ESP8266 Power cycle relay toggle

main.c

#include <ESP8266WiFi.h>
#include <FS.h>

const char *filename = "/relay_status.txt";
byte relON[] = {0xA0, 0x01, 0x01, 0xA2};
byte relOFF[] = {0xA0, 0x01, 0x00, 0xA1};

void setup() {
Serial.begin(9600);
Serial.write(0);
if (!SPIFFS.begin()) {
  return;
}

int previousStatus = readRelayStatus();
int newStatus = 1 - previousStatus;
saveRelayStatus(newStatus);

if (newStatus == 1) {
Serial.write(relON, sizeof(relON));
  } else {
Serial.write(relOFF, sizeof(relOFF));
  }
Serial.flush();
}

void loop() {
}

void saveRelayStatus(int status) {
File file = SPIFFS.open(filename, "w");
if (!file) {
  return;
  }
file.print(status);
file.close();
}

int readRelayStatus() {
int status = 0;
File file = SPIFFS.open(filename, "r");

if (file) {
status = file.parseInt();
file.close();
  }

return status;
}