//Working copy of ATTiny85 beatbug with TM1637 display.
//Includes the moving average library to display agerage of last three beats. 
// One side of button goes to GPIO2 (pin 7) and the other goes to ground.
//
//                  ATMEL ATTINY85
//
//                       +-\/-+
//        A0 (D 5) PB5  1|    |8  Vcc
//   A3/ DIO (D 3) PB3  2|    |7  PB2 (D 2) A1/SCL
//        CLK(D 4) PB4  3|    |6  PB1 (D 1)
//                 GND  4|    |5  PB0 (D 0) SDA
//                       +----+

#include <TM1637Display.h>
#include <math.h>
#include <Bounce2.h>
#include <movingAvg.h>

// Instantiate a button object
Bounce2::Button button = Bounce2::Button();

// Module connection pins (Digital Pins)
#define CLK 4 //pin 3
#define DIO 3 // pin 2
#define BUTTON_PIN 2
 
// Variables, button state, and debounce
int buttonState = 0;
int lastButtonState = HIGH;
int reading;
long lastBeat;

// Set up display library
TM1637Display display(CLK, DIO);

// Names the moving average. Number in () sets the number of values to evaluate
movingAvg bpmavg(3);

int calculateBPM(long thisTime, long lastTime) {
   long elapsed = thisTime - lastTime;
   double bpm = round(1000. / elapsed * 60.);
   return (int)bpm; 
}

void setup() {

// BUTTON SETUP 
  
// SELECT ONE OF THE FOLLOWING :
// 1) IF YOUR BUTTON HAS AN INTERNAL PULL-UP
button.attach( BUTTON_PIN ,  INPUT_PULLUP ); // USE INTERNAL PULL-UP
// 2) IF YOUR BUTTON USES AN EXTERNAL PULL-UP
// button.attach( BUTTON_PIN, INPUT ); // USE EXTERNAL PULL-UP

  // DEBOUNCE INTERVAL IN MILLISECONDS
  button.interval(5); 

  // INDICATE THAT THE HIGH STATE CORRESPONDS TO PHYSICALLY PRESSING THE BUTTON
  button.setPressedState(LOW); 

// Begins the averaging
  bpmavg.begin();

   // Set display brightness
   display.setBrightness(0x02);

  // Record first hit as now
   lastBeat = millis();
}

void loop() {

  // UPDATE THE BUTTON
  // YOU MUST CALL THIS EVERY LOOP
  button.update();
                                                                               
  if ( button.pressed() )
  {
      // Calculate bpm and display average result
      long thisBeat = millis();
      int bpm = calculateBPM(thisBeat, lastBeat);
      int avg= bpmavg.reading(bpm);
      display.showNumberDec(avg);
      
      // thisBeat is now lastBeat for the next button press
      lastBeat = thisBeat;
    }
}