from unittest.mock import AsyncMock, MagicMock

import pytest

from ingestor.connection.servers import CONNECTORS, ServerConfigResolver

LOOKED_UP = {
    'certificate_id': 1,
    'application_uri': 'urn:sientia:opc-ingestor',
    'cert': {'bucket': 'opc-certificates', 'object_name': 'client/p/cert.pem'},
    'private_key': {'bucket': 'opc-certificates', 'object_name': 'client/p/key.pem'},
}
# A connector as the aggregation returns it ($lookup on opc_certificates)
CONNECTOR = {
    'connector_id': 'kepserver',
    'url': 'opc.tcp://kepserver:49320',
    'subscription_period_ms': 500,
    'security': {
        'mode': 'SignAndEncrypt',
        'policy': 'Basic256Sha256',
        'client_certificate_id': 1,
    },
    'certificates': [LOOKED_UP],
}
# The same server in the slot v2 format
CONFIG = {
    'server_id': 'kepserver',
    'url': 'opc.tcp://kepserver:49320',
    'subscription_period_ms': 500,
    'security': {'mode': 'SignAndEncrypt', 'policy': 'Basic256Sha256'},
    'certificate': LOOKED_UP,
}


def make_resolver(connector=None, pooled=None, ttl_s=60.0):
    pool = MagicMock()
    pool.config_for = MagicMock(return_value=pooled)
    mongo = MagicMock()
    mongo.aggregate = AsyncMock(return_value=[connector] if connector is not None else [])
    return ServerConfigResolver(pool, mongo, MagicMock(), ttl_s=ttl_s)


@pytest.mark.asyncio
async def test_live_pooled_connection_wins_over_mongo():
    """Writes reuse exactly the settings the read path opened the connection with."""
    pooled = {'url': 'opc.tcp://read:1', 'security': CONFIG['security'], 'certificate': None}
    resolver = make_resolver(connector=CONNECTOR, pooled=pooled)

    assert await resolver.resolve('kepserver') == pooled
    resolver.pool.config_for.assert_called_once_with('kepserver')
    resolver.mongo.aggregate.assert_not_awaited()


@pytest.mark.asyncio
async def test_connector_with_its_certificate_in_the_slot_format():
    resolver = make_resolver(connector=CONNECTOR)

    assert await resolver.resolve('kepserver') == CONFIG
    collection, pipeline, _ = resolver.mongo.aggregate.await_args.args
    assert collection == CONNECTORS
    assert pipeline[0] == {
        '$match': {'connector_id': 'kepserver', 'type': 'opc_ua', 'status': 'Active'}
    }
    # The same rule as the orchestrator: only an active client certificate (D5)
    [lookup] = [stage['$lookup'] for stage in pipeline if '$lookup' in stage]
    assert lookup['from'] == 'opc_certificates'
    assert lookup['pipeline'][0]['$match']['status'] == 'active'
    assert lookup['pipeline'][0]['$match']['kind'] == 'client'
    resolver.logger.warning.assert_not_called()


@pytest.mark.asyncio
async def test_connector_without_certificate_id_connects_without_security():
    connector = {
        **CONNECTOR,
        'security': {'mode': 'None', 'policy': 'None', 'client_certificate_id': None},
        'certificates': [],
    }
    resolver = make_resolver(connector=connector)

    cfg = await resolver.resolve('kepserver')

    assert cfg['certificate'] is None
    assert cfg['security'] == {'mode': 'None', 'policy': 'None'}
    resolver.logger.warning.assert_not_called()


@pytest.mark.asyncio
async def test_certificate_id_without_an_active_client_certificate_warns():
    resolver = make_resolver(connector={**CONNECTOR, 'certificates': []})

    cfg = await resolver.resolve('kepserver')

    assert cfg == {**CONFIG, 'certificate': None}
    assert 'client_certificate_id 1' in resolver.logger.warning.call_args.args[0]


@pytest.mark.asyncio
@pytest.mark.parametrize(
    'connector',
    [
        pytest.param({**CONNECTOR, 'url': ''}, id='no-url'),
        pytest.param({**CONNECTOR, 'security': {'mode': 'Sign'}}, id='no-policy'),
        pytest.param({k: v for k, v in CONNECTOR.items() if k != 'security'}, id='no-security'),
    ],
)
async def test_incomplete_connectors_are_not_found(connector):
    resolver = make_resolver(connector=connector)

    assert await resolver.resolve('kepserver') is None
    resolver.logger.warning.assert_called_once()


@pytest.mark.asyncio
async def test_unknown_server_is_cached_briefly():
    resolver = make_resolver(ttl_s=60.0)
    resolver.missing_ttl_s = 10.0
    resolver.clock = MagicMock()
    resolver.clock.elapsed.side_effect = [0.0, 5.0, 11.0]

    assert await resolver.resolve('9') is None
    assert await resolver.resolve('9') is None  # within missing_ttl_s: no lookup
    assert await resolver.resolve('9') is None  # expired: looked up again
    assert resolver.mongo.aggregate.await_count == 2
    assert resolver.logger.warning.call_count == 2


@pytest.mark.asyncio
async def test_lookups_are_cached_for_the_ttl():
    resolver = make_resolver(connector=CONNECTOR, ttl_s=60.0)
    resolver.clock = MagicMock()
    resolver.clock.elapsed.side_effect = [0.0, 30.0, 61.0]

    first = await resolver.resolve('kepserver')
    first['url'] = 'mutated by the caller'
    second = await resolver.resolve('kepserver')  # within the TTL: cached, and a copy
    await resolver.resolve('kepserver')  # expired: looked up again

    assert second['url'] == 'opc.tcp://kepserver:49320'
    assert resolver.mongo.aggregate.await_count == 2


@pytest.mark.asyncio
async def test_mongo_errors_propagate_to_the_caller():
    resolver = make_resolver()
    resolver.mongo.aggregate = AsyncMock(side_effect=RuntimeError('mongo down'))

    with pytest.raises(RuntimeError, match='mongo down'):
        await resolver.resolve('kepserver')