#include "auth.h"

#include <crypt.h>
#include <string.h>

#include <stdexcept>
#include <iostream>

// crypt specified password
std::string Auth::generate(const std::string& pw)
{
 struct crypt_data data;
 memset((void *)&data, '\0', sizeof(data));

 char setting[1000];
 
 if (crypt_gensalt_rn("$6$", 2000, nullptr, 0, setting, sizeof(setting)) == nullptr)
  throw std::runtime_error("Error on crypt_gensalt_r()");

 char* result;

 if ((result = crypt_r(pw.data(), setting, &data)) == nullptr)
  throw std::runtime_error("Error on crypt_r()");

 return result;
}

// validate specified password against crypted hash
bool Auth::validate(const std::string& crypted, const std::string& pw)
{
 struct crypt_data data;
 memset((void *)&data, '\0', sizeof(data));

 size_t pos = crypted.find_last_of('$');
 if (pos == crypted.npos) {
  std::cerr << "Warning: Bad password hash configured (format)" << std::endl;
  return false;
 }

 std::string setting{crypted.substr(0, pos)};

 char* output;
 if ((output = crypt_r(pw.data(), setting.data(), &data)) == nullptr) {
  std::cerr << "Warning: Error on crypt_r()" << std::endl;
  return false;
 }

 return crypted == output;
}