#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <iostream>
#include <openssl/md5.h> /* md5sum */

#include "../include/calibrate.hpp"
#include "../include/exceptionhandler.hpp"

unsigned int Calibrate::_i = 0;

Calibrate::Calibrate(const std::string &path, const std::string &md5)
: Generic(std::move(path)), _md5(std::move(md5)) {}

bool Calibrate::CompareMD5(unsigned char *md5) const
{
  /*
  * Variable initialisation
  */
  int file_descript;
  unsigned long file_size;
  unsigned char* file_buffer;

  /* Checks if the file path can be opened. */
  file_descript = open(_path.c_str(), O_RDONLY);
  if (file_descript < 0)
  {
    throw ExceptionHandler(INVALID_PATH_ERROR, _path);
  }

  /* Grabs the size of file */
  file_size = GetSizeByFD(file_descript);

  /* Generates the buffer */
  file_buffer = static_cast<unsigned char*>(mmap(static_cast<caddr_t>(0), file_size, PROT_READ, MAP_SHARED, file_descript, 0));

  /* Computes the MD5 checksum to result */
  MD5(file_buffer, file_size, md5);

  /* Removes fime_buffer and file_size */
  munmap(file_buffer, file_size);

  MD5_wrapper md5_wrapper(md5);

  if (_md5.GetString() != md5_wrapper.GetString())
  {
    std::cout << "WARNING! " << _md5.GetString() << " != " << md5_wrapper.GetString() << "\n";
    return false;
  }

  return true;
}

/**
* Get the size of the file by its file descriptor
*
* @param file_descript
*/
unsigned long Calibrate::GetSizeByFD(const int fd) const
{
    struct stat statbuf;
    if (fstat(fd, &statbuf) < 0)
    {
      exit(EXIT_FAILURE);
    }
    return statbuf.st_size;
}