"""分层边界的测试。

这些断言不测业务，测的是**架构约束本身**。分层的价值全在「换供应商不动上层」，
而这个性质只要有人无意加一行 import 就会悄悄失效——没有测试守着，它迟早会失效。
"""

from __future__ import annotations

import ast
import pathlib

APP = pathlib.Path(__file__).resolve().parent.parent / "app"


def imports_of(path: pathlib.Path) -> set[str]:
    tree = ast.parse(path.read_text(encoding="utf-8"))
    names: set[str] = set()
    for node in ast.walk(tree):
        if isinstance(node, ast.Import):
            names.update(alias.name for alias in node.names)
        elif isinstance(node, ast.ImportFrom) and node.module:
            names.add(node.module)
    return names


def modules_under(*parts: str) -> list[pathlib.Path]:
    return sorted((APP.joinpath(*parts)).rglob("*.py"))


class TestDomainIsIndependent:
    """领域层是「换供应商不动上层」的支点。它一旦依赖厂商或 HTTP，分层就名存实亡。"""

    def test_domain_imports_no_provider_code(self):
        for module in modules_under("domain"):
            offenders = {name for name in imports_of(module) if "providers" in name}
            assert not offenders, f"{module.name} 不应依赖服务商代码：{offenders}"

    def test_domain_imports_no_http_library(self):
        for module in modules_under("domain"):
            offenders = {
                name
                for name in imports_of(module)
                if name.split(".")[0] in {"httpx", "requests"}
            }
            assert not offenders, f"{module.name} 不应依赖 HTTP 库：{offenders}"

    def test_domain_does_not_read_configuration(self):
        # 领域对象应当是纯数据；让它自己读配置会使单测必须摆弄环境变量。
        for module in modules_under("domain"):
            offenders = {
                name for name in imports_of(module) if name in {"os", "app.config"}
            }
            assert not offenders, f"{module.name} 不应读取配置：{offenders}"


class TestAbstractionDoesNotLeak:
    def test_provider_base_knows_no_specific_vendor(self):
        """抽象接口若 import 了火山，新增第二家供应商就得改抽象层。"""
        offenders = {
            name
            for name in imports_of(APP / "providers" / "base.py")
            if "volcengine" in name
        }
        assert not offenders, f"抽象层不应依赖具体服务商：{offenders}"

    def test_registry_knows_no_specific_vendor(self):
        offenders = {
            name
            for name in imports_of(APP / "providers" / "registry.py")
            if "volcengine" in name
        }
        assert not offenders, f"注册表不应依赖具体服务商：{offenders}"


class TestTransportStaysBusinessAgnostic:
    def test_ark_client_does_not_import_video_business(self):
        """传输层复用的前提是它不认识「视频」。

        一旦 client.py 依赖了 video.py，接火山的图片接口时就没法复用它，
        只能再抄一遍鉴权与错误解包——那正是拆分要避免的。
        """
        offenders = {
            name
            for name in imports_of(APP / "providers" / "volcengine" / "client.py")
            if name.endswith((".video", ".image")) or name.endswith("models")
        }
        assert not offenders, f"传输层不应依赖具体业务模块：{offenders}"


class TestVendorVocabularyIsContained:
    def test_only_the_volcengine_package_mentions_ark_paths(self):
        """厂商特有的路径、字段名只应出现在其适配包内。

        `framespersecond` 这种厂商拼法漏到上层，就意味着上层已经知道自己在跟
        火山说话——换供应商时会牵连到它。
        """
        vendor_markers = ("framespersecond", "contents/generations", "ark.cn-beijing")
        for module in sorted(APP.rglob("*.py")):
            if "volcengine" in module.parts:
                continue
            text = module.read_text(encoding="utf-8")
            for marker in vendor_markers:
                assert marker not in text, (
                    f"{module.relative_to(APP)} 出现了厂商专有词汇 {marker!r}，"
                    f"应收拢到 providers/volcengine/ 内"
                )


class TestDependencyDirectionIsOneWay:
    """配置 → 适配层，绝不反向。

    `config.py` 作为装配根知道有哪家供应商是合理的；反过来，适配层一旦自己去读
    配置，依赖注入就失效了——单测又得摆弄环境变量，而且同一进程内没法跑两套
    不同配置的适配器实例。
    """

    def test_providers_do_not_read_config(self):
        for module in modules_under("providers"):
            offenders = {
                name
                for name in imports_of(module)
                if name == "app.config" or name == "os"
            }
            assert not offenders, (
                f"{module.relative_to(APP)} 不应自行读取配置或环境变量："
                f"{offenders}。请通过构造参数注入。"
            )