"""Tests for the External Agent API — route layer.

Uses AsyncMock for all DB operations, stream_chat, and rate limiting.
No real DB or LLM connections required.
"""

from __future__ import annotations

import json
import uuid
from datetime import UTC, datetime
from unittest.mock import AsyncMock, MagicMock, patch

import pytest
from fastapi import FastAPI
from httpx import ASGITransport, AsyncClient

from app.plugins.builtins.ai_assistant.external_api import router as external_api_router
from app.plugins.builtins.ai_assistant.models import AIAgent


# Override conftest DB fixtures — these tests use mocks, no real DB needed
@pytest.fixture(autouse=True, scope="session")
def db_setup():
    """No-op override of conftest db_setup."""
    yield


@pytest.fixture(autouse=True)
def clean_tables(db_setup):
    """No-op override of conftest clean_tables."""
    yield


# ─── Helpers ───


def _make_agent(
    *,
    tenant_id: uuid.UUID | None = None,
    name: str = "Test Agent",
    is_active: bool = True,
    tool_ids: list[str] | None = None,
) -> AIAgent:
    """Create an AIAgent instance with defaults."""
    return AIAgent(
        id=uuid.uuid4(),
        tenant_id=tenant_id or uuid.uuid4(),
        name=name,
        description="A test agent",
        system_prompt="You are a helpful assistant.",
        tool_ids=tool_ids or [],
        is_active=is_active,
        is_default=False,
        config={},
        created_at=datetime.now(UTC),
        updated_at=datetime.now(UTC),
    )


def _mock_session() -> AsyncMock:
    """Create a mock AsyncSession."""
    session = AsyncMock()
    session.add = MagicMock()
    session.flush = AsyncMock()
    session.execute = AsyncMock()
    session.commit = AsyncMock()
    session.rollback = AsyncMock()
    return session


def _create_external_api_app(
    *,
    db: AsyncMock | None = None,
    current_user: dict | None = None,
) -> FastAPI:
    """Create a minimal FastAPI app with external_api router and mocked dependencies."""
    app = FastAPI()
    app.include_router(external_api_router)

    if db is None:
        db = _mock_session()

    if current_user is None:
        current_user = {
            "user_id": str(uuid.uuid4()),
            "tenant_id": str(uuid.uuid4()),
            "is_system_admin": True,
            "role": "admin",
            "permissions": [],
            "denied_permissions": [],
            "field_permissions": {},
            "token_prefix": "test_token",
        }

    async def _mock_get_db():
        yield db

    async def _mock_get_current_user_bearer():
        return current_user

    async def _mock_set_tenant_context(session, tenant_id):
        pass

    async def _mock_check_rate_limit(redis_key, max_attempts, window_seconds):
        pass

    from app.deps import get_current_user_bearer, get_current_user
    from app.core.db import get_db, set_tenant_context

    app.dependency_overrides[get_db] = _mock_get_db
    app.dependency_overrides[get_current_user_bearer] = _mock_get_current_user_bearer
    app.dependency_overrides[get_current_user] = _mock_get_current_user_bearer

    # Patch set_tenant_context and check_rate_limit at module level
    return app


# ─── Run Agent Tests ───


class TestRunAgentExternal:
    """Tests for POST /api/v1/external/agent/{agent_id}/run."""

    @pytest.mark.asyncio
    async def test_run_agent_success(self):
        """POST /run executes agent and returns response."""
        tenant_id = uuid.uuid4()
        agent = _make_agent(tenant_id=tenant_id, is_active=True)

        db = _mock_session()

        # First execute: find agent
        agent_result = MagicMock()
        agent_result.scalar_one_or_none.return_value = agent
        db.execute.return_value = agent_result

        current_user = {
            "user_id": str(uuid.uuid4()),
            "tenant_id": str(tenant_id),
            "is_system_admin": True,
            "role": "admin",
            "permissions": [],
            "denied_permissions": [],
            "field_permissions": {},
            "token_prefix": "test_token",
        }

        app = _create_external_api_app(db=db, current_user=current_user)

        # Mock stream_chat to return chunks
        async def _mock_stream_chat(*args, **kwargs):
            yield 'data: {"content": "Hello "}\n\n'
            yield 'data: {"content": "world!"}\n\n'
            yield "data: [DONE]\n\n"

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api.get_db") as mock_get_db,
            patch("app.plugins.builtins.ai_assistant.services.stream_chat", _mock_stream_chat),
        ):
            # Override get_db to return an async context manager for the inner stream_db
            class _FakeAsyncCtxMgr:
                async def __aenter__(self):
                    return db
                async def __aexit__(self, *args):
                    pass
            mock_get_db.return_value = _FakeAsyncCtxMgr()

            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.post(
                    f"/api/v1/external/agent/{agent.id}/run",
                    json={"message": "Say hello"},
                )

        assert resp.status_code == 200
        data = resp.json()
        assert "response" in data
        assert data["agent_id"] == str(agent.id)
        assert "session_id" in data
        assert data["tokens_used"] > 0

    @pytest.mark.asyncio
    async def test_run_agent_not_found(self):
        """POST /run returns 404 when agent does not exist."""
        db = _mock_session()

        mock_result = MagicMock()
        mock_result.scalar_one_or_none.return_value = None
        db.execute.return_value = mock_result

        app = _create_external_api_app(db=db)

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit", AsyncMock()),
        ):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.post(
                    f"/api/v1/external/agent/{uuid.uuid4()}/run",
                    json={"message": "test"},
                )

        assert resp.status_code == 404
        assert resp.json()["detail"] == "Agent not found"

    @pytest.mark.asyncio
    async def test_run_agent_inactive(self):
        """POST /run returns 400 when agent is inactive."""
        agent = _make_agent(is_active=False)

        db = _mock_session()
        mock_result = MagicMock()
        mock_result.scalar_one_or_none.return_value = agent
        db.execute.return_value = mock_result

        app = _create_external_api_app(db=db)

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit", AsyncMock()),
        ):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.post(
                    f"/api/v1/external/agent/{agent.id}/run",
                    json={"message": "test"},
                )

        assert resp.status_code == 400
        assert resp.json()["detail"] == "Agent is not active"

    @pytest.mark.asyncio
    async def test_run_agent_invalid_uuid(self):
        """POST /run returns 400 for invalid agent UUID."""
        app = _create_external_api_app()

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit", AsyncMock()),
        ):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.post(
                    "/api/v1/external/agent/not-a-uuid/run",
                    json={"message": "test"},
                )

        assert resp.status_code == 400
        assert resp.json()["detail"] == "Invalid agent ID"

    @pytest.mark.asyncio
    async def test_run_agent_rate_limited(self):
        """POST /run returns 429 when rate limit is exceeded."""
        from fastapi import HTTPException, status

        agent = _make_agent(is_active=True)

        db = _mock_session()
        mock_result = MagicMock()
        mock_result.scalar_one_or_none.return_value = agent
        db.execute.return_value = mock_result

        app = _create_external_api_app(db=db)

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch(
                "app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit",
                AsyncMock(side_effect=HTTPException(
                    status_code=status.HTTP_429_TOO_MANY_REQUESTS,
                    detail="Rate limit exceeded",
                )),
            ),
        ):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.post(
                    f"/api/v1/external/agent/{agent.id}/run",
                    json={"message": "test"},
                )

        assert resp.status_code == 429


# ─── Get Agent Status Tests ───


class TestGetAgentStatusExternal:
    """Tests for GET /api/v1/external/agent/{agent_id}/status."""

    @pytest.mark.asyncio
    async def test_get_status_success(self):
        """GET /status returns agent status information."""
        tenant_id = uuid.uuid4()
        agent = _make_agent(tenant_id=tenant_id, name="Status Agent", tool_ids=["tool1", "tool2"])

        db = _mock_session()

        # First execute: find agent
        agent_result = MagicMock()
        agent_result.scalar_one_or_none.return_value = agent

        # Second execute: count runs
        count_result = MagicMock()
        count_result.scalar.return_value = 5

        db.execute.side_effect = [agent_result, count_result]

        app = _create_external_api_app(db=db)

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit", AsyncMock()),
        ):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.get(f"/api/v1/external/agent/{agent.id}/status")

        assert resp.status_code == 200
        data = resp.json()
        assert data["agent_id"] == str(agent.id)
        assert data["name"] == "Status Agent"
        assert data["is_active"] is True
        assert data["tool_count"] == 2
        assert data["total_runs"] == 5

    @pytest.mark.asyncio
    async def test_get_status_not_found(self):
        """GET /status returns 404 when agent does not exist."""
        db = _mock_session()

        mock_result = MagicMock()
        mock_result.scalar_one_or_none.return_value = None
        db.execute.return_value = mock_result

        app = _create_external_api_app(db=db)

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit", AsyncMock()),
        ):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.get(f"/api/v1/external/agent/{uuid.uuid4()}/status")

        assert resp.status_code == 404

    @pytest.mark.asyncio
    async def test_get_status_invalid_uuid(self):
        """GET /status returns 400 for invalid agent UUID."""
        app = _create_external_api_app()

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit", AsyncMock()),
        ):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.get("/api/v1/external/agent/not-a-uuid/status")

        assert resp.status_code == 400
        assert resp.json()["detail"] == "Invalid agent ID"

    @pytest.mark.asyncio
    async def test_get_status_rate_limited(self):
        """GET /status returns 429 when rate limit is exceeded."""
        from fastapi import HTTPException, status

        app = _create_external_api_app()

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch(
                "app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit",
                AsyncMock(side_effect=HTTPException(
                    status_code=status.HTTP_429_TOO_MANY_REQUESTS,
                    detail="Rate limit exceeded",
                )),
            ),
        ):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.get(f"/api/v1/external/agent/{uuid.uuid4()}/status")

        assert resp.status_code == 429


# ─── Stream Agent Tests ───


class TestStreamAgentExternal:
    """Tests for POST /api/v1/external/agent/{agent_id}/stream."""

    @pytest.mark.asyncio
    async def test_stream_agent_success(self):
        """POST /stream returns SSE streaming response."""
        tenant_id = uuid.uuid4()
        agent = _make_agent(tenant_id=tenant_id, is_active=True)

        db = _mock_session()

        agent_result = MagicMock()
        agent_result.scalar_one_or_none.return_value = agent
        db.execute.return_value = agent_result

        app = _create_external_api_app(db=db)

        async def _mock_stream_chat(*args, **kwargs):
            yield 'data: {"content": "Hello "}\n\n'
            yield 'data: {"content": "world!"}\n\n'

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit", AsyncMock()),
            patch("app.core.db.get_session_factory") as mock_factory,
            patch("app.plugins.builtins.ai_assistant.services.stream_chat", _mock_stream_chat),
        ):
            # Mock session factory for the streaming inner DB session
            mock_session_ctx = AsyncMock()
            mock_session_ctx.__aenter__ = AsyncMock(return_value=db)
            mock_session_ctx.__aexit__ = AsyncMock(return_value=None)
            mock_factory.return_value.return_value = mock_session_ctx

            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.post(
                    f"/api/v1/external/agent/{agent.id}/stream",
                    json={"message": "Say hello"},
                )

        assert resp.status_code == 200
        assert "text/event-stream" in resp.headers.get("content-type", "")
        # Response should contain SSE data
        body = resp.text
        assert "data:" in body

    @pytest.mark.asyncio
    async def test_stream_agent_not_found(self):
        """POST /stream returns 404 when agent does not exist."""
        db = _mock_session()

        mock_result = MagicMock()
        mock_result.scalar_one_or_none.return_value = None
        db.execute.return_value = mock_result

        app = _create_external_api_app(db=db)

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit", AsyncMock()),
        ):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.post(
                    f"/api/v1/external/agent/{uuid.uuid4()}/stream",
                    json={"message": "test"},
                )

        assert resp.status_code == 404

    @pytest.mark.asyncio
    async def test_stream_agent_inactive(self):
        """POST /stream returns 400 when agent is inactive."""
        agent = _make_agent(is_active=False)

        db = _mock_session()
        mock_result = MagicMock()
        mock_result.scalar_one_or_none.return_value = agent
        db.execute.return_value = mock_result

        app = _create_external_api_app(db=db)

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit", AsyncMock()),
        ):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.post(
                    f"/api/v1/external/agent/{agent.id}/stream",
                    json={"message": "test"},
                )

        assert resp.status_code == 400
        assert resp.json()["detail"] == "Agent is not active"

    @pytest.mark.asyncio
    async def test_stream_agent_invalid_uuid(self):
        """POST /stream returns 400 for invalid agent UUID."""
        app = _create_external_api_app()

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit", AsyncMock()),
        ):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.post(
                    "/api/v1/external/agent/not-a-uuid/stream",
                    json={"message": "test"},
                )

        assert resp.status_code == 400
        assert resp.json()["detail"] == "Invalid agent ID"

    @pytest.mark.asyncio
    async def test_stream_agent_rate_limited(self):
        """POST /stream returns 429 when rate limit is exceeded."""
        from fastapi import HTTPException, status

        app = _create_external_api_app()

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch(
                "app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit",
                AsyncMock(side_effect=HTTPException(
                    status_code=status.HTTP_429_TOO_MANY_REQUESTS,
                    detail="Rate limit exceeded",
                )),
            ),
        ):
            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.post(
                    f"/api/v1/external/agent/{uuid.uuid4()}/stream",
                    json={"message": "test"},
                )

        assert resp.status_code == 429


# ─── Auth Tests ───


class TestExternalAgentAuth:
    """Tests for Bearer token authentication on external agent API."""

    @pytest.mark.asyncio
    async def test_bearer_token_required(self):
        """Endpoints require Bearer token authentication (mocked via dependency override)."""
        # When get_current_user_bearer is not overridden, the request should fail
        app = FastAPI()
        app.include_router(external_api_router)

        transport = ASGITransport(app=app)
        async with AsyncClient(transport=transport, base_url="http://test") as client:
            resp = await client.post(
                f"/api/v1/external/agent/{uuid.uuid4()}/run",
                json={"message": "test"},
            )

        # Should return 401 or 403 since no auth is provided
        assert resp.status_code in (401, 403, 422)

    @pytest.mark.asyncio
    async def test_user_context_passed_correctly(self):
        """The current_user dict from bearer auth is passed to stream_chat."""
        tenant_id = uuid.uuid4()
        user_id = uuid.uuid4()
        agent = _make_agent(tenant_id=tenant_id, is_active=True)

        db = _mock_session()
        agent_result = MagicMock()
        agent_result.scalar_one_or_none.return_value = agent
        db.execute.return_value = agent_result

        current_user = {
            "user_id": str(user_id),
            "tenant_id": str(tenant_id),
            "is_system_admin": False,
            "role": "editor",
            "permissions": ["ai:write"],
            "denied_permissions": [],
            "field_permissions": {"annual_revenue": "read"},
            "token_prefix": "abc123",
        }

        app = _create_external_api_app(db=db, current_user=current_user)

        captured_context = {}

        async def _mock_stream_chat(stream_db, session, agent_obj, message, user_context, tid):
            captured_context.update(user_context)
            yield 'data: {"content": "response"}\n\n'
            yield "data: [DONE]\n\n"

        with (
            patch("app.plugins.builtins.ai_assistant.external_api.set_tenant_context", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api._check_external_rate_limit", AsyncMock()),
            patch("app.plugins.builtins.ai_assistant.external_api.get_db") as mock_get_db,
            patch("app.plugins.builtins.ai_assistant.services.stream_chat", _mock_stream_chat),
        ):
            class _FakeAsyncCtxMgr:
                async def __aenter__(self):
                    return db
                async def __aexit__(self, *args):
                    pass
            mock_get_db.return_value = _FakeAsyncCtxMgr()

            transport = ASGITransport(app=app)
            async with AsyncClient(transport=transport, base_url="http://test") as client:
                resp = await client.post(
                    f"/api/v1/external/agent/{agent.id}/run",
                    json={"message": "test"},
                )

        assert resp.status_code == 200
        # Verify user context was passed correctly
        assert captured_context.get("user_id") == str(user_id)
        assert captured_context.get("tenant_id") == str(tenant_id)
        assert captured_context.get("role") == "editor"
        assert "ai:write" in captured_context.get("permissions", [])