"""books - Tools for loading the books"""

# 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

from typing import (

    Iterable,

    NamedTuple,

    Optional,

    Union,

)

class FiscalYear(NamedTuple):

    month: int = 3

    day: int = 1

    def for_date(self, date: Optional[datetime.date]=None) -> int:

        if date is None:

            date = datetime.date.today()

        if (date.month, date.day) < self:

            return date.year - 1

        else:

            return date.year

    def range(self,

              from_fy: Union[int, datetime.date],

              to_fy: Union[int, datetime.date, None]=None,

    ) -> Iterable[int]:

        """Return a range of fiscal years

        Both arguments can be either a year (represented as an integer) or a

        date. Dates will be converted into a year by calling for_date() on

        them.

        If the first argument is negative or below 1000, it will be treated as

        an offset. You'll get a range of fiscal years between the second

        argument offset by this amount.

        If the second argument is omitted, it defaults to the current fiscal

        year.

        Note that unlike normal Python ranges, these ranges include the final

        fiscal year.

        Examples:

          range(2015)  # Iterate all fiscal years from 2015 to today, inclusive

          range(-1)  # Iterate the previous fiscal year and current fiscal year

        """

        if not isinstance(from_fy, int):

            from_fy = self.for_date(from_fy)

        if to_fy is None:

            to_fy = self.for_date()

        elif not isinstance(to_fy, int):

            to_fy = self.for_date(to_fy - datetime.timedelta(days=1))

        if from_fy < 1:

            from_fy += to_fy

        elif from_fy < 1000:

            from_fy, to_fy = to_fy, from_fy + to_fy

        return range(from_fy, to_fy + 1)

"""test_books_fiscal_year - Unit tests for books.FiscalYear"""

# 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 itertools

import pytest

from conservancy_beancount import books

@pytest.fixture(scope='module')

def conservancy_fy():

    return books.FiscalYear(3, 1)

@pytest.fixture(scope='module')

def cy_fy():

    return books.FiscalYear(1, 1)

# Not bothering because it's too much trouble to override __new__

# @pytest.mark.parametrize('month,day', [

#     (0, 0),

#     (2, 29),

#     (4, 31),

#     (13, 15),

#     (-1, 1),

#     (1, -5),

# ])

# def test_values_checked(month, day):

#     with pytest.raises(ValueError):

#         books.FiscalYear(month, day)

def test_attribute_access():

    fy = books.FiscalYear(2, 15)

    assert fy.month == 2

    assert fy.day == 15

    with pytest.raises(AttributeError):

        fy.year

@pytest.mark.parametrize('month,day,expected', [

    (1, 1, 2019),

    (2, 15, 2019),

    (2, 28, 2019),

    (2, 29, 2019),

    (3, 1, 2020),

    (3, 9, 2020),

    (6, 1, 2020),

    (12, 31, 2020),

])

def test_for_date(conservancy_fy, month, day, expected):

    date = datetime.date(2020, month, day)

    assert conservancy_fy.for_date(date) == expected

def test_for_date_default_today(cy_fy):

    assert cy_fy.for_date() == datetime.date.today().year

@pytest.mark.parametrize('begin_date,end_date,expected', [

    ((2020, 3, 1), (2021, 2, 28), [2020]),

    ((2020, 1, 1), (2020, 3, 1), [2019]),

    ((2020, 1, 1), (2020, 3, 5), [2019, 2020]),

    ((2019, 2, 1), (2020, 6, 1), [2018, 2019, 2020]),

])

def test_range_two_dates(conservancy_fy, begin_date, end_date, expected):

    actual = list(conservancy_fy.range(datetime.date(*begin_date), datetime.date(*end_date)))

    assert actual == expected

@pytest.mark.parametrize('year_offset', range(3))

def test_range_one_date(cy_fy, year_offset):

    this_year = datetime.date.today().year

    actual = list(cy_fy.range(datetime.date(this_year - year_offset, 1, 1)))

    assert actual == list(range(this_year - year_offset, this_year + 1))

@pytest.mark.parametrize('begin_year,end_year', [

    (2006, 2020),

    (2019, 2020),

    (2020, 2020),

])

def test_range_two_years(conservancy_fy, begin_year, end_year):

    actual = list(conservancy_fy.range(begin_year, end_year))

    assert actual == list(range(begin_year, end_year + 1))

@pytest.mark.parametrize('year_offset', range(3))

def test_range_one_year(cy_fy, year_offset):

    this_year = datetime.date.today().year

    actual = list(cy_fy.range(this_year - year_offset))

    assert actual == list(range(this_year - year_offset, this_year + 1))

@pytest.mark.parametrize('year_offset,month_offset', itertools.product(

    range(-3, 3),

    [-1, 1]

))

def test_range_offset_and_date(conservancy_fy, year_offset, month_offset):

    end_date = datetime.date(2020, conservancy_fy.month + month_offset, 10)

    base_year = end_date.year

    if month_offset < 0:

        base_year -= 1

    if year_offset < 0:

        expected = range(base_year + year_offset, base_year + 1)

    else:

        expected = range(base_year, base_year + year_offset + 1)

    actual = list(conservancy_fy.range(year_offset, end_date))

    assert actual == list(expected)

@pytest.mark.parametrize('year_offset,year', itertools.product(

    range(-3, 3),

    [2010, 2015],

))

def test_range_offset_and_year(conservancy_fy, year_offset, year):

    if year_offset < 0:

        expected = range(year + year_offset, year + 1)

    else:

        expected = range(year, year + year_offset + 1)

    actual = list(conservancy_fy.range(year_offset, year))

    assert actual == list(expected)

@pytest.mark.parametrize('year_offset', range(-3, 3))

def test_range_offset_only(cy_fy, year_offset):

    year = datetime.date.today().year

    if year_offset < 0:

        expected = range(year + year_offset, year + 1)

    else:

        expected = range(year, year + year_offset + 1)

    actual = list(cy_fy.range(year_offset))

    assert actual == list(expected)