from __future__ import annotations

import unittest

from backend.application import (
    AUTHENTICATED_POST_HANDLERS,
    PUBLIC_POST_HANDLERS,
    RequestHandler,
)


class HttpDispatchContractTests(unittest.TestCase):
    @staticmethod
    def handler(path: str, calls: list[str]) -> RequestHandler:
        handler = RequestHandler.__new__(RequestHandler)
        handler.path = path
        handler.require_auth = lambda: calls.append("auth") or True
        handler.require_csrf = lambda: calls.append("csrf") or True
        handler.require_access = lambda method, route: (
            calls.append(f"access:{method}:{route}") or True
        )
        return handler

    def test_named_handlers_are_real_registered_post_routes(self) -> None:
        all_handlers = {**PUBLIC_POST_HANDLERS, **AUTHENTICATED_POST_HANDLERS}
        self.assertEqual(
            set(PUBLIC_POST_HANDLERS) & set(AUTHENTICATED_POST_HANDLERS), set()
        )
        for path, handler_name in all_handlers.items():
            with self.subTest(path=path):
                route = RequestHandler.route_registry.resolve("POST", path)
                self.assertIsNotNone(route)
                self.assertTrue(callable(getattr(RequestHandler, handler_name)))
                expected_access = "public" if path in PUBLIC_POST_HANDLERS else None
                if expected_access:
                    self.assertEqual(route.access, expected_access)
                else:
                    self.assertNotEqual(route.access, "public")

    def test_public_post_dispatches_without_authentication(self) -> None:
        for path, handler_name in PUBLIC_POST_HANDLERS.items():
            with self.subTest(path=path):
                calls: list[str] = []
                handler = self.handler(path, calls)
                handler.require_auth = lambda: (_ for _ in ()).throw(
                    AssertionError("public route required authentication")
                )
                setattr(handler, handler_name, lambda: calls.append(handler_name))

                RequestHandler.do_POST(handler)

                self.assertEqual(calls, [handler_name])

    def test_authenticated_post_preserves_guard_order(self) -> None:
        for path, handler_name in AUTHENTICATED_POST_HANDLERS.items():
            with self.subTest(path=path):
                calls: list[str] = []
                handler = self.handler(path, calls)
                setattr(handler, handler_name, lambda: calls.append(handler_name))

                RequestHandler.do_POST(handler)

                self.assertEqual(
                    calls,
                    ["auth", "csrf", f"access:POST:{path}", handler_name],
                )

    def test_failed_access_never_dispatches_protected_handler(self) -> None:
        path, handler_name = next(iter(AUTHENTICATED_POST_HANDLERS.items()))
        calls: list[str] = []
        handler = self.handler(path, calls)
        handler.require_access = lambda method, route: (
            calls.append(f"access:{method}:{route}") or False
        )
        setattr(handler, handler_name, lambda: calls.append(handler_name))

        RequestHandler.do_POST(handler)

        self.assertEqual(calls, ["auth", "csrf", f"access:POST:{path}"])


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