"""RuntimeSettings 单元测试：默认值 / 加载 / 保存 / 部分更新 / 重置 / 单例

每个测试通过 monkeypatch 把 RUNTIME_SETTINGS_PATH 指向独立临时文件，并在前后
重置模块级 `_runtime_settings` 单例，避免跨测试串扰。
"""

import json
from pathlib import Path

import pytest

from app.core import runtime_settings as rs


@pytest.fixture
def isolated_settings_path(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> Path:
    """每个测试独立持久化路径，并在前后清空模块级单例"""
    path = tmp_path / "runtime_settings.json"
    monkeypatch.setenv("RUNTIME_SETTINGS_PATH", str(path))
    # 重置单例，强制下次 get_runtime_settings 重新加载
    rs._runtime_settings = None
    yield path
    rs._runtime_settings = None


# ---------------------------------------------------------------------------- #
# 默认值
# ---------------------------------------------------------------------------- #


class TestDefaults:
    def test_default_models_provider_is_ollama(self):
        cfg = rs.RuntimeSettings()
        assert cfg.models.summarize.provider == "ollama"
        assert cfg.models.query.provider == "ollama"
        assert cfg.models.classify.provider == "ollama"

    def test_default_parsers_plugins(self):
        cfg = rs.RuntimeSettings()
        assert cfg.parsers.ocr.plugin == "rapidocr"
        assert cfg.parsers.pdf.plugin == "pypdf"
        assert cfg.parsers.docx.plugin == "python_docx"

    def test_default_dedup(self):
        cfg = rs.RuntimeSettings()
        assert cfg.dedup.strategy == "sha256"
        assert cfg.dedup.simhash_threshold == 3
        assert cfg.dedup.ttl_seconds == 86400

    def test_default_with_env_fallback_uses_ollama_env(self):
        """无持久化文件时，base_url/model 取自 settings.ollama_*"""
        cfg = rs._default_with_env_fallback()
        from app.config import settings

        assert cfg.models.summarize.base_url == settings.ollama_base_url
        assert cfg.models.summarize.model == settings.ollama_model
        assert cfg.models.query.base_url == settings.ollama_base_url
        assert cfg.models.classify.model == settings.ollama_model


# ---------------------------------------------------------------------------- #
# 加载
# ---------------------------------------------------------------------------- #


class TestLoad:
    def test_missing_file_returns_env_fallback(self, isolated_settings_path: Path):
        """文件不存在时回退到带 env 兜底的默认值（不抛异常）"""
        assert not isolated_settings_path.exists()
        cfg = rs.load_runtime_settings()
        # base_url 应来自 env fallback
        from app.config import settings

        assert cfg.models.summarize.base_url == settings.ollama_base_url

    def test_valid_file_parsed(self, isolated_settings_path: Path):
        isolated_settings_path.write_text(
            json.dumps(
                {
                    "models": {
                        "summarize": {"provider": "openai_compatible", "model": "gpt-4o-mini", "api_key": "k"}
                    },
                    "dedup": {"strategy": "simhash", "simhash_threshold": 5},
                }
            ),
            encoding="utf-8",
        )
        cfg = rs.load_runtime_settings()
        assert cfg.models.summarize.provider == "openai_compatible"
        assert cfg.models.summarize.model == "gpt-4o-mini"
        assert cfg.models.summarize.api_key == "k"
        assert cfg.dedup.strategy == "simhash"
        assert cfg.dedup.simhash_threshold == 5
        # 未指定的字段保留默认
        assert cfg.dedup.ttl_seconds == 86400
        assert cfg.models.query.provider == "ollama"

    def test_corrupted_file_falls_back(self, isolated_settings_path: Path):
        isolated_settings_path.write_text("not-json{", encoding="utf-8")
        cfg = rs.load_runtime_settings()
        # 回退到默认（ollama provider）
        assert cfg.models.summarize.provider == "ollama"

    def test_invalid_values_falls_back(self, isolated_settings_path: Path):
        """字段值非法（如未知 provider）时整体回退默认"""
        isolated_settings_path.write_text(
            json.dumps({"models": {"summarize": {"provider": "unknown_provider"}}}),
            encoding="utf-8",
        )
        cfg = rs.load_runtime_settings()
        assert cfg.models.summarize.provider == "ollama"  # 回退默认


# ---------------------------------------------------------------------------- #
# 保存
# ---------------------------------------------------------------------------- #


class TestSave:
    def test_save_writes_valid_json(self, isolated_settings_path: Path):
        cfg = rs.RuntimeSettings()
        cfg.dedup.strategy = "simhash"
        rs.save_runtime_settings(cfg)
        assert isolated_settings_path.exists()
        data = json.loads(isolated_settings_path.read_text(encoding="utf-8"))
        assert data["dedup"]["strategy"] == "simhash"

    def test_save_creates_parent_dir(self, tmp_path: Path, monkeypatch: pytest.MonkeyPatch):
        path = tmp_path / "nested" / "deep" / "runtime_settings.json"
        monkeypatch.setenv("RUNTIME_SETTINGS_PATH", str(path))
        rs.save_runtime_settings(rs.RuntimeSettings())
        assert path.exists()

    def test_save_atomic_no_tmp_left(self, isolated_settings_path: Path):
        """保存后同目录无残留 .tmp 临时文件"""
        rs.save_runtime_settings(rs.RuntimeSettings())
        tmps = list(isolated_settings_path.parent.glob(".runtime_settings.*.tmp"))
        assert tmps == []


# ---------------------------------------------------------------------------- #
# 单例 + reload
# ---------------------------------------------------------------------------- #


class TestSingleton:
    def test_get_returns_singleton(self, isolated_settings_path: Path):
        cfg1 = rs.get_runtime_settings()
        cfg2 = rs.get_runtime_settings()
        assert cfg1 is cfg2

    def test_reload_rereads_disk(self, isolated_settings_path: Path):
        """reload 强制重新读盘，单例替换为新对象"""
        cfg1 = rs.get_runtime_settings()
        # 直接改盘上文件
        isolated_settings_path.write_text(
            json.dumps({"dedup": {"strategy": "none"}}), encoding="utf-8"
        )
        cfg2 = rs.reload_runtime_settings()
        assert cfg2 is not cfg1
        assert cfg2.dedup.strategy == "none"


# ---------------------------------------------------------------------------- #
# 部分更新（深合并）
# ---------------------------------------------------------------------------- #


class TestUpdate:
    def test_partial_update_models_summarize(self, isolated_settings_path: Path):
        rs.get_runtime_settings()  # 初始化单例
        new_cfg = rs.update_runtime_settings(
            {"models": {"summarize": {"model": "qwen2.5:3b"}}}
        )
        assert new_cfg.models.summarize.model == "qwen2.5:3b"
        # 其他字段保留
        assert new_cfg.models.summarize.provider == "ollama"
        assert new_cfg.models.query.provider == "ollama"

    def test_partial_update_dedup(self, isolated_settings_path: Path):
        rs.get_runtime_settings()
        new_cfg = rs.update_runtime_settings(
            {"dedup": {"strategy": "simhash", "simhash_threshold": 5}}
        )
        assert new_cfg.dedup.strategy == "simhash"
        assert new_cfg.dedup.simhash_threshold == 5
        # ttl 未在 patch 中，保留默认
        assert new_cfg.dedup.ttl_seconds == 86400

    def test_update_persists_to_disk(self, isolated_settings_path: Path):
        rs.get_runtime_settings()
        rs.update_runtime_settings({"dedup": {"strategy": "none"}})
        data = json.loads(isolated_settings_path.read_text(encoding="utf-8"))
        assert data["dedup"]["strategy"] == "none"

    def test_update_replaces_singleton(self, isolated_settings_path: Path):
        old = rs.get_runtime_settings()
        new = rs.update_runtime_settings({"dedup": {"strategy": "none"}})
        assert new is not old
        # 后续 get 拿到的是新单例
        assert rs.get_runtime_settings() is new

    def test_update_empty_patch_keeps_all(self, isolated_settings_path: Path):
        """空 patch 不改变任何字段"""
        rs.get_runtime_settings()
        new_cfg = rs.update_runtime_settings({})
        assert new_cfg.dedup.strategy == "sha256"


# ---------------------------------------------------------------------------- #
# 重置
# ---------------------------------------------------------------------------- #


class TestReset:
    def test_reset_returns_defaults(self, isolated_settings_path: Path):
        # 先污染
        rs.get_runtime_settings()
        rs.update_runtime_settings({"dedup": {"strategy": "none"}})
        assert rs.get_runtime_settings().dedup.strategy == "none"
        # 重置
        cfg = rs.reset_runtime_settings()
        assert cfg.dedup.strategy == "sha256"
        assert cfg.dedup.simhash_threshold == 3
        assert cfg.parsers.ocr.plugin == "rapidocr"

    def test_reset_persists_to_disk(self, isolated_settings_path: Path):
        rs.get_runtime_settings()
        rs.update_runtime_settings({"dedup": {"strategy": "none"}})
        rs.reset_runtime_settings()
        data = json.loads(isolated_settings_path.read_text(encoding="utf-8"))
        assert data["dedup"]["strategy"] == "sha256"


# ---------------------------------------------------------------------------- #
# 深合并工具函数
# ---------------------------------------------------------------------------- #


class TestDeepMerge:
    def test_nested_dict_merged(self):
        target = {"a": {"b": 1, "c": 2}, "d": 3}
        rs._deep_merge(target, {"a": {"b": 10}})
        assert target == {"a": {"b": 10, "c": 2}, "d": 3}

    def test_non_dict_overrides(self):
        target = {"a": {"b": 1}}
        rs._deep_merge(target, {"a": 99})
        assert target == {"a": 99}

    def test_new_key_added(self):
        target = {"a": 1}
        rs._deep_merge(target, {"b": 2})
        assert target == {"a": 1, "b": 2}