"""镜像生成：成功造出正解相反的镜像；正解相同/生成 null → 返回 None。"""

import pytest

from app.question_gen.adversarial_filter import (
    _rebuild_material,
    generate_mirror_question,
)
from app.tree.index import (
    IndexMeta,
    L1Card,
    L1Node,
    L2Card,
    L2Node,
    L3Card,
    L3Node,
    TreeIndex,
)
from core.types import GeneratedQuestion, LLMResponse


class _FakeVLM:
    def __init__(self, content: str):
        self._content = content

    async def chat_with_images(self, messages, images, *, session_id=None, parent_call_id=None):
        return LLMResponse(
            content=self._content, thinking="", model="fake", provider="fake",
            prompt_tokens=0, completion_tokens=0, latency_ms=0,
            ttft_ms=None, max_inter_token_ms=None, cache_hit=False, call_id="c",
        )


def _q():
    return GeneratedQuestion(
        question_id="q1", video_id="v1", task_type="Action Recognition",
        question="X 之前做了什么？", options=("A. 蒸", "B. 炒", "C. 煮", "D. 炸"),
        answer="A", source_nodes=("n1",), difficulty="hard",
        sub_pattern="temporal_reasoning_failure",
    )


@pytest.mark.asyncio
async def test_mirror_distinct_correct_ok():
    vlm = _FakeVLM('{"mirror": {"question": "X 之后做了什么？", '
                   '"options": ["A. 炒", "B. 蒸", "C. 煮", "D. 炸"], "answer": "A"}}')
    mirror = await generate_mirror_question(
        _q(), flip_axis="before/after", vlm=vlm, material=_FakeMaterial(), session_id="s",
    )
    assert mirror is not None
    # 原正解 canonical="蒸"，镜像正解 canonical="炒" → 相异，有效
    assert mirror.answer == "A"
    assert mirror.options[0] == "A. 炒"


@pytest.mark.asyncio
async def test_mirror_same_correct_rejected():
    # 镜像正解 canonical 仍是"蒸" → 造不出有效对 → None
    vlm = _FakeVLM('{"mirror": {"question": "X 之后？", '
                   '"options": ["A. 蒸", "B. 炒", "C. 煮", "D. 炸"], "answer": "A"}}')
    mirror = await generate_mirror_question(
        _q(), flip_axis="before/after", vlm=vlm, material=_FakeMaterial(), session_id="s",
    )
    assert mirror is None


@pytest.mark.asyncio
async def test_mirror_null_returns_none():
    vlm = _FakeVLM('{"mirror": null}')
    mirror = await generate_mirror_question(
        _q(), flip_axis="before/after", vlm=vlm, material=_FakeMaterial(), session_id="s",
    )
    assert mirror is None


@pytest.mark.asyncio
async def test_mirror_malformed_response_returns_none():
    # 畸形 VLM 响应（连 json_repair 都救不回）不得抛异常中断本轮，须返 None
    vlm = _FakeVLM("对不起，我无法完成这个请求。")
    mirror = await generate_mirror_question(
        _q(), flip_axis="before/after", vlm=vlm, material=_FakeMaterial(), session_id="s",
    )
    assert mirror is None


class _FakeMaterial:
    subtitle_sentences = ["先炒后蒸"]
    frame_paths = ["/f1.jpg"]


class _NoCallVLM:
    """素材为空时被误调用即失败——断言空素材绝不触达 VLM。"""

    async def chat_with_images(self, *args, **kwargs):
        raise AssertionError("素材为空时不应调用 VLM")


class _EmptyMaterial:
    subtitle_sentences: list[str] = []
    frame_paths = ["/does/not/exist/frame_x.jpg"]


@pytest.mark.asyncio
async def test_mirror_empty_material_skips_vlm():
    # 无字幕 AND 帧全不存在 → 直接返 None，且绝不调用 VLM
    mirror = await generate_mirror_question(
        _q(), flip_axis="before/after", vlm=_NoCallVLM(),
        material=_EmptyMaterial(), session_id="s",
    )
    assert mirror is None


def _tiny_tree() -> tuple[TreeIndex, str, str]:
    """构建 1×L1→1×L2→2×L3 的最小真实树；返回 (tree, l2_id, first_l3_id)。

    L2 自带字幕，两个 L3 各带字幕与帧路径，便于验证父子重叠去重。
    """
    l3_nodes = [
        L3Node(
            id=f"l2a_l3_{i}",
            card=L3Card(
                frame_summary=f"帧{i}",
                visible_entities=[],
                ongoing_actions=[],
                visible_text=[],
                spatial_layout="居中",
                visual_attributes={},
                subtitle=f"字幕{i}",
            ),
            frame_path=f"frames/l2a_l3_{i}.jpg",
        )
        for i in range(2)
    ]
    l2 = L2Node(
        id="l2a",
        card=L2Card(
            event_description="事件A",
            entities=[],
            actions=[],
            action_subjects=[],
            visible_text=[],
            spatial_relations="并列",
            state_changes=None,
            subtitle="L2字幕",
        ),
        children=l3_nodes,
    )
    l1 = L1Node(
        id="l1a",
        card=L1Card(
            scene_summary="场景A",
            main_setting="室内",
            key_entities=[],
            main_actions=[],
            topic_keywords=[],
            visible_text=[],
            temporal_flow="顺序",
        ),
        children=[l2],
    )
    tree = TreeIndex(
        metadata=IndexMeta(source_path="/t.mp4", modality="video"), roots=[l1]
    )
    return tree, "l2a", "l2a_l3_0"


def test_rebuild_material_dedup_parent_child():
    # source_nodes 同含父 L2 与子 L3（子树重叠）→ 素材须保序去重、无冗余
    tree, l2_id, l3_id = _tiny_tree()
    material = _rebuild_material(tree, (l2_id, l3_id))
    assert len(material.subtitle_sentences) == len(set(material.subtitle_sentences))
    assert len(material.frame_paths) == len(set(material.frame_paths))
    # L2字幕 + 两条 L3 字幕 = 3 条；两帧 = 2 帧（去重后）
    assert material.subtitle_sentences == ["L2字幕", "字幕0", "字幕1"]
    assert material.frame_paths == ["frames/l2a_l3_0.jpg", "frames/l2a_l3_1.jpg"]