"""`retrieval_telemetry` says what is wrong, rather than implying it (#3431).

WHY THIS IS TESTED AS ARITHMETIC AND NOT THROUGH THE DATABASE. The warnings
are a pure function of the blocks the readout already built — that is the
design, so a verdict can never disagree with the numbers printed beside it —
and the risk in them is not whether rows load. It is whether a rule fires on
the wrong shape. Every case below is a shape that once produced, or would
produce, a wrong reading:

  * an arm that never declines, which is either a missing floor or a missing
    LOG (#3497 — the rule arms recorded only their hits, so their decline
    count was structurally zero and the obvious warning would have sent a
    reader to move a threshold that was never involved);
  * a search that never declines, which is a search working correctly;
  * a quiet window, where firing every check would describe an empty database
    rather than a broken one (rule 115);
  * a floor the band is sitting on, which is the case where tuning changes
    volume while looking like it changes quality.

The ε and N boundaries are tested from BOTH sides. A threshold asserted only
where it fires is half-tested: the expensive failure here is a false positive,
because a readout that cries wolf is one nobody reads.
"""
from __future__ import annotations

import pytest

from scribe.services.retrieval_telemetry import (
    WARN_FLOOR_EPSILON_DEFAULT, WARN_MIN_CALLS_DEFAULT,
    _compute_warnings, _num, _silent_surfaces,
)

N = WARN_MIN_CALLS_DEFAULT
EPS = WARN_FLOOR_EPSILON_DEFAULT


def src(**kw) -> dict:
    """One source block, shaped like the readout builds it."""
    b = {
        "calls": kw.pop("calls", 0),
        "zero_result_calls": kw.pop("zero_result_calls", 0),
        "top_score": {"p10": kw.pop("p10", None), "p50": None, "p90": None,
                      "min": None, "max": None},
        "avg_result_count": None,
        "p90_duration_ms": kw.pop("p90_duration_ms", 12.0),
    }
    b.update(kw)
    return b


def warn(sources, usage=None, rule_usage=None, floors=None,
         min_calls=N, epsilon=EPS) -> list[dict]:
    return _compute_warnings(
        sources, usage or {}, rule_usage or {}, floors or {}, min_calls, epsilon,
    )


def codes(ws, source=None) -> set[str]:
    return {w["code"] for w in ws if source is None or w["source"] == source}


# ── cannot_decline ────────────────────────────────────────────────────────

def test_an_unbidden_arm_that_never_declines_is_flagged() -> None:
    ws = warn({"auto_inject": src(calls=300, zero_result_calls=0)})
    assert "cannot_decline" in codes(ws, "auto_inject")


def test_the_warning_carries_the_numbers_that_produced_it() -> None:
    """Not "check auto_inject" — that is an instruction to redo the analysis."""
    w = next(w for w in warn({"auto_inject": src(calls=300)})
             if w["code"] == "cannot_decline")
    assert w["numbers"] == {"calls": 300, "zero_result_calls": 0}
    assert "300" in w["detail"]


def test_a_quiet_window_flags_nothing() -> None:
    """Three calls returning nothing is an afternoon, not a defect (rule 115)."""
    assert codes(warn({"auto_inject": src(calls=3, zero_result_calls=0)})) == set()


def test_the_call_count_boundary_holds_on_both_sides() -> None:
    assert "cannot_decline" not in codes(warn({"auto_inject": src(calls=N - 1)}))
    assert "cannot_decline" in codes(warn({"auto_inject": src(calls=N)}))


def test_an_asked_surface_is_never_flagged_for_not_declining() -> None:
    """A search returning a list every time is a search doing its job."""
    for asked in ("mcp_search", "wide_net", "rest_search", "browse_search"):
        assert "cannot_decline" not in codes(
            warn({asked: src(calls=500, zero_result_calls=0)}), asked)


def test_an_arm_that_does_decline_is_not_flagged() -> None:
    ws = warn({"auto_inject": src(calls=300, zero_result_calls=1)})
    assert "cannot_decline" not in codes(ws)


def test_an_arm_not_known_to_log_unconditionally_is_exempt(monkeypatch) -> None:
    """#3497: a structurally-zero decline count is a logging bug, not a floor.

    Flagging it would report a ranking problem and send the reader to a
    threshold that was never involved.
    """
    from dataclasses import replace

    from scribe.services import retrieval_registry as reg

    patched = dict(reg.POINTS)
    patched["auto_inject"] = replace(patched["auto_inject"],
                                     logs_unconditionally=False)
    monkeypatch.setattr(reg, "POINTS", patched)
    assert "cannot_decline" not in codes(
        warn({"auto_inject": src(calls=300, zero_result_calls=0)}))


# ── band_hugs_floor ───────────────────────────────────────────────────────

def test_a_band_sitting_on_its_floor_is_flagged() -> None:
    ws = warn({"auto_inject": src(calls=100, zero_result_calls=5, p10=0.705)},
              floors={"auto_inject": 0.70})
    assert "band_hugs_floor" in codes(ws, "auto_inject")


def test_a_band_clear_of_its_floor_is_not() -> None:
    ws = warn({"auto_inject": src(calls=100, zero_result_calls=5, p10=0.80)},
              floors={"auto_inject": 0.70})
    assert "band_hugs_floor" not in codes(ws)


@pytest.mark.parametrize("gap,flagged", [
    (EPS / 2, True),     # inside
    (EPS, False),        # exactly at the boundary is NOT "hugging"
    (EPS * 2, False),    # clear
])
def test_the_epsilon_boundary_holds_on_both_sides(gap, flagged) -> None:
    ws = warn({"auto_inject": src(calls=100, zero_result_calls=5,
                                  p10=round(0.70 + gap, 6))},
              floors={"auto_inject": 0.70})
    assert ("band_hugs_floor" in codes(ws)) is flagged


def test_an_arm_with_no_readable_floor_is_not_guessed_at() -> None:
    """Reserved slots borrow a parent's floor; naming it here would attribute
    the parent's setting to a child that has no dial of its own."""
    ws = warn({"preference_slot": src(calls=100, zero_result_calls=5, p10=0.7001)},
              floors={})
    assert "band_hugs_floor" not in codes(ws)


# ── no_duration ───────────────────────────────────────────────────────────

def test_rows_without_timings_are_a_logging_gap() -> None:
    ws = warn({"auto_inject": src(calls=1, zero_result_calls=1,
                                  p90_duration_ms=None)})
    assert "no_duration" in codes(ws)


def test_one_untimed_call_is_already_the_defect() -> None:
    """No minimum on this one — unlike the others, it is not about volume."""
    ws = warn({"auto_inject": src(calls=1, p90_duration_ms=None)})
    assert "no_duration" in codes(ws)
    assert "cannot_decline" not in codes(ws), "volume rules still need volume"


def test_a_source_with_no_calls_reports_no_timing_gap() -> None:
    assert "no_duration" not in codes(warn({"auto_inject": src(calls=0)}))


# ── surfaced_never_pulled ─────────────────────────────────────────────────

def test_records_shown_and_never_opened_are_reported_per_corpus() -> None:
    ws = warn(
        {},
        usage={"distinct_notes_surfaced": 171, "distinct_notes_pulled": 40},
        rule_usage={"distinct_rules_surfaced": 69, "distinct_rules_pulled": 11},
    )
    found = {w["numbers"]["corpus"]: w["numbers"]
             for w in ws if w["code"] == "surfaced_never_pulled"}
    assert found["notes"]["never_pulled"] == 131
    assert found["rules"]["never_pulled"] == 58


def test_everything_opened_reports_nothing() -> None:
    ws = warn({}, usage={"distinct_notes_surfaced": 5, "distinct_notes_pulled": 5})
    assert "surfaced_never_pulled" not in codes(ws)


def test_an_empty_corpus_reports_nothing_rather_than_zero() -> None:
    ws = warn({}, usage={"distinct_notes_surfaced": 0, "distinct_notes_pulled": 0})
    assert "surfaced_never_pulled" not in codes(ws)


# ── unregistered_source ───────────────────────────────────────────────────

def test_a_source_missing_from_the_registry_is_reported() -> None:
    """The check that covers what the static test cannot reach — a source
    arriving through a parameter or a dict key."""
    ws = warn({"a_fourth_write_path_arm": src(calls=50)})
    assert codes(ws, "a_fourth_write_path_arm") == {"unregistered_source"}


def test_an_unregistered_source_gets_no_other_verdict() -> None:
    """Its numbers are real, but nothing says whether it was asked."""
    ws = warn({"mystery": src(calls=500, zero_result_calls=0)})
    assert "cannot_decline" not in codes(ws)


def test_every_registered_source_stays_quiet_when_healthy() -> None:
    """The negative control for the whole suite (rule 167).

    A guard that cannot pass cleanly is not a guard — if a healthy window
    produced warnings, every assertion above would be meaningless.
    """
    from scribe.services.retrieval_registry import POINTS

    healthy = {s: src(calls=100, zero_result_calls=40, p10=0.90)
               for s in POINTS}
    assert warn(healthy, floors={s: 0.70 for s in POINTS}) == []


# ── silent surfaces ───────────────────────────────────────────────────────

def test_a_registered_point_with_no_rows_is_reported() -> None:
    quiet = _silent_surfaces({"auto_inject": src(calls=100)}, {}, {}, active=True)
    assert "prompt_rule" in {p["source"] for p in quiet}


def test_a_point_that_emitted_is_not_reported() -> None:
    quiet = _silent_surfaces({"auto_inject": src(calls=100)}, {}, {}, active=True)
    assert "auto_inject" not in {p["source"] for p in quiet}


def test_a_deliberately_quiet_point_is_never_reported() -> None:
    """A justified silence must not read as a gap (#2475)."""
    quiet = {p["source"] for p in _silent_surfaces({}, {}, {}, active=True)}
    for web_only in ("rest_search", "browse_search", "rest_note", "rest_rule"):
        assert web_only not in quiet


def test_an_inactive_window_reports_no_silence_at_all() -> None:
    """On a fresh install every point is silent; the list would be the
    registry printed back (rule 115)."""
    assert _silent_surfaces({}, {}, {}, active=False) == []


def test_a_point_seen_only_in_usage_counts_as_having_emitted() -> None:
    """The write-path arms and the pull sources never reach `sources` — they
    live in note_usage_events — so reading only retrieval_logs would report
    every one of them as silent."""
    quiet = {p["source"] for p in _silent_surfaces(
        {}, {"by_source": {"write_path_place": {}}},
        {"by_source": {"enter_project": {}}}, active=True)}
    assert "write_path_place" not in quiet
    assert "enter_project" not in quiet


# ── settings parsing ──────────────────────────────────────────────────────

@pytest.mark.parametrize("raw,fallback,want", [
    ("50", 30, 50),
    ("0.05", 0.02, 0.05),
    ("", 30, 30),
    ("banana", 30, 30),        # a malformed setting must not take the readout down
    (None, 0.02, 0.02),
])
def test_a_setting_falls_back_rather_than_raising(raw, fallback, want) -> None:
    assert _num(raw, fallback) == want