#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <EEPROM.h>

#define OLED_SDA 21
#define OLED_SCL 22
#define OLED_RST 16

#define BUTTON_PIN1 9
#define BUTTON_PIN2 8
#define BUTTON_PIN3 7

#define PULSE_SENSOR_PIN 2
#define OUTPUT_PIN A1

Adafruit_SSD1306 display(128, 64, &Wire, OLED_RST);

int threshold = 500; // initial threshold value
bool outputState = false; // initial output state
volatile int pulseCount = 0; // pulse count variable
unsigned long lastPulseTime = 0; // last pulse time variable

void handlePulse() {
  unsigned long now = millis();
  if (now - lastPulseTime > 10) {
    pulseCount++;
    lastPulseTime = now;
  }
}

void setup() {
  Serial.begin(9600);
  pinMode(OUTPUT_PIN, OUTPUT);
  digitalWrite(OUTPUT_PIN, outputState);

  pinMode(PULSE_SENSOR_PIN, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(PULSE_SENSOR_PIN), handlePulse, RISING);

  pinMode(BUTTON_PIN1, INPUT_PULLUP);
  pinMode(BUTTON_PIN2, INPUT_PULLUP);
  pinMode(BUTTON_PIN3, INPUT_PULLUP);

  threshold = readInt(0);
  Wire.begin(OLED_SDA, OLED_SCL);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Press button 1 to");
  display.println("activate/deactivate");
  display.println("output pin.");
  display.display();
}

void loop() {
  if (digitalRead(BUTTON_PIN1) == LOW) {
    while((digitalRead(BUTTON_PIN1) == LOW)){}
    outputState = !outputState;
    digitalWrite(OUTPUT_PIN, outputState);
    pulseCount = 0;
    display.clearDisplay();
    display.setCursor(0, 0);
    display.print("Output state: ");
    display.println(outputState ? "ON" : "OFF");
    display.display();
  }

  if (digitalRead(BUTTON_PIN2) == LOW) {
    unsigned long startMillis = millis();
    while (digitalRead(BUTTON_PIN2) == LOW) {
      if (millis() - startMillis > 2000) {
        display.clearDisplay();
        display.setCursor(0,0);
        display.print("Release button");
        display.display();
        while (digitalRead(BUTTON_PIN2) == LOW){}
        while((digitalRead(BUTTON_PIN1) == HIGH))
        {
        if(digitalRead(BUTTON_PIN2) == LOW)
        {
          delay(50);
          threshold += 10;
        }
        if(digitalRead(BUTTON_PIN3) == LOW)
        {
          delay(50);
          threshold -= 10;
        }
        display.clearDisplay();
        display.setCursor(0, 0);
        display.println("Set Value:");
        display.print(threshold);
        display.display();
        }
        writeInt(0,threshold);
        display.clearDisplay();
        display.setCursor(0,0);
        display.print("Release button");
        display.display();
        while((digitalRead(BUTTON_PIN1) == LOW)){}
        display.clearDisplay();
        display.setCursor(0,0);
        display.print("Press Start");
        display.display();
      }
    }
  }

  if (outputState) {
    display.clearDisplay();
    display.setCursor(0, 0);
    display.println("Pulse Count");
    display.println(pulseCount);
    display.display();

    if (pulseCount >= threshold) {
      outputState = false;
      digitalWrite(OUTPUT_PIN, outputState);
      pulseCount = 0;
      display.clearDisplay();
      display.setCursor(0, 0);
      display.println("Threshold reached.");
      display.println("Press Start");
      display.display();
    }
  }
}
void writeInt(int address, int number) {
  EEPROM.write(address, number >> 8);
  EEPROM.write(address + 1, number & 0xFF);
  }

int readInt(int address) {
  byte byte1 = EEPROM.read(address);
  byte byte2 = EEPROM.read(address + 1);
  int16_t number = (byte1 << 8) + byte2;
  return number;
}