# -*- coding: utf-8 -*-

from copy import deepcopy

import hypothesis.strategies as st
from hypothesis import assume
from hypothesis.stateful import Bundle, RuleBasedStateMachine, rule

import pytest

from tests import blow_up, uid_strategy

from vdirsyncer.storage.memory import MemoryStorage, _random_string
from vdirsyncer.sync import sync as _sync
from vdirsyncer.sync.exceptions import BothReadOnly, IdentConflict, \
    PartialSync, StorageEmpty, SyncConflict
from vdirsyncer.sync.status import SqliteStatus
from vdirsyncer.vobject import Item


def sync(a, b, status, *args, **kwargs):
    new_status = SqliteStatus(':memory:')
    new_status.load_legacy_status(status)
    rv = _sync(a, b, new_status, *args, **kwargs)
    status.clear()
    status.update(new_status.to_legacy_status())
    return rv


def empty_storage(x):
    return list(x.list()) == []


def items(s):
    return set(x[1].raw for x in s.items.values())


def test_irrelevant_status():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {'1': ('1', 1234, '1.ics', 2345)}
    sync(a, b, status)
    assert not status
    assert not items(a)
    assert not items(b)


def test_missing_status():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}
    item = Item(u'asdf')
    a.upload(item)
    b.upload(item)
    sync(a, b, status)
    assert len(status) == 1
    assert items(a) == items(b) == {item.raw}


def test_missing_status_and_different_items():
    a = MemoryStorage()
    b = MemoryStorage()

    status = {}
    item1 = Item(u'UID:1\nhaha')
    item2 = Item(u'UID:1\nhoho')
    a.upload(item1)
    b.upload(item2)
    with pytest.raises(SyncConflict):
        sync(a, b, status)
    assert not status
    sync(a, b, status, conflict_resolution='a wins')
    assert items(a) == items(b) == {item1.raw}


def test_read_only_and_prefetch():
    a = MemoryStorage()
    b = MemoryStorage()
    b.read_only = True

    status = {}
    item1 = Item(u'UID:1\nhaha')
    item2 = Item(u'UID:2\nhoho')
    a.upload(item1)
    a.upload(item2)

    sync(a, b, status, force_delete=True)
    sync(a, b, status, force_delete=True)

    assert not items(a) and not items(b)


def test_partial_sync_error():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}

    a.upload(Item('UID:0'))
    b.read_only = True

    with pytest.raises(PartialSync):
        sync(a, b, status, partial_sync='error')


def test_partial_sync_ignore():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}

    item0 = Item('UID:0\nhehe')
    a.upload(item0)
    b.upload(item0)

    b.read_only = True

    item1 = Item('UID:1\nhaha')
    a.upload(item1)

    sync(a, b, status, partial_sync='ignore')
    sync(a, b, status, partial_sync='ignore')

    assert items(a) == {item0.raw, item1.raw}
    assert items(b) == {item0.raw}


def test_partial_sync_ignore2():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}

    href, etag = a.upload(Item('UID:0'))
    a.read_only = True

    sync(a, b, status, partial_sync='ignore', force_delete=True)
    assert items(b) == items(a) == {'UID:0'}

    b.items.clear()
    sync(a, b, status, partial_sync='ignore', force_delete=True)
    sync(a, b, status, partial_sync='ignore', force_delete=True)
    assert items(a) == {'UID:0'}
    assert not b.items

    a.read_only = False
    a.update(href, Item('UID:0\nupdated'), etag)
    a.read_only = True
    sync(a, b, status, partial_sync='ignore', force_delete=True)
    assert items(b) == items(a) == {'UID:0\nupdated'}


def test_upload_and_update():
    a = MemoryStorage(fileext='.a')
    b = MemoryStorage(fileext='.b')
    status = {}

    item = Item(u'UID:1')  # new item 1 in a
    a.upload(item)
    sync(a, b, status)
    assert items(b) == items(a) == {item.raw}

    item = Item(u'UID:1\nASDF:YES')  # update of item 1 in b
    b.update('1.b', item, b.get('1.b')[1])
    sync(a, b, status)
    assert items(b) == items(a) == {item.raw}

    item2 = Item(u'UID:2')  # new item 2 in b
    b.upload(item2)
    sync(a, b, status)
    assert items(b) == items(a) == {item.raw, item2.raw}

    item2 = Item(u'UID:2\nASDF:YES')  # update of item 2 in a
    a.update('2.a', item2, a.get('2.a')[1])
    sync(a, b, status)
    assert items(b) == items(a) == {item.raw, item2.raw}


def test_deletion():
    a = MemoryStorage(fileext='.a')
    b = MemoryStorage(fileext='.b')
    status = {}

    item = Item(u'UID:1')
    a.upload(item)
    item2 = Item(u'UID:2')
    a.upload(item2)
    sync(a, b, status)
    b.delete('1.b', b.get('1.b')[1])
    sync(a, b, status)
    assert items(a) == items(b) == {item2.raw}

    a.upload(item)
    sync(a, b, status)
    assert items(a) == items(b) == {item.raw, item2.raw}
    a.delete('1.a', a.get('1.a')[1])
    sync(a, b, status)
    assert items(a) == items(b) == {item2.raw}


def test_insert_hash():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}

    item = Item('UID:1')
    href, etag = a.upload(item)
    sync(a, b, status)

    for d in status['1']:
        del d['hash']

    a.update(href, Item('UID:1\nHAHA:YES'), etag)
    sync(a, b, status)
    assert 'hash' in status['1'][0] and 'hash' in status['1'][1]


def test_already_synced():
    a = MemoryStorage(fileext='.a')
    b = MemoryStorage(fileext='.b')
    item = Item(u'UID:1')
    a.upload(item)
    b.upload(item)
    status = {
        '1': ({
            'href': '1.a',
            'hash': item.hash,
            'etag': a.get('1.a')[1]
        }, {
            'href': '1.b',
            'hash': item.hash,
            'etag': b.get('1.b')[1]
        })
    }
    old_status = deepcopy(status)
    a.update = b.update = a.upload = b.upload = \
        lambda *a, **kw: pytest.fail('Method shouldn\'t have been called.')

    for _ in (1, 2):
        sync(a, b, status)
        assert status == old_status
        assert items(a) == items(b) == {item.raw}


@pytest.mark.parametrize('winning_storage', 'ab')
def test_conflict_resolution_both_etags_new(winning_storage):
    a = MemoryStorage()
    b = MemoryStorage()
    item = Item(u'UID:1')
    href_a, etag_a = a.upload(item)
    href_b, etag_b = b.upload(item)
    status = {}
    sync(a, b, status)
    assert status
    item_a = Item(u'UID:1\nitem a')
    item_b = Item(u'UID:1\nitem b')
    a.update(href_a, item_a, etag_a)
    b.update(href_b, item_b, etag_b)
    with pytest.raises(SyncConflict):
        sync(a, b, status)
    sync(a, b, status, conflict_resolution='{} wins'.format(winning_storage))
    assert items(a) == items(b) == {
        item_a.raw if winning_storage == 'a' else item_b.raw
    }


def test_updated_and_deleted():
    a = MemoryStorage()
    b = MemoryStorage()
    href_a, etag_a = a.upload(Item(u'UID:1'))
    status = {}
    sync(a, b, status, force_delete=True)

    (href_b, etag_b), = b.list()
    b.delete(href_b, etag_b)
    updated = Item(u'UID:1\nupdated')
    a.update(href_a, updated, etag_a)
    sync(a, b, status, force_delete=True)

    assert items(a) == items(b) == {updated.raw}


def test_conflict_resolution_invalid_mode():
    a = MemoryStorage()
    b = MemoryStorage()
    item_a = Item(u'UID:1\nitem a')
    item_b = Item(u'UID:1\nitem b')
    a.upload(item_a)
    b.upload(item_b)
    with pytest.raises(ValueError):
        sync(a, b, {}, conflict_resolution='yolo')


def test_conflict_resolution_new_etags_without_changes():
    a = MemoryStorage()
    b = MemoryStorage()
    item = Item(u'UID:1')
    href_a, etag_a = a.upload(item)
    href_b, etag_b = b.upload(item)
    status = {'1': (href_a, 'BOGUS_a', href_b, 'BOGUS_b')}

    sync(a, b, status)

    (ident, (status_a, status_b)), = status.items()
    assert ident == '1'
    assert status_a['href'] == href_a
    assert status_a['etag'] == etag_a
    assert status_b['href'] == href_b
    assert status_b['etag'] == etag_b


def test_uses_get_multi(monkeypatch):
    def breakdown(*a, **kw):
        raise AssertionError('Expected use of get_multi')

    get_multi_calls = []

    old_get = MemoryStorage.get

    def get_multi(self, hrefs):
        hrefs = list(hrefs)
        get_multi_calls.append(hrefs)
        for href in hrefs:
            item, etag = old_get(self, href)
            yield href, item, etag

    monkeypatch.setattr(MemoryStorage, 'get', breakdown)
    monkeypatch.setattr(MemoryStorage, 'get_multi', get_multi)

    a = MemoryStorage()
    b = MemoryStorage()
    item = Item(u'UID:1')
    expected_href, etag = a.upload(item)

    sync(a, b, {})
    assert get_multi_calls == [[expected_href]]


def test_empty_storage_dataloss():
    a = MemoryStorage()
    b = MemoryStorage()
    a.upload(Item(u'UID:1'))
    a.upload(Item(u'UID:2'))
    status = {}
    sync(a, b, status)
    with pytest.raises(StorageEmpty):
        sync(MemoryStorage(), b, status)

    with pytest.raises(StorageEmpty):
        sync(a, MemoryStorage(), status)


def test_no_uids():
    a = MemoryStorage()
    b = MemoryStorage()
    a.upload(Item(u'ASDF'))
    b.upload(Item(u'FOOBAR'))
    status = {}
    sync(a, b, status)
    assert items(a) == items(b) == {u'ASDF', u'FOOBAR'}


def test_changed_uids():
    a = MemoryStorage()
    b = MemoryStorage()
    href_a, etag_a = a.upload(Item(u'UID:A-ONE'))
    href_b, etag_b = b.upload(Item(u'UID:B-ONE'))
    status = {}
    sync(a, b, status)

    a.update(href_a, Item(u'UID:A-TWO'), etag_a)
    sync(a, b, status)


def test_both_readonly():
    a = MemoryStorage(read_only=True)
    b = MemoryStorage(read_only=True)
    assert a.read_only
    assert b.read_only
    status = {}
    with pytest.raises(BothReadOnly):
        sync(a, b, status)


def test_partial_sync_revert():
    a = MemoryStorage(instance_name='a')
    b = MemoryStorage(instance_name='b')
    status = {}
    a.upload(Item(u'UID:1'))
    b.upload(Item(u'UID:2'))
    b.read_only = True

    sync(a, b, status, partial_sync='revert')
    assert len(status) == 2
    assert items(a) == {'UID:1', 'UID:2'}
    assert items(b) == {'UID:2'}

    sync(a, b, status, partial_sync='revert')
    assert len(status) == 1
    assert items(a) == {'UID:2'}
    assert items(b) == {'UID:2'}

    # Check that updates get reverted
    a.items[next(iter(a.items))] = ('foo', Item('UID:2\nupdated'))
    assert items(a) == {'UID:2\nupdated'}
    sync(a, b, status, partial_sync='revert')
    assert len(status) == 1
    assert items(a) == {'UID:2\nupdated'}
    sync(a, b, status, partial_sync='revert')
    assert items(a) == {'UID:2'}

    # Check that deletions get reverted
    a.items.clear()
    sync(a, b, status, partial_sync='revert', force_delete=True)
    sync(a, b, status, partial_sync='revert', force_delete=True)
    assert items(a) == {'UID:2'}


@pytest.mark.parametrize('sync_inbetween', (True, False))
def test_ident_conflict(sync_inbetween):
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}
    href_a, etag_a = a.upload(Item(u'UID:aaa'))
    href_b, etag_b = a.upload(Item(u'UID:bbb'))
    if sync_inbetween:
        sync(a, b, status)

    a.update(href_a, Item(u'UID:xxx'), etag_a)
    a.update(href_b, Item(u'UID:xxx'), etag_b)

    with pytest.raises(IdentConflict):
        sync(a, b, status)


def test_moved_href():
    '''
    Concrete application: ppl_ stores contact aliases in filenames, which means
    item's hrefs get changed. Vdirsyncer doesn't synchronize this data, but
    also shouldn't do things like deleting and re-uploading to the server.

    .. _ppl: http://ppladdressbook.org/
    '''
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}
    href, etag = a.upload(Item(u'UID:haha'))
    sync(a, b, status)

    b.items['lol'] = b.items.pop('haha')

    # The sync algorithm should prefetch `lol`, see that it's the same ident
    # and not do anything else.
    a.get_multi = blow_up  # Absolutely no prefetch on A
    # No actual sync actions
    a.delete = a.update = a.upload = b.delete = b.update = b.upload = blow_up

    sync(a, b, status)
    assert len(status) == 1
    assert items(a) == items(b) == {'UID:haha'}
    assert status['haha'][1]['href'] == 'lol'
    old_status = deepcopy(status)

    # Further sync should be a noop. Not even prefetching should occur.
    b.get_multi = blow_up

    sync(a, b, status)
    assert old_status == status
    assert items(a) == items(b) == {'UID:haha'}


def test_bogus_etag_change():
    '''Assert that sync algorithm is resilient against etag changes if content
    didn\'t change.

    In this particular case we test a scenario where both etags have been
    updated, but only one side actually changed its item content.
    '''
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}
    href_a, etag_a = a.upload(Item(u'UID:ASDASD'))
    sync(a, b, status)
    assert len(status) == len(list(a.list())) == len(list(b.list())) == 1

    (href_b, etag_b), = b.list()
    a.update(href_a, Item(u'UID:ASDASD'), etag_a)
    b.update(href_b, Item(u'UID:ASDASD\nACTUALCHANGE:YES'), etag_b)

    b.delete = b.update = b.upload = blow_up

    sync(a, b, status)
    assert len(status) == 1
    assert items(a) == items(b) == {u'UID:ASDASD\nACTUALCHANGE:YES'}


def test_unicode_hrefs():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}
    href, etag = a.upload(Item(u'UID:äää'))
    sync(a, b, status)


class ActionIntentionallyFailed(Exception):
    pass


def action_failure(*a, **kw):
    raise ActionIntentionallyFailed()


class SyncMachine(RuleBasedStateMachine):
    Status = Bundle('status')
    Storage = Bundle('storage')

    @rule(target=Storage,
          flaky_etags=st.booleans(),
          null_etag_on_upload=st.booleans())
    def newstorage(self, flaky_etags, null_etag_on_upload):
        s = MemoryStorage()
        if flaky_etags:
            def get(href):
                old_etag, item = s.items[href]
                etag = _random_string()
                s.items[href] = etag, item
                return item, etag
            s.get = get

        if null_etag_on_upload:
            _old_upload = s.upload
            _old_update = s.update
            s.upload = lambda item: (_old_upload(item)[0], 'NULL')
            s.update = lambda h, i, e: _old_update(h, i, e) and 'NULL'

        return s

    @rule(s=Storage, read_only=st.booleans())
    def is_read_only(self, s, read_only):
        assume(s.read_only != read_only)
        s.read_only = read_only

    @rule(s=Storage)
    def actions_fail(self, s):
        s.upload = action_failure
        s.update = action_failure
        s.delete = action_failure

    @rule(s=Storage)
    def none_as_etag(self, s):
        _old_upload = s.upload
        _old_update = s.update

        def upload(item):
            return _old_upload(item)[0], None

        def update(href, item, etag):
            _old_update(href, item, etag)

        s.upload = upload
        s.update = update

    @rule(target=Status)
    def newstatus(self):
        return {}

    @rule(storage=Storage,
          uid=uid_strategy,
          etag=st.text())
    def upload(self, storage, uid, etag):
        item = Item(u'UID:{}'.format(uid))
        storage.items[uid] = (etag, item)

    @rule(storage=Storage, href=st.text())
    def delete(self, storage, href):
        assume(storage.items.pop(href, None))

    @rule(
        status=Status,
        a=Storage, b=Storage,
        force_delete=st.booleans(),
        conflict_resolution=st.one_of((st.just('a wins'), st.just('b wins'))),
        with_error_callback=st.booleans(),
        partial_sync=st.one_of((
            st.just('ignore'), st.just('revert'), st.just('error')
        ))
    )
    def sync(self, status, a, b, force_delete, conflict_resolution,
             with_error_callback, partial_sync):
        assume(a is not b)
        old_items_a = items(a)
        old_items_b = items(b)

        a.instance_name = 'a'
        b.instance_name = 'b'

        errors = []

        if with_error_callback:
            error_callback = errors.append
        else:
            error_callback = None

        try:
            # If one storage is read-only, double-sync because changes don't
            # get reverted immediately.
            for _ in range(2 if a.read_only or b.read_only else 1):
                sync(a, b, status,
                     force_delete=force_delete,
                     conflict_resolution=conflict_resolution,
                     error_callback=error_callback,
                     partial_sync=partial_sync)

            for e in errors:
                raise e
        except PartialSync:
            assert partial_sync == 'error'
        except ActionIntentionallyFailed:
            pass
        except BothReadOnly:
            assert a.read_only and b.read_only
            assume(False)
        except StorageEmpty:
            if force_delete:
                raise
            else:
                assert not list(a.list()) or not list(b.list())
        else:
            items_a = items(a)
            items_b = items(b)

            assert items_a == items_b or partial_sync == 'ignore'
            assert items_a == old_items_a or not a.read_only
            assert items_b == old_items_b or not b.read_only

            assert set(a.items) | set(b.items) == set(status) or \
                partial_sync == 'ignore'


TestSyncMachine = SyncMachine.TestCase


@pytest.mark.parametrize('error_callback', [True, False])
def test_rollback(error_callback):
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}

    a.items['0'] = ('', Item('UID:0'))
    b.items['1'] = ('', Item('UID:1'))

    b.upload = b.update = b.delete = action_failure

    if error_callback:
        errors = []

        sync(a, b, status=status, conflict_resolution='a wins',
             error_callback=errors.append)

        assert len(errors) == 1
        assert isinstance(errors[0], ActionIntentionallyFailed)

        assert len(status) == 1
        assert status['1']
    else:
        with pytest.raises(ActionIntentionallyFailed):
            sync(a, b, status=status, conflict_resolution='a wins')


def test_duplicate_hrefs():
    a = MemoryStorage()
    b = MemoryStorage()
    a.list = lambda: [('a', 'a')] * 3
    a.items['a'] = ('a', Item('UID:a'))

    status = {}
    sync(a, b, status)
    with pytest.raises(AssertionError):
        sync(a, b, status)