# -*- coding: utf-8 -*-

# without this, pylint will fail when inner classes are used
# within the 'nested' kwarg of our TlvMeta metaclass on python 3.7 :(
# pylint: disable=undefined-variable

"""
APDU commands of 3GPP TS 31.102 V16.6.0
"""
from typing import Dict

from construct import BitStruct, Enum, BitsInteger, Int8ub, Bytes, this, Struct, If, Switch, Const
from construct import Optional as COptional
from osmocom.construct import *

from pySim.filesystem import *
from pySim.ts_31_102 import SUCI_TlvDataObject
from pySim.apdu import ApduCommand, ApduCommandSet

# Copyright (C) 2022 Harald Welte <laforge@osmocom.org>
#
# 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 2 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/>.
#

# Mapping between USIM Service Number and its description

# TS 31.102 Section 7.1
class UsimAuthenticateEven(ApduCommand, n='AUTHENTICATE', ins=0x88, cla=['0X', '4X', '6X']):
    _apdu_case = 4
    _construct_p2 = BitStruct('scope'/Enum(Flag, mf=0, df_adf_specific=1),
                              BitsInteger(4),
                              'authentication_context'/Enum(BitsInteger(3), gsm=0, umts=1,
                                                            vgcs_vbs=2, gba=4))
    _cs_cmd_gsm_3g =  Struct('_rand_len'/Int8ub, 'rand'/Bytes(this._rand_len),
                         '_autn_len'/COptional(Int8ub), 'autn'/If(this._autn_len, Bytes(this._autn_len)))
    _cs_cmd_vgcs = Struct('_vsid_len'/Int8ub, 'vservice_id'/Bytes(this._vsid_len),
                          '_vkid_len'/Int8ub, 'vk_id'/Bytes(this._vkid_len),
                          '_vstk_rand_len'/Int8ub, 'vstk_rand'/Bytes(this._vstk_rand_len))
    _cmd_gba_bs = Struct('_rand_len'/Int8ub, 'rand'/Bytes(this._rand_len),
                         '_autn_len'/Int8ub, 'autn'/Bytes(this._autn_len))
    _cmd_gba_naf = Struct('_naf_id_len'/Int8ub, 'naf_id'/Bytes(this._naf_id_len),
                          '_impi_len'/Int8ub, 'impi'/Bytes(this._impi_len))
    _cs_cmd_gba = Struct('tag'/Int8ub, 'body'/Switch(this.tag, { 0xDD: 'bootstrap'/_cmd_gba_bs,
                                                                 0xDE: 'naf_derivation'/_cmd_gba_naf }))
    _cs_rsp_gsm = Struct('_len_sres'/Int8ub, 'sres'/Bytes(this._len_sres),
                         '_len_kc'/Int8ub, 'kc'/Bytes(this._len_kc))
    _rsp_3g_ok = Struct('_len_res'/Int8ub, 'res'/Bytes(this._len_res),
                        '_len_ck'/Int8ub, 'ck'/Bytes(this._len_ck),
                        '_len_ik'/Int8ub, 'ik'/Bytes(this._len_ik),
                        '_len_kc'/COptional(Int8ub), 'kc'/If(this._len_kc, Bytes(this._len_kc)))
    _rsp_3g_sync = Struct('_len_auts'/Int8ub, 'auts'/Bytes(this._len_auts))
    _cs_rsp_3g = Struct('tag'/Int8ub, 'body'/Switch(this.tag, { 0xDB: 'success'/_rsp_3g_ok,
                                                                0xDC: 'sync_fail'/_rsp_3g_sync}))
    _cs_rsp_vgcs = Struct(Const(b'\xDB'), '_vstk_len'/Int8ub, 'vstk'/Bytes(this._vstk_len))
    _cs_rsp_gba_naf = Struct(Const(b'\xDB'), '_ks_ext_naf_len'/Int8ub, 'ks_ext_naf'/Bytes(this._ks_ext_naf_len))
    def _decode_cmd(self) -> Dict:
        r = {}
        r['p1'] = parse_construct(self._construct_p1, self.p1.to_bytes(1, 'big'))
        r['p2'] = parse_construct(self._construct_p2, self.p2.to_bytes(1, 'big'))
        auth_ctx = r['p2']['authentication_context']
        if auth_ctx in ['gsm', 'umts']:
            r['body'] = parse_construct(self._cs_cmd_gsm_3g, self.cmd_data)
        elif auth_ctx == 'vgcs_vbs':
            r['body'] = parse_construct(self._cs_cmd_vgcs, self.cmd_data)
        elif auth_ctx == 'gba':
            r['body'] = parse_construct(self._cs_cmd_gba, self.cmd_data)
        else:
            raise ValueError('Unsupported authentication_context: %s' % auth_ctx)
        return r

    def _decode_rsp(self) -> Dict:
        r = {}
        auth_ctx = self.cmd_dict['p2']['authentication_context']
        if auth_ctx == 'gsm':
            r['body'] = parse_construct(self._cs_rsp_gsm, self.rsp_data)
        elif auth_ctx == 'umts':
            r['body'] = parse_construct(self._cs_rsp_3g, self.rsp_data)
        elif auth_ctx == 'vgcs_vbs':
            r['body'] = parse_construct(self._cs_rsp_vgcs, self.rsp_data)
        elif auth_ctx == 'gba':
            if self.cmd_dict['body']['tag'] == 0xDD:
                r['body'] = parse_construct(self._cs_rsp_3g, self.rsp_data)
            else:
                r['body'] = parse_construct(self._cs_rsp_gba_naf, self.rsp_data)
        else:
            raise ValueError('Unsupported authentication_context: %s' % auth_ctx)
        return r

class UsimAuthenticateOdd(ApduCommand, n='AUTHENTICATE', ins=0x89, cla=['0X', '4X', '6X']):
    _apdu_case = 4
    _construct_p2 = BitStruct('scope'/Enum(Flag, mf=0, df_adf_specific=1),
                              BitsInteger(4),
                              'authentication_context'/Enum(BitsInteger(3), mbms=5, local_key=6))
# TS 31.102 Section 7.5
class UsimGetIdentity(ApduCommand, n='GET IDENTITY', ins=0x78, cla=['8X', 'CX', 'EX']):
    _apdu_case = 4
    _construct_p2 = BitStruct('scope'/Enum(Flag, mf=0, df_adf_specific=1),
                              'identity_context'/Enum(BitsInteger(7), suci=1, suci_5g_nswo=2))
    _tlv_rsp = SUCI_TlvDataObject

ApduCommands = ApduCommandSet('TS 31.102', cmds=[UsimAuthenticateEven, UsimAuthenticateOdd,
                                                 UsimGetIdentity])