#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#*****************************************************************************
#   Ledger App OpenPGP.
#   (c) 2024 Ledger SAS.
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.
#*****************************************************************************

import sys
from pathlib import Path
from argparse import ArgumentParser, RawTextHelpFormatter, Namespace
from gpgapp.gpgcard import GPGCard, GPGCardExcpetion
from gpgapp.gpgcmd import ErrorCodes, KeyTypes, PassWord
from gpgapp.gpgcmd import KEY_OPERATIONS, KEY_TEMPLATES, USER_SALUTATION


# ===============================================================================
#          Parse command line options
# ===============================================================================
def get_argparser() -> Namespace:
    """Parse the commandline options"""

    parser = ArgumentParser(
        description="Manage OpenPGP App on Ledger device",
        formatter_class=RawTextHelpFormatter
    )
    parser.add_argument("--info", action="store_true",
                        help="Get and display card information")
    parser.add_argument("--reader", type=str, default="Ledger",
                        help="PCSC reader name (default is '%(default)s')")

    parser.add_argument("--apdu", action="store_true", help="Log APDU exchange")
    parser.add_argument("--slot", type=int, choices=range(1, 4), help="Select slot (1 to 3)")
    parser.add_argument("--reset", action="store_true",
                        help="Reset the application (all data will be erased)")

    parser.add_argument("--pinpad", action="store_true",
                        help="PIN validation will be delegated to pinpad")
    parser.add_argument("--adm-pin", metavar="PIN",
                        help="Admin PIN (if pinpad not used)", required="--pinpad" not in sys.argv)
    parser.add_argument("--user-pin", metavar="PIN",
                        help="User PIN (if pinpad not used)", required="--pinpad" not in sys.argv)
    parser.add_argument("--new-user-pin", metavar="PIN",
                        help="Change User PIN")
    parser.add_argument("--new-adm-pin", metavar="PIN",
                        help="Change Admin PIN")
    group = parser.add_mutually_exclusive_group()
    group.add_argument("--reset-code", help="Update 'PW1 Resetting Code'")
    group.add_argument("--reset-pw1", help="Reset the User PIN")

    parser.add_argument("--serial", help="Update the 'serial' data (4 bytes)")
    parser.add_argument("--salutation",choices=list(USER_SALUTATION), help="Update 'salutation' data")
    parser.add_argument("--name", help="Update 'name' data")
    parser.add_argument("--url", help="Update 'url' data")
    parser.add_argument("--login",help="Update 'login' data")
    parser.add_argument("--lang", help="Update 'lang' data")

    parser.add_argument("--key-type", type=KeyTypes, choices=[k.value for k in KeyTypes],
                        help="Select key type SIG:DEC:AUT (default is all)")

    parser.add_argument("--key-action",choices=list(KEY_OPERATIONS),
                        help="Generate key pair or Read public key")
    parser.add_argument("--set-fingerprints", metavar="SIG:DEC:AUT",
                        help="Set fingerprints for selected 'key-type'\n" + \
                        "If 'key-type' is not specified, set for all keys (SIG:DEC:AUT)\n" + \
                        "Each fingerprint is 20 hex bytes long")
    parser.add_argument("--set-templates", metavar="SIG:DEC:AUT",
                        help="Set template identifier for selected 'key-type'\n" + \
                        "If 'key-type' is not specified, set for all keys (SIG:DEC:AUT)\n" + \
                        f"Valid values are {', '.join(list(KEY_TEMPLATES))}")
    parser.add_argument("--seed-key", action="store_true",
                        help="Regenerate all keys, based on seed mode")

    parser.add_argument("--file", type=str, default="pubkey",
                        help="Public Key export file (default is '%(default)s')")

    return parser.parse_args()


# ===============================================================================
#          Error handler
# ===============================================================================
def error(code: int, msg: str) -> None:
    """Print error message and exit

    Args:
        msg (str): Message to display
    """

    scode = f" {code:x}" if code else ""
    if not msg:
        if code in ErrorCodes.err_list:
            msg = ErrorCodes.err_list[code]
    print(f"\n### Error{scode}: {msg}\n")
    sys.exit()


# ===============================================================================
#          PIN codes verification
# ===============================================================================
def verify_pins(gpgcard: GPGCard, user_pin: str, adm_pin: str, pinpad: bool) -> None:
    """Verify the pin codes

    Args:
        gpgcard (GPGCard): smartcard object
        user_pin (str): User pin code
        adm_pin (str): Admin pin code
        pinpad (bool): Indicates to use pinpad
    """

    print("Verify PINs...")
    if not gpgcard.verify_pin(PassWord.PW1, user_pin, pinpad) or \
       not gpgcard.verify_pin(PassWord.PW2, user_pin, pinpad) or \
       not gpgcard.verify_pin(PassWord.PW3, adm_pin,  pinpad):
        error(ErrorCodes.ERR_INTERNAL, "PIN not verified")


# ===============================================================================
#          Reset the Application
# ===============================================================================
def reset_app(gpgcard: GPGCard) -> None:
    """Reset Application and re-init

    Args:
        gpgcard (GPGCard): smartcard object
    """

    print("Reset application...")
    gpgcard.terminate()
    gpgcard.activate()
    print(" -> OK")


# ===============================================================================
#          Retrieve the OpenPGP Card information
# ===============================================================================
def get_info(gpgcard: GPGCard, display: bool=True) -> None:
    """Retrieve and display Card information

    Args:
        gpgcard (GPGCard): smartcard object
        display (bool): Print Card info
    """

    print("Get card info...")
    gpgcard.get_all()

    if not display:
        return

    line = "=" * 15
    print(f"{line} Application Identifier {line}")
    for k, v in gpgcard.decode_AID().items():
        if k == "AID":
            print(f" # {k:20s}: {v}")
        else:
            print(f"   - {k:18s}: {v}")
    print(f"{line} Historical Bytes {line}")
    for k, v in gpgcard.decode_histo().items():
        print(f" - {k:20s}: {v}")
    print(f"{line} Max Extended Length {line}")
    for k, v in gpgcard.decode_extlength().items():
        print(f" - {k:20s}: {v}")
    print(f"{line} PIN Info {line}")
    for k, v in gpgcard.decode_pws().items():
        print(f" - {k:20s}: {v}")
    print(f"{line} Extended Capabilities {line}")
    for k, v in gpgcard.decode_ext_capabilities().items():
        print(f" - {k:20s}: {v}")
    print(f"{line} Hardware Features {line}")
    for k, v in gpgcard.decode_hardware().items():
        print(f" - {k:20s}: {v}")
    print(f"{line} User Info {line}")
    print(f" - {'Name':20s}: {gpgcard.get_name()}")
    print(f" - {'Login':20s}: {gpgcard.get_login()}")
    print(f" - {'URL':20s}: {gpgcard.get_url()}")
    print(f" - {'Salutation':20s}: {gpgcard.get_salutation()}")
    print(f" - {'Lang':20s}: {gpgcard.get_lang()}")
    print(f"{line} Slots Info {line}")
    for k, v in gpgcard.decode_slot().items():
        print(f" - {k:20s}: {v}")
    print(f"{line} Keys Info {line}")
    print(f" - {'CDS counter':20s}: {gpgcard.get_sig_count()}")
    print(f" - {'RSA Pub Exponent':20s}: 0x{gpgcard.get_rsa_pub_exp():06x}")

    for key in [k.value for k in KeyTypes]:
        print(f" # {key}:")
        print(f"   - {'UIF':18s}: {gpgcard.decode_key_uif(key)}")
        print(f"   - {'Fingerprint':18s}: {gpgcard.get_key_fingerprint(key)}")
        print(f"   - {'CA fingerprint':18s}: {gpgcard.get_key_CA_fingerprint(key)}")
        print(f"   - {'Creation date':18s}: {gpgcard.get_key_date(key)}")
        print(f"   - {'Attribute':18s}: {gpgcard.decode_attributes(key)}")
        print(f"   - {'Certificate':18s}: {gpgcard.get_key_cert(key)}")
        print("   - Key:")
        for k, v in gpgcard.decode_key(key).items():
            print(f"     * {k:16s}: {v}")


# ===============================================================================
#          Set fingerprints
# ===============================================================================
def set_fingerprints(gpgcard: GPGCard, fingerprints: str, key_type: KeyTypes | None = None) -> None:
    """Set Key template

    Args:
        gpgcard (GPGCard): smartcard object
        fingerprints (str): SIG, DEC, AUT fingerprints separated by ':'
        key_type (KeyTypes): Key type selected
    """

    d = {}
    if key_type is None:
        # Consider all keys fingerprints are given
        try:
            d[KeyTypes.KEY_SIG], d[KeyTypes.KEY_DEC], d[KeyTypes.KEY_AUT] = fingerprints.split(":")
        except ValueError as err:
            raise GPGCardExcpetion(0, f"Wrong fingerprints arguments: {err}") from err

    else:
        # a key_type is specified, using only this fingerprint
        d[key_type] = fingerprints

    for k, v in d.items():
        print(f"Set fingerprints for '{k}' Key...")
        gpgcard.set_key_fingerprint(k, bytes.fromhex(v))


# ===============================================================================
#          Set Key Templates
# ===============================================================================
def set_templates(gpgcard: GPGCard, templates: str, key_type: KeyTypes | None = None) -> None:
    """Set Key template

    Args:
        gpgcard (GPGCard): smartcard object
        templates (str): SIG, DEC, AUT template separated by ':'
        key_type (KeyTypes): Key type selected
    """

    d = {}
    if key_type is None:
        # Consider all keys template are given
        try:
            d[KeyTypes.KEY_SIG], d[KeyTypes.KEY_DEC], d[KeyTypes.KEY_AUT] = templates.split(":")
        except ValueError as err:
            raise GPGCardExcpetion(0, f"Wrong templates arguments: {err}") from err
    else:
        # a key_type is specified, using only this template
        d[key_type] = templates

    for _, v in d.items():
        if v not in KEY_TEMPLATES:
            raise GPGCardExcpetion(0, f"Invalid template: {v}")

    for k, v in d.items():
        print(f"Set template {v} for '{k}' Key...")
        gpgcard.set_template(k, v)


# ===============================================================================
#          Handle Asymmetric keys
# ===============================================================================
def handle_key(gpgcard: GPGCard, action: str, key_type: KeyTypes, file: str = "") -> None:
    """Generate Key pair and/or Read Public key

    Args:
        gpgcard (GPGCard): smartcard object
        action (str): Generate or Read
        key_type (KeyTypes): Key type selected
        file (str): Public key export file
    """

    if action not in KEY_OPERATIONS:
        raise GPGCardExcpetion(0, f"Invalid operation: {action}")

    key_list = [key_type] if key_type else list(KeyTypes)
    for key in key_list:
        print(f"{action} '{key}' Key...")
        key_action = "Read" if action == "Export" else action
        pubkey = gpgcard.asymmetric_key(key, key_action)
        if action == "Export":
            if len(key_list) > 1:
                filename = key + "_" + file
            else:
                filename = file
            path = Path(filename)
            if path.suffix == "":
                filename += ".pem"
            gpgcard.export_pub_key(pubkey, filename)
        else:
            for k, v in pubkey.items():
                print(f" - {k:13s}: {v}")


# ===============================================================================
#          MAIN
# ===============================================================================
def entrypoint() -> None:
    """Main function"""

    # Arguments parsing
    # -----------------
    args = get_argparser()

    # Arguments checking
    # ------------------
    if not args.pinpad:
        if not args.adm_pin or not args.user_pin:
            error(ErrorCodes.ERR_INTERNAL,
                  "If 'pinpad' is not use, 'userpin' and 'admpin' must be provided")

    if args.serial and len(args.serial) != 8 :
        error(ErrorCodes.ERR_INTERNAL,
              "Serial must be a 4 bytes hex string value (8 characters)")

    if args.reset_code and len(args.reset_code) != 8:
        error(ErrorCodes.ERR_INTERNAL,
              "Reset Code must be a 4 bytes hex string value (8 characters)")

    if args.key_action == "Export" and not args.file:
        error(ErrorCodes.ERR_INTERNAL, "Provide a file to export public key")

    # Processing
    # ----------
    try:
        print(f"Connect to card '{args.reader}'...")
        gpgcard: GPGCard = GPGCard()
        gpgcard.log_apdu(args.apdu)
        gpgcard.connect(args.reader)

        verify_pins(gpgcard, args.user_pin, args.adm_pin, args.pinpad)

        if args.slot:
            gpgcard.select_slot(args.slot - 1)

        if args.salutation:
            gpgcard.set_salutation(args.salutation)
        if args.name:
            gpgcard.set_name(args.name)
        if args.url:
            gpgcard.set_url(args.url)
        if args.login:
            gpgcard.set_login(args.login)
        if args.lang:
            gpgcard.set_lang(args.lang)

        if args.new_user_pin:
            gpgcard.change_pin(PassWord.PW1, args.user_pin, args.new_user_pin)
        if args.new_adm_pin:
            gpgcard.change_pin(PassWord.PW3, args.adm_pin, args.new_adm_pin)
        if args.reset_pw1:
            # Reset the User PIN with Resetting Code
            gpgcard.reset_PW1(args.reset_code, args.reset_pw1)
        elif args.reset_code:
            # Use the Resetting code to set the value
            gpgcard.set_RC(args.reset_code)

        get_info(gpgcard, args.info)

        if args.reset:
            reset_app(gpgcard)

        if args.set_templates:
            set_templates(gpgcard, args.set_templates, args.key_type)

        if args.seed_key:
            gpgcard.seed_key()

        if args.set_fingerprints:
            set_fingerprints(gpgcard, args.set_fingerprints, args.key_type)

        if args.serial:
            gpgcard.set_serial(args.serial)

        if args.key_action:
            handle_key(gpgcard, args.key_action, args.key_type, args.file)

        gpgcard.disconnect()

    except GPGCardExcpetion as err:
        error(err.code, err.message)


if __name__ == "__main__":

    entrypoint()