"""Regression tests for #25107: gateway /model switch left a stale
``base_url``/never persisted ``api_mode`` in config.yaml when switching to a
custom provider whose resolver returned an empty ``base_url``.

Root cause: both the picker-tap path (``_on_model_selected`` in
``gateway/slash_commands.py``) and the typed ``/model X --global`` path
(``_finish_switch``) guarded the persist block with two *independent*
``if``s:

    if result.base_url:
        model_cfg["base_url"] = result.base_url
    if target_provider != "custom":
        clear_model_endpoint_credentials(model_cfg, clear_base_url=True)

For a NAMED provider the second ``if`` always clears any stale value, so the
bug was invisible there. But for a ``custom`` provider with an empty
resolved ``base_url``, NEITHER branch fires: the old base_url survives
untouched, and ``api_mode`` was never written to ``model_cfg`` at all in
either branch (only present in the in-memory session override).

Fix: an explicit set-or-clear for both fields when the target provider is
custom, so a genuine switch always leaves config.yaml coherent with the
resolved result.
"""

import types

import hermes_yaml as yaml
import pytest

from gateway.config import Platform
from gateway.platforms.event import MessageEvent, MessageType
from gateway.run import GatewayRunner
from gateway.session import SessionSource


class _FakePickerAdapter:
    def __init__(self):
        self.captured_callback = None

    async def send_model_picker(self, *, on_model_selected, **kwargs):
        self.captured_callback = on_model_selected
        return types.SimpleNamespace(success=True)


def _make_runner(adapter=None):
    runner = object.__new__(GatewayRunner)
    runner.adapters = {Platform.TELEGRAM: adapter} if adapter else {}
    runner._voice_mode = {}
    runner._session_model_overrides = {}
    runner._running_agents = {}
    return runner


def _make_event(text):
    return MessageEvent(
        text=text,
        message_type=MessageType.TEXT,
        source=SessionSource(platform=Platform.TELEGRAM, chat_id="12345", chat_type="dm"),
    )


def _fake_switch_result(*, base_url="", api_mode=""):
    from hermes_cli.model_switch import ModelSwitchResult

    return ModelSwitchResult(
        success=True,
        new_model="local-llama",
        target_provider="custom",
        provider_changed=True,
        api_key="sk-local",
        base_url=base_url,
        api_mode=api_mode,
        provider_label="Custom",
        is_global=True,
    )


def _setup_isolated_home(tmp_path, monkeypatch, model_yaml_value, *, base_url="", api_mode=""):
    import gateway.run as gateway_run

    hermes_home = tmp_path / ".hermes"
    hermes_home.mkdir()
    cfg_path = hermes_home / "config.yaml"
    cfg_path.write_text(
        yaml.safe_dump({"model": model_yaml_value, "providers": {}}),
        encoding="utf-8",
    )

    monkeypatch.setattr(gateway_run, "_hermes_home", hermes_home)
    monkeypatch.setattr("agent.models_dev.fetch_models_dev", lambda: {})
    monkeypatch.setattr(
        "hermes_cli.model_switch_providers.list_picker_providers",
        lambda **kw: [{"slug": "custom", "name": "Custom", "models": ["local-llama"]}],
    )
    monkeypatch.setattr(
        "hermes_cli.model_switch.switch_model",
        lambda **kw: _fake_switch_result(base_url=base_url, api_mode=api_mode),
    )
    monkeypatch.setattr(
        "hermes_cli.model_switch.resolve_display_context_length",
        lambda *a, **k: 8192,
    )
    monkeypatch.setattr("hermes_constants.get_hermes_home", lambda: hermes_home)
    monkeypatch.setattr("hermes_cli.config.get_hermes_home", lambda: hermes_home)
    return cfg_path


_STALE_MODEL_CFG = {
    "default": "old-custom-model",
    "provider": "custom",
    "base_url": "https://old-stale-endpoint.example/v1",
    "api_key": "sk-stale",
    "api_mode": "anthropic_messages",
}


# ---------------------------------------------------------------------------
# Typed `/model X --global` path (_finish_switch)
# ---------------------------------------------------------------------------


@pytest.mark.asyncio
async def test_typed_switch_to_custom_clears_stale_base_url_and_api_mode(tmp_path, monkeypatch):
    """Switching to a custom provider whose resolver returns no base_url/
    api_mode must clear the previous custom endpoint's leftovers, not keep
    routing at the old host/protocol (#25107)."""
    cfg_path = _setup_isolated_home(tmp_path, monkeypatch, dict(_STALE_MODEL_CFG))

    result = await _make_runner()._handle_model_command(
        _make_event("/model local-llama --provider custom --global")
    )

    assert result is not None
    written = yaml.safe_load(cfg_path.read_text(encoding="utf-8"))
    assert written["model"]["default"] == "local-llama"
    assert "base_url" not in written["model"], (
        "stale base_url from the old custom endpoint must be cleared"
    )
    assert "api_mode" not in written["model"], (
        "stale api_mode from the old custom endpoint must be cleared"
    )


# ---------------------------------------------------------------------------
# Picker-tap path (_on_model_selected)
# ---------------------------------------------------------------------------


async def _drive_picker(runner, event):
    sent = await runner._handle_model_command(event)
    assert sent is None
    adapter = runner.adapters[Platform.TELEGRAM]
    assert adapter.captured_callback is not None, "picker callback was not wired"
    return await adapter.captured_callback("12345", "local-llama", "custom")


@pytest.mark.asyncio
async def test_picker_tap_to_custom_clears_stale_base_url_and_api_mode(tmp_path, monkeypatch):
    """Same bug, picker-tap path: tapping a custom-provider model with an
    empty resolved base_url must clear the previous custom endpoint (#25107).
    """
    adapter = _FakePickerAdapter()
    cfg_path = _setup_isolated_home(tmp_path, monkeypatch, dict(_STALE_MODEL_CFG))

    confirmation = await _drive_picker(_make_runner(adapter), _make_event("/model --global"))

    assert confirmation is not None
    written = yaml.safe_load(cfg_path.read_text(encoding="utf-8"))
    assert "base_url" not in written["model"]
    assert "api_mode" not in written["model"]