"""Page transitions are recaptured until screenshot and hierarchy agree."""

from unittest.mock import AsyncMock, Mock

import pytest
from PIL import Image

from artemis.mcp.action_executor import McpActionExecutor
from artemis.mcp.action_types import ObserveResult


def _screen(tmp_path, name: str, *, reverse: bool = False) -> str:
    image = Image.new("L", (64, 64))
    image.putdata([255 - x * 4 if reverse else x * 4 for _y in range(64) for x in range(64)])
    path = tmp_path / name
    image.save(path, format="JPEG")
    return str(path)


def _observation(path: str, page: str) -> ObserveResult:
    return ObserveResult(
        ok=True,
        screenshot_path=path,
        elements_text=f"[1] {page}",
        elements=[{"text": page, "resource_id": "page/title", "bounds": [0, 0, 64, 64]}],
    )


@pytest.mark.asyncio
async def test_navigation_recaptures_when_image_lags_behind_hierarchy(tmp_path):
    home = _screen(tmp_path, "home.jpg")
    detail = _screen(tmp_path, "detail.jpg", reverse=True)
    session = Mock()
    session.observe = AsyncMock(
        side_effect=[
            _observation(home, "存储空间"),
            _observation(detail, "存储空间"),
            _observation(detail, "存储空间"),
        ]
    )
    executor = McpActionExecutor(Mock(), actuator=Mock())

    observed, settled = await executor._observe_after_action(
        session, "click", home, _observation(home, "设置首页").elements
    )

    assert observed.screenshot_path == detail
    assert observed.elements_text == "[1] 存储空间"
    assert settled is True
    assert session.observe.await_count == 3


@pytest.mark.asyncio
async def test_navigation_waits_until_new_page_has_two_stable_frames(tmp_path):
    home = _screen(tmp_path, "home.jpg")
    detail = _screen(tmp_path, "detail.jpg", reverse=True)
    session = Mock()
    session.observe = AsyncMock(
        side_effect=[
            _observation(home, "设置首页"),
            _observation(home, "设置首页"),
            _observation(detail, "存储空间"),
            _observation(detail, "存储空间"),
        ]
    )
    executor = McpActionExecutor(Mock(), actuator=Mock())

    observed, settled = await executor._observe_after_action(
        session, "click", home, _observation(home, "设置首页").elements
    )

    assert observed.screenshot_path == detail
    assert settled is True
    assert session.observe.await_count == 4


@pytest.mark.asyncio
async def test_old_bitmap_with_new_hierarchy_is_never_marked_settled(tmp_path):
    home = _screen(tmp_path, "home.jpg")
    session = Mock()
    session.observe = AsyncMock(return_value=_observation(home, "存储空间"))
    executor = McpActionExecutor(Mock(), actuator=Mock())

    observed, settled = await executor._observe_after_action(
        session, "click", home, _observation(home, "设置首页").elements
    )

    assert observed.elements_text == "[1] 存储空间"
    assert settled is False
    assert session.observe.await_count == 4


@pytest.mark.asyncio
async def test_sequence_preserves_immediate_popup_evidence_without_claiming_stability(tmp_path):
    popup = _observation(_screen(tmp_path, "popup.jpg"), "缩放面板")
    session = Mock()
    session.observe = AsyncMock(return_value=popup)
    executor = McpActionExecutor(Mock(), actuator=Mock())

    observed, settled = await executor._observe_after_action(session, "action_sequence", None)

    assert observed is popup
    assert settled is None
    session.observe.assert_awaited_once_with(settle_ms=0)


@pytest.mark.asyncio
async def test_read_only_action_keeps_single_observation(tmp_path):
    home = _screen(tmp_path, "home.jpg")
    session = Mock()
    session.observe = AsyncMock(return_value=_observation(home, "设置首页"))
    executor = McpActionExecutor(Mock(), actuator=Mock())

    observed, settled = await executor._observe_after_action(session, "wait_for_delay", home)

    assert observed.screenshot_path == home
    assert settled is True
    session.observe.assert_awaited_once_with(settle_ms=400)