// best-effort batch lookup of verified signup emails against the internal
// `/_internal/email-did` route. returns only the emails that resolved; a
// transport or parse failure answers an empty map so hydration never throws.
export const resolveEmailToDid = async (
	fetchFn: typeof globalThis.fetch,
	emails: string[]
): Promise<Map<string, string>> => {
	if (emails.length === 0) return new Map();
	const params = new URLSearchParams();
	for (const email of emails) params.append("emails", email);
	try {
		const res = await fetchFn(`/_internal/email-did?${params}`);
		if (!res.ok) return new Map();
		const map: Record<string, string | null> = await res.json();
		const result = new Map<string, string>();
		for (const [email, did] of Object.entries(map)) {
			if (did) result.set(email, did);
		}
		return result;
	} catch {
		return new Map();
	}
};