/*
 * This file is part of the Trezor project, https://trezor.io/
 *
 * Copyright (c) SatoshiLabs
 *
 * This program 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 program 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 program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "py/objstr.h"

#include "embed/extmod/trezorobj.h"

#include "blake2b.h"
#include "memzero.h"

/// package: trezorcrypto.__init__

/// class blake2b:
///     """
///     Blake2b context.
///     """
///     block_size: int
///     digest_size: int
typedef struct _mp_obj_Blake2b_t {
  mp_obj_base_t base;
  BLAKE2B_CTX ctx;
} mp_obj_Blake2b_t;

STATIC mp_obj_t mod_trezorcrypto_Blake2b_update(mp_obj_t self, mp_obj_t data);

/// def __init__(
///     self,
///     data: bytes | None = None,
///     outlen: int = blake2b.digest_size,
///     key: bytes | None = None,
///     personal: bytes | None = None,
/// ) -> None:
///     """
///     Creates a hash context object.
///     """
STATIC mp_obj_t mod_trezorcrypto_Blake2b_make_new(const mp_obj_type_t *type,
                                                  size_t n_args, size_t n_kw,
                                                  const mp_obj_t *args) {
  STATIC const mp_arg_t allowed_args[] = {
      {MP_QSTR_data, MP_ARG_OBJ, {.u_obj = mp_const_empty_bytes}},
      {MP_QSTR_outlen,
       MP_ARG_KW_ONLY | MP_ARG_INT,
       {.u_int = BLAKE2B_DIGEST_LENGTH}},
      {MP_QSTR_key,
       MP_ARG_KW_ONLY | MP_ARG_OBJ,
       {.u_obj = mp_const_empty_bytes}},
      {MP_QSTR_personal,
       MP_ARG_KW_ONLY | MP_ARG_OBJ,
       {.u_obj = mp_const_empty_bytes}},
  };
  mp_arg_val_t vals[MP_ARRAY_SIZE(allowed_args)] = {0};
  mp_arg_parse_all_kw_array(n_args, n_kw, args, MP_ARRAY_SIZE(allowed_args),
                            allowed_args, vals);

  size_t data_len = 0;
  const uint8_t *data =
      (const uint8_t *)mp_obj_str_get_data(vals[0].u_obj, &data_len);
  const mp_int_t outlen = vals[1].u_int;
  size_t key_len = 0;
  const uint8_t *key =
      (const uint8_t *)mp_obj_str_get_data(vals[2].u_obj, &key_len);
  size_t personal_len = 0;
  const uint8_t *personal =
      (const uint8_t *)mp_obj_str_get_data(vals[3].u_obj, &personal_len);

  if (key_len > 0 && personal_len > 0) {
    mp_raise_ValueError(
        "Invalid Blake2b parameters: cannot use key and personal at the same "
        "time");
  }

  mp_obj_Blake2b_t *o = m_new_obj_with_finaliser(mp_obj_Blake2b_t);
  o->base.type = type;
  int res = 0;

  if (key_len > 0) {
    res = blake2b_InitKey(&(o->ctx), outlen, key, key_len);
  } else if (personal_len > 0) {
    res = blake2b_InitPersonal(&(o->ctx), outlen, personal, personal_len);
  } else {
    res = blake2b_Init(&(o->ctx), outlen);
  }

  if (res < 0) {
    mp_raise_ValueError("Invalid Blake2b parameters");
  }

  // constructor called with data argument set
  if (data_len > 0) {
    blake2b_Update(&(o->ctx), data, data_len);
  }

  return MP_OBJ_FROM_PTR(o);
}

/// def update(self, data: bytes) -> None:
///     """
///     Update the hash context with hashed data.
///     """
STATIC mp_obj_t mod_trezorcrypto_Blake2b_update(mp_obj_t self, mp_obj_t data) {
  mp_obj_Blake2b_t *o = MP_OBJ_TO_PTR(self);
  mp_buffer_info_t msg = {0};
  mp_get_buffer_raise(data, &msg, MP_BUFFER_READ);
  if (msg.len > 0) {
    blake2b_Update(&(o->ctx), msg.buf, msg.len);
  }
  return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorcrypto_Blake2b_update_obj,
                                 mod_trezorcrypto_Blake2b_update);

/// def digest(self) -> bytes:
///     """
///     Returns the digest of hashed data.
///     """
STATIC mp_obj_t mod_trezorcrypto_Blake2b_digest(mp_obj_t self) {
  mp_obj_Blake2b_t *o = MP_OBJ_TO_PTR(self);
  BLAKE2B_CTX ctx = {0};
  memcpy(&ctx, &(o->ctx), sizeof(BLAKE2B_CTX));
  vstr_t hash = {0};
  vstr_init_len(&hash, ctx.outlen);
  blake2b_Final(&ctx, (uint8_t *)hash.buf, hash.len);
  memzero(&ctx, sizeof(BLAKE2B_CTX));
  return mp_obj_new_str_from_vstr(&mp_type_bytes, &hash);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorcrypto_Blake2b_digest_obj,
                                 mod_trezorcrypto_Blake2b_digest);

STATIC mp_obj_t mod_trezorcrypto_Blake2b___del__(mp_obj_t self) {
  mp_obj_Blake2b_t *o = MP_OBJ_TO_PTR(self);
  memzero(&(o->ctx), sizeof(BLAKE2B_CTX));
  return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorcrypto_Blake2b___del___obj,
                                 mod_trezorcrypto_Blake2b___del__);

STATIC const mp_rom_map_elem_t mod_trezorcrypto_Blake2b_locals_dict_table[] = {
    {MP_ROM_QSTR(MP_QSTR_update),
     MP_ROM_PTR(&mod_trezorcrypto_Blake2b_update_obj)},
    {MP_ROM_QSTR(MP_QSTR_digest),
     MP_ROM_PTR(&mod_trezorcrypto_Blake2b_digest_obj)},
    {MP_ROM_QSTR(MP_QSTR___del__),
     MP_ROM_PTR(&mod_trezorcrypto_Blake2b___del___obj)},
    {MP_ROM_QSTR(MP_QSTR_block_size), MP_ROM_INT(BLAKE2B_BLOCK_LENGTH)},
    {MP_ROM_QSTR(MP_QSTR_digest_size), MP_ROM_INT(BLAKE2B_DIGEST_LENGTH)},
};
STATIC MP_DEFINE_CONST_DICT(mod_trezorcrypto_Blake2b_locals_dict,
                            mod_trezorcrypto_Blake2b_locals_dict_table);

STATIC const mp_obj_type_t mod_trezorcrypto_Blake2b_type = {
    {&mp_type_type},
    .name = MP_QSTR_Blake2b,
    .make_new = mod_trezorcrypto_Blake2b_make_new,
    .locals_dict = (void *)&mod_trezorcrypto_Blake2b_locals_dict,
};