"""/auth/login, /auth/callback, /auth/logout: cookies, rotation and CSRF."""

from __future__ import annotations

from uuid import uuid4

from fastapi.testclient import TestClient

from ragcore.application.auth import SessionService, SignedTokenCodec, decode_session
from ragcore.application.auth.ports import AuthorizationChallenge
from ragcore.domain.auth import OidcClaims
from ragcore.domain.control import Role
from ragcore.main import create_app
from ragcore.web.auth.dependencies import (
    PENDING_LOGIN_COOKIE_NAME,
    SESSION_COOKIE_NAME,
    get_session_codec,
    get_session_service,
)

SECRET = b"0" * 32


class FakeOidcProvider:
    def __init__(self, claims: OidcClaims) -> None:
        self.claims = claims

    async def build_authorization_challenge(self, *, redirect_uri: str) -> AuthorizationChallenge:
        return AuthorizationChallenge(
            redirect_url="https://idp.example.test/authorize?mock=1",
            state="fixed-state-for-tests",
            nonce="fixed-nonce-for-tests",
            code_verifier="fixed-verifier-for-tests",
        )

    async def complete_login(
        self, *, code: str, code_verifier: str, nonce: str, redirect_uri: str
    ) -> OidcClaims:
        return self.claims


def _fixture(*, https: bool = False) -> tuple[TestClient, SignedTokenCodec]:
    provider = FakeOidcProvider(
        OidcClaims(subject="alice", email="alice@example.test", groups=("ragcore-editors",))
    )
    service = SessionService(
        provider=provider, group_roles={"ragcore-editors": Role.EDITOR}, workspace_id=uuid4()
    )
    codec = SignedTokenCodec(secret=SECRET)
    api = create_app()
    api.dependency_overrides[get_session_service] = lambda: service
    api.dependency_overrides[get_session_codec] = lambda: codec
    base_url = "https://testserver" if https else "http://testserver"
    return TestClient(api, base_url=base_url, follow_redirects=False), codec


def test_login_redirects_and_sets_a_pending_login_cookie() -> None:
    client, _ = _fixture()
    response = client.get("/auth/login")

    assert response.status_code == 302
    assert response.headers["location"].startswith("https://idp.example.test/")
    set_cookie = response.headers.get("set-cookie", "")
    assert PENDING_LOGIN_COOKIE_NAME in set_cookie
    assert "HttpOnly" in set_cookie
    assert "samesite=lax" in set_cookie.lower()


def test_pending_login_cookie_is_marked_secure_over_https() -> None:
    client, _ = _fixture(https=True)
    response = client.get("/auth/login")
    assert "Secure" in response.headers.get("set-cookie", "")


def test_pending_login_cookie_is_not_marked_secure_over_plain_http() -> None:
    client, _ = _fixture(https=False)
    response = client.get("/auth/login")
    assert "Secure" not in response.headers.get("set-cookie", "")


def test_full_login_then_callback_sets_a_rotated_session_cookie() -> None:
    client, _ = _fixture()
    login_response = client.get("/auth/login")

    callback_response = client.get(
        "/auth/callback",
        params={"code": "auth-code", "state": "fixed-state-for-tests"},
    )

    assert callback_response.status_code == 302
    assert callback_response.headers["location"] == "/admin/dashboard"
    set_cookie = callback_response.headers.get("set-cookie", "")
    assert SESSION_COOKIE_NAME in set_cookie
    # The pending-login cookie is cleared once login completes.
    assert f"{PENDING_LOGIN_COOKIE_NAME}=" in set_cookie or any(
        PENDING_LOGIN_COOKIE_NAME in header
        for header in callback_response.headers.get_list("set-cookie")
    )
    session_cookie_value = client.cookies.get(SESSION_COOKIE_NAME)
    pending_cookie_value = client.cookies.get(PENDING_LOGIN_COOKIE_NAME)
    assert session_cookie_value
    assert not pending_cookie_value
    assert login_response.headers["set-cookie"] != callback_response.headers["set-cookie"]


def test_callback_with_mismatched_state_is_rejected() -> None:
    client, _ = _fixture()
    client.get("/auth/login")

    response = client.get(
        "/auth/callback",
        params={"code": "auth-code", "state": "an-attacker-supplied-state"},
    )

    assert response.status_code == 400
    assert response.json()["code"] == "INVALID_STATE"


def test_callback_without_a_pending_login_cookie_is_rejected() -> None:
    client, _ = _fixture()

    response = client.get(
        "/auth/callback",
        params={"code": "auth-code", "state": "fixed-state-for-tests"},
    )

    assert response.status_code == 400
    assert response.json()["code"] == "LOGIN_EXPIRED"


def test_logout_without_csrf_token_is_rejected() -> None:
    client, _ = _fixture()
    client.get("/auth/login")
    client.get("/auth/callback", params={"code": "auth-code", "state": "fixed-state-for-tests"})

    response = client.post("/auth/logout")

    assert response.status_code == 403
    assert response.json()["code"] == "CSRF_TOKEN_INVALID"


def test_logout_with_a_forged_csrf_token_is_rejected() -> None:
    client, _ = _fixture()
    client.get("/auth/login")
    client.get("/auth/callback", params={"code": "auth-code", "state": "fixed-state-for-tests"})

    response = client.post("/auth/logout", headers={"x-csrf-token": "not-the-real-token"})

    assert response.status_code == 403
    assert response.json()["code"] == "CSRF_TOKEN_INVALID"


def test_logout_with_the_correct_csrf_token_succeeds_and_clears_the_session() -> None:
    client, codec = _fixture()
    client.get("/auth/login")
    client.get("/auth/callback", params={"code": "auth-code", "state": "fixed-state-for-tests"})

    session = decode_session(client.cookies[SESSION_COOKIE_NAME], codec=codec)

    response = client.post("/auth/logout", headers={"x-csrf-token": session.csrf_token})

    assert response.status_code == 302
    assert response.headers["location"] == "/login"
    assert not client.cookies.get(SESSION_COOKIE_NAME)


def test_logout_requires_authentication_before_csrf_is_even_checked() -> None:
    client, _ = _fixture()
    response = client.post("/auth/logout", headers={"x-csrf-token": "anything"})
    assert response.status_code == 401
    assert response.json()["code"] == "AUTHENTICATION_REQUIRED"


def test_auth_routes_are_503_when_oidc_is_not_configured() -> None:
    api = create_app()
    client = TestClient(api, follow_redirects=False)
    response = client.get("/auth/login")
    assert response.status_code == 503
    assert response.json()["code"] == "AUTH_UNAVAILABLE"