from __future__ import annotations

import asyncio
import json
from unittest.mock import AsyncMock, MagicMock

import pytest
from cerbero_mcp.exchanges.ibkr.ws import IBKRWebSocket, WSError


class FakeWS:
    """Bidirectional async fake for WSS messages."""
    def __init__(self) -> None:
        self.sent: list[str] = []
        self._inbox: asyncio.Queue[str] = asyncio.Queue()
        self.closed = False
    async def send(self, msg: str) -> None:
        self.sent.append(msg)
    async def recv(self) -> str:
        return await self._inbox.get()
    async def close(self) -> None:
        self.closed = True
    async def push(self, payload: dict) -> None:
        await self._inbox.put(json.dumps(payload))


@pytest.fixture
def fake_signer():
    s = MagicMock()
    s.get_live_session_token = AsyncMock(return_value="LST==")
    return s


@pytest.mark.asyncio
async def test_subscribe_tick_caches_snapshot(fake_signer, monkeypatch):
    fake_ws = FakeWS()

    async def fake_connect(url, **kw):
        return fake_ws

    monkeypatch.setattr("cerbero_mcp.exchanges.ibkr.ws.websockets_connect", fake_connect)

    ws = IBKRWebSocket(
        signer=fake_signer,
        ws_url="wss://api.ibkr.com/v1/api/ws",
        base_url="https://api.ibkr.com/v1/api",
        max_subs=80, idle_timeout_s=300,
    )
    await ws.start()
    await ws.subscribe_tick(265598)

    await fake_ws.push({
        "topic": "smd+265598",
        "31": "150.5", "84": "150.4", "86": "150.6",
        "7295": "100", "7296": "200",
    })
    await asyncio.sleep(0.05)

    snap = ws.get_tick_snapshot(265598)
    assert snap is not None
    assert snap["last_price"] == 150.5
    assert snap["bid"] == 150.4

    await ws.stop()


@pytest.mark.asyncio
async def test_subscribe_limit(fake_signer, monkeypatch):
    fake_ws = FakeWS()

    async def fake_connect(url, **kw):
        return fake_ws

    monkeypatch.setattr("cerbero_mcp.exchanges.ibkr.ws.websockets_connect", fake_connect)

    ws = IBKRWebSocket(
        signer=fake_signer,
        ws_url="wss://x", base_url="https://x",
        max_subs=2, idle_timeout_s=300,
    )
    await ws.start()
    await ws.subscribe_tick(1)
    await ws.subscribe_tick(2)
    with pytest.raises(WSError, match="IBKR_WS_SUB_LIMIT"):
        await ws.subscribe_tick(3)
    await ws.stop()


@pytest.mark.asyncio
async def test_subscribe_before_start_raises(fake_signer):
    ws = IBKRWebSocket(
        signer=fake_signer,
        ws_url="wss://x", base_url="https://x",
        max_subs=10, idle_timeout_s=300,
    )
    with pytest.raises(WSError, match="IBKR_WS_NOT_STARTED"):
        await ws.subscribe_tick(1)


@pytest.mark.asyncio
async def test_start_after_stop_resumes_reader(fake_signer, monkeypatch):
    fake_ws_a = FakeWS()
    fake_ws_b = FakeWS()
    fakes = iter([fake_ws_a, fake_ws_b])

    async def fake_connect(url, **kw):
        return next(fakes)

    monkeypatch.setattr("cerbero_mcp.exchanges.ibkr.ws.websockets_connect", fake_connect)

    ws = IBKRWebSocket(
        signer=fake_signer,
        ws_url="wss://x", base_url="https://x",
        max_subs=10, idle_timeout_s=300,
    )
    await ws.start()
    await ws.stop()
    # Restart with fresh fake_ws_b
    await ws.start()
    await ws.subscribe_tick(42)
    await fake_ws_b.push({"topic": "smd+42", "31": "100"})
    await asyncio.sleep(0.05)
    assert ws.get_tick_snapshot(42) is not None
    await ws.stop()