Add BugetaryGroup class

from dataclasses import dataclass

from typing import Self

from collections.abc import Iterable, Sequence

from ..cash_flow.CashFlowDirection import CashFlowDirection

from .BudgetaryItem import BudgetaryItem

@dataclass(frozen=True, eq=False)

class BudgetaryGroup:

    """Group of budgetary items.

    Has a name and an id, and the items it consists of. Furthermore, a group has a cash flow direction that specifies whether its

    items are expenses (CashFlowDirection.OUTGOING) or income (CashFlowDirection.INCOMING). This means that a budget plan has always at least

    two groups, one for outgoing items and one for incoming items.

    Examples (every line is one group):

    * 1: Verwaltungseinnahmen

    * 2: gemischte Einnahmen

    * 3: Rücklagen aus 2023

    * 5: Verwaltungs- und Betriebsaufwand

    * 7: Projekte der FS

    """

    id: str

    name: str

    cash_flow_direction: CashFlowDirection

    _items: dict[str, BudgetaryItem]

    @classmethod

    def from_items(

        cls,

        id: str,

        name: str,

        cash_flow_direction: CashFlowDirection,

        items: Iterable[BudgetaryItem],

    ) -> Self:

        return cls(

            id=id,

            name=name,

            cash_flow_direction=cash_flow_direction,

            _items={item.id: item for item in items},

        )

    @property

    def items(self) -> Sequence[BudgetaryItem]:

        return tuple(self._items.values())

    def item(self, id: str) -> BudgetaryItem:

        return self._items[id]