LinkType = Union[str, Tuple[str, Optional[str]]]

RelatedType = TypeVar('RelatedType', bound='RelatedPostings')

RT = TypeVar('RT', bound=Sequence)

ST = TypeVar('ST')

T = TypeVar('T')

class Balance(Mapping[str, data.Amount]):

    """A collection of amounts mapped by currency

    Each key is a Beancount currency string, and each value represents the

    balance in that currency.

    """

    __slots__ = ('_currency_map', 'tolerance')

    TOLERANCE = Decimal('0.01')

    def __init__(self,

                 source: Iterable[data.Amount]=(),

                 tolerance: Optional[Decimal]=None,

    ) -> None:

        if tolerance is None:

            tolerance = self.TOLERANCE

        self.tolerance = tolerance

        self._currency_map: Dict[str, data.Amount] = {}

        for amount in source:

            self._add_amount(self._currency_map, amount)

    def _add_amount(self,

                    currency_map: MutableMapping[str, data.Amount],

                    amount: data.Amount,

    ) -> None:

        code = amount.currency

        try:

            current_number = currency_map[code].number

        except KeyError:

            current_number = Decimal(0)

        currency_map[code] = data.Amount(current_number + amount.number, code)

    def _add_other(self,

                   currency_map: MutableMapping[str, data.Amount],

                   other: Union[data.Amount, 'Balance'],

    ) -> None:

        if isinstance(other, Balance):

            for amount in other.values():

                self._add_amount(currency_map, amount)

        else:

            self._add_amount(currency_map, other)

    def __repr__(self) -> str:

        values = [repr(amt) for amt in self.values()]

        return f"{type(self).__name__}({values!r})"

    def __str__(self) -> str:

        return self.format()

    def __abs__(self: BalanceType) -> BalanceType:

        return type(self)(bc_amount.abs(amt) for amt in self.values())

    def __add__(self: BalanceType, other: Union[data.Amount, 'Balance']) -> BalanceType:

        retval_map = self._currency_map.copy()

        self._add_other(retval_map, other)

        return type(self)(retval_map.values())

    def __sub__(self: BalanceType, other: Union[data.Amount, 'Balance']) -> BalanceType:

        return self.__add__(-other)

    def __eq__(self, other: Any) -> bool:

        if isinstance(other, Balance):

            clean_self = self.clean_copy()

            clean_other = other.clean_copy()

            return len(clean_self) == len(clean_other) and all(

                clean_self[key] == clean_other.get(key) for key in clean_self

            )

        else:

            return super().__eq__(other)

    def __neg__(self: BalanceType) -> BalanceType:

        return type(self)(-amt for amt in self.values())

    def __pos__(self: BalanceType) -> BalanceType:

        return self

    def __getitem__(self, key: str) -> data.Amount:

        return self._currency_map[key]

    def __iter__(self) -> Iterator[str]:

        return iter(self._currency_map)

    def __len__(self) -> int:

        return len(self._currency_map)

    def _all_amounts(self,

                     op_func: Callable[[DecimalCompat, DecimalCompat], bool],

                     operand: DecimalCompat,

    ) -> bool:

        return all(op_func(amt.number, operand) for amt in self.values())

    def clean_copy(self: BalanceType, tolerance: Optional[Decimal]=None) -> BalanceType:

        if tolerance is None:

            tolerance = self.tolerance

        return type(self)(

            (amount for amount in self.values() if abs(amount.number) >= tolerance),

            tolerance,

        )

    @staticmethod

    def within_tolerance(dec: DecimalCompat, tolerance: DecimalCompat) -> bool:

        dec = cast(Decimal, dec)

        return abs(dec) < tolerance

    def eq_zero(self) -> bool:

        """Returns true if all amounts in the balance == 0, within tolerance."""

        return self._all_amounts(self.within_tolerance, self.tolerance)

    is_zero = eq_zero

    def ge_zero(self) -> bool:

        """Returns true if all amounts in the balance >= 0, within tolerance."""

        op_func = operator.gt if self.tolerance else operator.ge

        return self._all_amounts(op_func, -self.tolerance)

    def le_zero(self) -> bool:

        """Returns true if all amounts in the balance <= 0, within tolerance."""

        op_func = operator.lt if self.tolerance else operator.le

        return self._all_amounts(op_func, self.tolerance)

    def format(self,

               fmt: Optional[str]='#,#00.00 ¤¤',

               sep: str=', ',

               empty: str="Zero balance",

               tolerance: Optional[Decimal]=None,

    ) -> str:

        """Formats the balance as a string with the given parameters

        If the balance is zero (within tolerance), returns ``empty``.

        Otherwise, returns a string with each amount in the balance formatted

        as ``fmt``, separated by ``sep``.

        If you set ``fmt`` to None, amounts will be formatted according to the

        user's locale. The default format is Beancount's input format.

        """

        amounts = list(self.clean_copy(tolerance).values())

        if not amounts:

            return empty

        amounts.sort(key=lambda amt: abs(amt.number), reverse=True)

        return sep.join(

            babel.numbers.format_currency(amt.number, amt.currency, fmt)

            for amt in amounts

        )

class MutableBalance(Balance):

    __slots__ = ()

    def __iadd__(self: BalanceType, other: Union[data.Amount, Balance]) -> BalanceType:

        self._add_other(self._currency_map, other)

        return self

    def __isub__(self: BalanceType, other: Union[data.Amount, Balance]) -> BalanceType:

        self._add_other(self._currency_map, -other)

        return self

class RelatedPostings(Sequence[data.Posting]):

    """Collect and query related postings

    This class provides common functionality for collecting related postings

    and running queries on them: iterating over them, tallying their balance,

    etc.

    This class doesn't know anything about how the postings are related. That's

    entirely up to the caller.

    A common pattern is to use this class with collections.defaultdict

    to organize postings based on some key. See the group_by_meta classmethod

    for an example.

    """

    __slots__ = ('_postings',)

    def __init__(self,

                 source: Iterable[data.Posting]=(),

                 *,

                 _can_own: bool=False,

    ) -> None:

        self._postings: List[data.Posting]

        if _can_own and isinstance(source, list):

            self._postings = source

        else:

            self._postings = list(source)

    @classmethod

    def _group_by(cls: Type[RelatedType],