"""Tests for WebSocket helpers (ws_helpers) and Redis Pub/Sub (ws_pubsub).

Covers B-WS-TEST + B-ERR-WS-TEST requirements.
"""

from __future__ import annotations

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

import pytest
import pytest_asyncio

from app.core.ws_helpers import (
    authenticate_ws,
    check_ws_origin,
    cleanup_ws_connection,
    handle_ws_message,
    send_ws_error,
    start_heartbeat,
)
from app.core.ws_pubsub import (
    broadcast_to_tenants,
    get_tenant_channel,
    publish_to_channel,
    subscribe_to_channel,
)


# ─── Mock WebSocket ───────────────────────────────────────────────────────────


class MockWebSocket:
    """Minimal mock WebSocket for testing WS helpers."""

    def __init__(
        self,
        cookies: dict[str, str] | None = None,
        headers: dict[str, str] | None = None,
        query_params: dict[str, str] | None = None,
    ) -> None:
        self.cookies = cookies or {}
        self.headers = headers or {}
        self.query_params = query_params or {}
        self._closed = False
        self._close_code: int | None = None
        self._close_reason: str | None = None
        self._sent: list[str] = []
        self._accepted = False

    async def accept(self) -> None:
        self._accepted = True

    async def close(self, code: int = 1000, reason: str = "") -> None:
        self._closed = True
        self._close_code = code
        self._close_reason = reason

    async def send_text(self, text: str) -> None:
        if self._closed:
            raise RuntimeError("WebSocket is closed")
        self._sent.append(text)

    @property
    def sent_messages(self) -> list[dict]:
        return [json.loads(t) for t in self._sent]


# ─── authenticate_ws ──────────────────────────────────────────────────────────


@pytest.mark.asyncio
class TestAuthenticateWs:
    """Tests for authenticate_ws."""

    async def test_authenticate_ws_valid_session(self, db_session, redis_client):
        """authenticate_ws returns user info when session is valid."""
        from app.core.auth import create_session, hash_password
        from app.models.tenant import Tenant
        from app.models.user import User, UserTenant
        from app.models.role import Role

        # Create tenant, user, role, membership
        tenant = Tenant(name="Test Tenant", slug="test-tenant")
        db_session.add(tenant)
        await db_session.flush()

        user = User(
            email="wsauth@test.com",
            name="WS Auth Test",
            password_hash=hash_password("TestPass123!"),
            is_active=True,
            preferences={},
        )
        db_session.add(user)
        await db_session.flush()

        role = Role(
            tenant_id=tenant.id,
            name="admin",
            permissions={"*": {"*": True}},
            denied_permissions=[],
            field_permissions={},
        )
        db_session.add(role)
        await db_session.flush()

        ut = UserTenant(
            user_id=user.id,
            tenant_id=tenant.id,
            is_default=True,
            role="admin",
            role_id=role.id,
        )
        db_session.add(ut)
        await db_session.flush()
        await db_session.commit()

        # Create session
        session_id, csrf_token = await create_session(
            db_session, redis_client, user, tenant.id, role="admin"
        )

        # Create mock WebSocket with session cookie
        ws = MockWebSocket(cookies={"leocrm_session": session_id})

        auth = await authenticate_ws(ws, db_session)
        assert auth is not None
        assert auth["user_id"] == str(user.id)
        assert auth["tenant_id"] == str(tenant.id)
        assert auth["session_id"] == session_id
        assert auth["role"] == "admin"
        assert ws._closed is False

    async def test_authenticate_ws_missing_cookie(self, db_session):
        """authenticate_ws closes WS and returns None when no session cookie."""
        ws = MockWebSocket(cookies={})

        auth = await authenticate_ws(ws, db_session)
        assert auth is None
        assert ws._closed is True
        assert ws._close_code == 4401

    async def test_authenticate_ws_invalid_session(self, db_session):
        """authenticate_ws closes WS and returns None when session is invalid."""
        ws = MockWebSocket(cookies={"leocrm_session": "nonexistent-session-id"})

        auth = await authenticate_ws(ws, db_session)
        assert auth is None
        assert ws._closed is True
        assert ws._close_code == 4401


# ─── check_ws_origin ──────────────────────────────────────────────────────────


@pytest.mark.asyncio
class TestCheckWsOrigin:
    """Tests for check_ws_origin."""

    async def test_check_ws_origin_valid(self):
        """check_ws_origin returns True for valid origin + CSRF."""
        from app.core.auth import create_session, hash_password
        from app.models.tenant import Tenant
        from app.models.user import User, UserTenant
        from app.models.role import Role
        from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine

        # We need a full setup with session in Redis for CSRF validation
        # Use patch to mock verify_ws_origin returning True
        with patch("app.core.ws_helpers.verify_ws_origin", return_value=True):
            ws = MockWebSocket()
            result = await check_ws_origin(ws)
            assert result is True
            assert ws._closed is False

    async def test_check_ws_origin_invalid(self):
        """check_ws_origin closes WS and returns False for invalid origin."""
        with patch("app.core.ws_helpers.verify_ws_origin", return_value=False):
            ws = MockWebSocket()
            result = await check_ws_origin(ws)
            assert result is False
            assert ws._closed is True
            assert ws._close_code == 4403


# ─── send_ws_error ────────────────────────────────────────────────────────────


@pytest.mark.asyncio
class TestSendWsError:
    """Tests for send_ws_error."""

    async def test_send_ws_error_basic(self):
        """send_ws_error sends structured error message."""
        ws = MockWebSocket()
        await send_ws_error(ws, "test_error", "Something went wrong")

        assert len(ws.sent_messages) == 1
        msg = ws.sent_messages[0]
        assert msg["type"] == "error"
        assert msg["code"] == "test_error"
        assert msg["detail"] == "Something went wrong"
        assert "trace_id" not in msg

    async def test_send_ws_error_with_trace_id(self):
        """send_ws_error includes trace_id when provided."""
        ws = MockWebSocket()
        await send_ws_error(ws, "test_error", "Failed", trace_id="trace-123")

        msg = ws.sent_messages[0]
        assert msg["trace_id"] == "trace-123"

    async def test_send_ws_error_on_closed_ws(self):
        """send_ws_error does not raise when WS is closed."""
        ws = MockWebSocket()
        ws._closed = True
        # Should not raise
        await send_ws_error(ws, "closed_error", "WS already closed")


# ─── handle_ws_message ─────────────────────────────────────────────────────────


@pytest.mark.asyncio
class TestHandleWsMessage:
    """Tests for handle_ws_message."""

    async def test_handle_ws_message_dispatch(self):
        """handle_ws_message dispatches to correct handler."""
        ws = MockWebSocket()
        called = False

        async def ping_handler(websocket, msg):
            nonlocal called
            called = True
            assert msg["type"] == "ping"

        handlers = {"ping": ping_handler}
        message = json.dumps({"type": "ping"})
        await handle_ws_message(ws, message, handlers)

        assert called is True

    async def test_handle_ws_message_unknown_type(self):
        """handle_ws_message sends error for unknown type."""
        ws = MockWebSocket()
        handlers = {"ping": AsyncMock()}
        message = json.dumps({"type": "unknown_type"})
        await handle_ws_message(ws, message, handlers)

        assert len(ws.sent_messages) == 1
        msg = ws.sent_messages[0]
        assert msg["type"] == "error"
        assert msg["code"] == "unknown_type"

    async def test_handle_ws_message_handler_exception(self):
        """handle_ws_message sends error when handler raises exception."""
        ws = MockWebSocket()

        async def bad_handler(websocket, msg):
            raise ValueError("Handler crashed")

        handlers = {"ping": bad_handler}
        message = json.dumps({"type": "ping"})
        await handle_ws_message(ws, message, handlers)

        assert len(ws.sent_messages) == 1
        msg = ws.sent_messages[0]
        assert msg["type"] == "error"
        assert msg["code"] == "handler_error"
        assert "Handler crashed" in msg["detail"]

    async def test_handle_ws_message_invalid_json(self):
        """handle_ws_message sends error for invalid JSON."""
        ws = MockWebSocket()
        handlers = {}
        await handle_ws_message(ws, "not json at all", handlers)

        assert len(ws.sent_messages) == 1
        msg = ws.sent_messages[0]
        assert msg["code"] == "invalid_json"

    async def test_handle_ws_message_missing_type(self):
        """handle_ws_message sends error when type field is missing."""
        ws = MockWebSocket()
        handlers = {}
        message = json.dumps({"data": "no type here"})
        await handle_ws_message(ws, message, handlers)

        assert len(ws.sent_messages) == 1
        msg = ws.sent_messages[0]
        assert msg["code"] == "missing_type"


# ─── cleanup_ws_connection ─────────────────────────────────────────────────────


@pytest.mark.asyncio
class TestCleanupWsConnection:
    """Tests for cleanup_ws_connection."""

    async def test_cleanup_removes_from_registry(self):
        """cleanup_ws_connection removes WebSocket from registry."""
        ws1 = MockWebSocket()
        ws2 = MockWebSocket()
        registry: dict[str, list] = {"user1": [ws1, ws2]}

        await cleanup_ws_connection(ws1, "user1", registry)

        assert "user1" in registry
        assert ws1 not in registry["user1"]
        assert ws2 in registry["user1"]
        assert len(registry["user1"]) == 1

    async def test_cleanup_removes_empty_user(self):
        """cleanup_ws_connection removes user entry when no connections left."""
        ws = MockWebSocket()
        registry: dict[str, list] = {"user1": [ws]}

        await cleanup_ws_connection(ws, "user1", registry)

        assert "user1" not in registry

    async def test_cleanup_unknown_user(self):
        """cleanup_ws_connection handles unknown user gracefully."""
        ws = MockWebSocket()
        registry: dict[str, list] = {}

        await cleanup_ws_connection(ws, "unknown_user", registry)
        assert "unknown_user" not in registry


# ─── start_heartbeat ───────────────────────────────────────────────────────────


@pytest.mark.asyncio
class TestStartHeartbeat:
    """Tests for start_heartbeat."""

    async def test_heartbeat_sends_ping(self):
        """start_heartbeat sends ping messages at interval."""
        ws = MockWebSocket()
        task = await start_heartbeat(ws, interval=0)

        # Wait a tiny bit for the first ping
        await asyncio.sleep(0.05)
        task.cancel()
        try:
            await task
        except asyncio.CancelledError:
            pass

        assert len(ws._sent) >= 1
        msg = ws.sent_messages[0]
        assert msg["type"] == "ping"

    async def test_heartbeat_cancellable(self):
        """start_heartbeat task can be cancelled."""
        ws = MockWebSocket()
        task = await start_heartbeat(ws, interval=10)

        task.cancel()
        try:
            await task
        except asyncio.CancelledError:
            pass

        assert task.cancelled() or task.done()


# ─── get_tenant_channel ─────────────────────────────────────────────────────────


class TestGetTenantChannel:
    """Tests for get_tenant_channel."""

    def test_channel_naming(self):
        """get_tenant_channel returns ws:{tenant_id}:{topic}."""
        tenant_id = uuid.uuid4()
        channel = get_tenant_channel(tenant_id, "kommunikation")
        assert channel == f"ws:{tenant_id}:kommunikation"

    def test_channel_naming_different_topic(self):
        """get_tenant_channel works with different topics."""
        tenant_id = uuid.uuid4()
        channel = get_tenant_channel(tenant_id, "ai_ui_control")
        assert channel == f"ws:{tenant_id}:ai_ui_control"


# ─── publish_to_channel + subscribe_to_channel ──────────────────────────────────


@pytest.mark.asyncio
class TestPubSub:
    """Tests for Redis Pub/Sub helpers."""

    async def test_publish_subscribe_roundtrip(self, redis_client):
        """publish_to_channel + subscribe_to_channel roundtrip."""
        received: list[dict] = []
        channel = f"test-roundtrip-{uuid.uuid4()}"
        event = asyncio.Event()

        async def handler(msg: dict) -> None:
            received.append(msg)
            event.set()

        # Subscribe
        task = await subscribe_to_channel(channel, handler)

        # Give subscriber a moment to connect
        await asyncio.sleep(0.1)

        # Publish
        test_msg = {"type": "test", "data": "hello"}
        await publish_to_channel(channel, test_msg)

        # Wait for message
        await asyncio.wait_for(event.wait(), timeout=2.0)

        assert len(received) == 1
        assert received[0]["type"] == "test"
        assert received[0]["data"] == "hello"

        # Cleanup
        task.cancel()
        try:
            await task
        except asyncio.CancelledError:
            pass

    async def test_broadcast_to_tenants(self, redis_client):
        """broadcast_to_tenants publishes to the correct tenant channel."""
        tenant_id = uuid.uuid4()
        received: list[dict] = []
        event = asyncio.Event()

        channel = get_tenant_channel(tenant_id, "test_topic")

        async def handler(msg: dict) -> None:
            received.append(msg)
            event.set()

        task = await subscribe_to_channel(channel, handler)
        await asyncio.sleep(0.1)

        test_msg = {"type": "broadcast", "content": "tenant message"}
        await broadcast_to_tenants(tenant_id, "test_topic", test_msg)

        await asyncio.wait_for(event.wait(), timeout=2.0)

        assert len(received) == 1
        assert received[0]["type"] == "broadcast"
        assert received[0]["content"] == "tenant message"

        task.cancel()
        try:
            await task
        except asyncio.CancelledError:
            pass

    async def test_publish_to_channel_no_subscribers(self, redis_client):
        """publish_to_channel works even with no subscribers."""
        channel = f"test-no-sub-{uuid.uuid4()}"
        await publish_to_channel(channel, {"type": "noop"})
        # Should not raise

    async def test_subscribe_multiple_messages(self, redis_client):
        """subscribe_to_channel handler receives multiple messages."""
        received: list[dict] = []
        channel = f"test-multi-{uuid.uuid4()}"
        count_event = asyncio.Event()
        msg_count = 0

        async def handler(msg: dict) -> None:
            nonlocal msg_count
            received.append(msg)
            msg_count += 1
            if msg_count >= 3:
                count_event.set()

        task = await subscribe_to_channel(channel, handler)
        await asyncio.sleep(0.1)

        for i in range(3):
            await publish_to_channel(channel, {"type": "msg", "index": i})

        await asyncio.wait_for(count_event.wait(), timeout=3.0)

        assert len(received) == 3
        assert received[0]["index"] == 0
        assert received[2]["index"] == 2

        task.cancel()
        try:
            await task
        except asyncio.CancelledError:
            pass