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

""" pySim: SIM Card commands according to ISO 7816-4 and TS 11.11
"""

#
# Copyright (C) 2009-2010  Sylvain Munaut <tnt@246tNt.com>
# Copyright (C) 2010-2021  Harald Welte <laforge@gnumonks.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/>.
#

from construct import *
from pySim.construct import LV
from pySim.utils import rpad, b2h, h2b, sw_match, bertlv_encode_len, Hexstr, h2i, str_sanitize
from pySim.exceptions import SwMatchError


class SimCardCommands(object):
    def __init__(self, transport):
        self._tp = transport
        self.cla_byte = "a0"
        self.sel_ctrl = "0000"

    # Extract a single FCP item from TLV
    def __parse_fcp(self, fcp):
        # see also: ETSI TS 102 221, chapter 11.1.1.3.1 Response for MF,
        # DF or ADF
        from pytlv.TLV import TLV
        tlvparser = TLV(['82', '83', '84', 'a5', '8a', '8b',
                        '8c', '80', 'ab', 'c6', '81', '88'])

        # pytlv is case sensitive!
        fcp = fcp.lower()

        if fcp[0:2] != '62':
            raise ValueError(
                'Tag of the FCP template does not match, expected 62 but got %s' % fcp[0:2])

        # Unfortunately the spec is not very clear if the FCP length is
        # coded as one or two byte vale, so we have to try it out by
        # checking if the length of the remaining TLV string matches
        # what we get in the length field.
        # See also ETSI TS 102 221, chapter 11.1.1.3.0 Base coding.
        exp_tlv_len = int(fcp[2:4], 16)
        if len(fcp[4:]) // 2 == exp_tlv_len:
            skip = 4
        else:
            exp_tlv_len = int(fcp[2:6], 16)
            if len(fcp[4:]) // 2 == exp_tlv_len:
                skip = 6

        # Skip FCP tag and length
        tlv = fcp[skip:]
        return tlvparser.parse(tlv)

    # Tell the length of a record by the card response
    # USIMs respond with an FCP template, which is different
    # from what SIMs responds. See also:
    # USIM: ETSI TS 102 221, chapter 11.1.1.3 Response Data
    # SIM: GSM 11.11, chapter 9.2.1 SELECT
    def __record_len(self, r) -> int:
        if self.sel_ctrl == "0004":
            tlv_parsed = self.__parse_fcp(r[-1])
            file_descriptor = tlv_parsed['82']
            # See also ETSI TS 102 221, chapter 11.1.1.4.3 File Descriptor
            return int(file_descriptor[4:8], 16)
        else:
            return int(r[-1][28:30], 16)

    # Tell the length of a binary file. See also comment
    # above.
    def __len(self, r) -> int:
        if self.sel_ctrl == "0004":
            tlv_parsed = self.__parse_fcp(r[-1])
            return int(tlv_parsed['80'], 16)
        else:
            return int(r[-1][4:8], 16)

    def get_atr(self) -> str:
        """Return the ATR of the currently inserted card."""
        return self._tp.get_atr()

    def try_select_path(self, dir_list):
        """ Try to select a specified path

        Args:
                dir_list : list of hex-string FIDs
        """

        rv = []
        if type(dir_list) is not list:
            dir_list = [dir_list]
        for i in dir_list:
            data, sw = self._tp.send_apdu(
                self.cla_byte + "a4" + self.sel_ctrl + "02" + i)
            rv.append((data, sw))
            if sw != '9000':
                return rv
        return rv

    def select_path(self, dir_list):
        """Execute SELECT for an entire list/path of FIDs.

        Args:
                dir_list: list of FIDs representing the path to select

        Returns:
                list of return values (FCP in hex encoding) for each element of the path
        """
        rv = []
        if type(dir_list) is not list:
            dir_list = [dir_list]
        for i in dir_list:
            data, sw = self.select_file(i)
            rv.append(data)
        return rv

    def select_file(self, fid: str):
        """Execute SELECT a given file by FID.

        Args:
                fid : file identifier as hex string
        """

        return self._tp.send_apdu_checksw(self.cla_byte + "a4" + self.sel_ctrl + "02" + fid)

    def select_parent_df(self):
        """Execute SELECT to switch to the parent DF """
        return self._tp.send_apdu_checksw(self.cla_byte + "a4030400")

    def select_adf(self, aid: str):
        """Execute SELECT a given Applicaiton ADF.

        Args:
                aid : application identifier as hex string
        """

        aidlen = ("0" + format(len(aid) // 2, 'x'))[-2:]
        return self._tp.send_apdu_checksw(self.cla_byte + "a4" + "0404" + aidlen + aid)

    def read_binary(self, ef, length: int = None, offset: int = 0):
        """Execute READD BINARY.

        Args:
                ef : string or list of strings indicating name or path of transparent EF
                length : number of bytes to read
                offset : byte offset in file from which to start reading
        """
        r = self.select_path(ef)
        if len(r[-1]) == 0:
            return (None, None)
        if length is None:
            length = self.__len(r) - offset
        if length < 0:
            return (None, None)

        total_data = ''
        chunk_offset = 0
        while chunk_offset < length:
            chunk_len = min(255, length-chunk_offset)
            pdu = self.cla_byte + \
                'b0%04x%02x' % (offset + chunk_offset, chunk_len)
            try:
                data, sw = self._tp.send_apdu_checksw(pdu)
            except Exception as e:
                raise ValueError('%s, failed to read (offset %d)' %
                                 (str_sanitize(str(e)), offset))
            total_data += data
            chunk_offset += chunk_len
        return total_data, sw

    def update_binary(self, ef, data: str, offset: int = 0, verify: bool = False, conserve: bool = False):
        """Execute UPDATE BINARY.

        Args:
                ef : string or list of strings indicating name or path of transparent EF
                data : hex string of data to be written
                offset : byte offset in file from which to start writing
                verify : Whether or not to verify data after write
        """
        data_length = len(data) // 2

        # Save write cycles by reading+comparing before write
        if conserve:
            data_current, sw = self.read_binary(ef, data_length, offset)
            if data_current == data:
                return None, sw

        self.select_path(ef)
        total_data = ''
        chunk_offset = 0
        while chunk_offset < data_length:
            chunk_len = min(255, data_length - chunk_offset)
            # chunk_offset is bytes, but data slicing is hex chars, so we need to multiply by 2
            pdu = self.cla_byte + \
                'd6%04x%02x' % (offset + chunk_offset, chunk_len) + \
                data[chunk_offset*2: (chunk_offset+chunk_len)*2]
            try:
                chunk_data, chunk_sw = self._tp.send_apdu_checksw(pdu)
            except Exception as e:
                raise ValueError('%s, failed to write chunk (chunk_offset %d, chunk_len %d)' %
                                 (str_sanitize(str(e)), chunk_offset, chunk_len))
            total_data += data
            chunk_offset += chunk_len
        if verify:
            self.verify_binary(ef, data, offset)
        return total_data, chunk_sw

    def verify_binary(self, ef, data: str, offset: int = 0):
        """Verify contents of transparent EF.

        Args:
                ef : string or list of strings indicating name or path of transparent EF
                data : hex string of expected data
                offset : byte offset in file from which to start verifying
        """
        res = self.read_binary(ef, len(data) // 2, offset)
        if res[0].lower() != data.lower():
            raise ValueError('Binary verification failed (expected %s, got %s)' % (
                data.lower(), res[0].lower()))

    def read_record(self, ef, rec_no: int):
        """Execute READ RECORD.

        Args:
                ef : string or list of strings indicating name or path of linear fixed EF
                rec_no : record number to read
        """
        r = self.select_path(ef)
        rec_length = self.__record_len(r)
        pdu = self.cla_byte + 'b2%02x04%02x' % (rec_no, rec_length)
        return self._tp.send_apdu_checksw(pdu)

    def update_record(self, ef, rec_no: int, data: str, force_len: bool = False, verify: bool = False,
                      conserve: bool = False):
        """Execute UPDATE RECORD.

        Args:
                ef : string or list of strings indicating name or path of linear fixed EF
                rec_no : record number to read
                data : hex string of data to be written
                force_len : enforce record length by using the actual data length
                verify : verify data by re-reading the record
                conserve : read record and compare it with data, skip write on match
        """
        res = self.select_path(ef)

        if force_len:
            # enforce the record length by the actual length of the given data input
            rec_length = len(data) // 2
        else:
            # determine the record length from the select response of the file and pad
            # the input data with 0xFF if necessary. In cases where the input data
            # exceed we throw an exception.
            rec_length = self.__record_len(res)
            if (len(data) // 2 > rec_length):
                raise ValueError('Data length exceeds record length (expected max %d, got %d)' % (
                    rec_length, len(data) // 2))
            elif (len(data) // 2 < rec_length):
                data = rpad(data, rec_length * 2)

        # Save write cycles by reading+comparing before write
        if conserve:
            data_current, sw = self.read_record(ef, rec_no)
            data_current = data_current[0:rec_length*2]
            if data_current == data:
                return None, sw

        pdu = (self.cla_byte + 'dc%02x04%02x' % (rec_no, rec_length)) + data
        res = self._tp.send_apdu_checksw(pdu)
        if verify:
            self.verify_record(ef, rec_no, data)
        return res

    def verify_record(self, ef, rec_no: int, data: str):
        """Verify record against given data

        Args:
                ef : string or list of strings indicating name or path of linear fixed EF
                rec_no : record number to read
                data : hex string of data to be verified
        """
        res = self.read_record(ef, rec_no)
        if res[0].lower() != data.lower():
            raise ValueError('Record verification failed (expected %s, got %s)' % (
                data.lower(), res[0].lower()))

    def record_size(self, ef):
        """Determine the record size of given file.

        Args:
                ef : string or list of strings indicating name or path of linear fixed EF
        """
        r = self.select_path(ef)
        return self.__record_len(r)

    def record_count(self, ef):
        """Determine the number of records in given file.

        Args:
                ef : string or list of strings indicating name or path of linear fixed EF
        """
        r = self.select_path(ef)
        return self.__len(r) // self.__record_len(r)

    def binary_size(self, ef):
        """Determine the size of given transparent file.

        Args:
                ef : string or list of strings indicating name or path of transparent EF
        """
        r = self.select_path(ef)
        return self.__len(r)

    # TS 102 221 Section 11.3.1 low-level helper
    def _retrieve_data(self, tag: int, first: bool = True):
        if first:
            pdu = '80cb008001%02x' % (tag)
        else:
            pdu = '80cb000000'
        return self._tp.send_apdu_checksw(pdu)

    def retrieve_data(self, ef, tag: int):
        """Execute RETRIEVE DATA, see also TS 102 221 Section 11.3.1.

        Args
                ef : string or list of strings indicating name or path of transparent EF
                tag : BER-TLV Tag of value to be retrieved
        """
        r = self.select_path(ef)
        if len(r[-1]) == 0:
            return (None, None)
        total_data = ''
        # retrieve first block
        data, sw = self._retrieve_data(tag, first=True)
        total_data += data
        while sw == '62f1' or sw == '62f2':
            data, sw = self._retrieve_data(tag, first=False)
            total_data += data
        return total_data, sw

    # TS 102 221 Section 11.3.2 low-level helper
    def _set_data(self, data: str, first: bool = True):
        if first:
            p1 = 0x80
        else:
            p1 = 0x00
        if isinstance(data, bytes) or isinstance(data, bytearray):
            data = b2h(data)
        pdu = '80db00%02x%02x%s' % (p1, len(data)//2, data)
        return self._tp.send_apdu_checksw(pdu)

    def set_data(self, ef, tag: int, value: str, verify: bool = False, conserve: bool = False):
        """Execute SET DATA.

        Args
                ef : string or list of strings indicating name or path of transparent EF
                tag : BER-TLV Tag of value to be stored
                value : BER-TLV value to be stored
        """
        r = self.select_path(ef)
        if len(r[-1]) == 0:
            return (None, None)

        # in case of deleting the data, we only have 'tag' but no 'value'
        if not value:
            return self._set_data('%02x' % tag, first=True)

        # FIXME: proper BER-TLV encode
        tl = '%02x%s' % (tag, b2h(bertlv_encode_len(len(value)//2)))
        tlv = tl + value
        tlv_bin = h2b(tlv)

        first = True
        total_len = len(tlv_bin)
        remaining = tlv_bin
        while len(remaining) > 0:
            fragment = remaining[:255]
            rdata, sw = self._set_data(fragment, first=first)
            first = False
            remaining = remaining[255:]
        return rdata, sw

    def run_gsm(self, rand: str):
        """Execute RUN GSM ALGORITHM.

        Args:
                rand : 16 byte random data as hex string (RAND)
        """
        if len(rand) != 32:
            raise ValueError('Invalid rand')
        self.select_path(['3f00', '7f20'])
        return self._tp.send_apdu(self.cla_byte + '88000010' + rand)

    def authenticate(self, rand: str, autn: str, context='3g'):
        """Execute AUTHENTICATE (USIM/ISIM).

        Args:
                rand : 16 byte random data as hex string (RAND)
                autn : 8 byte Autentication Token (AUTN)
                context : 16 byte random data ('3g' or 'gsm')
        """
        # 3GPP TS 31.102 Section 7.1.2.1
        AuthCmd3G = Struct('rand'/LV, 'autn'/Optional(LV))
        AuthResp3GSyncFail = Struct(Const(b'\xDC'), 'auts'/LV)
        AuthResp3GSuccess = Struct(
            Const(b'\xDB'), 'res'/LV, 'ck'/LV, 'ik'/LV, 'kc'/Optional(LV))
        AuthResp3G = Select(AuthResp3GSyncFail, AuthResp3GSuccess)
        # build parameters
        cmd_data = {'rand': rand, 'autn': autn}
        if context == '3g':
            p2 = '81'
        elif context == 'gsm':
            p2 = '80'
        (data, sw) = self._tp.send_apdu_constr_checksw(
            self.cla_byte, '88', '00', p2, AuthCmd3G, cmd_data, AuthResp3G)
        if 'auts' in data:
            ret = {'synchronisation_failure': data}
        else:
            ret = {'successful_3g_authentication': data}
        return (ret, sw)

    def status(self):
        """Execute a STATUS command as per TS 102 221 Section 11.1.2."""
        return self._tp.send_apdu_checksw('80F20000ff')

    def deactivate_file(self):
        """Execute DECATIVATE FILE command as per TS 102 221 Section 11.1.14."""
        return self._tp.send_apdu_constr_checksw(self.cla_byte, '04', '00', '00', None, None, None)

    def activate_file(self, fid):
        """Execute ACTIVATE FILE command as per TS 102 221 Section 11.1.15.

        Args:
                fid : file identifier as hex string
        """
        return self._tp.send_apdu_checksw(self.cla_byte + '44000002' + fid)

    def manage_channel(self, mode='open', lchan_nr=0):
        """Execute MANAGE CHANNEL command as per TS 102 221 Section 11.1.17.

        Args:
                mode : logical channel operation code ('open' or 'close')
                lchan_nr : logical channel number (1-19, 0=assigned by UICC)
        """
        if mode == 'close':
            p1 = 0x80
        else:
            p1 = 0x00
        pdu = self.cla_byte + '70%02x%02x00' % (p1, lchan_nr)
        return self._tp.send_apdu_checksw(pdu)

    def reset_card(self):
        """Physically reset the card"""
        return self._tp.reset_card()

    def _chv_process_sw(self, op_name, chv_no, pin_code, sw):
        if sw_match(sw, '63cx'):
            raise RuntimeError('Failed to %s chv_no 0x%02X with code 0x%s, %i tries left.' %
                               (op_name, chv_no, b2h(pin_code).upper(), int(sw[3])))
        elif (sw != '9000'):
            raise SwMatchError(sw, '9000')

    def verify_chv(self, chv_no: int, code: str):
        """Verify a given CHV (Card Holder Verification == PIN)

        Args:
                chv_no : chv number (1=CHV1, 2=CHV2, ...)
                code : chv code as hex string
        """
        fc = rpad(b2h(code), 16)
        data, sw = self._tp.send_apdu(
            self.cla_byte + '2000' + ('%02X' % chv_no) + '08' + fc)
        self._chv_process_sw('verify', chv_no, code, sw)
        return (data, sw)

    def unblock_chv(self, chv_no: int, puk_code: str, pin_code: str):
        """Unblock a given CHV (Card Holder Verification == PIN)

        Args:
                chv_no : chv number (1=CHV1, 2=CHV2, ...)
                puk_code : puk code as hex string
                pin_code : new chv code as hex string
        """
        fc = rpad(b2h(puk_code), 16) + rpad(b2h(pin_code), 16)
        data, sw = self._tp.send_apdu(
            self.cla_byte + '2C00' + ('%02X' % chv_no) + '10' + fc)
        self._chv_process_sw('unblock', chv_no, pin_code, sw)
        return (data, sw)

    def change_chv(self, chv_no: int, pin_code: str, new_pin_code: str):
        """Change a given CHV (Card Holder Verification == PIN)

        Args:
                chv_no : chv number (1=CHV1, 2=CHV2, ...)
                pin_code : current chv code as hex string
                new_pin_code : new chv code as hex string
        """
        fc = rpad(b2h(pin_code), 16) + rpad(b2h(new_pin_code), 16)
        data, sw = self._tp.send_apdu(
            self.cla_byte + '2400' + ('%02X' % chv_no) + '10' + fc)
        self._chv_process_sw('change', chv_no, pin_code, sw)
        return (data, sw)

    def disable_chv(self, chv_no: int, pin_code: str):
        """Disable a given CHV (Card Holder Verification == PIN)

        Args:
                chv_no : chv number (1=CHV1, 2=CHV2, ...)
                pin_code : current chv code as hex string
                new_pin_code : new chv code as hex string
        """
        fc = rpad(b2h(pin_code), 16)
        data, sw = self._tp.send_apdu(
            self.cla_byte + '2600' + ('%02X' % chv_no) + '08' + fc)
        self._chv_process_sw('disable', chv_no, pin_code, sw)
        return (data, sw)

    def enable_chv(self, chv_no: int, pin_code: str):
        """Enable a given CHV (Card Holder Verification == PIN)

        Args:
                chv_no : chv number (1=CHV1, 2=CHV2, ...)
                pin_code : chv code as hex string
        """
        fc = rpad(b2h(pin_code), 16)
        data, sw = self._tp.send_apdu(
            self.cla_byte + '2800' + ('%02X' % chv_no) + '08' + fc)
        self._chv_process_sw('enable', chv_no, pin_code, sw)
        return (data, sw)

    def envelope(self, payload: str):
        """Send one ENVELOPE command to the SIM

        Args:
                payload : payload as hex string
        """
        return self._tp.send_apdu_checksw('80c20000%02x%s' % (len(payload)//2, payload))

    def terminal_profile(self, payload: str):
        """Send TERMINAL PROFILE to card

        Args:
                payload : payload as hex string
        """
        data_length = len(payload) // 2
        data, sw = self._tp.send_apdu(('80100000%02x' % data_length) + payload)
        return (data, sw)

    # ETSI TS 102 221 11.1.22
    def suspend_uicc(self, min_len_secs: int = 60, max_len_secs: int = 43200):
        """Send SUSPEND UICC to the card.

        Args:
                 min_len_secs : mimumum suspend time seconds
                 max_len_secs : maximum suspend time seconds
        """
        def encode_duration(secs: int) -> Hexstr:
            if secs >= 10*24*60*60:
                return '04%02x' % (secs // (10*24*60*60))
            elif secs >= 24*60*60:
                return '03%02x' % (secs // (24*60*60))
            elif secs >= 60*60:
                return '02%02x' % (secs // (60*60))
            elif secs >= 60:
                return '01%02x' % (secs // 60)
            else:
                return '00%02x' % secs

        def decode_duration(enc: Hexstr) -> int:
            time_unit = enc[:2]
            length = h2i(enc[2:4])
            if time_unit == '04':
                return length * 10*24*60*60
            elif time_unit == '03':
                return length * 24*60*60
            elif time_unit == '02':
                return length * 60*60
            elif time_unit == '01':
                return length * 60
            elif time_unit == '00':
                return length
            else:
                raise ValueError('Time unit must be 0x00..0x04')
        min_dur_enc = encode_duration(min_len_secs)
        max_dur_enc = encode_duration(max_len_secs)
        data, sw = self._tp.send_apdu_checksw(
            '8076000004' + min_dur_enc + max_dur_enc)
        negotiated_duration_secs = decode_duration(data[:4])
        resume_token = data[4:]
        return (negotiated_duration_secs, resume_token, sw)