"use server";

import { auth } from "@/auth";
import { prisma } from "@/lib/db/prisma";
import { Permission } from "@/generated/prisma/enums";
import { hasPermission } from "@/lib/auth/permissions";
import { redeemReward } from "@/services/loyalty/loyalty.service";
import { writeAuditLog } from "@/lib/audit/write-audit-log";

export interface RedeemRewardResult {
  success: boolean;
  error?: string;
  discountAmount?: string;
}

/**
 * Redemption is an operational action a permitted barber does day to day
 * (not "configure the loyalty programme"), so it's gated on
 * MANAGE_LOYALTY_STAMPS — the same permission Phase 5 already grants to
 * the Barber role for adding/correcting stamps — rather than
 * MANAGE_LOYALTY_PROGRAMME, which is owner-only configuration. Both Owner
 * and Barber roles hold MANAGE_LOYALTY_STAMPS in the seed. See
 * docs/phase-6-summary.md, "Loyalty configuration and redemption approach".
 */
export async function redeemRewardAction(params: {
  rewardId: string;
  appointmentId: string;
}): Promise<RedeemRewardResult> {
  const session = await auth();
  if (!session?.user) return { success: false, error: "You must be signed in." };

  const allowed = await hasPermission(session.user.id, Permission.MANAGE_LOYALTY_STAMPS);
  if (!allowed) return { success: false, error: "You don't have permission to do that." };

  const staff = await prisma.staffProfile.findUnique({ where: { userId: session.user.id } });
  if (!staff) return { success: false, error: "You must be signed in as staff." };

  const result = await redeemReward(prisma, {
    rewardId: params.rewardId,
    appointmentId: params.appointmentId,
    staffId: staff.id,
    businessId: staff.businessId,
  });

  if (!result.success) {
    return { success: false, error: result.validation.issues[0]?.message ?? "Couldn't redeem this reward." };
  }

  await writeAuditLog(prisma, {
    actorUserId: session.user.id,
    action: "LOYALTY_REWARD_REDEEMED",
    entityType: "LoyaltyReward",
    entityId: params.rewardId,
    metadata: { appointmentId: params.appointmentId, discountAmount: result.discountAmount },
  });

  return { success: true, discountAmount: result.discountAmount };
}