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

#define OLED_RESET 4
Adafruit_SSD1306 display(OLED_RESET);

const int buttonPin = 2;
int symbolIndex = 0;
char symbols[] = {'-','!', '@', '#', '$', '%', '&', '*', '?'};
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 100;
int lastButtonState = HIGH;

void setup() {
  Serial.begin(9600);
  pinMode(buttonPin, INPUT_PULLUP);


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

  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(20, 20);
  display.print(symbols[symbolIndex]);
  display.display();
}

void loop() 
{
  
  int reading = digitalRead(buttonPin);

  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (reading == LOW) {
      symbolIndex = (symbolIndex + 1) % (sizeof(symbols) / sizeof(symbols[0]));
      display.clearDisplay();
      display.setCursor(20, 20);
      display.print(symbols[symbolIndex]);
      display.display();
    }
  }

  lastButtonState = reading;



}