import ast
import unittest
from pathlib import Path

REPO_ROOT = Path(__file__).resolve().parents[1]
ADMIN_ROOT = REPO_ROOT / "admin_app"
PRODUCT_ROOT = REPO_ROOT / "app"

FORBIDDEN_ADMIN_IMPORT_PREFIXES = (
    "app.repositories.user_repository",
    "app.services.user",
)
FORBIDDEN_ADMIN_MODULE_IMPORTS = {
    ("app.db.mock_models", "User"),
}


def _iter_python_files(root: Path):
    for path in root.rglob("*.py"):
        if "__pycache__" in path.parts:
            continue
        yield path


def _iter_imports(path: Path):
    source = path.read_text(encoding="utf-8-sig")
    tree = ast.parse(source, filename=str(path))
    for node in ast.walk(tree):
        if isinstance(node, ast.Import):
            for alias in node.names:
                yield ("import", alias.name, None)
        elif isinstance(node, ast.ImportFrom):
            module = node.module or ""
            for alias in node.names:
                yield ("from", module, alias.name)


class AdminIdentityIsolationTests(unittest.TestCase):
    def test_admin_app_does_not_depend_on_product_user_identity_modules(self):
        violations: list[str] = []
        for path in _iter_python_files(ADMIN_ROOT):
            for import_kind, module, imported_name in _iter_imports(path):
                if import_kind == "import" and module.startswith(FORBIDDEN_ADMIN_IMPORT_PREFIXES):
                    violations.append(f"{path.relative_to(REPO_ROOT)} imports {module}")
                if import_kind == "from" and module.startswith(FORBIDDEN_ADMIN_IMPORT_PREFIXES):
                    violations.append(f"{path.relative_to(REPO_ROOT)} imports from {module}")
                if import_kind == "from" and (module, imported_name) in FORBIDDEN_ADMIN_MODULE_IMPORTS:
                    violations.append(f"{path.relative_to(REPO_ROOT)} imports {imported_name} from {module}")

        self.assertEqual(violations, [], "\n".join(violations))

    def test_product_runtime_does_not_depend_on_admin_app_modules(self):
        violations: list[str] = []
        for path in _iter_python_files(PRODUCT_ROOT):
            for _, module, _ in _iter_imports(path):
                if module.startswith("admin_app"):
                    violations.append(f"{path.relative_to(REPO_ROOT)} imports {module}")

        self.assertEqual(violations, [], "\n".join(violations))


if __name__ == "__main__":
    unittest.main()