from datetime import datetime
from unittest.mock import AsyncMock, MagicMock

import pytest
from sientia_do.temporal.constants import OPC_TIMEZONE

import ingestor.metrics as metrics
from ingestor.engines.subscription import SubscriptionEngine


def make_engine():
    eng = SubscriptionEngine(
        pool=AsyncMock(),
        sink=AsyncMock(),
        logger=MagicMock(),
        notification_handler=MagicMock(),
        metrics_controller=AsyncMock(),
        metadata={},
    )
    eng.emit_metric = AsyncMock()
    eng.send_notification_async = AsyncMock()
    return eng


def make_node(name='ns=2;i=2'):
    node = MagicMock()
    node.__str__ = lambda self: name
    return node


def make_data(value=42, timestamp=None):
    data = MagicMock()
    data.monitored_item.Value.Value.Value = value
    if timestamp is not None:
        data.monitored_item.Value.SourceTimestamp = timestamp
    return data


@pytest.mark.asyncio
async def test_datachange_fans_out():
    eng = make_engine()
    eng.nodes['ns=2;i=2'] = {
        'names': [{'tag_name': 'a'}, {'tag_name': 'b'}],
        'cycle_rule': {'cycle_increment': 1, 'cycle_count': 3},
    }
    node = make_node()
    data = make_data(42)

    await eng.datachange_notification(node, 42, data)

    assert eng.sink.publish_reading.await_count == 1
    _, kwargs = eng.sink.publish_reading.call_args
    assert len(kwargs['names']) == 2
    assert kwargs['tag'] == 'ns=2;i=2'
    assert kwargs['value'] == 42


@pytest.mark.asyncio
async def test_datachange_resets_cycle_count_and_non_receive_count():
    eng = make_engine()
    eng.non_receive_count = 7
    eng.nodes['ns=2;i=2'] = {
        'names': [{'tag_name': 'a'}],
        'cycle_rule': {'cycle_increment': 1, 'cycle_count': 3},
    }

    await eng.datachange_notification(make_node(), 42, make_data(42))

    assert eng.nodes['ns=2;i=2']['cycle_rule']['cycle_count'] == 0
    assert eng.non_receive_count == 0
    eng.emit_metric.assert_any_await(
        metric_object=metrics.OPC_CYCLES_WITHOUT_DATA,
        method='set',
        value=0,
        tags={'pod_id': eng.pod_id, 'server_name': 'unknown'},
    )


@pytest.mark.asyncio
async def test_datachange_emits_read_lag():
    eng = make_engine()
    eng.nodes['ns=2;i=2'] = {
        'names': [{'tag_name': 'a'}],
        'cycle_rule': {'cycle_increment': 1, 'cycle_count': 0},
        'server_name': 'srv1',
    }
    source_ts = datetime.now(tz=OPC_TIMEZONE)

    await eng.datachange_notification(make_node(), 42, make_data(42, timestamp=source_ts))

    lag_call = next(
        c
        for c in eng.emit_metric.await_args_list
        if c.kwargs['metric_object'] is metrics.OPC_READ_LAG
    )
    assert lag_call.kwargs['tags'] == {'pod_id': eng.pod_id, 'server_name': 'srv1'}
    assert abs(lag_call.kwargs['value']) < 5


@pytest.mark.asyncio
async def test_create_subscription_uses_pool_client():
    eng = make_engine()
    client = AsyncMock()
    eng.pool.get.return_value = client

    await eng.create_subscription('srv1', {'subscription_period_ms': 500}, 'sub1')

    eng.pool.get.assert_awaited_once_with('srv1', {'subscription_period_ms': 500})
    client.create_subscription.assert_awaited_once_with(500, eng)
    assert eng.subscriptions['sub1'] is not None
    eng.emit_metric.assert_any_await(
        metric_object=metrics.OPC_SUBSCRIPTIONS_CREATED,
        method='inc',
        value=1,
        tags={'pod_id': eng.pod_id, 'server_name': 'srv1', 'slot_name': 'sub1'},
    )


@pytest.mark.asyncio
async def test_subscribe_registers_nodes_with_cycle_rule():
    eng = make_engine()
    client = AsyncMock()
    eng.pool.get.return_value = client
    await eng.create_subscription('srv1', {'subscription_period_ms': 500}, 'sub1')

    nodes = {
        'ns=2;i=2': {
            'frequency': 1000,
            'names': [{'tag_name': 'a'}, {'tag_name': 'b'}],
            'active_read': {'enabled': False},
        }
    }

    await eng.subscribe('sub1', nodes, collect_period=1)

    assert eng.nodes['ns=2;i=2']['server_name'] == 'srv1'
    assert eng.nodes['ns=2;i=2']['cycle_rule']['cycle_count'] == 0
    assert eng.nodes['ns=2;i=2']['cycle_rule']['cycle_increment'] == pytest.approx(1.0)
    eng.subscriptions['sub1'].subscribe_data_change.assert_awaited_once()


@pytest.mark.asyncio
async def test_subscribe_without_subscription_raises():
    eng = make_engine()
    with pytest.raises(ValueError, match='Subscription not created'):
        await eng.subscribe('sub1', {}, collect_period=1)


@pytest.mark.asyncio
async def test_unsubscribe_missing_logs_warning():
    eng = make_engine()
    await eng.unsubscribe('sub1')
    eng.logger.warning.assert_called_once_with("Subscription 'sub1' not found. Cannot unsubscribe.")


@pytest.mark.asyncio
async def test_unsubscribe_deletes_subscription():
    eng = make_engine()
    client = AsyncMock()
    eng.pool.get.return_value = client
    await eng.create_subscription('srv1', {'subscription_period_ms': 500}, 'sub1')
    sub = eng.subscriptions['sub1']

    await eng.unsubscribe('sub1')

    sub.delete.assert_awaited_once()
    assert 'sub1' not in eng.subscriptions


@pytest.mark.asyncio
async def test_check_cycles_triggers_notification_over_threshold():
    eng = make_engine()
    eng.nodes['ns=2;i=2'] = {
        'names': [{'tag_name': 'a'}],
        'cycle_rule': {'cycle_increment': 5.5, 'cycle_count': 0},
    }

    await eng.check_cycles()

    eng.send_notification_async.assert_called_once()


@pytest.mark.asyncio
async def test_check_opc_listenning_below_threshold():
    eng = make_engine()
    eng.non_receive_count = 2

    result = await eng.check_opc_listenning('srv1')

    assert eng.non_receive_count == 3
    assert result is False
    eng.send_notification_async.assert_not_called()


@pytest.mark.asyncio
async def test_check_opc_listenning_triggers_reconnect_at_15():
    eng = make_engine()
    eng.non_receive_count = 14

    result = await eng.check_opc_listenning('srv1')

    assert result is True
    assert eng.send_notification_async.call_count == 2