"use client";

import { useEffect, useState } from "react";
import { useRouter, useSearchParams } from "next/navigation";
import { getUserFromSession } from "@/lib/auth/get-user";

interface SubscriptionInfo {
  status: "trialing" | "active" | "expired" | "canceled" | "canceling";
  isActive: boolean;
  daysRemainingInTrial: number | null;
  trialEndsAt: string | null;
  subscriptionEndsAt: string | null;
}

export default function BillingPage() {
  const router = useRouter();
  const searchParams = useSearchParams();
  const [subscriptionInfo, setSubscriptionInfo] = useState<SubscriptionInfo | null>(null);
  const [loading, setLoading] = useState(true);
  const [checkoutLoading, setCheckoutLoading] = useState(false);
  const [cancelLoading, setCancelLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const canceled = searchParams.get("canceled");

  useEffect(() => {
    async function loadSubscriptionStatus() {
      try {
        const res = await fetch("/api/subscription/status");
        if (!res.ok) {
          throw new Error("Failed to load subscription status");
        }
        const data = await res.json();
        setSubscriptionInfo(data);
        setLoading(false);
      } catch (err: any) {
        setError(err.message);
        setLoading(false);
      }
    }

    loadSubscriptionStatus();
  }, [searchParams]);

  const handleCheckout = async () => {
    setCheckoutLoading(true);
    setError(null);

    try {
      const res = await fetch("/api/stripe/subscription/checkout", {
        method: "POST",
      });

      if (!res.ok) {
        const error = await res.json();
        throw new Error(error.error || "Failed to create checkout session");
      }

      const { url } = await res.json();
      if (url) {
        window.location.href = url;
      }
    } catch (err: any) {
      setError(err.message);
      setCheckoutLoading(false);
    }
  };

  const handleCancel = async () => {
    setCancelLoading(true);
    setError(null);

    try {
      const res = await fetch("/api/stripe/subscription/portal", {
        method: "POST",
      });

      if (!res.ok) {
        const error = await res.json();
        throw new Error(error.error || "Failed to open billing portal");
      }

      const { url } = await res.json();
      if (url) {
        window.location.href = url;
      }
    } catch (err: any) {
      setError(err.message);
      setCancelLoading(false);
    }
  };


  if (loading) {
    return (
      <div className="min-h-screen bg-gradient-to-b from-slate-50 to-white flex items-center justify-center">
        <div className="text-center">
          <div className="inline-flex items-center justify-center w-12 h-12 mb-4">
            <span className="w-3 h-3 bg-blue-600 rounded-full animate-spin"></span>
          </div>
          <p className="text-slate-600">Loading billing information…</p>
        </div>
      </div>
    );
  }

  return (
    <div className="min-h-screen bg-gradient-to-b from-slate-50 to-white">
      {/* Navigation */}
      <nav className="fixed top-0 left-0 right-0 z-50 bg-white/80 backdrop-blur-sm border-b border-slate-200">
        <div className="max-w-6xl mx-auto px-6 h-16 flex items-center justify-between">
          <button
            onClick={() => router.push("/dashboard")}
            className="text-xl font-bold bg-gradient-to-r from-blue-600 to-blue-700 bg-clip-text text-transparent hover:opacity-80"
          >
            S2X
          </button>
          <div className="text-sm text-slate-600">Billing</div>
        </div>
      </nav>

      <main className="pt-20">
        <div className="max-w-3xl mx-auto px-6 py-16">
          {/* Canceled Message */}
          {canceled && (
            <div className="mb-6 p-4 bg-amber-50 border border-amber-200 rounded-lg">
              <p className="text-sm text-amber-700 font-medium">
                Payment was canceled. Please try again or contact support.
              </p>
            </div>
          )}

          {/* Header */}
          <div className="mb-12">
            <h1 className="text-4xl font-bold text-slate-900 mb-3">Billing & Subscription</h1>
            <p className="text-lg text-slate-600">
              Manage your subscription and billing information.
            </p>
          </div>

          {/* Error */}
          {error && (
            <div className="mb-6 p-4 bg-red-50 border border-red-200 rounded-lg">
              <p className="text-sm text-red-700">{error}</p>
            </div>
          )}

          {/* Status Card */}
          {subscriptionInfo && (
            <div className="bg-white border border-slate-200 rounded-xl shadow-sm p-8 mb-8">
              <h2 className="text-2xl font-bold text-slate-900 mb-6">Current Status</h2>

              {/* Status Badge */}
              <div className="mb-8">
                {subscriptionInfo.status === "active" && (
                  <div className="inline-flex items-center gap-2 px-4 py-2 bg-green-100 border border-green-300 rounded-full">
                    <span className="w-2 h-2 bg-green-600 rounded-full"></span>
                    <span className="text-sm font-semibold text-green-700">Subscription Active</span>
                  </div>
                )}
                {subscriptionInfo.status === "trialing" && (
                  <div className="inline-flex items-center gap-2 px-4 py-2 bg-blue-100 border border-blue-300 rounded-full">
                    <span className="w-2 h-2 bg-blue-600 rounded-full animate-pulse"></span>
                    <span className="text-sm font-semibold text-blue-700">
                      {subscriptionInfo.daysRemainingInTrial} days free trial remaining
                    </span>
                  </div>
                )}
                {subscriptionInfo.status === "expired" && (
                  <div className="inline-flex items-center gap-2 px-4 py-2 bg-red-100 border border-red-300 rounded-full">
                    <span className="w-2 h-2 bg-red-600 rounded-full"></span>
                    <span className="text-sm font-semibold text-red-700">Trial Expired</span>
                  </div>
                )}
                {subscriptionInfo.status === "canceling" && (
                  <div className="flex flex-col gap-3">
                    <div className="inline-flex items-center gap-2 px-4 py-2 bg-amber-100 border border-amber-300 rounded-full w-fit">
                      <span className="w-2 h-2 bg-amber-600 rounded-full animate-pulse"></span>
                      <span className="text-sm font-semibold text-amber-700">Scheduled for Cancellation</span>
                    </div>
                    {subscriptionInfo.subscriptionEndsAt && (
                      <p className="text-sm text-slate-700">
                        Ends on <span className="font-semibold text-amber-700">{new Date(subscriptionInfo.subscriptionEndsAt).toLocaleDateString('en-US', { year: 'numeric', month: 'long', day: 'numeric' })}</span>
                      </p>
                    )}
                  </div>
                )}
                {subscriptionInfo.status === "canceled" && (
                  <div className="inline-flex items-center gap-2 px-4 py-2 bg-orange-100 border border-orange-300 rounded-full">
                    <span className="w-2 h-2 bg-orange-600 rounded-full"></span>
                    <span className="text-sm font-semibold text-orange-700">Subscription Canceled</span>
                  </div>
                )}
              </div>

              {/* Manage Subscription Section */}
              {(subscriptionInfo.status === "active" || subscriptionInfo.status === "canceling") && (
                <div className="pt-4 border-t border-slate-200">
                  <p className="text-xs text-slate-600">
                    {subscriptionInfo.status === "canceling"
                      ? "You can reactivate your subscription anytime. "
                      : "Manage your subscription: "}
                    <button
                      onClick={handleCancel}
                      disabled={cancelLoading}
                      className="text-xs text-slate-500 hover:text-slate-700 underline disabled:opacity-50"
                    >
                      {cancelLoading ? "Opening..." : "Billing Portal"}
                    </button>
                  </p>
                </div>
              )}
            </div>
          )}

          {/* Pricing Card */}
          {!subscriptionInfo?.isActive && (
            <div className="bg-gradient-to-br from-blue-50 to-blue-100 border-2 border-blue-200 rounded-xl p-8 mb-8">
              <h2 className="text-2xl font-bold text-slate-900 mb-2">Upgrade to Pro</h2>
              <p className="text-slate-700 mb-6">
                Continue using Stripe to Invoice after your free trial ends.
              </p>

              <div className="mb-8">
                <div className="flex items-baseline gap-2 mb-4">
                  <span className="text-4xl font-bold text-slate-900">£50</span>
                  <span className="text-slate-600">/month</span>
                </div>
                <p className="text-sm text-slate-700 mb-4">
                  ✓ Unlimited invoice creation<br />
                  ✓ Real-time Stripe to Xero sync<br />
                  ✓ Priority support<br />
                  ✓ Cancel anytime
                </p>
              </div>

              <button
                onClick={handleCheckout}
                disabled={checkoutLoading}
                className="w-full px-6 py-3 bg-gradient-to-r from-blue-600 to-blue-700 text-white font-semibold rounded-lg hover:shadow-lg hover:from-blue-700 hover:to-blue-800 transition disabled:opacity-50 disabled:cursor-not-allowed"
              >
                {checkoutLoading ? "Redirecting..." : "Upgrade Now →"}
              </button>

              <p className="text-xs text-slate-600 text-center mt-4">
                Secure payment powered by Stripe
              </p>
            </div>
          )}

          {/* FAQ */}
          <div className="bg-white border border-slate-200 rounded-xl p-8">
            <h2 className="text-xl font-bold text-slate-900 mb-6">FAQ</h2>
            <div className="space-y-6">
              <div>
                <h3 className="font-semibold text-slate-900 mb-2">Can I cancel anytime?</h3>
                <p className="text-sm text-slate-600">
                  Yes, you can cancel your subscription anytime. Just click "Manage subscription" in the Current Status section above.
                </p>
              </div>
              <div>
                <h3 className="font-semibold text-slate-900 mb-2">What happens after the trial?</h3>
                <p className="text-sm text-slate-600">
                  After your 14-day trial ends, your access will be limited until you upgrade to a paid subscription.
                </p>
              </div>
              <div>
                <h3 className="font-semibold text-slate-900 mb-2">Is my payment information secure?</h3>
                <p className="text-sm text-slate-600">
                  All payments are processed securely through Stripe. We never see or store your credit card information.
                </p>
              </div>
            </div>
          </div>
        </div>
      </main>
    </div>
  );
}