from pathlib import Path

    Mapping,

PathLike = Union[str, Path]

PluginsSpec = Mapping[str, Optional[str]]

class Loader:

    """Load Beancount books organized by fiscal year"""

    DEFAULT_PLUGINS: PluginsSpec = {

        'conservancy_beancount.plugin': None,

    }

    def __init__(self,

                 books_root: Path,

                 fiscal_year: FiscalYear,

                 plugins: Optional[PluginsSpec]=None,

    ) -> None:

        """Set up a books loader

        Arguments:

        * books_root: A Path to a Beancount books checkout.

        * fiscal_year: A FiscalYear object, used to determine what books to

          load for a given date range.

        * plugins: A mapping that specifies what plugins should be loaded

          before any books. The keys are plugin names, and the values are the

          configuration parameters string to follow. A value of None means the

          plugin takes no configuration string. By default, the loader loads

          conservancy_beancount.plugin.

        """

        if plugins is None:

            plugins = self.DEFAULT_PLUGINS

        self.books_root = books_root

        self.fiscal_year = fiscal_year

        self.plugins = dict(plugins)

    def _format_include(self, year: int, subdir: PathLike='') -> str:

        file_path = Path(self.books_root, subdir, f'{year}.beancount')

        return f'include "{file_path}"'

    def _format_plugin(self, name: str, optstring: Optional[str]=None) -> str:

        if optstring is None:

            return f'plugin "{name}"'

        else:

            return f'plugin "{name}" "{optstring}"'

    def fy_range_string(self,

                        from_fy: Year,

                        to_fy: Optional[Year]=None,

                        plugins: Optional[PluginsSpec]=None,

    ) -> str:

        """Return a string to load books for a range of fiscal years

        This method generates a range of fiscal years by calling

        FiscalYear.range() with its first two arguments. It returns a string of

        Beancount directives to load all plugins and Beancount files for that

        range of fiscal years, suitable for passing to

        beancount.loader.load_string().

        You can specify what plugins to load with the plugins argument. If not

        specified, the string loads the plugins specified for this instance.

        See the __init__ docstring for details.

        """

        if plugins is None:

            plugins = self.plugins

        years = iter(self.fiscal_year.range(from_fy, to_fy))

        try:

            books_start = self._format_include(next(years), 'books')

        except StopIteration:

            return ''

        return '\n'.join([

            *(self._format_plugin(name, opts) for name, opts in plugins.items()),

            books_start,

            *(self._format_include(year) for year in years),

        ])

"""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/>.

from datetime import date

from pathlib import Path

import pytest

from . import testutil

from conservancy_beancount import books

books_path = testutil.test_path('booksroot')

@pytest.fixture(scope='module')

def conservancy_loader():

    return books.Loader(books_path, books.FiscalYear(3))

def format_include(year, subdir=''):

    path = Path(books_path, subdir, f'{year}.beancount')

    return f'include "{path}"'

def format_plugin(name, optstring=None):

    if optstring is None:

        return f'plugin "{name}"'

    else:

        return f'plugin "{name}" "{optstring}"'

def expect_string(years, plugins={'conservancy_beancount.plugin': None}):

    years = iter(years)

    year1_s = format_include(next(years), 'books')

    return '\n'.join([

        *(format_plugin(name, opts) for name, opts in plugins.items()),

        year1_s,

        *(format_include(year) for year in years),

    ])

@pytest.mark.parametrize('range_start,range_stop,expect_years', [

    (2019, 2020, [2019, 2020]),

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

    (date(2019, 1, 1), date(2020, 6, 1), range(2018, 2021)),

    (-1, date(2020, 2, 1), [2018, 2019]),

])

def test_fy_range_string(conservancy_loader, range_start, range_stop, expect_years):

    expected = expect_string(expect_years)

    assert conservancy_loader.fy_range_string(range_start, range_stop) == expected

@pytest.mark.parametrize('year_offset', range(-3, 1))

def test_fy_range_string_one_offset(conservancy_loader, year_offset):

    this_year = date.today().year

    expected = expect_string(range(this_year + year_offset, this_year + 1))

    assert conservancy_loader.fy_range_string(year_offset) == expected

@pytest.mark.parametrize('plugins', [

    {},

    {'conservancy_beancount.plugin': '-all'},

])

def test_fy_range_string_plugins_override(conservancy_loader, plugins):

    expected = expect_string([2019, 2020], plugins)

    assert conservancy_loader.fy_range_string(2019, 2020, plugins) == expected

def test_fy_range_string_empty_range(conservancy_loader):

    assert conservancy_loader.fy_range_string(2020, 2019) == ''