import asyncio
import concurrent.futures
import json
import threading
import time

from hermes_cli import mcp_startup
from tui_gateway import server
from tui_gateway import ws as ws_mod


def test_ws_startup_starts_background_mcp_discovery(monkeypatch):
    """The desktop app and dashboard chat reach the agent through this WS
    sidecar, not through tui_gateway.entry.main() (which spawns the discovery
    thread for the stdio TUI). handle_ws must start discovery itself, otherwise
    _make_agent's wait_for_mcp_discovery no-ops and the agent snapshots an
    MCP-less tool list. Regression test for #38945."""
    calls = []
    monkeypatch.setattr(
        mcp_startup,
        "start_background_mcp_discovery",
        lambda **kw: calls.append(kw),
    )

    class FakeWS:
        async def accept(self):
            pass

        async def send_text(self, line):
            pass

        async def receive_text(self):
            raise ws_mod._WebSocketDisconnect()

        async def close(self):
            pass

    server._sessions.clear()
    try:
        asyncio.run(ws_mod.handle_ws(FakeWS()))
    finally:
        server._sessions.clear()

    assert calls == [{"logger": ws_mod._log, "thread_name": "tui-ws-mcp-discovery"}]


def _run_disconnect(monkeypatch, seed):
    """Drive handle_ws to its disconnect `finally`, seeding sessions against the
    live WSTransport the moment it exists. Returns nothing; inspect _sessions."""
    # Disable the grace-reap Timer: detached sessions normally schedule a
    # threading.Timer via _schedule_ws_orphan_reap, which would outlive the test
    # and fire _reap during interpreter teardown — touching _sessions/DB and
    # producing spurious post-run errors under the per-file CI runner. Grace=0
    # short-circuits the Timer (see _schedule_ws_orphan_reap) so the test leaves
    # no lingering thread.
    monkeypatch.setattr(server, "_WS_ORPHAN_REAP_GRACE_S", 0)

    # Mirror the real _finalize_session chokepoint: it is the single place that
    # closes the slash-worker (#38095). Stub it but keep that behavior so the
    # disconnect-reap path still exercises worker teardown.
    def _fake_finalize(s, end_reason="tui_close"):
        w = s.get("slash_worker")
        if w:
            w.close()

    monkeypatch.setattr(server, "_finalize_session", _fake_finalize)

    created = []
    real_transport = ws_mod.WSTransport
    monkeypatch.setattr(
        ws_mod, "WSTransport",
        lambda ws, loop, **kw: created.append(real_transport(ws, loop, **kw)) or created[-1],
    )

    class FakeWS:
        async def accept(self):
            pass

        async def send_text(self, line):
            pass

        async def receive_text(self):
            seed(created[0])  # transport now exists; attach it to sessions
            raise ws_mod._WebSocketDisconnect()

        async def close(self):
            pass

    asyncio.run(ws_mod.handle_ws(FakeWS()))


def test_ws_disconnect_reaps_flagged_session_and_closes_worker(monkeypatch):
    closed = []

    class FakeWorker:
        def close(self):
            closed.append(True)

    server._sessions.clear()
    try:
        _run_disconnect(
            monkeypatch,
            lambda t: server._sessions.update(
                flagged={
                    "transport": t,
                    "close_on_disconnect": True,
                    "slash_worker": FakeWorker(),
                    "session_key": "k",
                }
            ),
        )
        assert "flagged" not in server._sessions
        assert closed == [True]
    finally:
        server._sessions.clear()


def test_ws_disconnect_preserves_and_repoints_reconnectable_session(monkeypatch):
    server._sessions.clear()
    try:
        _run_disconnect(
            monkeypatch,
            lambda t: server._sessions.update(
                plain={"transport": t, "close_on_disconnect": False, "session_key": "k"}
            ),
        )
        assert server._sessions["plain"]["transport"] is server._detached_ws_transport
    finally:
        server._sessions.clear()


def test_ws_connection_registers_then_disconnect_unregisters_live_transport(monkeypatch):
    """A connected client must be tracked in the live-transport registry so a
    session-less global broadcast (skin.changed from the background watcher)
    reaches it, and dropped on disconnect so no stale write targets a dead peer.
    This is the WS half of the cross-surface live-theme fix."""
    server._sessions.clear()
    server._live_transports.clear()
    seen = {}
    try:
        _run_disconnect(
            monkeypatch,
            lambda t: seen.__setitem__("registered", t in server._live_transports),
        )
        # Seeded at receive_text time — i.e. after gateway.ready registered it.
        assert seen["registered"] is True
        # handle_ws's finally must have unregistered it.
        assert not server._live_transports
    finally:
        server._sessions.clear()
        server._live_transports.clear()


def test_ws_write_loop_stall_does_not_latch_transport(monkeypatch):
    """A write that times out because the event loop is stalled (GIL-heavy
    agent turn) must NOT latch the transport closed — the frame is already
    scheduled and flushes when the loop recovers. Latching here permanently
    silenced live watch windows after one slow write."""
    monkeypatch.setattr(ws_mod, "_WS_WRITE_TIMEOUT_S", 0.05)
    sent = []

    class FakeWS:
        async def send_text(self, line):
            sent.append(line)

    loop = asyncio.new_event_loop()
    thread = threading.Thread(target=loop.run_forever, daemon=True)
    thread.start()
    try:
        transport = ws_mod.WSTransport(FakeWS(), loop, peer="stall-test")
        # Stall the loop well past the write timeout, then write from this
        # (non-loop) thread: the wait times out but the send stays in flight.
        loop.call_soon_threadsafe(time.sleep, 0.3)
        assert transport.write({"a": 1}) is True
        assert transport._closed is False

        # Once the loop breathes again, both the stalled frame and new writes
        # must reach the socket.
        assert transport.write({"b": 2}) is True
        deadline = time.time() + 2
        while len(sent) < 2 and time.time() < deadline:
            time.sleep(0.01)
        assert len(sent) == 2
        assert transport._closed is False
    finally:
        loop.call_soon_threadsafe(loop.stop)
        thread.join(timeout=2)
        loop.close()


def test_ws_transport_serializes_concurrent_sends():
    active_sends = 0
    max_active_sends = 0
    sent = []

    class FakeWS:
        async def send_text(self, line):
            nonlocal active_sends, max_active_sends
            active_sends += 1
            max_active_sends = max(max_active_sends, active_sends)
            try:
                await asyncio.sleep(0.05)
                sent.append(line)
            finally:
                active_sends -= 1

    loop = asyncio.new_event_loop()
    thread = threading.Thread(target=loop.run_forever, daemon=True)
    thread.start()
    try:
        transport = ws_mod.WSTransport(FakeWS(), loop, peer="serialize-test")
        with concurrent.futures.ThreadPoolExecutor(max_workers=2) as pool:
            futures = [
                pool.submit(transport.write, {"idx": 1}),
                pool.submit(transport.write, {"idx": 2}),
            ]
            assert [f.result(timeout=2) for f in futures] == [True, True]

        assert len(sent) == 2
        assert max_active_sends == 1
        assert transport._closed is False
    finally:
        loop.call_soon_threadsafe(loop.stop)
        thread.join(timeout=2)
        loop.close()


def test_ws_transport_preserves_cross_batch_order():
    async def scenario():
        entered = []
        first_entered = asyncio.Event()
        release_first = asyncio.Event()
        second_started = asyncio.Event()

        class FakeWS:
            async def send_text(self, line):
                entered.append(line)
                if line == "A1":
                    first_entered.set()
                    await release_first.wait()

        transport = ws_mod.WSTransport(
            FakeWS(), asyncio.get_running_loop(), peer="batch-order-test"
        )
        first = asyncio.create_task(transport._safe_send_many(["A1", "A2"]))
        await first_entered.wait()

        async def send_second():
            second_started.set()
            await transport._safe_send_many(["B1", "B2"])

        second = asyncio.create_task(send_second())
        await second_started.wait()

        # The second task has reached the transport. Without whole-batch
        # serialization it runs B1/B2 before this task can resume.
        assert entered == ["A1"]

        release_first.set()
        await asyncio.gather(first, second)
        assert entered == ["A1", "A2", "B1", "B2"]

    asyncio.run(scenario())


def test_ws_write_async_keeps_drained_tokens_with_current_frame():
    async def scenario():
        entered = []
        first_entered = asyncio.Event()
        release_first = asyncio.Event()
        current_started = asyncio.Event()

        class FakeWS:
            async def send_text(self, line):
                entered.append(line)
                if line == "A1":
                    first_entered.set()
                    await release_first.wait()

        transport = ws_mod.WSTransport(
            FakeWS(), asyncio.get_running_loop(), peer="async-order-test"
        )
        transport._pending_tokens.append("pending-token")

        first = asyncio.create_task(transport._safe_send_many(["A1", "A2"]))
        await first_entered.wait()

        async def send_current():
            current_started.set()
            await transport.write_async({"id": "current"})

        current = asyncio.create_task(send_current())
        await current_started.wait()
        later = asyncio.create_task(transport._safe_send_many(["later-batch"]))

        release_first.set()
        await asyncio.gather(first, current, later)
        assert entered == [
            "A1",
            "A2",
            "pending-token",
            json.dumps({"id": "current"}),
            "later-batch",
        ]

    asyncio.run(scenario())