"""meta_receipt - Validate receipt 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 decimal import Decimal

from . import core
from .. import config as configmod
from .. import data
from .. import errors as errormod
from ..beancount_types import (
    MetaKey,
    Transaction,
)

from typing import (
    Callable,
)

class MetaReceipt(core._RequireLinksPostingMetadataHook):
    CHECKED_METADATA = ['receipt']

    def __init__(self, config: configmod.Config) -> None:
        self.payment_threshold = abs(config.payment_threshold())

    def _run_on_post(self, txn: Transaction, post: data.Posting) -> bool:
        return (
            (post.account.is_cash_equivalent() or post.account.is_credit_card())
            and not post.account.is_under('Assets:PayPal')
            and post.units.number is not None
            and abs(post.units.number) >= self.payment_threshold
        )

    def _run_checking_debit(self, txn: Transaction, post: data.Posting) -> errormod.Iter:
        receipt_errors = list(self._check_metadata(txn, post, self.CHECKED_METADATA))
        if not receipt_errors:
            return
        for error in receipt_errors:
            if error.value is not None:
                yield error
        try:
            check_id = post.meta['check-id']
        except KeyError:
            check_id_ok = False
        else:
            check_id_ok = (isinstance(check_id, Decimal)
                           and check_id >= 1
                           and not check_id % 1)
            if not check_id_ok:
                yield errormod.InvalidMetadataError(txn, 'check-id', check_id, post, Decimal)
        if not check_id_ok:
            yield errormod.InvalidMetadataError(txn, 'receipt/check-id', post=post)

    def post_run(self, txn: Transaction, post: data.Posting) -> errormod.Iter:
        keys = list(self.CHECKED_METADATA)
        is_checking = post.account.is_checking()
        if is_checking and post.is_debit():
            return self._run_checking_debit(txn, post)
        elif is_checking:
            keys.append('check')
        elif post.account.is_credit_card() and not post.is_credit():
            keys.append('invoice')
        return self._check_metadata(txn, post, keys)