"""app/question_gen/loader.py 单元测试。"""

from __future__ import annotations

import json
from pathlib import Path

import pytest

from app.question_gen.loader import load_benchmark
from core.types import GeneratedQuestion


@pytest.fixture()
def benchmark_dir(tmp_path: Path) -> Path:
    """创建包含 benchmark JSON 的临时目录。"""
    data = [
        {
            "question_id": "1-1",
            "task_type": "Action Reasoning",
            "question": "What happened?",
            "options": ["A. X", "B. Y", "C. Z", "D. W"],
            "answer": "A",
        },
        {
            "question_id": "1-2",
            "task_type": "OCR Problems",
            "question": "What text is shown?",
            "options": ["A. Hello", "B. World", "C. Foo", "D. Bar"],
            "answer": "B",
        },
    ]
    (tmp_path / "video_abc.json").write_text(json.dumps(data), encoding="utf-8")
    return tmp_path


class TestLoadBenchmark:
    def test_loads_questions_from_json(self, benchmark_dir: Path) -> None:
        questions = load_benchmark(benchmark_dir)
        assert len(questions) == 2

    def test_video_id_from_filename(self, benchmark_dir: Path) -> None:
        questions = load_benchmark(benchmark_dir)
        assert all(q.video_id == "video_abc" for q in questions)

    def test_fields_mapped_correctly(self, benchmark_dir: Path) -> None:
        questions = load_benchmark(benchmark_dir)
        q = questions[0]
        assert q.question_id == "1-1"
        assert q.task_type == "Action Reasoning"
        assert q.question == "What happened?"
        assert q.options == ("A. X", "B. Y", "C. Z", "D. W")
        assert q.answer == "A"

    def test_options_is_tuple(self, benchmark_dir: Path) -> None:
        questions = load_benchmark(benchmark_dir)
        assert isinstance(questions[0].options, tuple)

    def test_source_nodes_is_empty_tuple(self, benchmark_dir: Path) -> None:
        questions = load_benchmark(benchmark_dir)
        assert questions[0].source_nodes == ()

    def test_difficulty_defaults_to_medium_for_legacy(self, benchmark_dir: Path) -> None:
        questions = load_benchmark(benchmark_dir)
        assert questions[0].difficulty == "medium"

    def test_difficulty_from_json_when_present(self, tmp_path: Path) -> None:
        data = [
            {
                "question_id": "2-1",
                "task_type": "OCR Problems",
                "question": "Q?",
                "options": ["A. 1", "B. 2", "C. 3", "D. 4"],
                "answer": "C",
                "difficulty": "hard",
            }
        ]
        (tmp_path / "vid.json").write_text(json.dumps(data), encoding="utf-8")
        questions = load_benchmark(tmp_path)
        assert questions[0].difficulty == "hard"

    def test_empty_directory_returns_empty_list(self, tmp_path: Path) -> None:
        questions = load_benchmark(tmp_path)
        assert questions == []

    def test_sorted_by_filename(self, tmp_path: Path) -> None:
        for name in ["z_video.json", "a_video.json"]:
            data = [
                {
                    "question_id": f"{name}-1",
                    "task_type": "T",
                    "question": "Q?",
                    "options": ["A", "B", "C", "D"],
                    "answer": "A",
                }
            ]
            (tmp_path / name).write_text(json.dumps(data), encoding="utf-8")
        questions = load_benchmark(tmp_path)
        assert questions[0].video_id == "a_video"
        assert questions[1].video_id == "z_video"

    def test_returns_generated_question_instances(self, benchmark_dir: Path) -> None:
        questions = load_benchmark(benchmark_dir)
        assert all(isinstance(q, GeneratedQuestion) for q in questions)

    def test_loads_real_benchmark(self) -> None:
        """使用真实 benchmark 数据验证加载正确性。"""
        real_dir = Path("store/questions/benchmarks/Video-MME")
        if not real_dir.exists():
            pytest.skip("真实 benchmark 数据不存在")
        questions = load_benchmark(real_dir)
        assert len(questions) > 0
        for q in questions:
            assert isinstance(q, GeneratedQuestion)
            assert len(q.options) == 4
            assert q.answer in ("A", "B", "C", "D")

    def test_malformed_json_raises(self, tmp_path: Path) -> None:
        """非法 JSON 文件应抛出 json.JSONDecodeError。"""
        (tmp_path / "bad.json").write_text("not valid json{{{", encoding="utf-8")
        with pytest.raises(json.JSONDecodeError):
            load_benchmark(tmp_path)

    def test_missing_required_field_raises(self, tmp_path: Path) -> None:
        """缺少必需字段（如 question_id）应抛出 KeyError。"""
        data = [{"task_type": "T", "question": "Q?", "options": ["A"], "answer": "A"}]
        (tmp_path / "vid.json").write_text(json.dumps(data), encoding="utf-8")
        with pytest.raises(KeyError):
            load_benchmark(tmp_path)