# Copyright (c) 2015 Yubico AB
# All rights reserved.
#
#   Redistribution and use in source and binary forms, with or
#   without modification, are permitted provided that the following
#   conditions are met:
#
#    1. Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#    2. Redistributions in binary form must reproduce the above
#       copyright notice, this list of conditions and the following
#       disclaimer in the documentation and/or other materials provided
#       with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
# COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.

import logging
import struct
from time import time
from typing import Optional

from yubikit.core.smartcard import SW, ApduError
from yubikit.oath import OATH_TYPE, Credential, OathSession

logger = logging.getLogger(__name__)


STEAM_CHAR_TABLE = "23456789BCDFGHJKMNPQRTVWXY"


def is_hidden(credential: Credential) -> bool:
    """Check if OATH credential is hidden."""
    return credential.issuer == "_hidden"


def is_steam(credential: Credential) -> bool:
    """Check if OATH credential is steam."""
    return credential.oath_type == OATH_TYPE.TOTP and credential.issuer == "Steam"


def calculate_steam(
    app: OathSession, credential: Credential, timestamp: Optional[int] = None
) -> str:
    """Calculate steam codes."""
    timestamp = int(timestamp or time())
    resp = app.calculate(credential.id, struct.pack(">q", timestamp // 30))
    offset = resp[-1] & 0x0F
    code = struct.unpack(">I", resp[offset : offset + 4])[0] & 0x7FFFFFFF
    chars = []
    for i in range(5):
        chars.append(STEAM_CHAR_TABLE[code % len(STEAM_CHAR_TABLE)])
        code //= len(STEAM_CHAR_TABLE)
    return "".join(chars)


def is_in_fips_mode(app: OathSession) -> bool:
    """Check if OATH application is in FIPS mode."""
    return app.locked


def delete_broken_credential(app: OathSession) -> bool:
    """Checks for credential in a broken state and deletes it."""
    logger.debug("Probing for broken credentials")
    creds = app.list_credentials()
    broken = []
    for c in creds:
        if c.oath_type == OATH_TYPE.TOTP and not c.touch_required:
            for i in range(5):
                try:
                    app.calculate_code(c)
                    logger.debug(f"Credential appears OK: {c.id!r}")
                    break
                except ApduError as e:
                    if e.sw == SW.MEMORY_FAILURE:
                        if i == 0:
                            logger.debug(f"Memory failure in: {c.id!r}")
                        continue
                    raise
            else:
                broken.append(c.id)
                logger.warning(f"Credential appears to be broken: {c.id!r}")

    if len(broken) == 1:
        logger.info("Deleting broken credential")
        app.delete_credential(broken[0])
        return True

    logger.warning(f"Requires a single broken credential, found {len(broken)}")
    return False
