"""Telethon Connection 模式（与 Telegram Desktop 使用的传输类似可选用 obfuscated）。"""

from __future__ import annotations

from typing import Type

from telethon.network.connection import (
    Connection,
    ConnectionTcpAbridged,
    ConnectionTcpFull,
    ConnectionTcpIntermediate,
    ConnectionTcpObfuscated,
)


def resolve_connection_class(mode: str) -> Type[Connection]:
    m = (mode or "").strip().lower().replace("-", "_")
    if not m or m == "tcp_full":
        return ConnectionTcpFull
    if m == "tcp_obfuscated":
        return ConnectionTcpObfuscated
    if m == "tcp_intermediate":
        return ConnectionTcpIntermediate
    if m == "tcp_abridged":
        return ConnectionTcpAbridged
    raise ValueError(
        f"不支持的 TELEGRAM_CONNECTION={mode!r}，可用: "
        "tcp_full, tcp_obfuscated, tcp_intermediate, tcp_abridged"
    )