import { siteSettings } from "@/lib/services/site-settings";

/**
 * Server-side CAPTCHA verification, driven by website_settings so staff pick the
 * provider in housekeeping. Supports Cloudflare Turnstile and Google reCAPTCHA
 * (the two AtomCMS offers, mutually exclusive).
 *
 * Behaviour:
 *   - provider "none" (or unset) → fail-open (allow)
 *   - provider configured but site key / secret missing, token absent, provider
 *     API error, or network failure → fail-closed (deny)
 *
 * Settings keys:
 *   captcha_provider   = "turnstile" | "recaptcha" | "none" (default none)
 *   turnstile_secret / turnstile_site_key
 *   recaptcha_secret  / recaptcha_site_key
 */
export interface CaptchaConfig {
	provider: "turnstile" | "recaptcha" | "none";
	siteKey: string;
	/** Form field the widget writes the token into. */
	field: string;
}

const TURNSTILE_URL =
	"https://challenges.cloudflare.com/turnstile/v0/siteverify";
const RECAPTCHA_URL = "https://www.google.com/recaptcha/api/siteverify";

/** Public config the register/login pages need to render the widget (no secrets). */
export async function captchaConfig(): Promise<CaptchaConfig> {
	const provider = (
		(await siteSettings.get("captcha_provider", "none")) ?? "none"
	).toLowerCase();
	if (provider === "turnstile") {
		return {
			provider: "turnstile",
			siteKey: (await siteSettings.get("turnstile_site_key", "")) ?? "",
			field: "cf-turnstile-response",
		};
	}
	if (provider === "recaptcha") {
		return {
			provider: "recaptcha",
			siteKey: (await siteSettings.get("recaptcha_site_key", "")) ?? "",
			field: "g-recaptcha-response",
		};
	}
	return { provider: "none", siteKey: "", field: "" };
}

/** Verify a submitted token. Fail-closed when a provider is configured. */
export async function verifyCaptcha(
	token: string | null,
	remoteIp?: string,
): Promise<boolean> {
	const cfg = await captchaConfig();
	if (cfg.provider === "none") return true;

	if (!cfg.siteKey) return false;

	const secretKey =
		cfg.provider === "turnstile" ? "turnstile_secret" : "recaptcha_secret";
	const secret = (await siteSettings.get(secretKey, "")) ?? "";
	if (!secret) return false;
	if (!token) return false;

	const url = cfg.provider === "turnstile" ? TURNSTILE_URL : RECAPTCHA_URL;
	const body = new URLSearchParams({ secret, response: token });
	if (remoteIp) body.set("remoteip", remoteIp);

	try {
		const controller = new AbortController();
		const timer = setTimeout(() => controller.abort(), 5000);
		const res = await fetch(url, {
			method: "POST",
			headers: { "content-type": "application/x-www-form-urlencoded" },
			body,
			signal: controller.signal,
			cache: "no-store",
		});
		clearTimeout(timer);
		if (!res.ok) return false;
		const data = (await res.json()) as { success?: boolean };
		return data?.success === true;
	} catch {
		// Network/timeout/misconfig — fail-closed so captcha can't be bypassed.
		return false;
	}
}