"""Unit coverage for the extracted Stop hook (the App Builder render gate). Not exercised by
the streaming harness (Stop fires from SDK internals), so pin it directly: the gate is inert
off view-builder mode / when not dirty, and blocks the stop when the preview errors under cap."""

import pytest
from unittest.mock import patch, MagicMock

from backend.apps.agents.core.models import AgentSession
from backend.apps.agents.manager.streaming.hook_context import HookContext
from backend.apps.agents.manager.streaming import stop_hook as stop_hook_mod
from backend.apps.agents.manager import view_builder_state


def _ctx(mode: str) -> HookContext:
    session = AgentSession(name="t", model="sonnet", dashboard_id="d", mode=mode)
    return HookContext(
        session=session, session_id=session.id, prompt="hi",
        builtin_perms={}, policy_defaults={}, sessions={},
    )


@pytest.mark.asyncio
async def test_stop_hook_inert_when_not_view_builder():
    ctx = _ctx("agent")
    assert await stop_hook_mod.stop_hook(ctx, {}, None, None) == {}


@pytest.mark.asyncio
async def test_stop_hook_inert_when_not_dirty():
    ctx = _ctx("view-builder")  # dirty set is empty -> nothing to gate
    assert await stop_hook_mod.stop_hook(ctx, {}, None, None) == {}


@pytest.mark.asyncio
async def test_stop_hook_blocks_on_render_error_under_cap():
    ctx = _ctx("view-builder")
    sid = ctx.session.id
    view_builder_state.view_builder_dirty_sessions.add(sid)
    fake_runtime = MagicMock()
    fake_runtime.get.return_value = object()  # workspace exists
    fake_runtime.get_render_state_for_workspace.return_value = ("error", "boom traceback")
    try:
        with patch("backend.apps.outputs.runtime.manager", fake_runtime):
            out = await stop_hook_mod.stop_hook(ctx, {}, None, None)
        assert out["decision"] == "block"
        assert "failed to render" in out["reason"]
        assert "boom traceback" in out["reason"]
    finally:
        view_builder_state.view_builder_dirty_sessions.discard(sid)
        view_builder_state.view_builder_render_retry_counts.pop(sid, None)