"""Unified district service - shared between CLI and HTTP API."""
from rec.districts import get_districts as _get_districts


def get_all_districts() -> dict[str, str]:
    """Get all available districts with their region IDs.

    Used by:
    - CLI: --district option choices
    - API: GET /api/get_districts

    Returns:
        Dictionary mapping district names to region IDs
    """
    return _get_districts()


def get_district_names() -> list[str]:
    """Get list of all district names.

    Returns:
        List of district names
    """
    return list(_get_districts().keys())


def validate_districts(district_names: list[str]) -> tuple[bool, list[str]]:
    """Validate that district names exist.

    Args:
        district_names: List of district names to validate

    Returns:
        Tuple of (all_valid, invalid_names)
    """
    valid_districts = set(_get_districts().keys())
    invalid = [d for d in district_names if d not in valid_districts]
    return len(invalid) == 0, invalid