"""Test for neo4j DB connector."""

from unittest import mock

from application import app
from neo4j.api import READ_ACCESS
from neo4j.api import WRITE_ACCESS
import pytest

from abacus_contract.connectors import neo4j


@mock.patch('neo4j.GraphDatabase.driver')
def test_read_connection(driver_create):
    """Test basic read connection management.

    Args:
        driver_create (MagicMock): mock of neo4j driver create method.
    Returns:
        None
    """
    with app.test_request_context():
        session_create = driver_create.return_value.session
        session = session_create.return_value
        session.has_transaction.return_value = False

        neo4j.neo4j_driver = None
        neo4j.init_driver('url', 'username', 'password')
        assert not session_create.called

        @neo4j.Neo4jSession()
        def func():
            assert session_create.called
            _, args, kwargs = session_create.mock_calls[0]
            assert args == ()
            assert kwargs == {
                'default_access_mode': READ_ACCESS
            }
            assert not session.close.called
            assert not session.begin_transaction.called
        func()
        assert session.close.called
        assert not session.commit_transaction.called
        assert not session.rollback_transaction.called


@mock.patch('neo4j.GraphDatabase.driver')
def test_write_connection(driver_create):
    """Test basic write connection management.

    Args:
        driver_create (MagicMock): mock of neo4j driver create method.
    Returns:
        None
    """
    with app.test_request_context():
        session_create = driver_create.return_value.session
        session = session_create.return_value
        session.has_transaction.return_value = True

        neo4j.neo4j_driver = None
        neo4j.init_driver('url', 'username', 'password')
        assert not session_create.called

        @neo4j.Neo4jSession(transaction=True)
        def func():
            assert session_create.called
            _, args, kwargs = session_create.mock_calls[0]
            assert args == ()
            assert kwargs == {'default_access_mode': WRITE_ACCESS}
            assert not session.close.called
            assert session.begin_transaction.called
        func()
        assert session.close.called
        assert not session.rollback_transaction.called


@mock.patch('neo4j.GraphDatabase.driver')
def test_driver_init(driver_create):
    """Test re-init of driver.

    Args:
        driver_create (MagicMock): mock of neo4j driver create method.
    Returns:
        None
    """
    neo4j.neo4j_driver = None
    assert not driver_create.called
    neo4j.init_driver('url', 'username', 'password')
    assert driver_create.called
    assert neo4j.neo4j_driver is not None
    with pytest.raises(neo4j.DriverAlreadyInitiated):
        neo4j.init_driver('url', 'username', 'password')


@mock.patch('abacus_contract.connectors.neo4j.neo4j_driver')
def test_session_create_fatal(driver):
    """Test fatal exception session create."""
    driver.session.side_effect = [Exception()]
    raised = False
    try:
        neo4j.create_session(READ_ACCESS, 5)
    except Exception:
        raised = True
    assert driver.session.call_count == 1
    assert raised


def test_nested_decorator():
    """Text exception raised when nesting decorators."""
    with app.test_request_context():
        with pytest.raises(neo4j.SessionAlreadyOpen):

            @neo4j.Neo4jSession()
            def func1():

                @neo4j.Neo4jSession()
                def func2():
                    pass

                func2()
            func1()


def test_missing_decorator():
    """Test exception on missing decorator."""
    with app.test_request_context():
        with pytest.raises(neo4j.SessionNotCreated):
            neo4j.get_session()


def test_session_saving():
    """Test session management."""
    with app.test_request_context():
        session = 'test'
        neo4j.set_session(session)
        assert session == neo4j.get_session()