"""A tuned number carries the space it was measured in — and only that (#4104).

WHY THIS EXISTS

Milestone 416 step 6 answers *"a path for thresholds to be inherited by the next
version or different model so that they don't have to recalibrate a lot."* The
mechanism is a stamp: every tuning event records the embedding model and
document shape the number was chosen under, and a mismatch is reported rather
than left to be noticed.

THE ONE THAT MATTERS MOST IS THE ABSENCE

`test_no_chat_model_identifier_reaches_the_calibration_path` is the load-bearing
guard here, and it is a guard against a plausible mistake rather than a
hypothetical one. These floors live in BAAI/bge-small-en-v1.5's vector space.
The CHAT model — Claude — produces none of these scores and changes none of
them, so a Claude upgrade must trigger nothing at all. If it ever did, the
operator would be asked to recalibrate six dials for no reason, learn that this
surface cries wolf, and ignore it on the day `bge-small` → `bge-base` actually
moves every score on the install. A false alarm here does not cost a
notification; it costs the real alarm.

The rest pins the honest-unknown behaviour: a row written before stamps existed
reports as `unstamped` with `stale: None`, never as fine and never as a model
name somebody guessed at.
"""
import re
from unittest.mock import AsyncMock, MagicMock, patch

import pytest

from scribe.services import embeddings as emb
from scribe.services import retrieval_tuning as rt
from scribe.services.retrieval_surfaces import SURFACES, get_surface
from tests.helpers import make_mock_session, tool_doc

# Names for the thing that talks, as opposed to the thing that embeds. Any of
# these appearing in the calibration path means a chat-model change could move a
# stamp — see the module docstring for why that is the expensive failure.
_CHAT_MODEL_WORDS = (
    "claude", "opus", "sonnet", "haiku", "gpt", "llama", "mistral", "gemini",
    "anthropic", "openai", "chat_model", "chatmodel", "model_version",
)


def test_calibration_stamp_names_the_embedder_and_the_shape():
    stamp = emb.calibration_stamp()
    assert stamp == {
        "embedding_model": emb.EMBEDDING_MODEL,
        "shape_version": emb.CHUNKER_VERSION,
    }
    # Two keys, never one fused string (rule 149): a mismatch has to be able to
    # say WHICH half moved, because a new embedder and a re-cut document
    # invalidate the same numbers for different reasons.
    assert len(stamp) == 2


def test_the_stamp_tracks_the_embedding_model_constant_not_a_copy_of_it():
    """A second literal would drift, and drift here reads as a model change."""
    with patch.object(emb, "EMBEDDING_MODEL", "some/other-model"):
        assert emb.calibration_stamp()["embedding_model"] == "some/other-model"
    with patch.object(emb, "CHUNKER_VERSION", 99):
        assert emb.calibration_stamp()["shape_version"] == 99


def test_no_chat_model_identifier_reaches_the_calibration_path():
    """THE GUARD. A Claude upgrade must move nothing in this path.

    Structural rather than behavioural on purpose: the failure is someone
    *adding* a chat-model field in good faith ("surely the model matters"), and
    no behavioural test catches a field that has not been written yet. Asserted
    over the source of every module that produces or consumes a stamp.
    """
    import inspect

    from scribe.services import retrieval_migration as rm

    for label, obj in (
        ("calibration_stamp", emb.calibration_stamp),
        ("_calibration", rt._calibration),
        ("migrate_floor", rm.migrate_floor),
    ):
        src = inspect.getsource(obj).lower()
        # Comments and docstrings here legitimately discuss the chat model in
        # order to rule it out, so strip prose and assert on code only.
        code = "\n".join(
            line.split("#", 1)[0]
            for line in re.sub(r'""".*?"""', "", src, flags=re.S).splitlines()
        )
        for word in _CHAT_MODEL_WORDS:
            assert word not in code, f"{label} names the chat model: {word!r}"


@pytest.mark.asyncio
async def test_a_moved_dial_is_written_with_the_live_stamp():
    session = make_mock_session()
    with patch.object(rt, "async_session", MagicMock(return_value=session)), \
         patch.object(rt, "set_setting", AsyncMock()), \
         patch.object(rt, "floor_for", AsyncMock(return_value=0.72)), \
         patch.object(rt, "budget_for", AsyncMock(return_value=3)), \
         patch.object(rt, "calibration_stamp",
                      MagicMock(return_value={"embedding_model": "m/x",
                                              "shape_version": 7})):
        await rt.set_dial(
            1, "prompt_rule", "floor", 0.66,
            reason="read the five refused records; four were genuine matches",
        )
    event = session.add.call_args[0][0]
    assert event.embedding_model == "m/x"
    assert event.shape_version == 7


def _row(model="BAAI/bge-small-en-v1.5", shape=1):
    return MagicMock(embedding_model=model, shape_version=shape)


def test_an_untouched_dial_reports_the_shipped_default_it_is_still_on():
    s = get_surface("prompt_rule")
    live = {"embedding_model": s.measured_model, "shape_version": s.measured_shape}
    cal = rt._calibration(None, s, live)
    assert cal["source"] == "shipped"
    assert cal["stale"] is False


def test_a_dial_moved_before_stamps_existed_is_unknown_not_fine():
    """`stale: None`, because "we don't know" and "it's fine" are not the same.

    Collapsing them would hide the dials MOST likely to be wrong — the ones
    somebody tuned longest ago.
    """
    s = get_surface("prompt_rule")
    cal = rt._calibration(_row(model=None, shape=None), s, emb.calibration_stamp())
    assert cal["source"] == "unstamped"
    assert cal["stale"] is None
    assert cal["model_changed"] is None and cal["shape_changed"] is None


def test_a_model_change_and_a_shape_change_are_reported_apart():
    """Rule 149. Two conditions, two answers — they call for different work."""
    s = get_surface("prompt_rule")
    live = {"embedding_model": "new/model", "shape_version": 1}
    cal = rt._calibration(_row(model="old/model", shape=1), s, live)
    assert (cal["model_changed"], cal["shape_changed"], cal["stale"]) == (
        True, False, True,
    )

    live = {"embedding_model": "old/model", "shape_version": 2}
    cal = rt._calibration(_row(model="old/model", shape=1), s, live)
    assert (cal["model_changed"], cal["shape_changed"], cal["stale"]) == (
        False, True, True,
    )


def test_a_dial_tuned_under_the_live_stamp_is_not_stale():
    s = get_surface("prompt_rule")
    live = emb.calibration_stamp()
    cal = rt._calibration(
        _row(model=live["embedding_model"], shape=live["shape_version"]), s, live,
    )
    assert cal["source"] == "tuned"
    assert cal["stale"] is False


def test_every_surface_ships_a_stamp_for_its_defaults():
    """A default with no stamp cannot be told from one measured yesterday."""
    for name, s in SURFACES.items():
        assert s.measured_model, f"{name} default has no measured model"
        assert isinstance(s.measured_shape, int), f"{name} shape is not a version"


def test_the_registry_stamp_is_a_literal_not_the_live_value():
    """It says what WAS true, so it must not follow the current constants.

    A field that tracked `EMBEDDING_MODEL` would agree with it forever and could
    never report the one thing it exists to report.
    """
    with patch.object(emb, "EMBEDDING_MODEL", "some/other-model"):
        assert get_surface("prompt_rule").measured_model != "some/other-model"


def test_the_tool_says_nothing_auto_retunes():
    """The contract an agent reads. A stale stamp is a prompt to MEASURE.

    Without this, the obvious next move on seeing `stale: true` is to move the
    dial — which is tuning from a statistic, the exact failure #4102 measured
    pointing the wrong way.
    """
    doc = tool_doc("scribe.mcp.tools.retrieval_tuning", "retrieval_surfaces")
    assert "calibration" in doc
    assert "NOTHING IS RETUNED AUTOMATICALLY" in doc
    assert "unstamped" in doc