import builtins
import importlib.util
from importlib import reload

import pytest

from lang_main.errors import DependencyMissingError


@pytest.fixture(scope='function')
def no_dep(monkeypatch):
    import_orig = builtins.__import__

    def mocked_import(name, globals, locals, fromlist, level):
        if name == 'py4cytoscape':
            raise ImportError()
        return import_orig(name, locals, fromlist, level)

    monkeypatch.setattr(builtins, '__import__', mocked_import)


@pytest.fixture(scope='function')
def patch_find_spec(monkeypatch):
    find_spec_orig = importlib.util.find_spec

    def mocked_find_spec(*args, **kwargs):
        if args[0] == 'py4cytoscape':
            return None
        else:
            return find_spec_orig(*args, **kwargs)

    monkeypatch.setattr(importlib.util, 'find_spec', mocked_find_spec)


def test_p4c_available():
    import lang_main.constants

    reload(lang_main.constants)

    assert lang_main.constants.Dependencies.PY4C.value


@pytest.mark.usefixtures('patch_find_spec')
def test_p4c_missing(monkeypatch):
    import lang_main.constants

    reload(lang_main.constants)

    assert not lang_main.constants.Dependencies.PY4C.value

    with pytest.raises(DependencyMissingError):
        from lang_main import render

        reload(render)