/*
 * 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 "blake2b.h"
#include "memzero.h"

/// class Blake2b:
///     '''
///     Blake2b context.
///     '''
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, outlen: int = Blake2b.digest_size, key: bytes = 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) {
    mp_arg_check_num(n_args, n_kw, 0, 3, false);
    mp_obj_Blake2b_t *o = m_new_obj(mp_obj_Blake2b_t);
    o->base.type = type;
    int res = 0;
    // constructor called with key argument set
    if (n_args == 3) {
        size_t outlen = mp_obj_get_int(args[1]);
        mp_buffer_info_t key;
        mp_get_buffer_raise(args[2], &key, MP_BUFFER_READ);
        res = blake2b_InitKey(&(o->ctx), outlen, key.buf, key.len);
    } else if (n_args == 2) {
        size_t outlen = mp_obj_get_int(args[1]);
        res = blake2b_Init(&(o->ctx), outlen);
    } else {
        res = blake2b_Init(&(o->ctx), BLAKE2B_DIGEST_LENGTH);
    }
    if (res < 0) {
        mp_raise_ValueError("Invalid Blake2b parameters");
    }
    // constructor called with data argument set
    if (n_args >= 1) {
        mod_trezorcrypto_Blake2b_update(MP_OBJ_FROM_PTR(o), args[0]);
    }
    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;
    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);
    uint8_t out[BLAKE2B_DIGEST_LENGTH];
    BLAKE2B_CTX ctx;
    memcpy(&ctx, &(o->ctx), sizeof(BLAKE2B_CTX));
    blake2b_Final(&ctx, out, ctx.outlen);
    memset(&ctx, 0, sizeof(BLAKE2B_CTX));
    return mp_obj_new_bytes(out, o->ctx.outlen);
}
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_OBJ_NEW_SMALL_INT(BLAKE2B_BLOCK_LENGTH) },
    { MP_ROM_QSTR(MP_QSTR_digest_size), MP_OBJ_NEW_SMALL_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,
};