"""Shared pytest fixtures.

Requires TEST_DATABASE_URL (a dedicated Postgres database, e.g. the
`kirche_einfach_test` database from the compose stack). The URL is mapped
onto DATABASE_URL *before* any app module is imported, so settings and the
alembic env both target the test database. Never point this at production.
"""

import os
from pathlib import Path

import pytest

TEST_DB_URL = os.environ.get("TEST_DATABASE_URL")
if not TEST_DB_URL:
    raise RuntimeError(
        "TEST_DATABASE_URL is not set. Refusing to run tests without "
        "an explicit test database (see .env.example)."
    )

# Must precede all `app.*` imports: Settings is instantiated at import time.
os.environ["DATABASE_URL"] = TEST_DB_URL

BACKEND_DIR = Path(__file__).resolve().parent.parent


@pytest.fixture(scope="session")
def db_engine():
    """Engine on the test DB, migrated to head once per session."""
    from alembic import command as alembic_command
    from alembic.config import Config

    from app import db as app_db

    app_db.reset_engine()
    engine = app_db.get_engine()

    cfg = Config()
    cfg.set_main_option("script_location", str(BACKEND_DIR / "migrations"))
    alembic_command.upgrade(cfg, "head")

    yield engine

    engine.dispose()
    app_db.reset_engine()


@pytest.fixture()
def session(db_engine):
    """Function-scoped session; tables are truncated after each test."""
    from sqlmodel import Session, SQLModel

    with Session(db_engine) as s:
        yield s
    with db_engine.begin() as conn:
        for table in reversed(SQLModel.metadata.sorted_tables):
            conn.execute(table.delete())


@pytest.fixture()
async def client():
    """ASGI test client for the FastAPI app."""
    from httpx import ASGITransport, AsyncClient

    from app.main import app

    transport = ASGITransport(app=app)
    async with AsyncClient(transport=transport, base_url="http://test") as c:
        yield c