"""Unit tests for PeerBus — request routing, circular detection, depth limit, timeout."""
import asyncio
import pytest
from unittest.mock import AsyncMock, MagicMock
from agent_service.agents.peer_bus import PeerBus, PeerResponse, PeerCircularRequestError


def _make_registry(agents=None, active=None):
    registry = MagicMock()
    agents = agents or {}
    active_set = set(active) if active is not None else set(agents.keys())

    async def is_active(key):
        return key in active_set

    registry.is_active = is_active
    registry.get_agent_instance = lambda key: agents.get(key)
    return registry


def _make_agent(response=None):
    agent = MagicMock()
    agent.handle_peer_request = AsyncMock(
        return_value=response if response is not None else {'answer': 42, 'success': True}
    )
    return agent


# ── basic request routing ────────────────────────────────────────────────────

@pytest.mark.asyncio
async def test_request_routes_to_agent():
    agent = _make_agent({'answer': 42, 'success': True})
    reg = _make_registry(agents={'mock_agent': agent})
    bus = PeerBus(reg, directive_id='d1')
    resp = await bus.request('from_agent', 'mock_agent', 'some_request', {}, 'reason')
    assert isinstance(resp, PeerResponse)
    assert resp.available is True
    assert resp.success is True
    assert resp.data.get('answer') == 42


@pytest.mark.asyncio
async def test_request_passes_correct_args_to_handler():
    agent = _make_agent()
    reg = _make_registry(agents={'mock_agent': agent})
    bus = PeerBus(reg, directive_id='d1')
    await bus.request('from_agent', 'mock_agent', 'query_type', {'key': 'val'}, 'reason')
    agent.handle_peer_request.assert_awaited_once_with('query_type', {'key': 'val'}, 'd1')


@pytest.mark.asyncio
async def test_request_records_call_log():
    agent = _make_agent()
    reg = _make_registry(agents={'mock_agent': agent})
    bus = PeerBus(reg, directive_id='d1')
    await bus.request('from_agent', 'mock_agent', 'some_type', {}, 'reason')
    assert len(bus.call_log) == 1
    assert bus.call_log[0]['from'] == 'from_agent'
    assert bus.call_log[0]['to'] == 'mock_agent'
    assert bus.call_log[0]['type'] == 'some_type'


# ── inactive / missing agent ─────────────────────────────────────────────────

@pytest.mark.asyncio
async def test_request_inactive_agent_returns_unavailable():
    reg = _make_registry(agents={}, active=set())
    bus = PeerBus(reg, directive_id='d1')
    resp = await bus.request('from_agent', 'inactive_agent', 'some_type', {}, 'reason')
    assert resp.available is False


@pytest.mark.asyncio
async def test_request_no_instance_returns_unavailable():
    reg = _make_registry(agents={}, active={'ghost_agent'})
    bus = PeerBus(reg, directive_id='d1')
    resp = await bus.request('from_agent', 'ghost_agent', 'some_type', {}, 'reason')
    assert resp.available is False


# ── circular detection ───────────────────────────────────────────────────────

@pytest.mark.asyncio
async def test_circular_request_raises():
    agent = _make_agent()
    reg = _make_registry(agents={'mock_agent': agent})
    bus = PeerBus(reg, directive_id='d1')
    bus._call_chain = ['mock_agent']
    with pytest.raises(PeerCircularRequestError):
        await bus.request('some_agent', 'mock_agent', 'some_type', {}, 'reason')


# ── max depth limit ──────────────────────────────────────────────────────────

@pytest.mark.asyncio
async def test_max_depth_returns_unavailable():
    agent = _make_agent()
    reg = _make_registry(agents={'mock_agent': agent})
    bus = PeerBus(reg, directive_id='d1')
    bus._call_chain = ['a', 'b', 'c']  # already at MAX_DEPTH=3
    resp = await bus.request('some_agent', 'mock_agent', 'some_type', {}, 'reason')
    assert resp.available is False
    assert 'depth' in str(resp.error).lower() or 'max' in str(resp.error).lower()


# ── timeout ──────────────────────────────────────────────────────────────────

@pytest.mark.asyncio
async def test_timeout_returns_success_false():
    agent = MagicMock()

    async def slow_handler(request_type, params, directive_id):
        await asyncio.sleep(35)
        return {}

    agent.handle_peer_request = slow_handler
    reg = _make_registry(agents={'slow_agent': agent})
    bus = PeerBus(reg, directive_id='d1')

    import unittest.mock as um
    with um.patch('asyncio.wait_for', side_effect=asyncio.TimeoutError):
        resp = await bus.request('from_agent', 'slow_agent', 'some_type', {}, 'reason')
    assert resp.available is True
    assert resp.success is False
    assert 'timeout' in str(resp.error).lower()


# ── exception from agent ─────────────────────────────────────────────────────

@pytest.mark.asyncio
async def test_agent_exception_returns_success_false():
    agent = MagicMock()
    agent.handle_peer_request = AsyncMock(side_effect=RuntimeError('boom'))
    reg = _make_registry(agents={'bad_agent': agent})
    bus = PeerBus(reg, directive_id='d1')
    resp = await bus.request('from_agent', 'bad_agent', 'some_type', {}, 'reason')
    assert resp.available is True
    assert resp.success is False
    assert 'boom' in str(resp.error)


# ── call_log ─────────────────────────────────────────────────────────────────

@pytest.mark.asyncio
async def test_call_log_grows_with_requests():
    agent = _make_agent()
    reg = _make_registry(agents={'mock_agent': agent})
    bus = PeerBus(reg, directive_id='d1')
    await bus.request('a', 'mock_agent', 't1', {}, 'r1')
    await bus.request('b', 'mock_agent', 't2', {}, 'r2')
    assert len(bus.call_log) == 2


@pytest.mark.asyncio
async def test_call_log_empty_initially():
    reg = _make_registry()
    bus = PeerBus(reg, directive_id='d1')
    assert bus.call_log == []


# ── PeerResponse fields ──────────────────────────────────────────────────────

@pytest.mark.asyncio
async def test_response_has_agent_and_request_type():
    agent = _make_agent()
    reg = _make_registry(agents={'mock_agent': agent})
    bus = PeerBus(reg, directive_id='d1')
    resp = await bus.request('from_agent', 'mock_agent', 'my_type', {}, 'reason')
    assert resp.agent == 'mock_agent'
    assert resp.request_type == 'my_type'