"""Point slack_sdk (and raw ``https://slack.com/api/`` aiohttp posts) at a local Slack stand-in.

slack_sdk has no base-URL environment variable, so this module is put on ``PYTHONPATH`` of the child
``hermes gateway run`` process by the contract harness. Python imports ``sitecustomize`` at startup;
when ``HERMES_STANDIN_SLACK_API`` is set (e.g. ``http://127.0.0.1:PORT/api/``) every Web API client
the Slack adapter builds defaults its ``base_url`` to the stand-in, which also moves
``apps.connections.open`` and therefore the Socket Mode websocket. Nothing in Hermes is touched: the
redirect lives at the SDK/HTTP boundary, exactly where DNS would send the real traffic.

Side effect: when the variable is set, slack_sdk (and aiohttp) are imported eagerly at interpreter
startup, before Hermes runs, so the child pays that import up front even if Slack never connects.
"""

import os

_API = os.environ.get("HERMES_STANDIN_SLACK_API", "")
_REAL_API = "https://slack.com/api/"


def _wrap_init(cls):
    original = cls.__init__
    if getattr(original, "_standin_wrapped", False):
        return

    def __init__(self, *args, **kwargs):
        # base_url is the 2nd positional parameter of both base clients (after token).
        if len(args) < 2:
            kwargs.setdefault("base_url", _API)
        original(self, *args, **kwargs)
        if getattr(self, "base_url", "") == _REAL_API:
            self.base_url = _API

    __init__._standin_wrapped = True  # type: ignore[attr-defined]
    cls.__init__ = __init__


def _install_sdk() -> None:
    try:
        from slack_sdk.web.async_base_client import AsyncBaseClient
        from slack_sdk.web.base_client import BaseClient
    except Exception:  # slack_sdk not installed: nothing to redirect
        return
    _wrap_init(AsyncBaseClient)
    _wrap_init(BaseClient)


def _install_aiohttp() -> None:
    """The adapter's standalone (out-of-gateway) sender POSTs to ``https://slack.com/api/<m>``."""
    try:
        import aiohttp
    except Exception:
        return
    original = aiohttp.ClientSession._request
    if getattr(original, "_standin_wrapped", False):
        return

    async def _request(self, method, str_or_url, *args, **kwargs):
        url = str(str_or_url)
        if url.startswith(_REAL_API):
            str_or_url = _API + url[len(_REAL_API):]
        return await original(self, method, str_or_url, *args, **kwargs)

    _request._standin_wrapped = True  # type: ignore[attr-defined]
    aiohttp.ClientSession._request = _request


if _API:
    if not _API.endswith("/"):
        _API += "/"
    _install_sdk()
    _install_aiohttp()