import numpy as np
import pytest

from ase.utils.filecache import (CombinedJSONCache, Locked, MultiFileJSONCache,
                                 MultiFileULMCache)

pytestmark = pytest.mark.usefixtures('testdir')


@pytest.fixture(params=['json', 'ulm'])
def cache(request):
    caches = {'json': MultiFileJSONCache('cache_json'),
              'ulm': MultiFileULMCache('cache_ulm')}
    return caches[request.param]


def sample_dict():
    return {'hello': [1, 2, 3], 'world': 'grumble'}


def test_basic(cache):
    assert len(cache) == 0

    cache['hello'] = 'grumble'
    assert len(cache) == 1
    assert 'hello' in cache

    grumble = cache.pop('hello')
    assert grumble == 'grumble'
    assert 'hello' not in cache
    assert len(cache) == 0


def test_numpy_array(cache):
    assert len(cache) == 0
    cache['a'] = np.array([3.4, 2.4, 1.4j])
    cache['b'] = np.array([3.4, 2.4, 1.4])
    assert len(cache) == 2
    assert 'a' in cache
    aa = cache.pop('a')
    bb = cache.pop('b')
    assert np.allclose(aa, np.array([3.4, 2.4, 1.4j]))
    assert np.allclose(bb, np.array([3.4, 2.4, 1.4]))
    assert len(cache) == 0


@pytest.mark.parametrize('dct', [{}, sample_dict()])
def test_cache(dct, cache):
    cache.update(dct)
    assert dict(cache) == dct


def test_combine(cache):
    dct = sample_dict()
    cache.update(dct)
    combined = cache.combine()
    assert dict(combined) == dct


def test_split():
    dct = sample_dict()
    combined = CombinedJSONCache.dump_cache('cache', dct)
    assert dict(combined) == dct
    cache = combined.split()
    assert dict(cache) == dct
    assert len(combined) == 0


def test_lock(cache):
    with cache.lock('hello'):
        # When element is locked but nothing is written, the
        # cache is defined to "contain" None
        assert 'hello' in cache
        assert cache['hello'] is None

        # Other keys should function as normal:
        cache['xx'] = 1
        assert cache['xx'] == 1


def test_already_locked(cache):
    with cache.lock('hello') as handle:
        assert handle is not None
        with cache.lock('hello') as otherhandle:
            assert otherhandle is None

        with pytest.raises(Locked):
            cache['hello'] = 'world'


def test_no_overwrite_combine(cache):
    cache.combine()
    with pytest.raises(RuntimeError, match='Already exists'):
        cache.combine()
