import pytest

import api.routes as routes
from api.request_diagnostics import RequestDiagnostics


@pytest.fixture(autouse=True)
def _stable_session_list_cache_stamp(monkeypatch):
    """Pin the session-list cache source stamp so these stage-emission unit
    tests are independent of leaked filesystem state.

    ``_get_cached_session_list_payload`` stores then re-reads the cache, and the
    cache's freshness check compares the source stamp captured at store time
    against the stamp recomputed at read time. That stamp folds in a content
    fingerprint of the active ``state.db``: computing it opens the DB in WAL
    mode, which creates a zero-byte ``-wal`` sidecar as a side effect. If an
    earlier test in the same pytest shard left a ``state.db`` in the shared test
    STATE_DIR, the FIRST stamp computation materialises the ``-wal`` file and the
    immediately-following one sees a different sidecar stat — so the stamps
    differ, the cache reports a (spurious) miss, the builder runs, and the
    cache-hit assertion fails. In isolation no ``state.db`` exists, the stamp is
    a stable all-zero tuple, and the test passes — masking the bug at the
    current 3-shard split. These are unit tests of diagnostic STAGE emission, not
    of stamp derivation, so we stabilise the stamp the same way
    test_session_sidebar_cache.py does. (Patches the binding the cache's
    resolved-stamp lookup actually reads; auto-restored by monkeypatch.)
    """
    monkeypatch.setattr(routes, "_session_list_cache_source_stamp", lambda _key: ("stable",))



def test_request_diagnostics_maybe_start_still_covers_sessions_route():
    assert RequestDiagnostics.maybe_start("GET", "/api/sessions") is not None


def _session_cache_diag_stage_names(diag: RequestDiagnostics) -> list[str]:
    return [stage["name"] for stage in diag._stages] + [diag._current_stage]


def _session_cache_key() -> tuple:
    return routes._session_list_cache_key(
        active_profile="default",
        all_profiles=False,
        show_cli_sessions=False,
        show_previous_messaging_sessions=False,
        show_cron_sessions=False,
    )


def test_sessions_route_emits_cache_hit_diagnostic_stages():
    key = _session_cache_key()
    routes._session_list_cache_clear()
    routes._session_list_cache_set(key, {"sessions": [], "cli_count": 0})

    diag = RequestDiagnostics("GET", "/api/sessions", auto_start=False)
    payload = routes._get_cached_session_list_payload(
        key=key,
        builder=lambda: {"sessions": ["unexpected"]},
        diag=diag,
    )

    assert payload == {"sessions": [], "cli_count": 0}
    assert _session_cache_diag_stage_names(diag) == [
        "start",
        "session_list_cache_lookup",
        "session_list_cache_hit",
    ]


def test_sessions_route_emits_cache_store_diagnostic_stages():
    key = _session_cache_key()
    routes._session_list_cache_clear()

    diag = RequestDiagnostics("GET", "/api/sessions", auto_start=False)
    payload = routes._get_cached_session_list_payload(
        key=key,
        builder=lambda: {"sessions": ["rebuilt"], "cli_count": 0},
        diag=diag,
    )

    assert payload == {"sessions": ["rebuilt"], "cli_count": 0}
    assert _session_cache_diag_stage_names(diag) == [
        "start",
        "session_list_cache_lookup",
        "session_list_cache_rebuild_owner",
        "session_list_cache_stored",
    ]


def test_sessions_route_emits_invalidation_retry_diagnostic_stage():
    key = _session_cache_key()
    routes._session_list_cache_clear()
    calls = {"count": 0}

    def _builder():
        calls["count"] += 1
        if calls["count"] == 1:
            routes._session_list_cache_clear()
        return {"sessions": [calls["count"]], "cli_count": 0}

    diag = RequestDiagnostics("GET", "/api/sessions", auto_start=False)
    payload = routes._get_cached_session_list_payload(
        key=key,
        builder=_builder,
        diag=diag,
    )

    assert payload == {"sessions": [2], "cli_count": 0}
    assert calls["count"] == 2
    assert _session_cache_diag_stage_names(diag) == [
        "start",
        "session_list_cache_lookup",
        "session_list_cache_rebuild_owner",
        "session_list_cache_invalidated_during_rebuild",
        "session_list_cache_stored",
    ]