#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "fileUtilities.h"
#include "../fileReader.h"


//Reads the given amount of bytes from the currently open file into the given buffer.
void readBytesIntoBuffer(uint8_t* buffer, long numBytes) {
  const size_t result = fread(buffer, 1, numBytes, file.filePointer);
  file.offset += result;

  if (result != numBytes) {
    fprintf(stderr, "Could not read %lu bytes from file: %s\n", numBytes, strerror(errno));
    exit(1);
  }
}


//Skips the given amount of bytes in the file
void skipBytes(long numBytes) {
  const int result = fseek(file.filePointer, numBytes, SEEK_CUR);

  if (result != 0) {
    fprintf(stderr, "Could not skip %lu bytes from file: %s\n", numBytes, strerror(errno));
    exit(1);
  } else {
    file.offset += numBytes;
  }
}


//Closes the currently opened file and opens the next file at its beginning.
void openNextFile() {
  const int closeResult = fclose(file.filePointer);
  if (closeResult != 0) {
    fprintf(stderr, "Could not close file: %s\n", strerror(errno));
    exit(1);
  }

  //Open next file
  const size_t fileNameLength = strlen(file.name);
  //We need to transfer carry if necessary (e.g. .z09 to .z10), otherwise just increase last digit
  if (file.name[fileNameLength - 1] == '9') {
    file.name[fileNameLength - 2] += 1;
    file.name[fileNameLength - 1] = 0;
  } else {
    file.name[fileNameLength - 1] += 1;
  }
  initFileReader(file.name, 0UL);
}