"""Test bootstrap.

CI provides DATABASE_URL (a Postgres service container). Locally, when it is unset, a throwaway
Postgres is started with `pgserver` so `pytest` needs no Docker. Set REQUIRE_DB=1 to turn a missing
database into a failure instead of a skip (CI does this).

DATABASE_URL must be settled before anything imports `app`, because `app.config.settings` and the
engine in `app.db` are created at import time.
"""
import os
import tempfile
from collections.abc import AsyncIterator, Iterator
from pathlib import Path
from typing import TYPE_CHECKING

import pytest
from httpx import ASGITransport, AsyncClient

if TYPE_CHECKING:
    from alembic.config import Config

API_DIR = Path(__file__).resolve().parents[1]
_pg_server = None  # keeps the pgserver handle alive for the whole session


def _resolve_database_url() -> str | None:
    global _pg_server
    if url := os.environ.get("DATABASE_URL"):
        return url
    try:
        import pgserver
    except ImportError:
        return None
    _pg_server = pgserver.get_server(tempfile.mkdtemp(prefix="rarelens-pg-"), cleanup_mode="delete")
    socket_dir = _pg_server.get_uri().split("host=", 1)[1]
    return f"postgresql+asyncpg://postgres@/postgres?host={socket_dir}"


DATABASE_URL = _resolve_database_url()
if DATABASE_URL:
    os.environ["DATABASE_URL"] = DATABASE_URL


@pytest.fixture(scope="session")
def alembic_cfg() -> "Config":
    if not DATABASE_URL:
        if os.environ.get("REQUIRE_DB"):
            pytest.fail("REQUIRE_DB is set but no database is available")
        pytest.skip("no DATABASE_URL and pgserver is not installed")
    from alembic.config import Config

    cfg = Config(str(API_DIR / "alembic.ini"))
    cfg.set_main_option("script_location", str(API_DIR / "alembic"))
    return cfg


@pytest.fixture(scope="session")
def migrated_db(alembic_cfg: "Config") -> Iterator[None]:
    from alembic import command

    command.upgrade(alembic_cfg, "head")
    yield


@pytest.fixture
async def db(migrated_db: None) -> AsyncIterator[None]:
    from sqlalchemy import text

    from app.db import engine

    async with engine.begin() as conn:
        await conn.execute(
            text("TRUNCATE samples, jobs, variants, predictions RESTART IDENTITY CASCADE")
        )
    yield


@pytest.fixture
async def client() -> AsyncIterator[AsyncClient]:
    from app.main import app

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