k-skill/scripts/ktx_booking.py

#!/usr/bin/env python3
from __future__ import annotations

import argparse
import base64
import json
import os
import random
import re
import string
import sys
import time
from functools import reduce

try:
    from Crypto.Cipher import AES
    from Crypto.Util.Padding import pad
except ModuleNotFoundError as exc:
    AES = None
    pad = None
    _CRYPTO_IMPORT_ERROR = exc
else:
    _CRYPTO_IMPORT_ERROR = None

try:
    from korail2 import (
        AdultPassenger,
        ChildPassenger,
        Korail,
        KorailError,
        NeedToLoginError,
        NoResultsError,
        Passenger,
        ReserveOption,
        SeniorPassenger,
        SoldOutError,
        ToddlerPassenger,
        TrainType,
    )
    import korail2.korail2 as korail_mod
except ModuleNotFoundError as exc:
    _KORAIL_IMPORT_ERROR = exc

    class KorailError(Exception):
        pass

    class NeedToLoginError(KorailError):
        pass

    class NoResultsError(KorailError):
        pass

    class SoldOutError(KorailError):
        pass

    class Passenger:
        def __init__(self, count: int = 1):
            self.count = count

        @staticmethod
        def reduce(passengers):
            return passengers

        def get_dict(self, _: int) -> dict[str, str]:
            return {}

    class AdultPassenger(Passenger):
        pass

    class ChildPassenger(Passenger):
        pass

    class ToddlerPassenger(Passenger):
        pass

    class SeniorPassenger(Passenger):
        pass

    class ReserveOption:
        GENERAL_FIRST = "GENERAL_FIRST"
        GENERAL_ONLY = "GENERAL_ONLY"
        SPECIAL_FIRST = "SPECIAL_FIRST"
        SPECIAL_ONLY = "SPECIAL_ONLY"

    class TrainType:
        # Fallback constants used only when korail2 is missing so module
        # import succeeds and ensure_runtime_dependencies() can surface
        # the install message. Values mirror upstream korail2.TrainType.
        KTX = "100"
        KTX_SANCHEON = "100"
        ITX_SAEMAEUL = "101"
        SAEMAEUL = "101"
        MUGUNGHWA = "102"
        NURIRO = "102"
        TONGGUEN = "103"
        ITX_CHEONGCHUN = "104"
        AIRPORT = "105"
        ALL = "109"

    class Korail:
        def __init__(self, *args, **kwargs):
            raise ModuleNotFoundError("korail2")

    class _FallbackKorailModule:
        EMAIL_REGEX = re.compile(r".+@.+")
        PHONE_NUMBER_REGEX = re.compile(r"(\d{3})-(\d{3,4})-(\d{4})")

    korail_mod = _FallbackKorailModule()
else:
    _KORAIL_IMPORT_ERROR = None

try:
    from korail2 import NCardPassenger
    _NCARD_AVAILABLE = True
except ImportError:
    _NCARD_AVAILABLE = False

    class NCardPassenger(AdultPassenger):
        def __init__(self, count=1, card_no='', card='', card_pw='', discount_type='153'):
            AdultPassenger.__init__(self, count)
            self.card_no = card_no
            self.card = card
            self.card_pw = card_pw
            self.discount_type = discount_type

DEFAULT_USER_AGENT = "Dalvik/2.1.0 (Linux; U; Android 13; SM-S928N Build/UP1A.231005.007)"
DYNAPATH_PATHS = [
    "/classes/com.korail.mobile.certification.TicketReservation",
    "/classes/com.korail.mobile.nonMember.NonMemTicket",
    "/classes/com.korail.mobile.research.TrainResearch",
    "/classes/com.korail.mobile.research.ResidualSeatsResearch.do",
    "/classes/com.korail.mobile.seatMovie.ScheduleView",
    "/classes/com.korail.mobile.seatMovie.ScheduleViewSpecial",
    "/classes/com.korail.mobile.trn.prcFare.do",
    "/classes/com.korail.mobile.login.Login",
]
KORAIL_CARS_INFO = "https://smart.letskorail.com:443/classes/com.korail.mobile.research.TrainResearch"
KORAIL_CAR_DETAIL = "https://smart.letskorail.com:443/classes/com.korail.mobile.research.ResidualSeatsResearch.do"
RESERVE_OPTION_MAP = {
    "general-first": ReserveOption.GENERAL_FIRST,
    "general-only": ReserveOption.GENERAL_ONLY,
    "special-first": ReserveOption.SPECIAL_FIRST,
    "special-only": ReserveOption.SPECIAL_ONLY,
}
TRAIN_TYPE_MAP = {
    "ktx": TrainType.KTX,                       # 100 — KTX/KTX-산천
    "itx-saemaeul": TrainType.ITX_SAEMAEUL,     # 101 — ITX-새마을
    "mugunghwa": TrainType.MUGUNGHWA,           # 102 — 무궁화호
    "nuriro": TrainType.NURIRO,                 # 102 — 누리로
    "tonggeun": TrainType.TONGGUEN,             # 103 — 통근열차
    "itx-cheongchun": TrainType.ITX_CHEONGCHUN, # 104 — ITX-청춘
    "airport": TrainType.AIRPORT,               # 105 — 공항직통
    "all": TrainType.ALL,                       # 109 — 전체
}
TRAIN_ID_PREFIX = "ktx:v1:"
TRAIN_ID_INVALID_MESSAGE = "train_id is invalid; rerun search and copy a fresh train_id"
TRAIN_ID_STALE_MESSAGE = "train_id no longer matches any current search result; rerun search and choose a fresh train_id"
TRAIN_ID_FIELDS = (
    "train_no",
    "dep_date",
    "dep_time",
    "arr_date",
    "arr_time",
    "run_date",
    "train_group",
    "dep_code",
    "arr_code",
)

PHONE_NUMBER_DIGITS_REGEX = re.compile(r"^01\d{8,9}$")
ROOM_CLASS_MAP = {
    "general": "1",
    "special": "2",
}
ROOM_CLASS_NAME = {
    "1": "일반실",
    "2": "특실",
}
SEAT_DIRECTION_NAME = {
    "009": "순방향",
    "010": "역방향",
}
SEAT_POSITION_NAME = {
    "011": "1인",
    "012": "창측",
    "013": "내측",
}
SEAT_TYPE_NAME = {
    "015": "일반석",
    "018": "2층석",
    "019": "유아동반석",
    "021": "휠체어석",
    "023": "4인동반석",
    "027": "4인석",
    "028": "전동휠체어석",
    "032": "자전거",
    "052": "대피도우미",
}
POWER_OUTLET_ROWS = {1, 3, 5, 7, 10, 12, 14, 15}
POWER_OUTLET_DIRECT_COLUMNS = {"A", "D"}
POWER_OUTLET_ADJACENT_COLUMNS = {"B", "C"}


def is_phone_login_id(korail_id: str) -> bool:
    return bool(korail_mod.PHONE_NUMBER_REGEX.fullmatch(korail_id) or PHONE_NUMBER_DIGITS_REGEX.fullmatch(korail_id))


def ensure_runtime_dependencies() -> None:
    missing: list[str] = []
    if _KORAIL_IMPORT_ERROR is not None:
        missing.append("korail2")
    if _CRYPTO_IMPORT_ERROR is not None:
        missing.append("pycryptodome")
    if missing:
        install_command = f"python3 -m pip install {' '.join(missing)}"
        raise SystemExit(
            "scripts/ktx_booking.py requires additional Python packages "
            f"({', '.join(missing)}). Install them before running this helper: {install_command}"
        )


class DynaPathMasterEngine:
    APP_ID = "com.korail.talk"
    AS_VALUE = "%5B38ff229cb34c7dda8e28220a2d750cce%5D"
    DEVICE_MODEL = "SM-S928N"
    OS_TYPE = "Android"
    SDK_VERSION = "v1"

    def __init__(self) -> None:
        self.table = "3FE9jgRD4KdCyuawklqGJYmvfMn15P7US8XbxeLQtWT6OicBAopINs2Vh0HZrz"
        self.i8 = 161
        self.i9 = 30
        self.i10 = 2
        self.app_start_ts = str(int(time.time() * 1000))

    def string2xa1s(self, data: str) -> list[int]:
        result: list[int] = []
        idx = 0
        while idx < len(data):
            codepoint = ord(data[idx])
            idx += 1
            if codepoint < 128:
                result.append(codepoint)
            elif codepoint < 2048:
                result.append(128 | ((codepoint >> 7) & 15))
                result.append(codepoint & 127)
            elif codepoint >= 262144:
                result.append(160)
                result.append((codepoint >> 14) & 127)
                result.append((codepoint >> 7) & 127)
                result.append(codepoint & 127)
            elif (63488 & codepoint) != 55296:
                result.append(((codepoint >> 14) & 15) | 144)
                result.append((codepoint >> 7) & 127)
                result.append(codepoint & 127)
        return result

    def make_key(self, key: str) -> int:
        total = 0
        for char in key:
            codepoint = ord(char)
            bit = 32768
            for _ in range(16):
                if bit & codepoint:
                    break
                bit >>= 1
            total = (total * (bit << 1)) + codepoint
        return total

    def internal_char(self, base_table: str, remainder: int, current: str) -> str:
        seen = 0
        for char in base_table:
            if char in current:
                continue
            if seen == remainder:
                return char
            seen += 1
        return " "

    def make_encode_table(self, number: int, encode_size: int, base_table: str) -> str:
        chars = ""
        temp = number
        for index in range(encode_size):
            divisor = encode_size - index
            remainder = temp % divisor
            chars += self.internal_char(base_table, remainder, chars)
            temp //= divisor
        return chars

    def encode_normal_be(self, data: str, table: str) -> str:
        values = self.string2xa1s(data)
        output: list[str] = []
        digits = [0] * (self.i10 + 1)
        idx = 0
        tail = len(values) % self.i10
        body_size = len(values) - tail
        while idx < body_size:
            value = 0
            for _ in range(self.i10):
                value = (value * self.i8) + values[idx]
                idx += 1
            for digit_index in range(self.i10 + 1):
                digits[digit_index] = value % self.i9
                value //= self.i9
            for digit_index in range(self.i10, -1, -1):
                output.append(table[digits[digit_index]])
        if tail > 0:
            value = 0
            for _ in range(tail):
                value = (value * self.i8) + values[idx]
                idx += 1
            for digit_index in range(tail + 1):
                digits[digit_index] = value % self.i9
                value //= self.i9
            while tail >= 0:
                output.append(table[digits[tail]])
                tail -= 1
        return "".join(output)

    def generate_token(self, device_id: str, timestamp_ms: int, nonce: str) -> str:
        plaintext = (
            f"ai={self.APP_ID}&di={device_id}&as={self.AS_VALUE}&su=false&dbg=false&emu=false&hk=false"
            f"&it={self.app_start_ts}&ts={timestamp_ms}&rt=0&os=13&dm={self.DEVICE_MODEL}&st={self.OS_TYPE}&sv={self.SDK_VERSION}"
        )
        dyn_key = f"v1+{nonce}+{timestamp_ms}"
        key_encoded = self.encode_normal_be(dyn_key, self.table)
        table = self.make_encode_table(self.make_key(dyn_key), self.i9, self.table)
        body_encoded = self.encode_normal_be(plaintext, table)
        return f"bEeEP{self.table[len(key_encoded)]}{key_encoded}{body_encoded}"


class PatchedKorail(Korail):
    _device = "AD"
    _version = "250601002"
    _sid_key = b"2485dd54d9deaa36"
    _device_id = "558a4f02041657ea"

    def __init__(self, korail_id: str, korail_pw: str, auto_login: bool = True, want_feedback: bool = False):
        import requests

        self._session = requests.session()
        self._session.headers.update({"User-Agent": DEFAULT_USER_AGENT})
        self._engine = DynaPathMasterEngine()
        super().__init__(korail_id, korail_pw, auto_login=False, want_feedback=want_feedback)
        self._session.headers.update({"User-Agent": DEFAULT_USER_AGENT})
        if auto_login:
            self.login(korail_id, korail_pw)

    def _generate_sid(self, timestamp_ms: int) -> str:
        ensure_runtime_dependencies()
        plaintext = f"{self._device}{timestamp_ms}".encode("utf-8")
        cipher = AES.new(self._sid_key, AES.MODE_CBC, iv=self._sid_key)
        return base64.b64encode(cipher.encrypt(pad(plaintext, 16))).decode("utf-8") + "\n"

    def _auth_headers_and_sid(self, url: str) -> tuple[dict[str, str], str | None]:
        headers: dict[str, str] = {}
        sid = None
        if any(path in url for path in DYNAPATH_PATHS):
            timestamp_ms = int(time.time() * 1000)
            nonce = "".join(random.choices(string.ascii_uppercase + string.digits, k=4))
            headers["x-dynapath-m-token"] = self._engine.generate_token(self._device_id, timestamp_ms, nonce)
            sid = self._generate_sid(timestamp_ms)
        return headers, sid

    def login(self, korail_id: str | None = None, korail_pw: str | None = None) -> bool:
        if korail_id is None:
            korail_id = self.korail_id
        else:
            self.korail_id = korail_id

        if korail_pw is None:
            korail_pw = self.korail_pw
        else:
            self.korail_pw = korail_pw

        if korail_mod.EMAIL_REGEX.match(korail_id):
            input_flag = "5"
        elif is_phone_login_id(korail_id):
            input_flag = "4"
        else:
            input_flag = "2"

        headers, sid = self._auth_headers_and_sid(korail_mod.KORAIL_LOGIN)
        payload = {
            "Device": self._device,
            "Version": self._version,
            "txtInputFlg": input_flag,
            "txtMemberNo": korail_id,
            "txtPwd": self._Korail__enc_password(korail_pw),
            "idx": self._idx,
        }
        if sid:
            payload["Sid"] = sid

        response = self._session.post(korail_mod.KORAIL_LOGIN, data=payload, headers=headers)
        data = json.loads(response.text)
        if data["strResult"] == "SUCC" and data.get("strMbCrdNo") is not None:
            self._key = data["Key"]
            self.membership_number = data["strMbCrdNo"]
            self.name = data["strCustNm"]
            self.email = data["strEmailAdr"]
            self.logined = True
            return True

        self.logined = False
        return False

    def search_train_details(
        self,
        dep: str,
        arr: str,
        date: str | None = None,
        time_value: str | None = None,
        train_type: str = TrainType.ALL,
        passengers: list[Passenger] | None = None,
        include_no_seats: bool = False,
        include_waiting_list: bool = False,
    ):
        kst_now = korail_mod.datetime.now(korail_mod.timezone.utc) + korail_mod.timedelta(hours=9)
        if date is None:
            date = kst_now.strftime("%Y%m%d")
        if time_value is None:
            time_value = kst_now.strftime("%H%M%S")
        if passengers is None:
            passengers = [AdultPassenger()]

        passengers = Passenger.reduce(passengers)
        adult_count = reduce(lambda total, passenger: total + passenger.count, [p for p in passengers if isinstance(p, AdultPassenger)], 0)
        child_count = reduce(lambda total, passenger: total + passenger.count, [p for p in passengers if isinstance(p, ChildPassenger)], 0)
        toddler_count = reduce(
            lambda total, passenger: total + passenger.count,
            [p for p in passengers if isinstance(p, ToddlerPassenger)],
            0,
        )
        senior_count = reduce(lambda total, passenger: total + passenger.count, [p for p in passengers if isinstance(p, SeniorPassenger)], 0)

        headers, sid = self._auth_headers_and_sid(korail_mod.KORAIL_SEARCH_SCHEDULE)
        payload = {
            "Device": self._device,
            "radJobId": "1",
            "selGoTrain": train_type,
            "txtCardPsgCnt": "0",
            "txtGdNo": "",
            "txtGoAbrdDt": date,
            "txtGoEnd": arr,
            "txtGoHour": time_value,
            "txtGoStart": dep,
            "txtJobDv": "",
            "txtMenuId": "11",
            "txtPsgFlg_1": adult_count,
            "txtPsgFlg_2": child_count,
            "txtPsgFlg_8": toddler_count,
            "txtPsgFlg_3": senior_count,
            "txtPsgFlg_4": "0",
            "txtPsgFlg_5": "0",
            "txtSeatAttCd_2": "000",
            "txtSeatAttCd_3": "000",
            "txtSeatAttCd_4": "015",
            "txtTrnGpCd": train_type,
            "Version": self._version,
        }
        if sid:
            payload["Sid"] = sid

        response = self._session.post(korail_mod.KORAIL_SEARCH_SCHEDULE, params=payload, headers=headers)
        data = json.loads(response.text)
        if self._result_check(data):
            train_infos = data["trn_infos"]["trn_info"]
            if isinstance(train_infos, dict):
                train_infos = [train_infos]
            details = [(korail_mod.Train(info), info) for info in train_infos]
            details = [(train, info) for train, info in details if train.dep_name == dep and train.arr_name == arr]
            filters = [lambda train: train.has_seat()]
            if include_no_seats:
                filters.append(lambda train: not train.has_seat())
            if include_waiting_list:
                filters.append(lambda train: train.has_waiting_list())
            details = [(train, info) for train, info in details if any(check(train) for check in filters)]
            if not details:
                raise NoResultsError()
            return details

    def search_train(
        self,
        dep: str,
        arr: str,
        date: str | None = None,
        time_value: str | None = None,
        train_type: str = TrainType.ALL,
        passengers: list[Passenger] | None = None,
        include_no_seats: bool = False,
        include_waiting_list: bool = False,
    ):
        return [
            train
            for train, _ in self.search_train_details(
                dep,
                arr,
                date,
                time_value,
                train_type=train_type,
                passengers=passengers,
                include_no_seats=include_no_seats,
                include_waiting_list=include_waiting_list,
            )
        ]

    def train_cars(self, raw_train: dict[str, object], passenger_count: int = 1, room_class: str = "1") -> list[dict[str, object]]:
        payload = self._seat_lookup_payload(raw_train, passenger_count, room_class)
        headers, sid = self._auth_headers_and_sid(KORAIL_CARS_INFO)
        if sid:
            payload["Sid"] = sid
        response = self._session.post(KORAIL_CARS_INFO, data=payload, headers=headers)
        data = json.loads(response.text)
        if self._result_check(data):
            cars = data.get("srcar_infos", {}).get("srcar_info", [])
            if isinstance(cars, dict):
                cars = [cars]
            return cars
        return []

    def car_seats(
        self,
        raw_train: dict[str, object],
        car_no: str,
        passenger_count: int = 1,
        room_class: str = "1",
    ) -> dict[str, object]:
        payload = self._seat_lookup_payload(raw_train, passenger_count, room_class)
        payload["txtSrcarNo"] = car_no
        headers, sid = self._auth_headers_and_sid(KORAIL_CAR_DETAIL)
        if sid:
            payload["Sid"] = sid
        response = self._session.post(KORAIL_CAR_DETAIL, data=payload, headers=headers)
        data = json.loads(response.text)
        if self._result_check(data):
            return data
        return {}

    def _seat_lookup_payload(self, raw_train: dict[str, object], passenger_count: int, room_class: str) -> dict[str, object]:
        return {
            "Device": self._device,
            "Version": self._version,
            "Key": self._key,
            "txtArvRsStnCd": raw_train.get("h_arv_rs_stn_cd", ""),
            "txtArvStnRunOrdr": raw_train.get("h_arv_stn_run_ordr", ""),
            "txtDptDt": raw_train.get("h_dpt_dt", ""),
            "txtDptRsStnCd": raw_train.get("h_dpt_rs_stn_cd", ""),
            "txtDptStnRunOrdr": raw_train.get("h_dpt_stn_run_ordr", ""),
            "txtGdNo": "",
            "txtMenuId": "11",
            "txtPsrmClCd": room_class,
            "txtRunDt": raw_train.get("h_run_dt", ""),
            "txtSeatAttCd": "015",
            "txtTotPsgCnt": str(passenger_count),
            "txtTrnClsfCd": raw_train.get("h_trn_clsf_cd", ""),
            "txtTrnGpCd": raw_train.get("h_trn_gp_cd", ""),
            "txtTrnNo": raw_train.get("h_trn_no", ""),
        }

    def reserve(self, train, passengers=None, option=ReserveOption.GENERAL_FIRST, try_waiting=False):
        reserving_seat = True
        try:
            if not train.has_seat():
                raise SoldOutError()
            if option == ReserveOption.GENERAL_ONLY:
                if train.has_general_seat():
                    seat_type = "1"
                else:
                    raise SoldOutError()
            elif option == ReserveOption.SPECIAL_ONLY:
                if train.has_special_seat():
                    seat_type = "2"
                else:
                    raise SoldOutError()
            elif option == ReserveOption.GENERAL_FIRST:
                seat_type = "1" if train.has_general_seat() else "2"
            elif option == ReserveOption.SPECIAL_FIRST:
                seat_type = "2" if train.has_special_seat() else "1"
            else:
                raise ValueError(f"unsupported reserve option: {option}")
        except SoldOutError:
            if try_waiting and option != ReserveOption.SPECIAL_ONLY and train.has_general_waiting_list():
                reserving_seat = False
                seat_type = "1"
            else:
                raise

        if passengers is None:
            passengers = [AdultPassenger()]

        passengers = Passenger.reduce(passengers)
        passenger_count = reduce(lambda total, passenger: total + passenger.count, passengers, 0)
        headers, sid = self._auth_headers_and_sid(korail_mod.KORAIL_TICKETRESERVATION)
        payload = {
            "Device": self._device,
            "Version": self._version,
            "Key": self._key,
            "txtGdNo": "",
            "txtJobId": "1101" if reserving_seat else "1102",
            "txtTotPsgCnt": passenger_count,
            "txtSeatAttCd1": "000",
            "txtSeatAttCd2": "000",
            "txtSeatAttCd3": "000",
            "txtSeatAttCd4": "015",
            "txtSeatAttCd5": "000",
            "hidFreeFlg": "N",
            "txtStndFlg": "N",
            "txtMenuId": "11",
            "txtSrcarCnt": "0",
            "txtJrnyCnt": "1",
            "txtJrnySqno1": "001",
            "txtJrnyTpCd1": "11",
            "txtDptDt1": train.dep_date,
            "txtDptRsStnCd1": train.dep_code,
            "txtDptTm1": train.dep_time,
            "txtArvRsStnCd1": train.arr_code,
            "txtTrnNo1": train.train_no,
            "txtRunDt1": train.run_date,
            "txtTrnClsfCd1": train.train_type,
            "txtPsrmClCd1": seat_type,
            "txtTrnGpCd1": train.train_group,
            "txtChgFlg1": "",
            "txtJrnySqno2": "",
            "txtJrnyTpCd2": "",
            "txtDptDt2": "",
            "txtDptRsStnCd2": "",
            "txtDptTm2": "",
            "txtArvRsStnCd2": "",
            "txtTrnNo2": "",
            "txtRunDt2": "",
            "txtTrnClsfCd2": "",
            "txtPsrmClCd2": "",
            "txtChgFlg2": "",
        }
        if sid:
            payload["Sid"] = sid

        for index, passenger in enumerate(passengers, start=1):
            payload.update(passenger.get_dict(index))

        response = self._session.get(korail_mod.KORAIL_TICKETRESERVATION, params=payload, headers=headers)
        data = json.loads(response.text)
        if self._result_check(data):
            reservation_id = data["h_pnr_no"]
            matches = [reservation for reservation in self.reservations() if reservation.rsv_id == reservation_id]
            if len(matches) == 1:
                return matches[0]
            raise KorailError(f"reservation {reservation_id} was created but could not be reloaded")

    def reservations(self):
        payload = {"Device": self._device, "Version": self._version, "Key": self._key}
        response = self._session.get(korail_mod.KORAIL_MYRESERVATIONLIST, params=payload)
        data = json.loads(response.text)
        try:
            if self._result_check(data):
                return [
                    korail_mod.Reservation(train_info)
                    for journey in data["jrny_infos"]["jrny_info"]
                    for train_info in journey["train_infos"]["train_info"]
                ]
        except NoResultsError:
            return []
        return []

    def cancel(self, reservation):
        assert isinstance(reservation, korail_mod.Reservation)
        payload = {
            "Device": self._device,
            "Version": self._version,
            "Key": self._key,
            "txtPnrNo": reservation.rsv_id,
            "txtJrnySqno": reservation.journey_no,
            "txtJrnyCnt": reservation.journey_cnt,
            "hidRsvChgNo": reservation.rsv_chg_no,
        }
        response = self._session.get(korail_mod.KORAIL_CANCEL, params=payload)
        data = json.loads(response.text)
        if self._result_check(data):
            return True
        return False


def parse_passengers(args: argparse.Namespace) -> list[Passenger]:
    passengers: list[Passenger] = []
    if args.adults:
        passengers.append(AdultPassenger(args.adults))
    if args.children:
        passengers.append(ChildPassenger(args.children))
    if args.toddlers:
        passengers.append(ToddlerPassenger(args.toddlers))
    if args.seniors:
        passengers.append(SeniorPassenger(args.seniors))
    if not passengers:
        passengers.append(AdultPassenger())
    return passengers


def build_train_id_payload(train) -> dict[str, str]:
    return {field: getattr(train, field) for field in TRAIN_ID_FIELDS}


def build_train_id(train) -> str:
    payload = json.dumps(build_train_id_payload(train), ensure_ascii=False, separators=(",", ":")).encode("utf-8")
    encoded = base64.urlsafe_b64encode(payload).decode("ascii").rstrip("=")
    return f"{TRAIN_ID_PREFIX}{encoded}"


def parse_train_id(train_id: str) -> dict[str, str]:
    if not train_id.startswith(TRAIN_ID_PREFIX):
        raise SystemExit("train_id must start with ktx:v1:")
    encoded = train_id.removeprefix(TRAIN_ID_PREFIX)
    padded = encoded + ("=" * ((4 - len(encoded) % 4) % 4))
    try:
        payload = json.loads(base64.urlsafe_b64decode(padded.encode("ascii")).decode("utf-8"))
    except (ValueError, json.JSONDecodeError, UnicodeDecodeError) as exc:
        raise SystemExit(TRAIN_ID_INVALID_MESSAGE) from exc
    if not isinstance(payload, dict):
        raise SystemExit(TRAIN_ID_INVALID_MESSAGE)
    invalid_fields = [field for field in TRAIN_ID_FIELDS if not isinstance(payload.get(field), str) or not payload[field]]
    if invalid_fields:
        raise SystemExit(TRAIN_ID_INVALID_MESSAGE)
    return {field: payload[field] for field in TRAIN_ID_FIELDS}


def find_train_by_id(trains, train_id: str):
    expected = parse_train_id(train_id)
    for train in trains:
        if build_train_id_payload(train) == expected:
            return train
    return None


def find_train_detail_by_id(details, train_id: str):
    expected = parse_train_id(train_id)
    for train, raw_train in details:
        if build_train_id_payload(train) == expected:
            return train, raw_train
    return None


def normalize_train(train, index: int) -> dict[str, object]:
    return {
        "index": index,
        "train_id": build_train_id(train),
        "train_no": train.train_no,
        "train_type": train.train_type_name,
        "dep_name": train.dep_name,
        "dep_date": train.dep_date,
        "dep_time": train.dep_time,
        "arr_name": train.arr_name,
        "arr_date": train.arr_date,
        "arr_time": train.arr_time,
        "has_general_seat": train.has_general_seat(),
        "has_special_seat": train.has_special_seat(),
        "has_waiting_list": train.has_waiting_list(),
        "description": str(train),
    }


def parse_seat_label(seat_label: str) -> tuple[int | None, str]:
    match = re.match(r"^(\d+)([A-Za-z])$", seat_label or "")
    if not match:
        return None, ""
    return int(match.group(1)), match.group(2).upper()


def power_outlet_match(seat_label: str) -> str:
    row, column = parse_seat_label(seat_label)
    if row not in POWER_OUTLET_ROWS:
        return "none"
    if column in POWER_OUTLET_DIRECT_COLUMNS:
        return "direct"
    if column in POWER_OUTLET_ADJACENT_COLUMNS:
        return "adjacent"
    return "none"


def normalize_seat(raw_seat: dict[str, object]) -> dict[str, object]:
    seat_label = str(raw_seat.get("h_con_seat_no", ""))
    return {
        "seat": seat_label,
        "seat_no": str(raw_seat.get("h_seat_no", "")),
        "available": raw_seat.get("h_sale_psb_flg") == "Y",
        "direction": SEAT_DIRECTION_NAME.get(str(raw_seat.get("h_for_rev_dir_dv", "")), str(raw_seat.get("h_for_rev_dir_dv", ""))),
        "position": SEAT_POSITION_NAME.get(str(raw_seat.get("h_sigl_win_in_dv", "")), str(raw_seat.get("h_sigl_win_in_dv", ""))),
        "seat_type": SEAT_TYPE_NAME.get(str(raw_seat.get("h_dmd_seat_att", "")), str(raw_seat.get("h_dmd_seat_att", ""))),
        "near_door": raw_seat.get("h_door_nbor_flg") == "Y",
        "power_outlet": power_outlet_match(seat_label),
    }


def validate_raw_seat(raw_seat: dict[str, object]) -> None:
    required_fields = ("h_con_seat_no", "h_seat_no", "h_sale_psb_flg")
    if any(raw_seat.get(field) in (None, "") for field in required_fields):
        raise ValueError("seat row is missing required fields")


def parse_nonnegative_int_field(raw: object, field_name: str) -> int:
    text = "" if raw is None else str(raw)
    if not text.isdigit():
        raise ValueError(f"{field_name} is not a non-negative integer")
    return int(text)


def normalize_car(raw_car: object) -> dict[str, object]:
    if not isinstance(raw_car, dict):
        raise ValueError("car row is not an object")
    return {
        "car_no": parse_nonnegative_int_field(raw_car.get("h_srcar_no"), "h_srcar_no"),
        "car_no_raw": str(raw_car.get("h_srcar_no", "")),
        "room_class": ROOM_CLASS_NAME.get(str(raw_car.get("h_psrm_cl_cd", "")), str(raw_car.get("h_psrm_cl_nm", ""))),
        "room_class_code": str(raw_car.get("h_psrm_cl_cd", "")),
        "total_seats": parse_nonnegative_int_field(raw_car.get("h_seat_cnt"), "h_seat_cnt"),
        "remaining_seats": parse_nonnegative_int_field(raw_car.get("h_rest_seat_cnt"), "h_rest_seat_cnt"),
    }


def car_center_priority(car: dict[str, object], car_numbers: list[int]) -> tuple[float, int]:
    car_no = int(car["car_no"])
    if not car_numbers:
        return (0.0, car_no)
    center = (min(car_numbers) + max(car_numbers)) / 2
    return (abs(car_no - center), car_no)


def sort_cars_for_booking(cars: list[dict[str, object]]) -> list[dict[str, object]]:
    car_numbers = [int(car["car_no"]) for car in cars]
    return sorted(cars, key=lambda car: car_center_priority(car, car_numbers))


def seat_preference_key(seat: dict[str, object]) -> tuple[int, int, int, str]:
    power_rank = {"direct": 0, "adjacent": 1, "none": 2}.get(str(seat.get("power_outlet")), 2)
    direction_rank = 0 if seat.get("direction") == "순방향" else 1
    row, column = parse_seat_label(str(seat.get("seat", "")))
    return (power_rank, direction_rank, row if row is not None else 999, column)


def sort_seats_for_booking(seats: list[dict[str, object]]) -> list[dict[str, object]]:
    return sorted(seats, key=seat_preference_key)


def mask_identifier(value: object, visible: int = 4) -> str:
    text = str(value or "")
    if not text:
        return ""
    if len(text) <= visible:
        return "*" * len(text)
    return f"{'*' * (len(text) - visible)}{text[-visible:]}"


def normalize_reservation(reservation) -> dict[str, object]:
    return {
        "reservation_id": reservation.rsv_id,
        "train_no": reservation.train_no,
        "train_type": reservation.train_type_name,
        "dep_name": reservation.dep_name,
        "dep_date": reservation.dep_date,
        "dep_time": reservation.dep_time,
        "arr_name": reservation.arr_name,
        "arr_date": reservation.arr_date,
        "arr_time": reservation.arr_time,
        "seat_count": reservation.seat_no_count,
        "price": reservation.price,
        "buy_limit_date": reservation.buy_limit_date,
        "buy_limit_time": reservation.buy_limit_time,
        "journey_no": reservation.journey_no,
        "journey_cnt": reservation.journey_cnt,
        "rsv_chg_no": reservation.rsv_chg_no,
        "description": str(reservation),
    }


def print_json(payload: dict[str, object]) -> None:
    print(json.dumps(payload, ensure_ascii=False, indent=2))


def build_client() -> PatchedKorail:
    ensure_runtime_dependencies()
    korail_id = os.environ.get("KSKILL_KTX_ID")
    korail_pw = os.environ.get("KSKILL_KTX_PASSWORD")
    if not korail_id or not korail_pw:
        raise SystemExit(
            "이 작업에는 KSKILL_KTX_ID, KSKILL_KTX_PASSWORD 환경변수가 필요합니다. "
            "환경변수가 설정되어 있지 않으면 ~/.config/k-skill/secrets.env 에 추가하거나 "
            "에이전트의 secret vault에서 주입해 주세요."
        )
    client = PatchedKorail(korail_id, korail_pw)
    if not client.logined:
        raise NeedToLoginError()
    return client


def command_search(args: argparse.Namespace) -> None:
    client = build_client()
    passengers = parse_passengers(args)
    trains = client.search_train(
        args.dep,
        args.arr,
        args.date,
        args.time,
        train_type=TRAIN_TYPE_MAP[args.train_type],
        passengers=passengers,
        include_no_seats=args.include_no_seats,
        include_waiting_list=args.include_waiting_list,
    )
    visible_trains = trains[: args.limit]
    print_json({
        "count": len(visible_trains),
        "trains": [normalize_train(train, index) for index, train in enumerate(visible_trains, start=1)],
    })


def command_seats(args: argparse.Namespace) -> None:
    client = build_client()
    passengers = parse_passengers(args)
    passenger_count = sum(passenger.count for passenger in Passenger.reduce(passengers))
    details = client.search_train_details(
        args.dep,
        args.arr,
        args.date,
        args.time,
        train_type=TRAIN_TYPE_MAP[args.train_type],
        passengers=passengers,
        include_no_seats=True,
        include_waiting_list=True,
    )
    match = find_train_detail_by_id(details, args.train_id)
    if match is None:
        raise SystemExit(TRAIN_ID_STALE_MESSAGE)

    train, raw_train = match
    room_class = ROOM_CLASS_MAP[args.room]
    seat_car_unavailable = f"seat car data is unavailable for {args.room}; retry search or choose another train"
    try:
        cars = [normalize_car(car) for car in client.train_cars(raw_train, passenger_count, room_class)]
    except (TypeError, ValueError, AttributeError) as exc:
        raise SystemExit(seat_car_unavailable) from exc
    if not cars:
        raise SystemExit(seat_car_unavailable)
    if args.car_no is not None:
        cars = [car for car in cars if car["car_no"] == args.car_no]
        if not cars:
            raise SystemExit(f"car_no {args.car_no} is not available for {args.room}")
    else:
        cars = sort_cars_for_booking(cars)

    car_payloads: list[dict[str, object]] = []
    for car in cars:
        raw = client.car_seats(raw_train, str(car["car_no_raw"]), passenger_count, room_class)
        seat_infos = raw.get("seat_infos") if isinstance(raw, dict) else None
        seat_detail_unavailable = (
            f"seat detail data is unavailable for car_no {car['car_no']}; "
            "retry search or choose another train"
        )
        if not isinstance(seat_infos, dict):
            raise SystemExit(seat_detail_unavailable)
        if "seat_info" not in seat_infos:
            raise SystemExit(seat_detail_unavailable)
        raw_seats = seat_infos["seat_info"]
        if isinstance(raw_seats, dict):
            raw_seats = [raw_seats]
        if not isinstance(raw_seats, list):
            raise SystemExit(seat_detail_unavailable)
        if any(not isinstance(seat, dict) for seat in raw_seats):
            raise SystemExit(seat_detail_unavailable)
        try:
            for raw_seat in raw_seats:
                validate_raw_seat(raw_seat)
        except ValueError as exc:
            raise SystemExit(seat_detail_unavailable) from exc
        remaining_seats = car["remaining_seats"]
        if not isinstance(remaining_seats, int):
            raise SystemExit(seat_detail_unavailable)
        if not raw_seats and remaining_seats > 0:
            raise SystemExit(seat_detail_unavailable)
        all_seats = [normalize_seat(seat) for seat in raw_seats if seat.get("h_con_seat_no") != "0A"]
        if not all_seats and remaining_seats > 0:
            raise SystemExit(seat_detail_unavailable)
        seats = sort_seats_for_booking(all_seats)
        if args.available_only:
            seats = [seat for seat in seats if seat["available"]]
        if args.power_only:
            seats = [seat for seat in seats if seat["power_outlet"] != "none"]
        available_seats = [seat for seat in seats if seat["available"]]
        seats = seats[: args.limit]
        car_payload = dict(car)
        car_payload["available_seat_count"] = len(available_seats)
        car_payload["available_seats"] = [seat["seat"] for seat in available_seats]
        car_payload["shown_seat_count"] = len(seats)
        car_payload["seats"] = seats
        car_payloads.append(car_payload)

    print_json({
        "train": normalize_train(train, 1),
        "room": args.room,
        "passenger_count": passenger_count,
        "available_only": args.available_only,
        "power_only": args.power_only,
        "cars": car_payloads,
    })


def ensure_ncard_available() -> None:
    if not _NCARD_AVAILABLE:
        raise SystemExit(
            "N카드 기능을 사용하려면 korail2-ncard 패키지가 필요합니다: "
            "pip install korail2-ncard pycryptodome"
        )


def resolve_ncard_no(client: PatchedKorail, ncard_index: int | None, ncard_no: str | None) -> str | None:
    if ncard_index is None and not ncard_no:
        return None
    ensure_ncard_available()
    if ncard_index is None:
        return ncard_no
    ncards = client.owned_ncards()
    if not ncards:
        raise SystemExit("보유한 N카드가 없습니다.")
    if ncard_index < 1 or ncard_index > len(ncards):
        raise SystemExit(f"ncard-index는 1~{len(ncards)} 사이여야 합니다.")
    selected = ncards[ncard_index - 1]
    selected_no = getattr(selected, "discount_card_no", None)
    if not selected_no:
        raise SystemExit("선택한 N카드에서 카드 번호를 확인할 수 없습니다.")
    return selected_no


def command_reserve(args: argparse.Namespace) -> None:
    client = build_client()
    ncard_no = resolve_ncard_no(
        client,
        getattr(args, "ncard_index", None),
        getattr(args, "ncard_no", None),
    )
    if ncard_no:
        passengers = [NCardPassenger(card_no=ncard_no)]
    else:
        passengers = parse_passengers(args)
    include_waiting_list = args.include_waiting_list or args.try_waiting
    trains = client.search_train(
        args.dep,
        args.arr,
        args.date,
        args.time,
        train_type=TRAIN_TYPE_MAP[args.train_type],
        passengers=passengers,
        include_no_seats=args.include_no_seats,
        include_waiting_list=include_waiting_list,
    )
    selected_train = find_train_by_id(trains, args.train_id)
    if selected_train is None:
        raise SystemExit(TRAIN_ID_STALE_MESSAGE)
    reservation = client.reserve(
        selected_train,
        passengers=passengers,
        option=RESERVE_OPTION_MAP[args.seat_option],
        try_waiting=args.try_waiting,
    )
    print_json({"reservation": normalize_reservation(reservation)})


def command_reservations(_: argparse.Namespace) -> None:
    client = build_client()
    reservations = client.reservations()
    print_json({
        "count": len(reservations),
        "reservations": [normalize_reservation(reservation) for reservation in reservations],
    })


def normalize_ncard(ncard, index: int) -> dict[str, object]:
    return {
        "index": index,
        "card_no": mask_identifier(getattr(ncard, "discount_card_no", "")),
        "card_no_masked": True,
        "ticket_kind": ncard.ticket_kind_name or "",
        "dep_name": ncard.dep_name or "",
        "arr_name": ncard.arr_name or "",
        "valid": ncard.valid or "",
        "description": str(ncard),
    }


def normalize_ncard_train(train, index: int) -> dict[str, object]:
    base = normalize_train(train, index)
    base["price"] = getattr(train, "price", None)
    base["discount_name"] = getattr(train, "discount_name", None)
    base["general_remaining_seats"] = getattr(train, "general_remaining_seats", None)
    base["standing_remaining_seats"] = getattr(train, "standing_remaining_seats", None)
    return base


def command_ncard_list(args: argparse.Namespace) -> None:
    ensure_ncard_available()
    client = build_client()
    ncards = client.owned_ncards()
    print_json({
        "count": len(ncards),
        "ncards": [normalize_ncard(ncard, index) for index, ncard in enumerate(ncards, start=1)],
    })


def command_ncard_search(args: argparse.Namespace) -> None:
    ensure_ncard_available()
    client = build_client()
    ncards = client.owned_ncards()
    if not ncards:
        raise SystemExit("보유한 N카드가 없습니다.")
    if args.ncard_index < 1 or args.ncard_index > len(ncards):
        raise SystemExit(f"ncard-index는 1~{len(ncards)} 사이여야 합니다.")
    ncard = ncards[args.ncard_index - 1]
    trains = client.search_owned_ncard_trains(
        ncard,
        dep=args.dep,
        arr=args.arr,
        date=args.date,
        time=args.time,
        train_type=TRAIN_TYPE_MAP[args.train_type],
    )
    visible_trains = trains[: args.limit]
    print_json({
        "count": len(visible_trains),
        "ncard": normalize_ncard(ncard, args.ncard_index),
        "trains": [normalize_ncard_train(train, index) for index, train in enumerate(visible_trains, start=1)],
    })


def command_cancel(args: argparse.Namespace) -> None:
    client = build_client()
    reservations = client.reservations()
    match = next((reservation for reservation in reservations if reservation.rsv_id == args.reservation_id), None)
    if match is None:
        raise SystemExit(f"reservation {args.reservation_id} not found")
    client.cancel(match)
    print_json({"cancelled": True, "reservation_id": args.reservation_id})


def add_common_trip_args(parser: argparse.ArgumentParser) -> None:
    parser.add_argument("dep", help="출발역")
    parser.add_argument("arr", help="도착역")
    parser.add_argument("date", help="출발일 YYYYMMDD")
    parser.add_argument("time", help="희망 시작 시각 HHMMSS")
    parser.add_argument("--adults", type=int, default=1, help="성인 수")
    parser.add_argument("--children", type=int, default=0, help="어린이 수")
    parser.add_argument("--toddlers", type=int, default=0, help="유아 수")
    parser.add_argument("--seniors", type=int, default=0, help="경로 수")


def build_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(description="Patched KTX/Korail booking helper for k-skill")
    subparsers = parser.add_subparsers(dest="command", required=True)

    search_parser = subparsers.add_parser("search", help="KTX/Korail 열차를 조회합니다")
    add_common_trip_args(search_parser)
    search_parser.add_argument("--limit", type=int, default=5, help="출력할 최대 열차 수")
    search_parser.add_argument(
        "--train-type",
        choices=sorted(TRAIN_TYPE_MAP),
        default="ktx",
        help="조회할 열차 종류 (기본 ktx). ITX-청춘 노선은 itx-cheongchun, 무궁화는 mugunghwa, 전체는 all 사용",
    )
    search_parser.add_argument("--include-no-seats", action="store_true", help="매진 열차도 포함")
    search_parser.add_argument("--include-waiting-list", action="store_true", help="예약 대기 가능 열차도 포함")
    search_parser.set_defaults(func=command_search)

    seats_parser = subparsers.add_parser("seats", help="조회 결과 중 하나의 호차별 좌석번호를 조회합니다")
    add_common_trip_args(seats_parser)
    seats_parser.add_argument("--train-id", required=True, help="search 결과에서 복사한 stable train_id")
    seats_parser.add_argument(
        "--room",
        choices=sorted(ROOM_CLASS_MAP),
        default="general",
        help="좌석을 조회할 객실 등급 (기본 general)",
    )
    seats_parser.add_argument(
        "--train-type",
        choices=sorted(TRAIN_TYPE_MAP),
        default="ktx",
        help="재조회할 열차 종류 — search 단계에서 사용한 값과 동일하게 지정 (기본 ktx)",
    )
    seats_parser.add_argument("--car-no", type=int, default=None, help="특정 호차만 조회")
    seats_parser.add_argument(
        "--available-only",
        "--remaining-only",
        dest="available_only",
        action="store_true",
        help="예약 가능한/남은 좌석만 출력",
    )
    seats_parser.add_argument("--power-only", action="store_true", help="콘센트 꿀팁 좌석(direct/adjacent)만 출력")
    seats_parser.add_argument("--limit", type=int, default=100, help="호차별 출력할 최대 좌석 수")
    seats_parser.set_defaults(func=command_seats)

    reserve_parser = subparsers.add_parser("reserve", help="조회 결과 중 하나를 예약합니다")
    add_common_trip_args(reserve_parser)
    reserve_parser.add_argument("--train-id", required=True, help="search 결과에서 복사한 stable train_id")
    reserve_parser.add_argument("--seat-option", choices=sorted(RESERVE_OPTION_MAP), default="general-first")
    reserve_parser.add_argument(
        "--train-type",
        choices=sorted(TRAIN_TYPE_MAP),
        default="ktx",
        help="재조회할 열차 종류 — search 단계에서 사용한 값과 동일하게 지정 (기본 ktx)",
    )
    reserve_parser.add_argument("--include-no-seats", action="store_true", help="검색 시 매진 열차도 포함")
    reserve_parser.add_argument("--include-waiting-list", action="store_true", help="검색 시 예약대기 열차도 포함")
    reserve_parser.add_argument(
        "--try-waiting",
        action="store_true",
        help="좌석이 없으면 예약대기를 시도 (reserve 재조회 시 예약대기 열차 자동 포함)",
    )
    reserve_parser.add_argument(
        "--ncard-index",
        type=int,
        metavar="N",
        default=None,
        help="ncard-list 결과의 N카드 순번 (권장). 지정하면 N카드 할인 승객으로 예약",
    )
    reserve_parser.add_argument(
        "--ncard-no",
        metavar="CARD_NO",
        default=None,
        help="N카드 번호 직접 입력 (비권장: 셸 히스토리에 남을 수 있음)",
    )
    reserve_parser.set_defaults(func=command_reserve)

    ncard_list_parser = subparsers.add_parser("ncard-list", help="보유한 N카드 목록을 조회합니다")
    ncard_list_parser.set_defaults(func=command_ncard_list)

    ncard_search_parser = subparsers.add_parser("ncard-search", help="N카드 할인 열차를 조회합니다")
    ncard_search_parser.add_argument("dep", help="출발역")
    ncard_search_parser.add_argument("arr", help="도착역")
    ncard_search_parser.add_argument("date", help="출발일 YYYYMMDD")
    ncard_search_parser.add_argument("time", help="희망 시작 시각 HHMMSS")
    ncard_search_parser.add_argument(
        "--ncard-index", type=int, required=True, metavar="N",
        help="ncard-list 결과의 N카드 순번 (1부터)",
    )
    ncard_search_parser.add_argument("--limit", type=int, default=5, help="출력할 최대 열차 수")
    ncard_search_parser.add_argument(
        "--train-type",
        choices=sorted(TRAIN_TYPE_MAP),
        default="ktx",
        help="조회할 열차 종류 (기본 ktx)",
    )
    ncard_search_parser.set_defaults(func=command_ncard_search)

    reservations_parser = subparsers.add_parser("reservations", help="현재 예약 목록을 조회합니다")
    reservations_parser.set_defaults(func=command_reservations)

    cancel_parser = subparsers.add_parser("cancel", help="예약번호로 예약을 취소합니다")
    cancel_parser.add_argument("reservation_id", help="취소할 예약번호")
    cancel_parser.set_defaults(func=command_cancel)

    return parser


def main() -> int:
    parser = build_parser()
    args = parser.parse_args()
    try:
        args.func(args)
    except (KorailError, NeedToLoginError, NoResultsError, SoldOutError) as exc:
        print(str(exc), file=sys.stderr)
        return 1
    return 0


if __name__ == "__main__":
    raise SystemExit(main())