import { useEffect, useState, useMemo } from "react";
import { useNavigate, useParams } from "react-router-dom";
import { ArrowLeft, House, CreditCard, BadgeCheck, User } from "lucide-react";
import { Badge } from "@/components/ui/badge";
import { Button } from "@/components/ui/button";
import { Skeleton } from "@/components/ui/skeleton";
import { Separator } from "@/components/ui/separator";
import AppBreadcrumb from "@/components/generic/Breadcrumb/AppBreadcrumb";
import { useTiers } from "@/contexts/AdminTiersContext";
import { useDateFormat } from "@/hooks/useDateFormat";
import { PageMeta } from "@/contexts/MetadataContext";
import api from "@/utils/api.util";
import { resolveTierBadge } from "@/utils/tierBadge.util";

const STATUS_BADGE = {
  pending:   "secondary",
  completed: "default",
  failed:    "destructive",
  cancelled: "outline",
  expired:   "outline",
  refunded:  "outline",
};

// ─── Provider label map (extend as you add more providers) ───────────────────
const PROVIDER_LABELS = {
  paypal: "PayPal",
  stripe: "Stripe",
  gcash:  "GCash",
};

function InfoRow({ label, children }) {
  return (
    <div className="flex flex-col gap-0.5">
      <span className="text-xs text-muted-foreground uppercase tracking-wide">{label}</span>
      <span className="text-sm font-medium break-all">
        {children ?? <span className="text-muted-foreground italic">—</span>}
      </span>
    </div>
  );
}

function SectionCard({ icon: Icon, title, children }) {
  return (
    <div className="rounded-lg border bg-card p-5 space-y-4">
      <div className="flex items-center gap-2">
        {Icon && <Icon className="h-4 w-4 text-muted-foreground" />}
        <h2 className="text-sm font-semibold">{title}</h2>
      </div>
      <Separator />
      {children}
    </div>
  );
}

// ─── Provider reference section — renders differently per provider ────────────
function ProviderReference({ payment }) {
  const provider  = payment.provider ?? "paypal";
  const payload   = payment.provider_payload ?? {};
  const title     = `${PROVIDER_LABELS[provider] ?? provider} Reference`;

  return (
    <SectionCard icon={CreditCard} title={title}>
      <div className="grid grid-cols-1 gap-3">

        {/* PayPal */}
        {provider === "paypal" && (
          <>
            <InfoRow label="Order ID">{payload.order_id}</InfoRow>
            <InfoRow label="Capture ID">{payload.capture_id}</InfoRow>
            <InfoRow label="Payer ID">{payload.payer_id}</InfoRow>
            {payload.checkout && (
              <>
                <InfoRow label="Subtotal">
                  {payment.currency} {Number(payload.checkout.subtotal ?? 0).toFixed(2)}
                </InfoRow>
                {Number(payload.checkout.discount) > 0 && (
                  <InfoRow label="Promo Applied">
                    {payload.checkout.promo_code} — -{payment.currency}{" "}
                    {Number(payload.checkout.discount).toFixed(2)}
                  </InfoRow>
                )}
              </>
            )}
          </>
        )}

        {/* Stripe — extend when needed */}
        {provider === "stripe" && (
          <>
            <InfoRow label="Payment Intent ID">{payload.payment_intent_id}</InfoRow>
            <InfoRow label="Charge ID">{payload.charge_id}</InfoRow>
            <InfoRow label="Customer ID">{payload.customer_id}</InfoRow>
          </>
        )}

        {/* GCash / other — generic fallback */}
        {provider !== "paypal" && provider !== "stripe" && (
          <>
            <InfoRow label="Reference ID">{payload.reference_id}</InfoRow>
            <InfoRow label="Transaction ID">{payload.transaction_id}</InfoRow>
          </>
        )}

        {/* Cancelled info — shown for any provider */}
        {payload.cancelled_at && (
          <InfoRow label="Cancelled At">
            {fmtDateTime(payload.cancelled_at)}
          </InfoRow>
        )}

      </div>
    </SectionCard>
  );
}

// ─── Main ─────────────────────────────────────────────────────────────────────

export default function ViewPayment() {
  const navigate = useNavigate();
  const { paymentId } = useParams();
  const { fetchPayment, payment, loading } = useTiers();
  const { fmtDateTime } = useDateFormat();

  const [tierCategories, setTierCategories] = useState([]);
  const tierMap = useMemo(() => Object.fromEntries(tierCategories.map((c) => [c.slug, c])), [tierCategories]);

  useEffect(() => {
    fetchPayment(paymentId);
    api.get("/admin/tiers/categories").then(({ data }) => setTierCategories(data.data ?? [])).catch(() => {});
  }, [paymentId]);

  return (
    <section className="bg-muted/60 min-h-full">
      <PageMeta title={payment ? `${payment.plan?.label ?? 'Payment'} – Payment - STARR` : undefined} />
      <div className="lg:container lg:mx-auto lg:px-0 flex flex-col items-start px-4 py-10">
        <div className="w-full max-w-2xl mx-auto">

          <div className="flex flex-col gap-2 mb-6">
            <AppBreadcrumb items={[
              { label: "Home",     icon: <House className="size-4" />, to: "/admin" },
              { label: "Payments", to: "/admin/tiers/payments" },
              { label: `Payment #${paymentId}` },
            ]} />
          </div>

          <div className="flex items-center gap-3 mb-6">
            <Button type="button" variant="ghost" size="icon" onClick={() => navigate("/admin/tiers/payments")}>
              <ArrowLeft className="h-4 w-4" />
            </Button>
            <div>
              <h1 className="text-xl font-semibold">Payment Details</h1>
              <p className="text-sm text-muted-foreground">Payment #{paymentId}</p>
            </div>
          </div>

          {loading && !payment ? (
            <div className="space-y-5">
              {[...Array(3)].map((_, i) => <Skeleton key={i} className="h-32 w-full" />)}
            </div>
          ) : !payment ? (
            <p className="text-sm text-muted-foreground">Payment not found.</p>
          ) : (
            <div className="space-y-5">

              {/* Transaction */}
              <SectionCard icon={CreditCard} title="Transaction">
                <div className="grid grid-cols-2 gap-4">
                  <InfoRow label="Status">
                    <Badge variant={STATUS_BADGE[payment.status] ?? "outline"} className="capitalize mt-0.5">
                      {payment.status}
                    </Badge>
                  </InfoRow>
                  <InfoRow label="Provider">
                    {PROVIDER_LABELS[payment.provider] ?? payment.provider ?? "—"}
                  </InfoRow>
                  <InfoRow label="Amount">
                    {payment.currency} {Number(payment.amount).toFixed(2)}
                  </InfoRow>
                  {Number(payment.discount) > 0 && (
                    <InfoRow label="Discount">
                      -{payment.currency} {Number(payment.discount).toFixed(2)}
                      {payment.promo_code && ` (${payment.promo_code})`}
                    </InfoRow>
                  )}
                  <InfoRow label="Paid At">
                    {payment.paid_at ? fmtDateTime(payment.paid_at) : "—"}
                  </InfoRow>
                  <InfoRow label="Created At">
                    {payment.createdAt ? fmtDateTime(payment.createdAt) : "—"}
                  </InfoRow>
                </div>
              </SectionCard>

              {/* User */}
              <SectionCard icon={User} title="User">
                <div className="grid grid-cols-2 gap-4">
                  <InfoRow label="User ID">{String(payment.user_id)}</InfoRow>
                  <InfoRow label="Email">{payment.user?.email}</InfoRow>
                </div>
              </SectionCard>

              {/* Plan */}
              {payment.plan && (
                <SectionCard icon={BadgeCheck} title="Plan">
                  <div className="grid grid-cols-2 gap-4">
                    <InfoRow label="Label">{payment.plan.label}</InfoRow>
                    <InfoRow label="Subscription">
                      {(() => { const { cls, label } = resolveTierBadge(payment.plan.tier, tierMap); return <Badge className={`${cls} mt-0.5`}>{label}</Badge>; })()}
                    </InfoRow>
                    <InfoRow label="Duration">{payment.plan.duration_days} days</InfoRow>
                  </div>
                </SectionCard>
              )}

              {/* Provider reference — dynamic per provider */}
              <ProviderReference payment={payment} />

            </div>
          )}
        </div>
      </div>
    </section>
  );
}