"""Creating a lesson, and tying it to what taught it (milestone 385 step 4).

THE TRIGGER IS THE RECORD, so the door refuses a lesson without one.

Step 1 could have chosen "flag it visibly" instead. Refusing is the stronger
answer for the same reason `create_rule` makes enforcement the deciding
question: a lesson with no trigger is not a weaker lesson, it is a note that
will never surface, and nothing downstream can tell the difference. It saves,
it reads correctly in every listing, and it is silently absent from the one
moment it was written for. A flag would be a warning nobody is present to read
— the write path is where the writer still is.

THE SOURCE IDS ARE A LIST, and `test_a_lesson_keeps_every_incident_that_taught
_it` is why. The founding example generalised three incidents into one claim;
`arose_from_id` holds one, and a record that keeps the first and drops two
reads as complete.
"""
from __future__ import annotations

from types import SimpleNamespace
from unittest.mock import AsyncMock, patch

import pytest

from scribe.mcp._context import _user_id_ctx
from scribe.mcp.tools.lessons import create_lesson, update_lesson
from scribe.services import lessons as lessons_svc

TRIGGER = "a test fails on code you believe is correct"
SUBJECT = "Suspect the guard before the code"


def _stub_note(**kw):
    """A stand-in lesson row — every attribute the tool's _to_dict reads."""
    base = dict(
        id=1, title="t", body="b", tags=[], project_id=None,
        note_type="lesson", data={}, arose_from_id=None,
        created_at=None, updated_at=None,
    )
    base.update(kw)
    return SimpleNamespace(**base)


@pytest.mark.asyncio
async def test_a_lesson_without_a_trigger_is_refused():
    """THE guard. Falsifiable: it names the parameter, so a door that stopped
    asking for it fails here rather than quietly writing an unfindable record."""
    _user_id_ctx.set(7)
    with pytest.raises(ValueError) as err:
        await create_lesson(what=SUBJECT, when_to_apply="")

    message = str(err.value)
    assert "when_to_apply" in message
    # It says what to write, not just that something is missing — the writer is
    # here now, and "required" alone produces a topic where a symptom was wanted.
    assert "symptom" in message.lower()


@pytest.mark.asyncio
async def test_whitespace_is_not_a_trigger():
    """The refusal reads the stripped value. A door checking only falsiness
    accepts a space and produces exactly the record it meant to prevent."""
    _user_id_ctx.set(7)
    with pytest.raises(ValueError):
        await create_lesson(what=SUBJECT, when_to_apply="   ")


@pytest.mark.asyncio
async def test_a_lesson_keeps_every_incident_that_taught_it():
    """Three sources in, three sources stored — and `arose_from_id` left NULL,
    because one of three on a surface that renders it as THE origin would make
    that surface state something false."""
    _user_id_ctx.set(7)
    created = AsyncMock(return_value=_stub_note())
    with patch.object(lessons_svc, "create_lesson", created), \
         patch("scribe.mcp.tools.lessons.dedup_svc.find_duplicate_note",
               AsyncMock(return_value=None)), \
         patch("scribe.mcp.tools.lessons.systems_tools.attach_systems", AsyncMock()):
        await create_lesson(
            what=SUBJECT, when_to_apply=TRIGGER, learned_from=[11, 22, 33],
        )

    assert created.await_args.kwargs["learned_from"] == [11, 22, 33]
    assert lessons_svc.sole_source([11, 22, 33]) is None
    assert lessons_svc.compose_data(SUBJECT, TRIGGER, [11, 22, 33])["taught_by"] == [
        11, 22, 33,
    ]


def test_a_single_source_still_reaches_arose_from_id():
    """The existing provenance field keeps working for the ordinary case — a
    lesson drawn from one issue is not made less connected by the list."""
    assert lessons_svc.sole_source([11]) == 11


@pytest.mark.asyncio
async def test_the_duplicate_gate_runs_before_anything_is_created():
    """A near-match returns the existing id and writes nothing: two lessons
    about one failure class want to be one lesson."""
    _user_id_ctx.set(7)
    hit = SimpleNamespace(id=99, title="already recorded", similarity=0.97,
                          reason="semantic")
    created = AsyncMock()
    with patch("scribe.mcp.tools.lessons.dedup_svc.find_duplicate_note",
               AsyncMock(return_value=hit)), \
         patch.object(lessons_svc, "create_lesson", created):
        out = await create_lesson(what=SUBJECT, when_to_apply=TRIGGER)

    assert created.await_count == 0
    assert out["duplicate"] is True
    assert out["existing_id"] == 99
    # The hint names the lesson's own updater, so the caller is pointed at a
    # tool that exists rather than at update_note.
    assert "update_lesson" in out["message"]


@pytest.mark.asyncio
async def test_the_gate_compares_the_composed_document_not_the_raw_fields():
    """What reaches the gate is the title and body a lesson will actually be
    stored as. Comparing `what` alone would miss that the trigger is half the
    document, and would judge two lessons alike that rank nothing alike."""
    _user_id_ctx.set(7)
    gate = AsyncMock(return_value=None)
    with patch("scribe.mcp.tools.lessons.dedup_svc.find_duplicate_note", gate), \
         patch.object(lessons_svc, "create_lesson",
                      AsyncMock(return_value=_stub_note())), \
         patch("scribe.mcp.tools.lessons.systems_tools.attach_systems", AsyncMock()):
        await create_lesson(what=SUBJECT, when_to_apply=TRIGGER, insight="Look.")

    title, body = gate.await_args.args[1], gate.await_args.args[2]
    assert title == f"{SUBJECT} — {TRIGGER}"
    assert body.startswith(f"**When to apply:** {TRIGGER}")
    assert gate.await_args.kwargs["note_type"] == "lesson"


def test_a_lesson_is_judged_at_the_trigger_dominated_bar():
    """#2518 measured deliberately-parallel siblings at 0.92 on a document that
    is mostly prose ABOUT the thing. A lesson's document is that shape, so the
    bar sits above that band — otherwise two different lessons about one area
    block each other, which is the failure step 4 asked to check for."""
    from scribe.services.dedup import (
        _LESSON_SEMANTIC_THRESHOLD,
        _SEMANTIC_THRESHOLD,
        _semantic_threshold,
    )

    assert _semantic_threshold("lesson") == _LESSON_SEMANTIC_THRESHOLD
    assert _LESSON_SEMANTIC_THRESHOLD > 0.92, (
        "below the observed sibling band, so two genuinely different lessons "
        "about one area would refuse each other"
    )
    assert _LESSON_SEMANTIC_THRESHOLD > _SEMANTIC_THRESHOLD
    # An ordinary note is untouched — the carve-out is per kind, not a
    # loosening of the gate.
    assert _semantic_threshold("note") == _SEMANTIC_THRESHOLD


@pytest.mark.asyncio
async def test_an_update_recomposes_both_halves_of_the_document():
    """A new trigger has to reach the title AND the head of the body. Patching
    one would leave a lesson that reads correctly and ranks on the old
    situation — the failure mode with no symptom."""
    _user_id_ctx.set(7)
    stored = _stub_note(
        title=f"{SUBJECT} — {TRIGGER}",
        body=f"**When to apply:** {TRIGGER}\n\nLook at the guard.",
        data={"what": SUBJECT, "when_to_apply": TRIGGER},
    )
    updated = AsyncMock(return_value=_stub_note())
    with patch.object(lessons_svc, "get_lesson", AsyncMock(return_value=stored)), \
         patch("scribe.services.notes.update_note", updated):
        await lessons_svc.update_lesson(7, 1, when_to_apply="a guard goes red")

    fields = updated.await_args.kwargs
    assert fields["title"] == f"{SUBJECT} — a guard goes red"
    assert fields["body"].startswith("**When to apply:** a guard goes red")
    assert fields["data"]["when_to_apply"] == "a guard goes red"


@pytest.mark.asyncio
async def test_an_update_does_not_stack_the_composed_lines():
    """The insight is handed back to `compose_body`, which re-adds the trigger
    and provenance lines. Without stripping them first they accumulate a copy
    per edit — and because the trigger line is half of what makes the document
    rank, the duplicates would look like the shape working."""
    _user_id_ctx.set(7)
    stored = _stub_note(
        body=f"**When to apply:** {TRIGGER}\n\nLook at the guard."
             "\n\n**Learned from:** #5",
        data={"what": SUBJECT, "when_to_apply": TRIGGER, "taught_by": [5]},
    )
    updated = AsyncMock(return_value=_stub_note())
    with patch.object(lessons_svc, "get_lesson", AsyncMock(return_value=stored)), \
         patch("scribe.services.notes.update_note", updated):
        await lessons_svc.update_lesson(7, 1, what="Suspect the guard")

    body = updated.await_args.kwargs["body"]
    assert body.count("**When to apply:**") == 1
    assert body.count("**Learned from:**") == 1
    assert "Look at the guard." in body