#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Create an LCD object (assuming I2C address of the LCD is 0x27)
LiquidCrystal_I2C lcd(0x27, 20, 4); 

// Button pin
const int buttonPin = 2;
int buttonState = 0;
int lastButtonState = 0;

// Variables to store data
#define DATA_SIZE 100
int dataBuffer[DATA_SIZE];
int dataIndex = 0;

// Variables for replay
bool replayMode = false;
int replayIndex = 0;

// IO signal pin
const int ioPin = A0;

void setup() {
  pinMode(buttonPin, INPUT_PULLUP);  // Configure button as input with pull-up
  lcd.begin();
  lcd.backlight();
  
  // Initialize LCD
  lcd.setCursor(0, 0);
  lcd.print("Data Monitor");
  delay(1000);
  lcd.clear();
}

void loop() {
  // Read the IO signal (replace with actual frequency/data calculation)
  int ioData = analogRead(ioPin);
  
  // Store the data into the buffer
  if (dataIndex < DATA_SIZE) {
    dataBuffer[dataIndex++] = ioData;
  }

  // Display the data on the LCD (recent data)
  if (!replayMode) {
    lcd.setCursor(0, 0);
    lcd.print("IO Signal: ");
    lcd.print(ioData);

    lcd.setCursor(0, 1);
    lcd.print("Buffer Pos: ");
    lcd.print(dataIndex);
  }

  // Read the button state
  buttonState = digitalRead(buttonPin);

  // If the button is pressed, switch to replay mode
  if (buttonState == LOW && lastButtonState == HIGH) {
    replayMode = !replayMode;
    replayIndex = 0;  // Reset replay index
  }
  lastButtonState = buttonState;

  // Replay the data on the LCD when in replay mode
  if (replayMode) {
    lcd.setCursor(0, 2);
    lcd.print("Replay Data: ");
    lcd.print(dataBuffer[replayIndex]);

    // Cycle through stored data
    replayIndex = (replayIndex + 1) % dataIndex;
    delay(500);  // Slow down the replay speed
  }

  delay(200);  // Adjust this delay as needed
}