber) + "&Body=" + messageBody;

  // Create and configure the HTTP client for Twilio
  HTTPClient http;
  http.begin(url);
  http.addHeader("Authorization", "Basic " + encodedCredentials);
  http.addHeader("Content-Type", "application/x-www-form-urlencoded");

  /* -> If the heartRate is above 120pm, an alert led with be initiated along with the speed of the fan going to a high simulated with a relay.
     -> If the heartRate is below 50bpm, the information along with low heartrate alert will be display in the OLED*/
  
  
  if (heartRate < minHeartRate){
   
    display.clearDisplay();
    display.setTextSize(1);      
    display.setTextColor(SSD1306_WHITE);  
    display.setCursor(0,0);
    display.print("Heart Rate is below");
    display.setCursor(0,15);
    display.print("Minimum Threshold");
    display.setCursor(20,30);
    display.print(String(heartRate)+" bpm");
    display.display();
    digitalWrite(RELAY, LOW);
    digitalWrite(alertLed, LOW);

  }
  else if (heartRate > maxHeartRate){
    
    display.clearDisplay();
    display.setTextSize(1);      
    display.setTextColor(SSD1306_WHITE);  
    display.setCursor(0,0);
    display.print("Heart Rate is above");
    display.setCursor(0,15);
    display.print("Maximum Threshold");
    display.setCursor(20,30);
    display.print(String(heartRate)+" bpm");
    display.setCursor(10,50);
    display.print("Speed set at Max");
    display.display();

    digitalWrite(alertLed, HIGH); // Turning on the LED

    digitalWrite(RELAY, HIGH);    //Turning on the relay(simulating a fan)
    
    
  }else{
    
    display.clearDisplay();
    display.setTextSize(1);      
    display.setTextColor(SSD1306_WHITE);  
    display.setCursor(0,0);
    display.print("Heart Rate is Normal");
    display.setCursor(20,40);
    display.print(String(heartRate)+" bpm");
    display.display();
    digitalWrite(RELAY, LOW);
    digitalWrite(alertLed, LOW);

  }

  
  if (heartRate > maxHeartRate){
    int httpCode = http.POST(postData);     //Sending the message once the heartRate is above the threshold.
    Serial.println("Heart Rate: "+String(heartRate));
    
    if (httpCode == HTTP_CODE_OK) {
      ;
  } 

  // Close the connection
  http.end();

  }



  delay(2000); 

}