"""Regression tests for #60955: gateway must not freeze fallback_providers.

Cron reloads ``fallback_providers`` from disk on every job. The gateway used to
freeze ``self._fallback_model`` at process start, so a chain configured (or
edited) after ``hermes gateway`` was already running never reached messaging
sessions — even though cron in the same process fell back correctly.

These tests pin the reload + cached-agent apply helpers without driving the
full Feishu session path.
"""

from __future__ import annotations

import time
from types import SimpleNamespace


def test_refresh_fallback_model_rereads_config(tmp_path, monkeypatch):
    from gateway.run import GatewayRunner

    monkeypatch.setattr("gateway.run._hermes_home", tmp_path)
    cfg = tmp_path / "config.yaml"
    cfg.write_text(
        "fallback_providers:\n"
        "  - provider: deepseek\n"
        "    model: deepseek-v4-flash\n"
    )

    runner = SimpleNamespace(
        _fallback_model=None,
    )
    runner._load_fallback_model = GatewayRunner._load_fallback_model
    bound = GatewayRunner._refresh_fallback_model.__get__(runner)
    chain = bound()

    assert chain == [{"provider": "deepseek", "model": "deepseek-v4-flash"}]
    assert runner._fallback_model == chain

    cfg.write_text(
        "fallback_providers:\n"
        "  - provider: openrouter\n"
        "    model: anthropic/claude-sonnet-4.6\n"
    )
    updated = bound()
    assert updated == [
        {"provider": "openrouter", "model": "anthropic/claude-sonnet-4.6"}
    ]
    assert runner._fallback_model == updated


def test_apply_fallback_chain_skips_while_cooldown_holds_fallback():
    """Do not clobber a live fallback activation during its cooldown window."""
    from gateway.run import GatewayRunner

    live = [{"provider": "deepseek", "model": "deepseek-v4-flash"}]
    agent = SimpleNamespace(
        _fallback_chain=live,
        _fallback_model=live[0],
        _fallback_index=1,
        _fallback_activated=True,
        _rate_limited_until=time.monotonic() + 30,
    )
    GatewayRunner._apply_fallback_chain_to_agent(
        agent,
        [{"provider": "openrouter", "model": "anthropic/claude-sonnet-4.6"}],
    )

    assert agent._fallback_chain == live
    assert agent._fallback_index == 1
    assert agent._fallback_activated is True


def test_background_and_main_agent_paths_call_refresh():
    """Both AIAgent construction sites must pass a refreshed chain, not the
    startup snapshot, and the cached-agent reuse path must apply the refreshed
    chain. Source-level invariant for call sites that resist unit testing.
    """
    from pathlib import Path

    source = (
        Path(__file__).resolve().parent.parent.parent / "gateway" / "run.py"
    ).read_text(encoding="utf-8")
    # The agent-construction site inside TurnRunner.run_sync (extracted from
    # the old _run_agent_inner closure) references the runner as
    # ``self._runner``; the background-agent site still uses bare ``self``.
    _refresh_calls = (
        source.count("fallback_model=self._refresh_fallback_model()")
        + source.count("fallback_model=self._runner._refresh_fallback_model()")
    )
    assert _refresh_calls >= 2
    # The cached-agent reuse path (the load-bearing fix for a long-lived
    # session in a running gateway) must apply the refreshed chain.
    assert (
        "self._apply_fallback_chain_to_agent(" in source
        or "self._runner._apply_fallback_chain_to_agent(" in source
    )
    # The stale startup-snapshot form must not remain at create sites.
    assert "fallback_model=self._fallback_model," not in source
    assert "fallback_model=self._runner._fallback_model," not in source


def test_load_fallback_model_static_unchanged_contract(tmp_path, monkeypatch):
    """_load_fallback_model remains a pure static reader used by refresh."""
    from gateway.run import GatewayRunner

    monkeypatch.setattr("gateway.run._hermes_home", tmp_path)
    (tmp_path / "config.yaml").write_text(
        "fallback_providers:\n"
        "  - provider: deepseek\n"
        "    model: deepseek-v4-flash\n"
        "fallback_model:\n"
        "  provider: nous\n"
        "  model: Hermes-4\n"
    )

    chain = GatewayRunner._load_fallback_model()
    assert chain == [
        {"provider": "deepseek", "model": "deepseek-v4-flash"},
        {"provider": "nous", "model": "Hermes-4"},
    ]