import type { BillingPaneTab, MembershipPlanAlias } from "@/lib/membership";

export const SETTINGS_QUERY_KEY = "settings";

export type SettingsQuery = {
  readonly pane: "billing";
  readonly source: string | null;
  readonly plan: MembershipPlanAlias | null;
  readonly tab: BillingPaneTab | null;
};

const PLAN_ALIASES: ReadonlySet<string> = new Set(["trial", "monthly", "yearly"]);
const BILLING_TABS: ReadonlySet<string> = new Set(["membership", "credits", "redeem", "orders"]);

function searchParams(search: string) {
  return new URLSearchParams(search.startsWith("?") ? search.slice(1) : search);
}

export function parseSettingsQuery(search: string): SettingsQuery | null {
  const params = searchParams(search);
  if (params.get(SETTINGS_QUERY_KEY) !== "billing") return null;
  const planRaw = params.get("plan");
  const tabRaw = params.get("tab");
  return {
    pane: "billing",
    source: params.get("source"),
    plan: planRaw && PLAN_ALIASES.has(planRaw) ? planRaw as MembershipPlanAlias : null,
    tab: tabRaw && BILLING_TABS.has(tabRaw) ? tabRaw as BillingPaneTab : null,
  };
}

export function stripSettingsQuery(search: string, pathname = "/") {
  const params = searchParams(search);
  params.delete(SETTINGS_QUERY_KEY);
  params.delete("source");
  params.delete("plan");
  params.delete("tab");
  const query = params.toString();
  return query ? `${pathname}?${query}` : pathname || "/";
}