"""Схема БД конфигурируема (`DB_SCHEMA`, issue #38): миграции и приложение работают в схеме с нестандартным именем.

`SCHEMA` читается при импорте моделей, поэтому и Alembic, и «приложение» запускаются отдельными процессами с
`DB_SCHEMA=dkb_alt` в окружении (обычная переменная приоритетнее `.env.test`).
"""

import os
import subprocess
import sys
from typing import Any

import pytest
from sqlalchemy import text
from sqlalchemy.ext.asyncio import AsyncConnection, create_async_engine

from tests.pg_helpers import API_DIR, alembic_async
from tests.test_models_part_07_09 import ALL_TABLES, EXPECTED_ENUM_COUNT

ALT = "dkb_alt"
ALT_ENV = {"DB_SCHEMA": ALT}

#: «Приложение» в схеме ALT: движок и сессия из `src.db.db` (search_path из настроек), запрос ORM без указания схемы.
APP_PROBE = """
import asyncio
from sqlalchemy import func, select, text
from src.db.db import session_transaction
from src.models import Base
from src.models.access import AppUser

async def main() -> None:
    async with session_transaction() as session:
        assert (await session.execute(text("SHOW search_path"))).scalar() == "dkb_alt"
        assert (await session.execute(select(func.count()).select_from(AppUser))).scalar() == 0
    assert Base.metadata.schema == "dkb_alt"
    print("PROBE_OK")

asyncio.run(main())
"""


async def _scalar(conn: AsyncConnection, sql: str, **params: str) -> Any:
    return (await conn.execute(text(sql), params)).scalar()


@pytest.mark.integration
async def test_migrations_and_app_work_in_custom_schema(scratch_db_url: str) -> None:
    """upgrade head -> приложение читает таблицу через сессию -> downgrade base; схема `dkb` не создаётся."""
    engine = create_async_engine(scratch_db_url)
    try:
        await alembic_async(scratch_db_url, "upgrade", "head", env=ALT_ENV)
        async with engine.connect() as conn:
            tables = set(
                (
                    await conn.execute(
                        text("SELECT table_name FROM information_schema.tables WHERE table_schema = :s"), {"s": ALT}
                    )
                ).scalars()
            )
            assert tables == ALL_TABLES | {"alembic_version"}
            namespaces = set((await conn.execute(text("SELECT nspname FROM pg_namespace"))).scalars())
            assert "dkb" not in namespaces
            enums = await _scalar(
                conn,
                "SELECT count(*) FROM pg_type WHERE typnamespace = CAST(:s AS regnamespace) AND typtype = 'e'",
                s=ALT,
            )
            assert enums == EXPECTED_ENUM_COUNT
            # все внешние ключи ведут в таблицы схемы ALT (строковые FK миграций тоже берут схему из настроек)
            foreign_elsewhere = await _scalar(
                conn,
                "SELECT count(*) FROM pg_constraint WHERE contype = 'f' AND confrelid::regclass::text NOT LIKE :p",
                p=f"{ALT}.%",
            )
            assert foreign_elsewhere == 0

        probe = subprocess.run(
            [sys.executable, "-c", APP_PROBE],
            cwd=API_DIR,
            capture_output=True,
            text=True,
            check=False,
            env={**os.environ, **ALT_ENV, "OPENBAO__DATABASE__DATABASE_URL": scratch_db_url},
        )
        assert probe.returncode == 0 and "PROBE_OK" in probe.stdout, probe.stdout + probe.stderr

        await alembic_async(scratch_db_url, "downgrade", "base", env=ALT_ENV)
        async with engine.connect() as conn:
            left = await _scalar(
                conn,
                "SELECT count(*) FROM pg_class WHERE relnamespace = CAST(:s AS regnamespace) "
                "AND relname NOT IN ('alembic_version', 'alembic_version_pkc')",
                s=ALT,
            )
            assert left == 0
    finally:
        await engine.dispose()