"""The lesson → rule link at its doors (milestone 440 step 1, #4630).

The link's own behaviour — states, cascade, ACL — is tested against Postgres in
tests/test_integration_lesson_rule_links.py. These pin the wiring a mock CAN
see: that a bad rule id stops a lesson create before anything is written, that
the doors pass the set through with the semantics their docstrings promise,
that the judge tool is registered, that backup skips a link it cannot map, and
that the migration and the model agree about the states.
"""
from __future__ import annotations

import importlib.util
from pathlib import Path
from types import SimpleNamespace
from unittest.mock import AsyncMock, patch

import pytest

from scribe.mcp._context import _user_id_ctx
from scribe.mcp.tools import lessons as lesson_tools
from scribe.models.lesson_rule_link import LINK_STATES
from scribe.services import backup
from scribe.services import lesson_rules as links_svc
from scribe.services import lessons as lessons_svc

TRIGGER = "a CI run is still in_progress far past its usual time"


def _stub_note(**kw):
    base = dict(
        id=41, 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)


def _create_patches(created):
    return (
        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()),
    )


@pytest.mark.asyncio
async def test_an_unreadable_rule_stops_the_lesson_before_it_is_written():
    """All-or-nothing at the door: the rule ids are validated BEFORE the
    lesson exists, so a bad id cannot leave a lesson saved and unlinked."""
    _user_id_ctx.set(7)
    created = AsyncMock(return_value=_stub_note())
    p1, p2, p3 = _create_patches(created)
    with p1, p2, p3, patch.object(
        links_svc, "require_rules", AsyncMock(side_effect=ValueError("rule(s) [9] not found")),
    ):
        with pytest.raises(ValueError):
            await lesson_tools.create_lesson(what="x", when_to_apply=TRIGGER, rule_ids=[9])
    created.assert_not_awaited()


@pytest.mark.asyncio
async def test_create_links_the_named_rules_to_the_new_lesson():
    _user_id_ctx.set(7)
    created = AsyncMock(return_value=_stub_note(id=41))
    linked = AsyncMock()
    p1, p2, p3 = _create_patches(created)
    with p1, p2, p3, \
         patch.object(links_svc, "require_rules", AsyncMock(return_value=[5, 6])), \
         patch.object(links_svc, "set_lesson_rules", linked):
        await lesson_tools.create_lesson(what="x", when_to_apply=TRIGGER, rule_ids=[5, 6])
    linked.assert_awaited_once()
    assert linked.await_args.args[1:] == (41, [5, 6])


@pytest.mark.asyncio
async def test_create_without_rules_writes_no_link():
    _user_id_ctx.set(7)
    linked = AsyncMock()
    p1, p2, p3 = _create_patches(AsyncMock(return_value=_stub_note()))
    with p1, p2, p3, patch.object(links_svc, "set_lesson_rules", linked):
        await lesson_tools.create_lesson(what="x", when_to_apply=TRIGGER)
    linked.assert_not_awaited()


@pytest.mark.parametrize("rule_ids, expect_call", [(None, False), ([], True), ([5], True)])
@pytest.mark.asyncio
async def test_update_leaves_links_alone_on_none_and_replaces_on_a_list(rule_ids, expect_call):
    """None is "unchanged"; a list — including [] — is the full new set, which
    the service turns into confirmations and rejections."""
    _user_id_ctx.set(7)
    linked = AsyncMock()
    with patch.object(lessons_svc, "update_lesson", AsyncMock(return_value=_stub_note())), \
         patch.object(links_svc, "require_rules", AsyncMock(side_effect=lambda uid, ids: list(ids))), \
         patch.object(links_svc, "set_lesson_rules", linked):
        await lesson_tools.update_lesson(lesson_id=41, rule_ids=rule_ids)
    assert linked.await_count == (1 if expect_call else 0)
    if expect_call:
        assert linked.await_args.args[1:] == (41, rule_ids)


def test_the_judge_tool_is_registered():
    names = []
    fake = SimpleNamespace(tool=lambda name: (lambda fn: names.append(name) or fn))
    lesson_tools.register(fake)
    assert "judge_lesson_link" in names


def test_verdicts_name_real_states():
    assert set(links_svc.VERDICTS.values()) <= set(LINK_STATES)


def test_the_migration_check_and_the_model_agree_on_the_states():
    """Rule 36's drift, guarded: the CHECK is written from the migration's
    tuple and the code from the model's, so they must be the same tuple."""
    path = Path(__file__).resolve().parents[1] / "alembic" / "versions" / "0111_lesson_rule_links.py"
    spec = importlib.util.spec_from_file_location("m0111", path)
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)
    assert tuple(module._STATES) == tuple(LINK_STATES)


@pytest.mark.parametrize("lesson_mapped, rule_mapped", [(False, True), (True, False)])
def test_backup_skips_a_link_whose_end_did_not_restore(lesson_mapped, rule_mapped):
    maps = backup._Maps()
    if lesson_mapped:
        maps.notes[10] = 110
    if rule_mapped:
        maps.rules[20] = 120
    row = {"lesson_id": 10, "rule_id": 20, "state": "confirmed"}
    assert backup._build_lesson_rule_link(row, maps) is None


def test_backup_keeps_an_unjudged_link_unjudged():
    """A suggested link was never judged; restoring it with the restore's time
    in judged_at would say it was."""
    maps = backup._Maps()
    maps.notes[10] = 110
    maps.rules[20] = 120
    built = backup._build_lesson_rule_link(
        {"lesson_id": 10, "rule_id": 20, "state": "suggested", "judged_at": None}, maps,
    )
    assert (built.lesson_id, built.rule_id, built.state) == (110, 120, "suggested")
    assert built.judged_at is None


# ── #4631: judged when written ───────────────────────────────────────────────


@pytest.mark.asyncio
async def test_an_unanswered_lesson_comes_back_with_rules_to_judge_against():
    """Neither answer given: the create offers the rules the lesson resembles,
    searched with its claim and trigger and scoped to its project."""
    _user_id_ctx.set(7)
    offered = [{"id": 5, "title": "Read the log", "kind": "rule",
                "when_to_apply": "a run overran", "score": 0.61}]
    search = AsyncMock(return_value=offered)
    p1, p2, p3 = _create_patches(AsyncMock(return_value=_stub_note()))
    with p1, p2, p3, patch.object(links_svc, "rule_candidates", search):
        out = await lesson_tools.create_lesson(what="x", when_to_apply=TRIGGER, project_id=2)
    assert search.await_args.args == (7, "x", TRIGGER, 2)
    assert out["rule_candidates"] == offered
    assert out["rule_judgment"] == links_svc.UNJUDGED
    assert "no_rule" in out["rule_hint"] and "rule_ids" in out["rule_hint"]


@pytest.mark.asyncio
async def test_a_search_that_could_not_run_offers_no_list_rather_than_an_empty_one():
    """None means unavailable; an empty list would claim nothing resembles it."""
    _user_id_ctx.set(7)
    p1, p2, p3 = _create_patches(AsyncMock(return_value=_stub_note()))
    with p1, p2, p3, patch.object(links_svc, "rule_candidates", AsyncMock(return_value=None)):
        out = await lesson_tools.create_lesson(what="x", when_to_apply=TRIGGER)
    assert "rule_candidates" not in out
    assert out["rule_judgment"] == links_svc.UNJUDGED


@pytest.mark.asyncio
async def test_no_rule_on_create_records_the_answer_and_offers_nothing():
    _user_id_ctx.set(7)
    answered = AsyncMock()
    search = AsyncMock(return_value=[])
    p1, p2, p3 = _create_patches(AsyncMock(return_value=_stub_note(id=41)))
    with p1, p2, p3, patch.object(links_svc, "set_no_rule", answered), \
         patch.object(links_svc, "rule_candidates", search):
        out = await lesson_tools.create_lesson(
            what="x", when_to_apply=TRIGGER, no_rule="a one-off of this CI host",
        )
    assert answered.await_args.args[1:] == (41, "a one-off of this CI host")
    search.assert_not_awaited()
    assert "rule_candidates" not in out


@pytest.mark.asyncio
async def test_rules_and_no_rule_together_write_nothing():
    _user_id_ctx.set(7)
    created = AsyncMock(return_value=_stub_note())
    p1, p2, p3 = _create_patches(created)
    with p1, p2, p3, patch.object(links_svc, "require_rules", AsyncMock(return_value=[5])):
        with pytest.raises(ValueError, match="no_rule"):
            await lesson_tools.create_lesson(
                what="x", when_to_apply=TRIGGER, rule_ids=[5], no_rule="none fits",
            )
    created.assert_not_awaited()


@pytest.mark.asyncio
async def test_update_records_no_rule_and_refuses_it_beside_named_rules():
    _user_id_ctx.set(7)
    answered = AsyncMock()
    updated = AsyncMock(return_value=_stub_note())
    with patch.object(lessons_svc, "update_lesson", updated), \
         patch.object(links_svc, "set_no_rule", answered):
        await lesson_tools.update_lesson(lesson_id=41, no_rule="stands alone")
    assert answered.await_args.args[1:] == (41, "stands alone")

    updated.reset_mock()
    with patch.object(lessons_svc, "update_lesson", updated), \
         patch.object(links_svc, "require_rules", AsyncMock(return_value=[5])):
        with pytest.raises(ValueError):
            await lesson_tools.update_lesson(lesson_id=41, rule_ids=[5], no_rule="none")
    updated.assert_not_awaited()


def test_an_empty_rule_list_beside_no_rule_is_one_answer_not_two():
    """`rule_ids=[]` clears; it does not name a rule, so it cannot contradict."""
    links_svc.require_one_answer([], "none fits")
    links_svc.require_one_answer(None, "none fits")
    links_svc.require_one_answer([5], "")
    with pytest.raises(ValueError):
        links_svc.require_one_answer([5], "none fits")


@pytest.mark.asyncio
async def test_list_unjudged_is_a_listing_and_routes_to_its_own_query():
    _user_id_ctx.set(7)
    listed = AsyncMock(return_value=([], 0))
    with patch.object(links_svc, "list_unjudged", listed), \
         patch("scribe.mcp.tools.lessons.access_svc.label_shared_items", AsyncMock(return_value=[])), \
         patch("scribe.mcp.tools.lessons.attach_usage", AsyncMock()):
        out = await lesson_tools.list_lessons(unjudged=True, tag="ci", project_id=2)
    assert out == {"lessons": [], "total": 0}
    assert listed.await_args.kwargs["tag"] == "ci"
    assert listed.await_args.kwargs["project_id"] == 2
    with pytest.raises(ValueError):
        await lesson_tools.list_lessons(unjudged=True, q="log")


def test_backup_skips_a_no_rule_answer_whose_lesson_did_not_restore():
    maps = backup._Maps()
    assert backup._build_lesson_no_rule({"lesson_id": 10, "why": "alone"}, maps) is None
    maps.notes[10] = 110
    built = backup._build_lesson_no_rule({"lesson_id": 10, "why": "alone"}, maps)
    assert (built.lesson_id, built.why) == (110, "alone")
    # An answer with no reason is not an answer; it restores as unjudged.
    assert backup._build_lesson_no_rule({"lesson_id": 10, "why": " "}, maps) is None


def test_the_no_rule_migration_follows_the_link_migration():
    path = Path(__file__).resolve().parents[1] / "alembic" / "versions" / "0112_lesson_no_rule.py"
    spec = importlib.util.spec_from_file_location("m0112", path)
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)
    assert (module.revision, module.down_revision) == ("0112", "0111")