from typing import Any

from psycopg import AsyncConnection


class NetworkSettingsRepository:
    @staticmethod
    async def get_result_units(conn: AsyncConnection) -> dict[str, str]:
        async with conn.cursor() as cur:
            await cur.execute(
                """
                SELECT engine_version, key, value
                FROM network.simulation_settings
                WHERE (engine_version = 'v3' AND key IN ('FLOW_UNITS', 'PRESSURE_UNITS'))
                   OR (engine_version = 'legacy' AND key IN ('UNITS', 'PRESSURE'))
                ORDER BY CASE engine_version WHEN 'v3' THEN 0 ELSE 1 END
                """
            )
            rows: list[dict[str, Any]] = await cur.fetchall()

        units: dict[str, str] = {}
        for row in rows:
            key = str(row["key"])
            metric = "flow" if key in {"FLOW_UNITS", "UNITS"} else "pressure"
            units.setdefault(metric, str(row["value"]).strip())
        missing = {"flow", "pressure"} - units.keys()
        if missing:
            raise ValueError(
                "network simulation settings missing result units: "
                + ", ".join(sorted(missing))
            )
        return units