"""Real-Postgres tests for moving a rule between homes (milestone 414, step 3).

A rule's home is its reach: a rulebook topic makes it global, a project makes
it that project's. The alternative to a move — recreate the rule in the other
home and trash the original — loses the id every record cites, the edit
history, the area tags and the typed edges. These pin that a move keeps all
four, and that the refusals happen before anything is written: the topic/
project CHECK (migration 0059) and the per-topic title index would otherwise
fail the commit with a raw database error.
"""
import uuid
from unittest.mock import MagicMock, patch

import pytest
import pytest_asyncio

from scribe.models import async_session
from scribe.models.project import Project
from scribe.models.rulebook import Rule
from scribe.services import canonical_systems as canonical_svc
from scribe.services import rule_versions as rv_svc
from scribe.services import rulebooks as rulebooks_svc
from tests.helpers import ensure_user

pytestmark = [pytest.mark.integration, pytest.mark.usefixtures("_dispose_engine")]


@pytest.fixture(autouse=True)
def _no_reindex():
    """Rule writes detach an embedding refresh that outlives the test's loop
    and races the next fixture; nothing here is about recall."""
    with patch("scribe.services.rulebooks._refresh_rule_embedding", MagicMock()):
        yield


@pytest_asyncio.fixture
async def homes():
    """A project rule with a version, an area tag and an incoming edge, plus a
    topic to move it into and a second project."""
    tag = uuid.uuid4().hex[:8]
    async with async_session() as s:
        owner = await ensure_user(s, f"rule_move_owner_{tag}")
        stranger = await ensure_user(s, f"rule_move_stranger_{tag}")
        home = Project(user_id=owner.id, title="Where it started")
        other = Project(user_id=owner.id, title="Somewhere else")
        theirs = Project(user_id=stranger.id, title="Not yours")
        s.add_all([home, other, theirs])
        await s.flush()
        ids = {"owner": owner.id, "stranger": stranger.id, "home": home.id,
               "other": other.id, "theirs": theirs.id}
        await s.commit()

    owner = ids["owner"]
    book = await rulebooks_svc.create_rulebook(owner, "House style")
    topic = await rulebooks_svc.create_topic(book.id, owner, "transport")
    rule = await rulebooks_svc.create_project_rule(
        ids["home"], owner, "Plain HTTP only", "No app-level TLS.",
        when_to_apply="setting a cookie flag or a URL scheme",
    )
    await rulebooks_svc.update_rule(rule.id, owner, statement="No app-level TLS, ever.")
    area = await canonical_svc.find_by_name("CI & Release")
    await rulebooks_svc.set_rule_systems(rule.id, owner, [area.id])
    downstream = await rulebooks_svc.create_project_rule(
        ids["home"], owner, "No Secure-Context APIs", "Browsers withhold them.",
        when_to_apply="reaching for the clipboard API",
    )
    await rulebooks_svc.add_rule_relation(owner, downstream.id, rule.id, "elaborates")
    ids.update(topic=topic.id, rule=rule.id, area=area.id)
    return ids


async def _row(rule_id: int) -> Rule:
    async with async_session() as s:
        return await s.get(Rule, rule_id)


async def test_a_project_rule_becomes_global_and_keeps_everything(homes):
    owner, rule_id = homes["owner"], homes["rule"]
    moved = await rulebooks_svc.move_rule(rule_id, owner, topic_id=homes["topic"])

    assert moved.id == rule_id
    row = await _row(rule_id)
    assert (row.topic_id, row.project_id) == (homes["topic"], None)
    assert len(await rv_svc.list_versions(rule_id)) == 1, "the move must not drop history"
    areas = await rulebooks_svc.list_rule_systems([rule_id])
    assert [a["id"] for a in areas[rule_id]] == [homes["area"]]
    edges = await rulebooks_svc.list_rule_relations([rule_id])
    assert [e["kind"] for e in edges[rule_id]] == ["elaborates"]


async def test_a_move_writes_no_version(homes):
    """A version records what a rule SAID (milestone 323, decision 4). A move
    changes where it binds, not a word of it."""
    before = len(await rv_svc.list_versions(homes["rule"]))
    await rulebooks_svc.move_rule(homes["rule"], homes["owner"], topic_id=homes["topic"])
    assert len(await rv_svc.list_versions(homes["rule"])) == before


async def test_a_global_rule_can_move_onto_a_project(homes):
    owner, rule_id = homes["owner"], homes["rule"]
    await rulebooks_svc.move_rule(rule_id, owner, topic_id=homes["topic"])
    await rulebooks_svc.move_rule(rule_id, owner, project_id=homes["other"])
    row = await _row(rule_id)
    assert (row.topic_id, row.project_id) == (None, homes["other"])


async def test_refusals_happen_before_anything_is_written(homes):
    owner, rule_id = homes["owner"], homes["rule"]

    with pytest.raises(ValueError, match="exactly one"):
        await rulebooks_svc.move_rule(rule_id, owner)
    with pytest.raises(ValueError, match="exactly one"):
        await rulebooks_svc.move_rule(rule_id, owner, topic_id=homes["topic"],
                                      project_id=homes["other"])
    with pytest.raises(ValueError, match="already on project"):
        await rulebooks_svc.move_rule(rule_id, owner, project_id=homes["home"])
    with pytest.raises(ValueError, match="not found"):
        await rulebooks_svc.move_rule(rule_id, owner, project_id=homes["theirs"])

    # A topic already holding a live rule with this title: named, not a raw
    # IntegrityError from uq_rule_per_topic at commit.
    clash = await rulebooks_svc.create_rule(
        homes["topic"], owner, "Plain HTTP only", "Already here.",
        when_to_apply="setting a cookie flag",
    )
    with pytest.raises(ValueError, match=f"rule {clash.id}"):
        await rulebooks_svc.move_rule(rule_id, owner, topic_id=homes["topic"])

    row = await _row(rule_id)
    assert (row.topic_id, row.project_id) == (None, homes["home"])


async def test_someone_elses_rule_is_not_found(homes):
    """None, like every other rule read the caller cannot see — not an error
    that confirms the rule exists."""
    assert await rulebooks_svc.move_rule(
        homes["rule"], homes["stranger"], project_id=homes["theirs"],
    ) is None