from __future__ import annotations

from app.repositories.scheme_seats import (
    bulk_remap_scheme_version_seats,
    list_scheme_version_seats,
)
from app.services.api_errors import raise_unprocessable
from app.services.editor_validation import validate_remap_target_references


def _match_seat(
    seat,
    *,
    seat_record_ids: set[str] | None,
    from_sector_id: str | None,
    from_group_id: str | None,
) -> bool:
    if seat_record_ids is not None and seat.seat_record_id not in seat_record_ids:
        return False
    if from_sector_id is not None and seat.sector_id != from_sector_id:
        return False
    if from_group_id is not None and seat.group_id != from_group_id:
        return False
    return True


async def preview_remap(
    *,
    scheme_version_id: str,
    seat_record_ids: list[str] | None,
    from_sector_id: str | None,
    to_sector_id: str | None,
    from_group_id: str | None,
    to_group_id: str | None,
) -> list[dict]:
    if not any([seat_record_ids, from_sector_id, from_group_id]):
        raise_unprocessable(
            code="remap_filter_required",
            message="At least one remap filter must be provided",
        )

    await validate_remap_target_references(
        scheme_version_id=scheme_version_id,
        to_sector_id=to_sector_id,
        to_group_id=to_group_id,
    )

    seats = await list_scheme_version_seats(scheme_version_id)
    seat_record_id_set = set(seat_record_ids) if seat_record_ids else None

    matched: list[dict] = []
    for seat in seats:
        if not _match_seat(
            seat,
            seat_record_ids=seat_record_id_set,
            from_sector_id=from_sector_id,
            from_group_id=from_group_id,
        ):
            continue

        matched.append(
            {
                "seat_record_id": seat.seat_record_id,
                "seat_id": seat.seat_id,
                "before_sector_id": seat.sector_id,
                "after_sector_id": to_sector_id if to_sector_id is not None else seat.sector_id,
                "before_group_id": seat.group_id,
                "after_group_id": to_group_id if to_group_id is not None else seat.group_id,
            }
        )

    return matched


async def apply_remap(
    *,
    scheme_version_id: str,
    seat_record_ids: list[str] | None,
    from_sector_id: str | None,
    to_sector_id: str | None,
    from_group_id: str | None,
    to_group_id: str | None,
) -> list[dict]:
    preview_items = await preview_remap(
        scheme_version_id=scheme_version_id,
        seat_record_ids=seat_record_ids,
        from_sector_id=from_sector_id,
        to_sector_id=to_sector_id,
        from_group_id=from_group_id,
        to_group_id=to_group_id,
    )

    if not preview_items:
        return []

    await bulk_remap_scheme_version_seats(
        scheme_version_id=scheme_version_id,
        items=preview_items,
    )

    return preview_items