"""test_reports_period_postings - Unit tests for PeriodPostings"""
# 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 datetime
import operator

from decimal import Decimal

import pytest

from . import testutil

from conservancy_beancount import data
from conservancy_beancount.reports import core

def check_balance_attrs(balance_postings, start_usd, stop_usd):
    if start_usd:
        expected = {'USD': testutil.Amount(start_usd)}
        assert balance_postings.start_bal == expected
        assert balance_postings.begin_bal == expected
    else:
        assert balance_postings.start_bal.is_zero()
        assert balance_postings.begin_bal.is_zero()
    expected = {'USD': testutil.Amount(stop_usd)}
    assert balance_postings.stop_bal == expected
    assert balance_postings.end_bal == expected
    expected = {'USD': testutil.Amount(stop_usd - start_usd)}
    assert balance_postings.period_bal == expected

@pytest.mark.parametrize('start_date,expect_start_bal', [
    (datetime.date(2019, 2, 1), 0),
    (datetime.date(2019, 4, 1), 30),
    (datetime.date(2019, 6, 1), 120),
])
def test_balance_postings_attrs(start_date, expect_start_bal):
    entries = [testutil.Transaction(date=datetime.date(2019, n, 15), postings=[
        ('Income:Donations', -n * 10),
        ('Assets:Cash', n * 10),
    ]) for n in range(3, 7)]
    cls = core.PeriodPostings.with_start_date(start_date)
    actual = dict(cls.group_by_account(data.Posting.from_entries(entries)))
    assert len(actual) == 2
    check_balance_attrs(actual['Assets:Cash'], expect_start_bal, 180)
    check_balance_attrs(actual['Income:Donations'], -expect_start_bal, -180)

@pytest.mark.parametrize('start_date,expect_count', [
    (datetime.date(2019, 2, 1), 4),
    (datetime.date(2019, 4, 1), 3),
    (datetime.date(2019, 6, 1), 1),
])
def test_balance_postings_filter(start_date, expect_count):
    entries = [testutil.Transaction(date=datetime.date(2019, n, 15), postings=[
        ('Income:Donations', -n * 10),
        ('Assets:Cash', n * 10),
    ]) for n in range(3, 7)]
    cls = core.PeriodPostings.with_start_date(start_date)
    for _, related in cls.group_by_account(data.Posting.from_entries(entries)):
        assert len(related) == expect_count