"""test_books_loader - Unit tests for books Loader 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 collections
import re

from datetime import date
from pathlib import Path

import pytest

from . import testutil

from beancount.core import data as bc_data
from conservancy_beancount import books

FY_START_MONTH = 3

books_path = testutil.test_path('books')

@pytest.fixture(scope='module')
def conservancy_loader():
    return books.Loader(books_path, books.FiscalYear(FY_START_MONTH))

def check_openings(entries):
    openings = collections.defaultdict(int)
    for entry in entries:
        if isinstance(entry, bc_data.Open):
            openings[entry.account] += 1
    for account, count in openings.items():
        assert count == 1, f"found {count} open directives for {account}"

def txn_dates(entries):
    for entry in entries:
        if isinstance(entry, bc_data.Transaction):
            yield entry.date

def txn_years(entries):
    return frozenset(date.year for date in txn_dates(entries))

@pytest.mark.parametrize('from_fy,to_fy,expect_years', [
    (2019, 2019, range(2019, 2020)),
    (0, 2019, range(2019, 2020)),
    (2018, 2019, range(2018, 2020)),
    (1, 2018, range(2018, 2020)),
    (-1, 2019, range(2018, 2020)),
    (2019, 2020, range(2019, 2021)),
    (1, 2019, range(2019, 2021)),
    (-1, 2020, range(2019, 2021)),
    (2010, 2030, range(2018, 2021)),
    (20, 2010, range(2018, 2021)),
    (-20, 2030, range(2018, 2021)),
])
def test_load_fy_range(conservancy_loader, from_fy, to_fy, expect_years):
    entries, errors, options_map = conservancy_loader.load_fy_range(from_fy, to_fy)
    assert not errors
    actual_years = txn_years(entries)
    assert actual_years.issuperset(expect_years)
    assert min(actual_years) == expect_years.start

def test_load_fy_range_does_not_duplicate_openings(conservancy_loader):
    entries, errors, options_map = conservancy_loader.load_fy_range(2010, 2030)
    check_openings(entries)

def test_load_fy_range_empty(conservancy_loader):
    entries, errors, options_map = conservancy_loader.load_fy_range(2020, 2019)
    assert not errors
    assert not entries
    assert not options_map

@pytest.mark.parametrize('from_year', [None, *range(2018, 2021)])
def test_load_all(conservancy_loader, from_year):
    entries, errors, options_map = conservancy_loader.load_all(from_year)
    from_year = from_year or 2018
    assert not errors
    check_openings(entries)
    actual_years = txn_years(entries)
    assert actual_years.issuperset(range(from_year, 2021))
    assert min(actual_years) == from_year

@pytest.mark.parametrize('from_date', [
    date(2019, 2, 1),
    date(2019, 9, 15),
    date(2020, 1, 20),
    date(2020, 5, 31),
])
def test_load_all_from_date(conservancy_loader, from_date):
    from_year = from_date.year
    if from_date.month < FY_START_MONTH:
        from_year -= 1
    entries, errors, options_map = conservancy_loader.load_all(from_date)
    assert not errors
    check_openings(entries)
    actual_years = txn_years(entries)
    assert actual_years.issuperset(range(from_year, 2021))
    assert min(actual_years) == from_year