/**
 * Feature gating for PAYG billing.
 * 
 * If user has an active subscription → all features unlocked.
 * If no subscription → free features only.
 * 
 * Usage in server actions:
 *   await requireSubscription("payroll");
 * 
 * Usage in client components:
 *   const hasAccess = await checkSubscription();
 */

import { createAdminClient } from "@/lib/supabase/server";
import { auth } from "@clerk/nextjs/server";

interface SubscriptionCheck {
  hasSubscription: boolean;
  status: string;
  currentPeriodEnd: string | null;
  cancelAtPeriodEnd: boolean;
}

/**
 * Check if the organisation has an active subscription.
 */
export async function checkSubscription(): Promise<SubscriptionCheck> {
  const { userId } = await auth();
  if (!userId) return { hasSubscription: false, status: "none", currentPeriodEnd: null, cancelAtPeriodEnd: false };

  const supabase = await createAdminClient();

  const { data: member } = await supabase
    .from("organisation_members")
    .select("organisation_id")
    .eq("user_id", userId)
    .single();

  if (!member) return { hasSubscription: false, status: "none", currentPeriodEnd: null, cancelAtPeriodEnd: false };

  const { data: sub } = await supabase
    .from("subscriptions")
    .select("status, current_period_end, cancel_at_period_end")
    .eq("organisation_id", member.organisation_id)
    .single();

  const isActive = sub?.status === "active" || sub?.status === "trialing";

  return {
    hasSubscription: isActive,
    status: sub?.status || "none",
    currentPeriodEnd: sub?.current_period_end || null,
    cancelAtPeriodEnd: sub?.cancel_at_period_end || false,
  };
}

/**
 * Require an active subscription for a specific feature.
 * Throws an error if no active subscription.
 */
export async function requireSubscription(feature: string): Promise<void> {
  const check = await checkSubscription();
  if (!check.hasSubscription) {
    throw new Error(`"${feature}" requires an active subscription. Go to Settings → Billing to subscribe.`);
  }
}