from contextlib import asynccontextmanager
from datetime import datetime, timezone
from types import SimpleNamespace
from uuid import uuid4

import pytest
from fastapi import HTTPException

from app.api.v1.endpoints import workbench_events as endpoint
from app.auth.project_dependencies import ProjectContext
from app.infra.db.project_routing import ActiveProjectRouting


@pytest.fixture
def anyio_backend():
    return "asyncio"


class FakeHub:
    generation = 0

    async def oldest_cursor(self):
        return 5

    async def current_cursor(self):
        return 8


class FakeHubManager:
    @asynccontextmanager
    async def subscribe(self, _project_id, _dsn):
        yield FakeHub()


class FakeMetadataRepository:
    def __init__(self, routings):
        self.routings = routings
        self.session = SimpleNamespace(closed=False, close=self.close)

    async def close(self):
        self.session.closed = True

    async def list_active_project_db_routings(self, _role):
        return self.routings


class FakeSnapshotConnection:
    def __init__(self):
        self.statements = []

    @asynccontextmanager
    async def transaction(self):
        yield

    async def execute(self, statement):
        self.statements.append(statement)


class FakeEventRepository:
    def __init__(self, _conn, _project_id):
        pass

    async def current_cursor(self):
        return 12


class FakeOperationalTaskService:
    async def list(self, **_kwargs):
        return [], None

    async def list_notifications(self, **_kwargs):
        return [], None


@pytest.mark.anyio
async def test_sync_snapshot_starts_psycopg_read_only_repeatable_read_transaction(monkeypatch):
    project_id = uuid4()
    conn = FakeSnapshotConnection()
    now = datetime.now(timezone.utc)

    async def fake_runtime(**_kwargs):
        return {
            "availability": "not_configured",
            "source": "none",
            "scenario_availability": "not_configured",
            "artifact_availability": "not_configured",
            "schedule_availability": "not_configured",
            "work_order_availability": "not_configured",
            "alert_availability": "not_configured",
            "generated_at": now,
            "conditions": [],
            "alerts": [],
            "scenarios": [],
            "latest_analysis": None,
            "work_orders": [],
        }

    monkeypatch.setattr(endpoint, "WorkbenchEventRepository", FakeEventRepository)
    monkeypatch.setattr(endpoint, "workbench_runtime", fake_runtime)
    monkeypatch.setattr(endpoint, "_service", lambda _ctx, _conn: FakeOperationalTaskService())

    snapshot = await endpoint.workbench_sync_snapshot(
        ctx=ProjectContext(
            project_id=project_id,
            project_code="project-a",
            user_id=uuid4(),
            project_role="member",
        ),
        conn=conn,
    )

    assert snapshot.event_cursor == 12
    assert conn.statements == [
        "SET TRANSACTION ISOLATION LEVEL REPEATABLE READ READ ONLY"
    ]


@pytest.mark.anyio
async def test_expired_event_cursor_requires_snapshot_reset(monkeypatch):
    project_id = uuid4()
    dsn = "postgresql://test@db.example:5432/project_a"
    routing = ActiveProjectRouting("project-a", dsn, project_id=project_id)
    metadata = FakeMetadataRepository([
        SimpleNamespace(project_id=project_id, dsn=dsn)
    ])
    monkeypatch.setattr(endpoint, "workbench_event_hubs", FakeHubManager())

    response = await endpoint.workbench_events(
        after=1,
        last_event_id=None,
        ctx=ProjectContext(
            project_id=project_id, project_code="project-a", user_id=uuid4(),
            project_role="member",
        ),
        routing=routing,
        metadata_repo=metadata,
    )
    first = await anext(response.body_iterator)

    assert metadata.session.closed is True
    assert "event: reset_required" in first
    assert '"cursor":1' in first


@pytest.mark.anyio
async def test_shared_business_database_disables_event_stream():
    project_id = uuid4()
    dsn = "postgresql://user:secret@db.example:5432/shared"
    metadata = FakeMetadataRepository([
        SimpleNamespace(project_id=project_id, dsn=dsn),
        SimpleNamespace(project_id=uuid4(), dsn="postgresql://other:other@db.example/shared"),
    ])

    with pytest.raises(HTTPException) as exc:
        await endpoint.workbench_events(
            after=0,
            last_event_id=None,
            ctx=ProjectContext(
                project_id=project_id, project_code="project-a", user_id=uuid4(),
                project_role="member",
            ),
            routing=ActiveProjectRouting("project-a", dsn, project_id=project_id),
            metadata_repo=metadata,
        )

    assert exc.value.status_code == 503