# smb_excel.py (обновлённый фрагмент)
from io import BytesIO
from typing import Optional, Union, Any, Dict
#from smb.SMBConnection import SMBConnection
import pandas as pd
import re

class SMBDownloadError(Exception):
    pass

def _normalize_path(p: str) -> str:
    """Убирает случайные r"..."/"...", лишние кавычки и ставит прямые слэши."""
    if p is None:
        return p
    # уберём обрамляющие кавычки/префикс r"..."
    m = re.fullmatch(r"""r?["'](.*)["']""", p.strip())
    if m:
        p = m.group(1)
    # заменим \ на /
    p = p.replace("\\", "/").lstrip("/")  # путь внутри шары не должен начинаться с /
    return p

def _try_connect(
    remote_name: str,
    server_ip: str,
    username: str,
    password: str,
    *,
    client_machine_name: str,
    domain: str,
    port: int
) -> Optional[SMBConnection]:
    conn = SMBConnection(
        username,
        password,
        client_machine_name,
        remote_name,          # ВАЖНО: remote_name — имя сервера (или IP как fallback)
        domain=domain,
        use_ntlm_v2=True,
        is_direct_tcp=True
    )
    try:
        if conn.connect(server_ip, port):
            return conn
    except Exception:
        pass
    return None

def _connect_smb(
    server_name: str,
    server_ip: str,
    username: str,
    password: str,
    *,
    client_machine_name: str = "client",
    domain: str = "",
    port: int = 445,
) -> SMBConnection:
    """
    Пробуем два варианта remote_name: (1) реальное имя сервера, (2) IP.
    """
    for remote_name in (server_name, server_ip):
        if not remote_name:
            continue
        conn = _try_connect(
            remote_name=remote_name,
            server_ip=server_ip,
            username=username,
            password=password,
            client_machine_name=client_machine_name,
            domain=domain,
            port=port,
        )
        if conn:
            return conn
    raise SMBDownloadError(
        f"Не удалось подключиться к SMB {server_ip}:{port}. "
        f"Проверь server_name (реальное имя хоста), домен/логин и доступность порта 445."
    )

def fetch_smb_file(
    *,
    server_name: str,
    server_ip: str,
    share_name: str,
    file_path_in_share: str,
    username: str,
    password: str,
    client_machine_name: str = "client",
    domain: str = "",
    port: int = 445,
) -> BytesIO:
    """
    Возвращает содержимое файла из SMB как BytesIO.
    """
    file_path_in_share = _normalize_path(file_path_in_share)
    conn: Optional[SMBConnection] = None
    try:
        conn = _connect_smb(
            server_name=server_name,
            server_ip=server_ip,
            username=username,
            password=password,
            client_machine_name=client_machine_name,
            domain=domain,
            port=port,
        )
        # Быстрая проверка существования каталога/файла
        parent = "/".join(file_path_in_share.split("/")[:-1]) or ""
        # listPath кидает исключение, если каталога/шары нет — получим понятную ошибку
        if parent:
            conn.listPath(share_name, parent)

        buf = BytesIO()
        conn.retrieveFile(share_name, file_path_in_share, buf)
        buf.seek(0)
        return buf
    except Exception as e:
        raise SMBDownloadError(
            f"Ошибка скачивания {share_name}/{file_path_in_share}: {e}"
        ) from e
    finally:
        if conn:
            try:
                conn.close()
            except Exception:
                pass

def read_excel_from_smb(
    *,
    server_name: str,
    server_ip: str,
    share_name: str,
    file_path_in_share: str,
    username: str,
    password: str,
    client_machine_name: str = "client",
    domain: str = "",
    port: int = 445,
    sheet_name: Optional[Union[str, int, list]] = None,
    **read_excel_kwargs: Dict[str, Any],
) -> pd.DataFrame:
    file_obj = fetch_smb_file(
        server_name=server_name,
        server_ip=server_ip,
        share_name=share_name,
        file_path_in_share=file_path_in_share,
        username=username,
        password=password,
        client_machine_name=client_machine_name,
        domain=domain,
        port=port,
    )
    return pd.read_excel(file_obj, sheet_name=sheet_name, **read_excel_kwargs)