"""Watcher-level tests for scale-to-zero: the idle watcher's dormant sequence and
the arm-gate wiring, exercised against the real GatewayRunner methods bound onto
a lightweight stand-in (booting a full gateway is unnecessary for this logic and
would be slow/flaky).

These cover the parts gateway/test_scale_to_zero.py (pure helpers) can't: that
the watcher calls the relay adapter's go_dormant() exactly when idle+armed,
respects the cooldown, and skips when busy — the F7/D3 + D12 behaviour.
"""

from __future__ import annotations

import asyncio
import time

import pytest

from gateway.run import GatewayRunner


class _FakeRelayAdapter:
    def __init__(self):
        self.go_dormant_calls = 0

    async def go_dormant(self):
        self.go_dormant_calls += 1
        return True


def _runner_with(monkeypatch, *, idle, armed_adapter=True):
    """Build a GatewayRunner without booting it, stubbing just what the watcher
    touches. Real methods (_scale_to_zero_is_idle composition, the watcher body)
    run; only their dependencies are stubbed."""
    r = GatewayRunner.__new__(GatewayRunner)
    r._running = True
    r._scale_to_zero_cooldown_until = 0.0
    r._last_inbound_at = time.time()
    r._running_agents = {}
    r._background_tasks = set()
    adapter = _FakeRelayAdapter() if armed_adapter else None

    monkeypatch.setattr(r, "_scale_to_zero_is_idle", lambda: idle, raising=False)
    monkeypatch.setattr(r, "_relay_adapter_for_dormancy", lambda: adapter, raising=False)
    monkeypatch.setattr(r, "_scale_to_zero_idle_timeout_seconds", lambda: 300.0, raising=False)
    monkeypatch.setattr(r, "_update_runtime_status", lambda *a, **k: None, raising=False)
    return r, adapter


@pytest.mark.asyncio
async def test_watcher_goes_dormant_when_idle(monkeypatch):
    r, adapter = _runner_with(monkeypatch, idle=True)
    # Run one iteration: stop after the first sleep so the loop exits cleanly.
    task = asyncio.create_task(r._scale_to_zero_watcher(interval=0.01))
    await asyncio.sleep(0.1)
    r._running = False
    await asyncio.wait_for(task, timeout=2)
    assert adapter.go_dormant_calls >= 1
    # After driving dormant, a re-arm cooldown is set (0.F).
    assert r._scale_to_zero_cooldown_until > time.time()


@pytest.mark.asyncio
async def test_watcher_does_not_go_dormant_when_busy(monkeypatch):
    r, adapter = _runner_with(monkeypatch, idle=False)
    task = asyncio.create_task(r._scale_to_zero_watcher(interval=0.01))
    await asyncio.sleep(0.1)
    r._running = False
    await asyncio.wait_for(task, timeout=2)
    assert adapter.go_dormant_calls == 0


@pytest.mark.asyncio
async def test_watcher_respects_cooldown(monkeypatch):
    r, adapter = _runner_with(monkeypatch, idle=True)
    # Cooldown active far in the future: even though idle, no dormancy fires.
    r._scale_to_zero_cooldown_until = time.time() + 3600
    task = asyncio.create_task(r._scale_to_zero_watcher(interval=0.01))
    await asyncio.sleep(0.1)
    r._running = False
    await asyncio.wait_for(task, timeout=2)
    assert adapter.go_dormant_calls == 0


@pytest.mark.asyncio
async def test_watcher_noop_when_no_relay_adapter(monkeypatch):
    # Armed-but-no-relay-adapter (e.g. relay not yet connected): must not crash.
    r, _ = _runner_with(monkeypatch, idle=True, armed_adapter=False)
    task = asyncio.create_task(r._scale_to_zero_watcher(interval=0.01))
    await asyncio.sleep(0.1)
    r._running = False
    await asyncio.wait_for(task, timeout=2)
    # No exception, loop exits cleanly — nothing to assert beyond survival.


def test_bg_work_blocks_idle_via_background_tasks(monkeypatch):
    """_scale_to_zero_has_live_background_work() reports True when a tracked
    background task is still live (D3/F7) — the guard that keeps a gateway with
    an in-flight backgrounded subagent/terminal awake."""
    r = GatewayRunner.__new__(GatewayRunner)

    async def _never():
        await asyncio.sleep(3600)

    loop = asyncio.new_event_loop()
    try:
        t = loop.create_task(_never())
        r._background_tasks = {t}
        # process_registry has nothing active in this fresh process.
        assert r._scale_to_zero_has_live_background_work() is True
        t.cancel()
    finally:
        loop.run_until_complete(asyncio.gather(t, return_exceptions=True))
        loop.close()


def test_bg_work_false_when_quiet():
    r = GatewayRunner.__new__(GatewayRunner)
    r._background_tasks = set()
    # No background tasks, no active processes in this fresh process.
    assert r._scale_to_zero_has_live_background_work() is False