"""Regression coverage for the openGauss/GaussDB persistence backend."""

from __future__ import annotations

from datetime import UTC, datetime

import pytest
from pydantic import ValidationError
from sqlalchemy.engine import make_url
from sqlalchemy.schema import CreateIndex, CreateTable

from deerflow.config.database_config import DatabaseConfig
from deerflow.persistence.types import BeijingDateTime


@pytest.mark.parametrize(
    ("configured", "expected"),
    [
        (
            "opengauss://user:pass@127.0.0.1:26000/deerflow",
            "opengauss+asyncpg://user:pass@127.0.0.1:26000/deerflow",
        ),
        (
            "postgresql://user:pass@127.0.0.1:26000/deerflow?ssl=require",
            "opengauss+asyncpg://user:pass@127.0.0.1:26000/deerflow?ssl=require",
        ),
        (
            "opengauss+asyncpg://user:pass@127.0.0.1:26000/deerflow",
            "opengauss+asyncpg://user:pass@127.0.0.1:26000/deerflow",
        ),
    ],
)
def test_gauss_urls_always_select_the_opengauss_async_dialect(
    configured: str,
    expected: str,
) -> None:
    config = DatabaseConfig(backend="gauss", gauss_url=configured)
    assert config.app_sqlalchemy_url == expected


def test_gauss_backend_requires_a_supported_nonempty_url() -> None:
    with pytest.raises(ValueError, match="gauss_url is required"):
        _ = DatabaseConfig(backend="gauss").app_sqlalchemy_url

    with pytest.raises(ValueError, match="must use opengauss"):
        _ = DatabaseConfig(
            backend="gauss",
            gauss_url="mysql://user:pass@127.0.0.1/deerflow",
        ).app_sqlalchemy_url

    with pytest.raises(ValidationError):
        DatabaseConfig(backend="unknown")


def test_gauss_timestamps_keep_timezone_information() -> None:
    dialect = type("GaussDialect", (), {"name": "opengauss"})()
    value = datetime(2026, 9, 2, 8, 30, tzinfo=UTC)
    column_type = BeijingDateTime()

    assert column_type.process_bind_param(value, dialect) is value
    assert column_type.process_result_value(value, dialect) is value


def test_official_async_dialect_compiles_the_complete_orm_schema() -> None:
    """Every registered table/index must compile before startup touches GaussDB."""
    pytest.importorskip("opengauss_sqlalchemy")

    import deerflow.persistence.models  # noqa: F401 -- register ORM metadata
    from deerflow.persistence.base import Base

    dialect_cls = make_url("opengauss+asyncpg://user:pass@localhost/db").get_dialect(
        _is_async=True
    )
    dialect = dialect_cls()

    assert dialect.__class__.__module__.startswith("opengauss_sqlalchemy")
    assert Base.metadata.sorted_tables
    for table in Base.metadata.sorted_tables:
        assert str(CreateTable(table).compile(dialect=dialect)).startswith("\nCREATE TABLE")
        for index in table.indexes:
            assert str(CreateIndex(index).compile(dialect=dialect)).startswith("CREATE")