#include "LittleFS.h"

const String FILENAME="/test.txt";

int readData() {
  File f = LittleFS.open(FILENAME, "r");
  if (!f) {
    Serial.println("File open failed on read.");
  } else {
    while(f.available()) {
      //Lets read line by line from the file
      String line = f.readStringUntil('\n');
      return line.toInt();
      break; //if left in, we'll just read the first line then break out of the while.
    } 
    f.close();
  }
  return -1;
}

void writeData(int data) {
  //opening "w" will truncate the file, so we know we only store our 1 value.
  File f = LittleFS.open(FILENAME, "w"); 

  if (!f) {
    Serial.println("File open failed on update.");
    delay(10000);
  } else {
    f.println(data); 
    f.close();
    Serial.println("File updated");
  }  
}

void setup() {
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");

  int loadedData = readData();

  Serial.print("Stored data is ");
  Serial.print(loadedData);
}


void loop() {
  // put your main code here, to run repeatedly:
  delay(10); // this speeds up the simulation
  writeData(millis());
}