"""Enhanced Beancount data structures for Conservancy"""

# 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.abc

from typing import (

    Iterable,

    Iterator,

    Optional,

)

from .beancount_types import (

    MetaKey,

    MetaValue,

    Posting,

    Transaction,

)

class PostingMeta(collections.abc.MutableMapping):

    def __init__(self, txn: Transaction, index: int, post: Optional[Posting]=None) -> None:

        if post is None:

            post = txn.postings[index]

        self.txn = txn

        self.index = index

        self.post = post

    def __iter__(self) -> Iterator[MetaKey]:

        keys: Iterable[MetaKey]

        if self.post.meta is None:

            keys = self.txn.meta.keys()

        else:

            keys = frozenset(self.post.meta.keys()).union(self.txn.meta.keys())

        return iter(keys)

    def __len__(self) -> int:

        return sum(1 for _ in self)

    def __getitem__(self, key: MetaKey) -> MetaValue:

        if self.post.meta:

            try:

                return self.post.meta[key]

            except KeyError:

                pass

        return self.txn.meta[key]

    def __setitem__(self, key: MetaKey, value: MetaValue) -> None:

        if self.post.meta is None:

            self.post = self.post._replace(meta={key: value})

            self.txn.postings[self.index] = self.post

        else:

            self.post.meta[key] = value

    def __delitem__(self, key: MetaKey) -> None:

        if self.post.meta is None:

            raise KeyError(key)

        else:

            del self.post.meta[key]

"""Test PostingMeta 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 pytest

from . import testutil

from conservancy_beancount import data

@pytest.fixture

def simple_txn(index=None, key=None):

    return testutil.Transaction(note='txn note', postings=[

        ('Assets:Cash', 5),

        ('Income:Donations', -5, {'note': 'donation love', 'extra': 'Extra'}),

    ])

SIMPLE_TXN_METAKEYS = frozenset(['filename', 'lineno', 'note'])

def test_getitem_transaction(simple_txn):

    assert data.PostingMeta(simple_txn, 0)['note'] == 'txn note'

def test_getitem_posting(simple_txn):

    assert data.PostingMeta(simple_txn, 1)['note'] == 'donation love'

def test_getitem_keyerror(simple_txn):

    with pytest.raises(KeyError):

        data.PostingMeta(simple_txn, 1)['InvalidMetadata']

def test_setitem_overwrite(simple_txn):

    meta = data.PostingMeta(simple_txn, 1)

    meta['note'] = 'overwritten'

    assert meta['note'] == 'overwritten'

    assert data.PostingMeta(simple_txn, 0)['note'] == 'txn note'

def test_setitem_over_txn(simple_txn):

    meta = data.PostingMeta(simple_txn, 0)

    meta['note'] = 'overwritten'

    assert meta['note'] == 'overwritten'

    assert simple_txn.meta['note'] == 'txn note'

    assert data.PostingMeta(simple_txn, 1)['note'] == 'donation love'

def test_setitem_new_meta(simple_txn):

    meta = data.PostingMeta(simple_txn, 0)

    meta['newkey'] = 'testvalue'

    assert meta['newkey'] == 'testvalue'

    assert 'newkey' not in simple_txn.meta

    assert 'newkey' not in simple_txn.postings[1].meta

def test_delitem(simple_txn):

    meta = data.PostingMeta(simple_txn, 1)

    del meta['note']

    assert 'note' not in simple_txn.postings[1].meta

def test_delitem_fails_on_txn_meta(simple_txn):

    meta = data.PostingMeta(simple_txn, 0)

    with pytest.raises(KeyError):

        del meta['note']

def test_len_with_empty_post_meta(simple_txn):

    assert len(data.PostingMeta(simple_txn, 0)) == len(SIMPLE_TXN_METAKEYS)

def test_len_with_post_meta_over_txn(simple_txn):

    assert len(data.PostingMeta(simple_txn, 1)) == len(SIMPLE_TXN_METAKEYS) + 1

def test_iter_with_empty_post_meta(simple_txn):

    assert set(data.PostingMeta(simple_txn, 0)) == SIMPLE_TXN_METAKEYS

def test_iter_with_post_meta_over_txn(simple_txn):

    assert set(data.PostingMeta(simple_txn, 1)) == SIMPLE_TXN_METAKEYS.union(['extra'])

# The .get() tests are arguably testing the stdlib, but they're short and

# they confirm that we're using the stdlib as we intend.

def test_get_with_meta_value(simple_txn):

    assert data.PostingMeta(simple_txn, 1).get('note') == 'donation love'

def test_get_with_txn_value(simple_txn):

    assert data.PostingMeta(simple_txn, 0).get('note') == 'txn note'

def test_get_with_no_value(simple_txn):

    assert data.PostingMeta(simple_txn, 0).get('extra') is None

def test_get_with_specified_default(simple_txn):

    assert data.PostingMeta(simple_txn, 0).get('extra', 'blank') == 'blank'