/*

* (C) 2013,2015 Jack Lloyd

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/aead.h>

#include <botan/scan_name.h>

#include <botan/parsing.h>

#include <sstream>

#if defined(BOTAN_HAS_BLOCK_CIPHER)

  #include <botan/block_cipher.h>

#endif

#if defined(BOTAN_HAS_AEAD_CCM)

  #include <botan/ccm.h>

#endif

#if defined(BOTAN_HAS_AEAD_CHACHA20_POLY1305)

  #include <botan/chacha20poly1305.h>

#endif

#if defined(BOTAN_HAS_AEAD_EAX)

  #include <botan/eax.h>

#endif

#if defined(BOTAN_HAS_AEAD_GCM)

  #include <botan/gcm.h>

#endif

#if defined(BOTAN_HAS_AEAD_OCB)

  #include <botan/ocb.h>

#endif

#if defined(BOTAN_HAS_AEAD_SIV)

  #include <botan/siv.h>

#endif

namespace Botan {

std::unique_ptr<AEAD_Mode> AEAD_Mode::create_or_throw(const std::string& algo,

                                                      Cipher_Dir dir,

                                                      const std::string& provider)

   {

   if(auto aead = AEAD_Mode::create(algo, dir, provider))

      return aead;

   throw Lookup_Error("AEAD", algo, provider);

   }

std::unique_ptr<AEAD_Mode> AEAD_Mode::create(const std::string& algo,

                                             Cipher_Dir dir,

                                             const std::string& provider)

   {

   BOTAN_UNUSED(provider);

#if defined(BOTAN_HAS_AEAD_CHACHA20_POLY1305)

   if(algo == "ChaCha20Poly1305")

      {

      if(dir == ENCRYPTION)

         return std::unique_ptr<AEAD_Mode>(new ChaCha20Poly1305_Encryption);

      else

         return std::unique_ptr<AEAD_Mode>(new ChaCha20Poly1305_Decryption);

      }

#endif

   if(algo.find('/') != std::string::npos)

      {

      const std::vector<std::string> algo_parts = split_on(algo, '/');

      const std::string cipher_name = algo_parts[0];

      const std::vector<std::string> mode_info = parse_algorithm_name(algo_parts[1]);

      if(mode_info.empty())

         return std::unique_ptr<AEAD_Mode>();

      std::ostringstream alg_args;

      alg_args << '(' << cipher_name;

      for(size_t i = 1; i < mode_info.size(); ++i)

         alg_args << ',' << mode_info[i];

      for(size_t i = 2; i < algo_parts.size(); ++i)

         alg_args << ',' << algo_parts[i];

      alg_args << ')';

      const std::string mode_name = mode_info[0] + alg_args.str();

      return AEAD_Mode::create(mode_name, dir);

      }

#if defined(BOTAN_HAS_BLOCK_CIPHER)

   SCAN_Name req(algo);

   if(req.arg_count() == 0)

      {

      return std::unique_ptr<AEAD_Mode>();

      }

   std::unique_ptr<BlockCipher> bc(BlockCipher::create(req.arg(0), provider));

   if(!bc)

      {

      return std::unique_ptr<AEAD_Mode>();

      }

#if defined(BOTAN_HAS_AEAD_CCM)

   if(req.algo_name() == "CCM")

      {

      size_t tag_len = req.arg_as_integer(1, 16);

      size_t L_len = req.arg_as_integer(2, 3);

      if(dir == ENCRYPTION)

         return std::unique_ptr<AEAD_Mode>(new CCM_Encryption(bc.release(), tag_len, L_len));

      else

         return std::unique_ptr<AEAD_Mode>(new CCM_Decryption(bc.release(), tag_len, L_len));

      }

#endif

#if defined(BOTAN_HAS_AEAD_GCM)

   if(req.algo_name() == "GCM")

      {

      size_t tag_len = req.arg_as_integer(1, 16);

      if(dir == ENCRYPTION)

         return std::unique_ptr<AEAD_Mode>(new GCM_Encryption(bc.release(), tag_len));

      else

         return std::unique_ptr<AEAD_Mode>(new GCM_Decryption(bc.release(), tag_len));

      }

#endif

#if defined(BOTAN_HAS_AEAD_OCB)

   if(req.algo_name() == "OCB")

      {

      size_t tag_len = req.arg_as_integer(1, 16);

      if(dir == ENCRYPTION)

         return std::unique_ptr<AEAD_Mode>(new OCB_Encryption(bc.release(), tag_len));

      else

         return std::unique_ptr<AEAD_Mode>(new OCB_Decryption(bc.release(), tag_len));

      }

#endif

#if defined(BOTAN_HAS_AEAD_EAX)

   if(req.algo_name() == "EAX")

      {

      size_t tag_len = req.arg_as_integer(1, bc->block_size());

      if(dir == ENCRYPTION)

         return std::unique_ptr<AEAD_Mode>(new EAX_Encryption(bc.release(), tag_len));

      else

         return std::unique_ptr<AEAD_Mode>(new EAX_Decryption(bc.release(), tag_len));

      }

#endif

#if defined(BOTAN_HAS_AEAD_SIV)

   if(req.algo_name() == "SIV")

      {

      if(dir == ENCRYPTION)

         return std::unique_ptr<AEAD_Mode>(new SIV_Encryption(bc.release()));

      else

         return std::unique_ptr<AEAD_Mode>(new SIV_Decryption(bc.release()));

      }

#endif

#endif

   return std::unique_ptr<AEAD_Mode>();

   }

}