"use client";

import React from "react";

import { logout } from "@/lib/frontend/apiClient";
import { buildLoginUrl, LOGIN_REASONS } from "@/lib/frontend/authRedirect";
import { Button } from "@/components/ui/button";

/**
 * LogoutButton (RHL-020)
 *
 * Responsibilities:
 * - Call apiClient.logout() to clear the HTTP-only session cookie.
 * - Then redirect to /login?reason=logged-out.
 *
 * Important test/runtime note:
 * - We intentionally avoid next/navigation hooks here.
 * - Some unit tests render AppShell via react-dom/server without Next.js runtime.
 * - Using window.location inside the click handler avoids needing router context
 *   during server rendering (handler is not invoked in SSR tests).
 *
 * UX rule:
 * - All user-facing text must be German.
 */
export default function LogoutButton() {
	const [isLoggingOut, setIsLoggingOut] = React.useState(false);

	async function handleLogout() {
		if (isLoggingOut) return;

		setIsLoggingOut(true);

		try {
			// Backend endpoint is idempotent; even if no cookie exists it returns ok.
			await logout();
		} catch (err) {
			// If logout fails due to network issues, we still redirect to login.
			// This keeps UX predictable; user can log in again if needed.
			console.error("[LogoutButton] logout failed:", err);
		}

		const loginUrl = buildLoginUrl({ reason: LOGIN_REASONS.LOGGED_OUT });

		// Replace so "Back" won't bring the user into a protected page.
		window.location.replace(loginUrl);
	}

	return (
		<Button
			variant="outline"
			size="sm"
			type="button"
			disabled={isLoggingOut}
			aria-disabled={isLoggingOut ? "true" : "false"}
			onClick={handleLogout}
			title={isLoggingOut ? "Abmeldung läuft…" : "Abmelden"}
		>
			{isLoggingOut ? "Abmeldung…" : "Abmelden"}
		</Button>
	);
}