from collections.abc import Generator

import pytest

# Attempt import of testcontainers
postgres_container_cls = None
try:
    try:
        from testcontainers.community.postgres import PostgresContainer as _PostgresContainer

        postgres_container_cls = _PostgresContainer
    except ImportError:
        from testcontainers.postgres import PostgresContainer as _PostgresContainer

        postgres_container_cls = _PostgresContainer
except ImportError:
    postgres_container_cls = None


@pytest.fixture(scope="session")
def postgres_container_url() -> Generator[str]:
    """Provides a disposable PostgreSQL 16 container URL strictly via Docker testcontainers.

    Scoped to session to avoid duplicating container startup across tests.
    No ambient admin or SQLite fallbacks.
    """
    if postgres_container_cls is None:
        raise RuntimeError(
            "testcontainers package is required for PostgreSQL integration tests. "
            "SQLite/localhost fallbacks are strictly prohibited."
        )

    try:
        container = postgres_container_cls("postgres:16-alpine")
        container.start()
        host = container.get_container_host_ip()
        port = container.get_exposed_port(5432)
        user = container.username
        password = container.password
        dbname = container.dbname
        url = f"postgresql+asyncpg://{user}:{password}@{host}:{port}/{dbname}"
        try:
            yield url
        finally:
            container.stop()
    except Exception as exc:
        raise RuntimeError(
            f"Failed to start PostgreSQL testcontainer: {exc}. "
            "Docker daemon must be running and accessible for integration tests. "
            "SQLite/localhost fallbacks are prohibited."
        ) from exc


@pytest.fixture
def temp_postgres_db(postgres_container_url: str) -> str:
    """Yields disposable PostgreSQL container database URL."""
    return postgres_container_url