/**
 * libgammamm -- C++ wrapper for libgamma
 * Copyright (C) 2014  Mattias Andrée (maandree@member.fsf.org)
 * 
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "libgamma-error.hh"

#include <iostream>
#include <cstring>


namespace libgamma
{
  /**
   * Prints an error to stderr in a `perror` fashion,
   * however this function will not translate the `libgamma`
   * errors into human-readable strings, it will simply
   * print the name of the error. If the value `error_code`
   * is the value of `LIBGAMMA_ERRNO_SET`, `perror` will be
   * used to print the current error stored in `errno`.
   * If `error_code` is non-negative (an `errno` value`), that
   * value will be stored in `errno` and `perror` will be
   * used to print it. Additionally, if the `error_code` is
   * the value of `LIBGAMMA_DEVICE_REQUIRE_GROUP` the
   * required group will be printed with its numerical value
   * and, if known, its name.
   * 
   * @param  name   The text to add at the beginning.
   * @param  value  The error code, may be an `errno` value.
   */
  void perror(const std::string name, int error_code)
  {
    libgamma_perror(name.c_str(), error_code);
  }
  
  /**
   * Returns the name of the definition associated with a `nullptr` error code.
   * 
   * @param   value  The error code.
   * @return         The name of the definition associated with the error code,
   *                 `nullptr` if the error code does not exist.
   */
  std::string* name_of_error(int value)
  {
    const char* cstr = libgamma_name_of_error(value);
    if (cstr == nullptr)
      return nullptr;
    return new std::string(cstr);
  }
  
  /**
   * Return the value of a `libgamma` error definition refered to by name.
   * 
   * @param   name  The name of the definition associated with the error code.
   * @return        The error code, zero if the name is `nullptr`
   *                or does not refer to a `libgamma` error.
   */
  int value_of_error(const std::string* name)
  {
    const char* cstr = nullptr;
    if (name != nullptr)
      cstr = name->c_str();
    return libgamma_value_of_error(cstr);
  }
  

#ifdef __GCC__
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wshadow"
#endif

  /**
   * Constructor.
   * 
   * @param  error_code  The error code.
   */
  LibgammaException::LibgammaException(int error_code) throw() :
    error_code(error_code)
  {
    /* Do nothing. */
  }
  
  /**
   * Destructor.
   */
  LibgammaException::~LibgammaException() throw()
  {
    /* Do nothing. */
  }
  
  /**
   * Get the error as a string.
   */
  const char* LibgammaException::what() const throw()
  {
    if (this->error_code < 0)
      return libgamma_name_of_error(this->error_code);
    else
      return strerror(this->error_code);
  }
  
#ifdef __GCC__
# pragma GCC diagnostic pop
#endif
  
  
  /**
   * Create an exception from an error code
   * that may come from `errno.h` or be a
   * `libgamma` error code.
   * 
   * @param   error_code  The error code.
   * @return              The error object.
   */
  LibgammaException create_error(int error_code)
  {
    if (error_code == LIBGAMMA_ERRNO_SET)
      error_code = errno;
    return LibgammaException(error_code);
  }
  
  
  /**
   * Group that the user needs to be a member of if
   * `LIBGAMMA_DEVICE_REQUIRE_GROUP` is returned.
   */
  GroupGid group_gid;
  
  /**
   * Group that the user needs to be a member of if
   * `LIBGAMMA_DEVICE_REQUIRE_GROUP` is returned,
   * `nullptr` if the name of the group
   * `libgamma::group_gid` cannot be determined.
   */
  GroupName group_name;
  
}