"""Enhanced Beancount data structures for Conservancy"""

# Copyright © 2020  Brett Smith

#

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU Affero General Public License as published by

# the Free Software Foundation, either version 3 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU Affero General Public License for more details.

#

# You should have received a copy of the GNU Affero General Public License

# along with this program.  If not, see <https://www.gnu.org/licenses/>.

import collections.abc

from beancount.core import account as bc_account

from typing import (

    Iterable,

    Iterator,

    MutableMapping,

    Optional,

)

from .beancount_types import (

    MetaKey,

    MetaValue,

    Posting as BasePosting,

    Transaction,

)

class Account(str):

    SEP = bc_account.sep

    def is_real_asset(self) -> bool:

        return bool(

            self.is_under('Assets:')

            and not self.is_under('Assets:PrepaidExpenses')

            and not self.is_under('Assets:PrepaidVacation')

        )

    def is_under(self, *acct_seq: str) -> Optional[str]:

        for prefix in acct_seq:

            if self.startswith(prefix) and (

                prefix.endswith(self.SEP)

                or self == prefix

                or self[len(prefix)] == self.SEP

            ):

                return prefix

        return None

class PostingMeta(collections.abc.MutableMapping):

    def __init__(self,

                 txn: Transaction,

                 index: int,

                 post: Optional[BasePosting]=None,

    ) -> None:

        if post is None:

            post = txn.postings[index]

        self.txn = txn

        self.index = index

        self.post = post

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

        keys: Iterable[MetaKey]

        if self.post.meta is None:

            keys = self.txn.meta.keys()

        else:

            keys = frozenset(self.post.meta.keys()).union(self.txn.meta.keys())

        return iter(keys)

    def __len__(self) -> int:

        return sum(1 for _ in self)

    def __getitem__(self, key: MetaKey) -> MetaValue:

        if self.post.meta:

            try:

                return self.post.meta[key]

            except KeyError:

                pass

        return self.txn.meta[key]

    def __setitem__(self, key: MetaKey, value: MetaValue) -> None:

        if self.post.meta is None:

            self.post = self.post._replace(meta={key: value})

            self.txn.postings[self.index] = self.post

        else:

            self.post.meta[key] = value

    def __delitem__(self, key: MetaKey) -> None:

        if self.post.meta is None:

            raise KeyError(key)

        else:

            del self.post.meta[key]

class Posting(BasePosting):

    account: Account

    # mypy correctly complains that our MutableMapping is not compatible with

    # Beancount's meta type declaration of Optional[Dict]. IMO this is a case

    # of Beancount's type declaration being a smidge too specific: I think it

    # would be very unusual for code to actually require a dict over a more

    # generic mapping. If it did, this would work fine.

    meta: MutableMapping[MetaKey, MetaValue]  # type:ignore[assignment]

def iter_postings(txn: Transaction) -> Iterator[Posting]:

    for index, source in enumerate(txn.postings):

        yield Posting(

            Account(source.account),

            *source[1:5],

            # see rationale above about Posting.meta

            PostingMeta(txn, index, source), # type:ignore[arg-type]

        )

"""meta_income_type - Validate income-type metadata"""

# Copyright © 2020  Brett Smith

#

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU Affero General Public License as published by

# the Free Software Foundation, either version 3 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU Affero General Public License for more details.

#

# You should have received a copy of the GNU Affero General Public License

# along with this program.  If not, see <https://www.gnu.org/licenses/>.

from . import core

from .. import data

from .. import errors as errormod

from ..beancount_types import (

    MetaValueEnum,

    Transaction,

)

class MetaIncomeType(core._NormalizePostingMetadataHook):

    VALUES_ENUM = core.MetadataEnum('income-type', {

        'Donations',

        'Payable-Derecognition',

        'RBI',

        'UBTI',

    })

    DEFAULT_VALUES = {

        'Income:Donations': 'Donations',

        'Income:Honoraria': 'RBI',

        'Income:Interest': 'RBI',

        'Income:Interest:Dividend': 'RBI',

        'Income:Royalties': 'RBI',

        'Income:Sales': 'RBI',

        'Income:SoftwareDevelopment': 'RBI',

        'Income:TrademarkLicensing': 'RBI',

        'UnearnedIncome:Conferences:Registrations': 'RBI',

        'UnearnedIncome:MatchPledges': 'Donations',

    }

    def _run_on_post(self, txn: Transaction, post: data.Posting) -> bool:

    def _default_value(self, txn: Transaction, post: data.Posting) -> MetaValueEnum:

        try:

            return self.DEFAULT_VALUES[post.account]

        except KeyError:

            raise errormod.InvalidMetadataError(txn, post, self.METADATA_KEY) from None

"""Test Account class"""

# Copyright © 2020  Brett Smith

#

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU Affero General Public License as published by

# the Free Software Foundation, either version 3 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU Affero General Public License for more details.

#

# You should have received a copy of the GNU Affero General Public License

# along with this program.  If not, see <https://www.gnu.org/licenses/>.

import pytest

from conservancy_beancount import data

@pytest.mark.parametrize('acct_name,under_arg,expected', [

    ('Expenses:Tax:Sales', 'Expenses:Tax:Sales:', False),

    ('Expenses:Tax:Sales', 'Expenses:Tax:Sales', True),

    ('Expenses:Tax:Sales', 'Expenses:Tax:', True),

    ('Expenses:Tax:Sales', 'Expenses:Tax', True),

    ('Expenses:Tax:Sales', 'Expenses:', True),

    ('Expenses:Tax:Sales', 'Expenses', True),

    ('Expenses:Tax:Sales', 'Expense', False),

    ('Expenses:Tax:Sales', 'Accrued:', False),

    ('Expenses:Tax:Sales', 'Accrued', False),

])

def test_is_under_one_arg(acct_name, under_arg, expected):

    expected = under_arg if expected else None

    assert data.Account(acct_name).is_under(under_arg) == expected

@pytest.mark.parametrize('acct_name,expected', [

    ('Income:Other', 'Income'),

    ('UnearnedIncome:Other', 'UnearnedIncome'),

    ('Accrued:AccountsPayable', None),

    ('Expenses:General', None),

])

def test_is_under_multi_arg(acct_name, expected):

    assert data.Account(acct_name).is_under('Income', 'UnearnedIncome') == expected

    if expected:

        expected += ':'

    assert data.Account(acct_name).is_under('Income:', 'UnearnedIncome:') == expected

@pytest.mark.parametrize('acct_name,expected', [

    ('Accrued:AccountsPayable', False),

    ('Accrued:AccountsReceivable', False),

    ('Assets:Cash', True),

    ('Assets:Cash:EUR', True),

    ('Assets:PrepaidExpenses', False),

    ('Assets:PrepaidVacation', False),

    ('Assets:Bank:Checking', True),

    ('Expenses:General', False),

    ('Income:Donations', False),

])

def test_is_real_asset(acct_name, expected):

    assert data.Account(acct_name).is_real_asset() == expected