from __future__ import annotations

from types import SimpleNamespace
from uuid import uuid4

from ag_ui.core import RunAgentInput
from fastapi.testclient import TestClient

from app import app
from core.auth.models import CurrentUser
from v1.agent import router as agent_router
from v1.agent.dependencies import get_agent_service
from v1.users.dependencies import get_current_user


class _FakeAgentService:
    def __init__(self) -> None:
        self._stream_called = False

    async def enqueue_run(self, *, run_input: RunAgentInput, current_user: CurrentUser):
        del current_user
        return SimpleNamespace(
            task_id="task-run-1",
            thread_id=run_input.thread_id,
            run_id=run_input.run_id,
            created=False,
        )

    async def enqueue_resume(
        self,
        *,
        thread_id: str,
        run_input: RunAgentInput,
        current_user: CurrentUser,
    ):
        del thread_id, current_user
        return SimpleNamespace(
            task_id="task-resume-1",
            thread_id=run_input.thread_id,
            run_id=run_input.run_id,
            created=False,
        )

    async def stream_events(
        self,
        *,
        thread_id: str,
        last_event_id: str | None,
        current_user: CurrentUser,
    ) -> list[dict[str, object]]:
        del thread_id, current_user
        if self._stream_called:
            return []
        self._stream_called = True
        return [
            {
                "id": "2-0",
                "event": {
                    "type": "RUN_STARTED",
                    "threadId": "00000000-0000-0000-0000-000000000001",
                    "runId": "run-1",
                },
                "cursor": last_event_id,
            }
        ]

    async def get_history_snapshot(
        self,
        *,
        thread_id: str,
        before: str | None,
        current_user: CurrentUser,
    ) -> dict[str, object]:
        del current_user
        return {
            "type": "STATE_SNAPSHOT",
            "threadId": thread_id,
            "snapshot": {
                "scope": "history_day",
                "day": before or "2026-03-07",
                "hasMore": False,
                "messages": [
                    {
                        "id": "msg-h1",
                        "role": "assistant",
                        "content": "history-message",
                    }
                ],
            },
        }

    async def get_user_history_snapshot(
        self,
        *,
        current_user: CurrentUser,
        thread_id: str | None,
        before: str | None,
    ) -> dict[str, object]:
        del current_user, before
        return {
            "type": "STATE_SNAPSHOT",
            "threadId": thread_id or "00000000-0000-0000-0000-000000000001",
            "snapshot": {
                "scope": "history_day",
                "day": "2026-03-07",
                "hasMore": False,
                "messages": [],
            },
        }


def test_run_requires_auth_and_returns_202_task_id() -> None:
    app.dependency_overrides[get_agent_service] = lambda: _FakeAgentService()
    client = TestClient(app)
    original_allow_run = agent_router._allow_run_request

    async def _allow_run(*, user_id: str) -> bool:
        del user_id
        return True

    agent_router._allow_run_request = _allow_run  # type: ignore[assignment]

    try:
        unauthorized = client.post(
            "/api/v1/agent/runs",
            json={
                "threadId": "00000000-0000-0000-0000-000000000001",
                "runId": "run-1",
                "state": {},
                "messages": [{"id": "u1", "role": "user", "content": "hello"}],
                "tools": [],
                "context": [],
                "forwardedProps": {},
            },
        )
        assert unauthorized.status_code == 401

        app.dependency_overrides[get_current_user] = lambda: CurrentUser(
            id=uuid4(), email="user@example.com"
        )
        authorized = client.post(
            "/api/v1/agent/runs",
            json={
                "threadId": "00000000-0000-0000-0000-000000000001",
                "runId": "run-1",
                "state": {},
                "messages": [{"id": "u1", "role": "user", "content": "hello"}],
                "tools": [],
                "context": [],
                "forwardedProps": {},
            },
        )
        assert authorized.status_code == 202
        assert authorized.json()["taskId"] == "task-run-1"
        assert authorized.json()["threadId"] == "00000000-0000-0000-0000-000000000001"
        assert authorized.json()["runId"] == "run-1"
        assert authorized.json()["created"] is False
    finally:
        agent_router._allow_run_request = original_allow_run  # type: ignore[assignment]
        app.dependency_overrides = {}


def test_stream_reads_from_last_event_id() -> None:
    app.dependency_overrides[get_agent_service] = lambda: _FakeAgentService()
    app.dependency_overrides[get_current_user] = lambda: CurrentUser(
        id=uuid4(), email="user@example.com"
    )
    client = TestClient(app)
    original_acquire = agent_router._acquire_sse_slot
    original_release = agent_router._release_sse_slot

    async def _allow_slot(*, user_id: str) -> bool:
        del user_id
        return True

    async def _noop_release(*, user_id: str) -> None:
        del user_id
        return None

    agent_router._acquire_sse_slot = _allow_slot  # type: ignore[assignment]
    agent_router._release_sse_slot = _noop_release  # type: ignore[assignment]

    try:
        response = client.get(
            "/api/v1/agent/runs/00000000-0000-0000-0000-000000000001/events?idle_limit=1",
            headers={"Last-Event-ID": "1-0"},
        )
        assert response.status_code == 200
        assert response.headers["content-type"].startswith("text/event-stream")
        assert "id: 2-0" in response.text
        assert "event: RUN_STARTED" in response.text
        assert '"threadId":"00000000-0000-0000-0000-000000000001"' in response.text
    finally:
        agent_router._acquire_sse_slot = original_acquire  # type: ignore[assignment]
        agent_router._release_sse_slot = original_release  # type: ignore[assignment]
        app.dependency_overrides = {}


def test_stream_rejects_invalid_last_event_id() -> None:
    app.dependency_overrides[get_agent_service] = lambda: _FakeAgentService()
    app.dependency_overrides[get_current_user] = lambda: CurrentUser(
        id=uuid4(), email="user@example.com"
    )
    client = TestClient(app)

    try:
        response = client.get(
            "/api/v1/agent/runs/00000000-0000-0000-0000-000000000001/events",
            headers={"Last-Event-ID": "bad-id"},
        )
        assert response.status_code == 422
    finally:
        app.dependency_overrides = {}


def test_history_returns_state_snapshot() -> None:
    app.dependency_overrides[get_agent_service] = lambda: _FakeAgentService()
    client = TestClient(app)

    try:
        unauthorized = client.get(
            "/api/v1/agent/runs/00000000-0000-0000-0000-000000000001/history"
        )
        assert unauthorized.status_code == 401

        app.dependency_overrides[get_current_user] = lambda: CurrentUser(
            id=uuid4(), email="user@example.com"
        )
        authorized = client.get(
            "/api/v1/agent/runs/00000000-0000-0000-0000-000000000001/history",
            params={"before": "2026-03-07"},
        )
        assert authorized.status_code == 200
        payload = authorized.json()
        assert payload["type"] == "STATE_SNAPSHOT"
        assert payload["threadId"] == "00000000-0000-0000-0000-000000000001"
        assert payload["snapshot"]["scope"] == "history_day"
        assert payload["snapshot"]["day"] == "2026-03-07"
    finally:
        app.dependency_overrides = {}


def test_user_history_returns_latest_snapshot() -> None:
    app.dependency_overrides[get_agent_service] = lambda: _FakeAgentService()
    app.dependency_overrides[get_current_user] = lambda: CurrentUser(
        id=uuid4(), email="user@example.com"
    )
    client = TestClient(app)
    try:
        response = client.get("/api/v1/agent/history")
        assert response.status_code == 200
        body = response.json()
        assert body["type"] == "STATE_SNAPSHOT"
        assert body["threadId"] == "00000000-0000-0000-0000-000000000001"
    finally:
        app.dependency_overrides = {}


def test_run_rejects_oversized_user_text_payload() -> None:
    app.dependency_overrides[get_agent_service] = lambda: _FakeAgentService()
    app.dependency_overrides[get_current_user] = lambda: CurrentUser(
        id=uuid4(), email="user@example.com"
    )
    client = TestClient(app)

    try:
        response = client.post(
            "/api/v1/agent/runs",
            json={
                "threadId": "00000000-0000-0000-0000-000000000001",
                "runId": "run-oversize",
                "state": {},
                "messages": [
                    {
                        "id": "u1",
                        "role": "user",
                        "content": "x" * 11000,
                    }
                ],
                "tools": [],
                "context": [],
                "forwardedProps": {},
            },
        )
        assert response.status_code == 422
    finally:
        app.dependency_overrides = {}


def test_run_rejects_client_supplied_history_messages() -> None:
    app.dependency_overrides[get_agent_service] = lambda: _FakeAgentService()
    app.dependency_overrides[get_current_user] = lambda: CurrentUser(
        id=uuid4(), email="user@example.com"
    )
    client = TestClient(app)

    try:
        response = client.post(
            "/api/v1/agent/runs",
            json={
                "threadId": "00000000-0000-0000-0000-000000000001",
                "runId": "run-history",
                "state": {},
                "messages": [
                    {"id": "a1", "role": "assistant", "content": "old"},
                    {"id": "u1", "role": "user", "content": "new"},
                ],
                "tools": [],
                "context": [],
                "forwardedProps": {},
            },
        )
        assert response.status_code == 422
    finally:
        app.dependency_overrides = {}


def test_resume_accepts_tool_message_without_user_message() -> None:
    app.dependency_overrides[get_agent_service] = lambda: _FakeAgentService()
    app.dependency_overrides[get_current_user] = lambda: CurrentUser(
        id=uuid4(), email="user@example.com"
    )
    client = TestClient(app)

    try:
        response = client.post(
            "/api/v1/agent/runs/00000000-0000-0000-0000-000000000001/resume",
            json={
                "threadId": "00000000-0000-0000-0000-000000000001",
                "runId": "run-resume-1",
                "state": {},
                "messages": [
                    {
                        "id": "tool-1",
                        "role": "tool",
                        "toolCallId": "call-1",
                        "content": '{"toolName":"navigate_to_route","toolArgs":{"target":"/calendar/dayweek"},"nonce":"n1","result":{"ok":true}}',
                    }
                ],
                "tools": [],
                "context": [],
                "forwardedProps": {},
            },
        )
        assert response.status_code == 202
        assert response.json()["taskId"] == "task-resume-1"
    finally:
        app.dependency_overrides = {}