"""Unit tests for service_api._month_cache (MonthCache / TTLCache).

Client-side wiring of these caches is covered in test_service_cache_ttl.py
and test_reservation_guards.py; this file tests the cache mechanics directly.
"""
import asyncio
import time

from room_cal.service_api._month_cache import MonthCache, TTLCache
from room_cal.service_api._utils import CACHE_TTL

_KEY = (7, 2026)
_EXPIRED = -(CACHE_TTL + 1)


def _counting_fetch(results=None):
  calls = []
  async def _fetch(m, y):
    calls.append((m, y))
    if results:
      return results.pop(0)
    return ['data']
  return _fetch, calls


class TestMonthCache:

  async def test_fetch_and_cache(self):
    fetch, calls = _counting_fetch()
    cache = MonthCache(fetch)
    assert await cache.get(7, 2026) == ['data']
    assert await cache.get(7, 2026) == ['data']
    assert calls == [_KEY]

  async def test_ttl_expiry_refetches(self):
    fetch, calls = _counting_fetch()
    cache = MonthCache(fetch)
    await cache.get(7, 2026)
    cache._fetched_at[_KEY] += _EXPIRED
    await cache.get(7, 2026)
    assert calls == [_KEY, _KEY]

  async def test_missing_timestamp_treated_as_expired(self):
    fetch, calls = _counting_fetch()
    cache = MonthCache(fetch)
    cache._data[_KEY] = ['seeded']
    assert await cache.get(7, 2026) == ['data']
    assert calls == [_KEY]

  async def test_inflight_dedup(self):
    calls = []
    async def _fetch(m, y):
      calls.append((m, y))
      await asyncio.sleep(0.01)
      return ['data']
    cache = MonthCache(_fetch)
    results = await asyncio.gather(cache.get(7, 2026), cache.get(7, 2026), cache.get(7, 2026))
    assert calls == [_KEY]
    assert all(r == ['data'] for r in results)

  async def test_suspect_retries_once(self, caplog):
    fetch, calls = _counting_fetch(results=[[], ['data']])
    cache = MonthCache(fetch, suspect=lambda key, r: not r, label='Test', retry_delay=0)
    assert await cache.get(7, 2026) == ['data']
    assert calls == [_KEY, _KEY]
    assert 'empty or priceless calendar for 2026-07; retrying' in caplog.text

  async def test_suspect_persists_returns_bad_data(self, caplog):
    fetch, calls = _counting_fetch(results=[[], []])
    cache = MonthCache(fetch, suspect=lambda key, r: not r, label='Test', retry_delay=0)
    assert await cache.get(7, 2026) == []
    assert calls == [_KEY, _KEY]
    assert 'still empty/priceless calendar for 2026-07 after retry' in caplog.text

  async def test_good_result_skips_retry(self):
    fetch, calls = _counting_fetch()
    cache = MonthCache(fetch, suspect=lambda key, r: not r, retry_delay=0)
    await cache.get(7, 2026)
    assert calls == [_KEY]

  async def test_revalidate_false_evicts_and_refetches(self):
    fetch, calls = _counting_fetch()
    seen = []
    cache = MonthCache(
      fetch,
      revalidate=lambda key, cached: False,
      on_fetch=lambda key, result, revalidation_failed: seen.append(revalidation_failed),
    )
    cache._data[_KEY] = ['stale']
    cache._fetched_at[_KEY] = time.monotonic()
    assert await cache.get(7, 2026) == ['data']
    assert calls == [_KEY]
    assert seen == [True]

  async def test_revalidate_true_serves_cache(self):
    fetch, calls = _counting_fetch()
    cache = MonthCache(fetch, revalidate=lambda key, cached: True)
    cache._data[_KEY] = ['cached']
    cache._fetched_at[_KEY] = time.monotonic()
    assert await cache.get(7, 2026) == ['cached']
    assert calls == []

  async def test_on_fetch_flag_false_on_plain_fetch(self):
    fetch, _ = _counting_fetch()
    seen = []
    cache = MonthCache(fetch, on_fetch=lambda key, result, revalidation_failed: seen.append(revalidation_failed))
    await cache.get(7, 2026)
    assert seen == [False]

  async def test_on_evict_called_on_expiry_and_invalidate_not_clear(self):
    fetch, _ = _counting_fetch()
    evicted = []
    cache = MonthCache(fetch, on_evict=evicted.append)
    await cache.get(7, 2026)
    cache._fetched_at[_KEY] += _EXPIRED
    await cache.get(7, 2026)
    assert evicted == [_KEY]
    cache.invalidate(7, 2026)
    assert evicted == [_KEY, _KEY]
    await cache.get(7, 2026)
    cache.clear()
    assert evicted == [_KEY, _KEY]
    assert cache._data == {}


class TestTTLCache:

  def test_set_get(self):
    cache = TTLCache()
    cache.set('k', {'v': 1})
    assert cache.get('k') == {'v': 1}

  def test_missing_key(self):
    assert TTLCache().get('nope') is None

  def test_expired_entry_dropped(self):
    cache = TTLCache()
    cache.set('k', {'v': 1})
    cache._fetched_at['k'] += _EXPIRED
    assert cache.get('k') is None
    assert 'k' not in cache._data

  def test_missing_timestamp_treated_as_expired(self):
    cache = TTLCache()
    cache._data['k'] = {'v': 1}
    assert cache.get('k') is None

  def test_clear(self):
    cache = TTLCache()
    cache.set('k', {'v': 1})
    cache.clear()
    assert cache.get('k') is None