#include <Adafruit_SSD1306.h>
#include <Arduino.h>
#include <SPI.h>
#include <Wire.h>
#include <array>
#include <Adafruit_GFX.h>


#define TYPING_BUTTON 15
#define BACKSPACE_BUTTON 4
#define POSITION_BUTTON 17
#define BUTTON_DELAY 250

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

#define OLED_RESET -1        // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3c  ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);


char text[] = "0000000000";
unsigned int pos = 0;
unsigned long next_pos_time;
const byte maxPos = sizeof text - 1;
bool typing = false;

void displayText(const char *c) {
  oled.clearDisplay();
  oled.setTextColor(SSD1306_WHITE);
  oled.setCursor(0, 50);
  oled.setTextSize(2);

  oled.print(c);

  oled.display();
}

bool is_button_pressed(uint8_t pin) {
  return digitalRead(pin) == LOW;
}

void setup() {
  Serial.begin(115200);
  delay(2000);

  pinMode(TYPING_BUTTON, INPUT_PULLUP);
  pinMode(BACKSPACE_BUTTON, INPUT_PULLUP);
  pinMode(POSITION_BUTTON, INPUT_PULLUP);

  if (!oled.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("SSD1306 allocation failed");
    return;
  }

  oled.clearDisplay();
  oled.display();
}
int i;
void loop() {
  oled.setCursor(0, 0);
  displayText(text);
  if (typing && next_pos_time <= millis()) {
    typing = false;
    pos++;
  }
  if (is_button_pressed(BACKSPACE_BUTTON)) {
    if (typing) {
      typing = false;
      text[pos] = '/';
    } else if (pos>0) {
        pos--;
      }


           text[pos] = '/';
           delay(BUTTON_DELAY);
  }
  if (is_button_pressed(TYPING_BUTTON)) {
    if (text[pos] == '9') text[pos] = '/';
    text[pos]++;



    next_pos_time = millis() + 1250;
    typing = true;
    delay(BUTTON_DELAY);
  }

}