/*
* (C) 2015,2017 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/ffi.h>

#include <botan/assert.h>
#include <botan/kdf.h>
#include <botan/pwdhash.h>
#include <botan/internal/ffi_rng.h>
#include <botan/internal/ffi_util.h>

#if defined(BOTAN_HAS_BCRYPT)
   #include <botan/bcrypt.h>
#endif

extern "C" {

using namespace Botan_FFI;

int botan_pbkdf(const char* algo,
                uint8_t out[],
                size_t out_len,
                const char* pass,
                const uint8_t salt[],
                size_t salt_len,
                size_t iterations) {
   return botan_pwdhash(algo, iterations, 0, 0, out, out_len, pass, 0, salt, salt_len);
}

int botan_pbkdf_timed(const char* algo,
                      uint8_t out[],
                      size_t out_len,
                      const char* password,
                      const uint8_t salt[],
                      size_t salt_len,
                      size_t ms_to_run,
                      size_t* iterations_used) {
   return botan_pwdhash_timed(algo,
                              static_cast<uint32_t>(ms_to_run),
                              iterations_used,
                              nullptr,
                              nullptr,
                              out,
                              out_len,
                              password,
                              0,
                              salt,
                              salt_len);
}

int botan_pwdhash(const char* algo,
                  size_t param1,
                  size_t param2,
                  size_t param3,
                  uint8_t out[],
                  size_t out_len,
                  const char* password,
                  size_t password_len,
                  const uint8_t salt[],
                  size_t salt_len) {
   if(any_null_pointers(algo, password)) {
      return BOTAN_FFI_ERROR_NULL_POINTER;
   }
   if(out_len > 0 && out == nullptr) {
      return BOTAN_FFI_ERROR_NULL_POINTER;
   }
   if(salt_len > 0 && salt == nullptr) {
      return BOTAN_FFI_ERROR_NULL_POINTER;
   }

   if(password_len == 0) {
      password_len = std::strlen(password);
   }

   return ffi_guard_thunk(__func__, [=]() -> int {
      auto pwdhash_fam = Botan::PasswordHashFamily::create(algo);

      if(!pwdhash_fam) {
         return BOTAN_FFI_ERROR_NOT_IMPLEMENTED;
      }

      auto pwdhash = pwdhash_fam->from_params(param1, param2, param3);

      pwdhash->derive_key(out, out_len, password, password_len, salt, salt_len);

      return BOTAN_FFI_SUCCESS;
   });
}

int botan_pwdhash_timed(const char* algo,
                        uint32_t msec,
                        size_t* param1,
                        size_t* param2,
                        size_t* param3,
                        uint8_t out[],
                        size_t out_len,
                        const char* password,
                        size_t password_len,
                        const uint8_t salt[],
                        size_t salt_len) {
   if(any_null_pointers(algo, password)) {
      return BOTAN_FFI_ERROR_NULL_POINTER;
   }
   if(out_len > 0 && out == nullptr) {
      return BOTAN_FFI_ERROR_NULL_POINTER;
   }
   if(salt_len > 0 && salt == nullptr) {
      return BOTAN_FFI_ERROR_NULL_POINTER;
   }

   if(password_len == 0) {
      password_len = std::strlen(password);
   }

   return ffi_guard_thunk(__func__, [=]() -> int {
      auto pwdhash_fam = Botan::PasswordHashFamily::create(algo);

      if(!pwdhash_fam) {
         return BOTAN_FFI_ERROR_NOT_IMPLEMENTED;
      }

      auto pwdhash = pwdhash_fam->tune_params(out_len, msec);

      if(param1 != nullptr) {
         *param1 = pwdhash->iterations();
      }
      if(param2 != nullptr) {
         *param2 = pwdhash->parallelism();
      }
      if(param3 != nullptr) {
         *param3 = pwdhash->memory_param();
      }

      pwdhash->derive_key(out, out_len, password, password_len, salt, salt_len);

      return BOTAN_FFI_SUCCESS;
   });
}

int botan_kdf(const char* kdf_algo,
              uint8_t out[],
              size_t out_len,
              const uint8_t secret[],
              size_t secret_len,
              const uint8_t salt[],
              size_t salt_len,
              const uint8_t label[],
              size_t label_len) {
   if(kdf_algo == nullptr) {
      return BOTAN_FFI_ERROR_NULL_POINTER;
   }
   if((out_len > 0 && out == nullptr) || (secret_len > 0 && secret == nullptr) || (salt_len > 0 && salt == nullptr) ||
      (label_len > 0 && label == nullptr)) {
      return BOTAN_FFI_ERROR_NULL_POINTER;
   }
   return ffi_guard_thunk(__func__, [=]() -> int {
      auto kdf = Botan::KDF::create_or_throw(kdf_algo);
      kdf->kdf(out, out_len, secret, secret_len, salt, salt_len, label, label_len);
      return BOTAN_FFI_SUCCESS;
   });
}

int botan_scrypt(uint8_t out[],
                 size_t out_len,
                 const char* password,
                 const uint8_t salt[],
                 size_t salt_len,
                 size_t N,
                 size_t r,
                 size_t p) {
   return botan_pwdhash("Scrypt", N, r, p, out, out_len, password, 0, salt, salt_len);
}

int botan_bcrypt_generate(
   uint8_t* out, size_t* out_len, const char* pass, botan_rng_t rng_obj, size_t wf, uint32_t flags) {
#if defined(BOTAN_HAS_BCRYPT)
   return ffi_guard_thunk(__func__, [=]() -> int {
      if(any_null_pointers(out, out_len, pass)) {
         return BOTAN_FFI_ERROR_NULL_POINTER;
      }

      if(flags != 0) {
         return BOTAN_FFI_ERROR_BAD_FLAG;
      }

      if(wf < 4 || wf > 18) {
         return BOTAN_FFI_ERROR_BAD_PARAMETER;
      }

      if(*out_len < 61) {
         *out_len = 61;
         return BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE;
      }

      Botan::RandomNumberGenerator& rng = safe_get(rng_obj);
      const std::string bcrypt = Botan::generate_bcrypt(pass, rng, static_cast<uint16_t>(wf));
      // TODO(Botan4) change the type of out and remove this cast
      return write_str_output(reinterpret_cast<char*>(out), out_len, bcrypt);
   });
#else
   BOTAN_UNUSED(out, out_len, pass, rng_obj, wf, flags);
   return BOTAN_FFI_ERROR_NOT_IMPLEMENTED;
#endif
}

int botan_bcrypt_is_valid(const char* pass, const char* hash) {
   if(any_null_pointers(pass, hash)) {
      return BOTAN_FFI_ERROR_NULL_POINTER;
   }
#if defined(BOTAN_HAS_BCRYPT)
   return ffi_guard_thunk(__func__, [=]() -> int {
      return Botan::check_bcrypt(pass, hash) ? BOTAN_FFI_SUCCESS : BOTAN_FFI_INVALID_VERIFIER;
   });
#else
   BOTAN_UNUSED(pass, hash);
   return BOTAN_FFI_ERROR_NOT_IMPLEMENTED;
#endif
}
}
