# SPDX-License-Identifier: MIT
# Copyright (c) 2015, Elaborated Networks GmbH
# Copyright (c) 2019, Mathias Laurin

"""Generic message digest wrapper (hash algorithm)."""

from __future__ import annotations

from typing import Optional, Protocol

# pylint: disable=no-name-in-module
from mbedtls._md import Hmac as Hmac
from mbedtls._md import algorithms_available as algorithms_available
from mbedtls._md import algorithms_guaranteed as algorithms_guaranteed

# pylint: enable=no-name-in-module


# Work around pyflakes' F401: imported but unused
assert algorithms_available
assert algorithms_guaranteed


class Algorithm(Protocol):
    def __call__(self, key: bytes, buffer: Optional[bytes] = ...) -> Hmac: ...


def new(
    key: bytes, buffer: Optional[bytes] = None, digestmod: Optional[str] = None
) -> Hmac:
    """A generic constructor that takes the key algorithm as its first
    parameter.

    """
    if digestmod is None:
        digestmod = "md5"
    block_size = {
        "md2": 16,
        "md4": 64,
        "md5": 64,
        "sha1": 64,
        "sha224": 64,
        "sha256": 64,
        "sha384": 128,
        "sha512": 128,
        "ripemd160": 64,
    }.get(digestmod.lower(), 64)
    return Hmac(key, digestmod, buffer, block_size=block_size)


def md2(key: bytes, buffer: Optional[bytes] = None) -> Hmac:
    """MD2 message-digest algorithm."""
    return new(key, buffer, "md2")  # pragma: no cover


def md4(key: bytes, buffer: Optional[bytes] = None) -> Hmac:
    """MD4 message-digest algorithm."""
    return new(key, buffer, "md4")  # pragma: no cover


def md5(key: bytes, buffer: Optional[bytes] = None) -> Hmac:
    """MD5 message-digest algorithm."""
    return new(key, buffer, "md5")


def sha1(key: bytes, buffer: Optional[bytes] = None) -> Hmac:
    """Secure Hmac Algorithm 1 (SHA-1)."""
    return new(key, buffer, "sha1")


def sha224(key: bytes, buffer: Optional[bytes] = None) -> Hmac:
    """Secure Hmac Algorithm 2 (SHA-2) with 224 bits hash value."""
    return new(key, buffer, "sha224")


def sha256(key: bytes, buffer: Optional[bytes] = None) -> Hmac:
    """Secure Hmac Algorithm 2 (SHA-2) with 256 bits hash value."""
    return new(key, buffer, "sha256")


def sha384(key: bytes, buffer: Optional[bytes] = None) -> Hmac:
    """Secure Hmac Algorithm 2 (SHA-2) with 384 bits hash value."""
    return new(key, buffer, "sha384")


def sha512(key: bytes, buffer: Optional[bytes] = None) -> Hmac:
    """Secure Hmac Algorithm 2 (SHA-2) with 512 bits hash value."""
    return new(key, buffer, "sha512")


def ripemd160(key: bytes, buffer: Optional[bytes] = None) -> Hmac:
    """RACE Integrity Primitives Evaluation Message Digest (RIPEMD) with
    160 bits hash value."""
    return new(key, buffer, "ripemd160")