"use client";

import { useState, useEffect } from "react";

interface CartItem {
  id: string;
  product_slug: string;
  product_name: string;
  variant: string | null;
  quantity: number;
  unit_price: number;
  subtotal: number;
}

interface Cart {
  id: string;
  items: CartItem[];
  item_count: number;
  subtotal: number;
}

export default function CartPage() {
  const [cart, setCart] = useState<Cart | null>(null);
  const [loading, setLoading] = useState(true);
  const [checkingOut, setCheckingOut] = useState(false);

  useEffect(() => {
    const cartId = localStorage.getItem("cart_id");
    if (cartId) {
      fetch(
        `${process.env.NEXT_PUBLIC_API_URL || "http://localhost:8000/api"}/cart/${cartId}`
      )
        .then((res) => (res.ok ? res.json() : null))
        .then(setCart)
        .finally(() => setLoading(false));
    } else {
      setLoading(false);
    }
  }, []);

  const handleCheckout = async () => {
    if (!cart) return;
    setCheckingOut(true);

    try {
      const res = await fetch(
        `${process.env.NEXT_PUBLIC_API_URL || "http://localhost:8000/api"}/checkout/session`,
        {
          method: "POST",
          headers: { "Content-Type": "application/json" },
          body: JSON.stringify({
            cart_id: cart.id,
            success_url: `${window.location.origin}/checkout/success`,
            cancel_url: `${window.location.origin}/cart`,
          }),
        }
      );

      if (res.ok) {
        const { checkout_url } = await res.json();
        window.location.href = checkout_url;
      }
    } catch (error) {
      console.error("Checkout error:", error);
    } finally {
      setCheckingOut(false);
    }
  };

  if (loading) {
    return (
      <div className="container mx-auto px-4 py-16 text-center">
        <p>Loading cart...</p>
      </div>
    );
  }

  if (!cart || cart.items.length === 0) {
    return (
      <div className="container mx-auto px-4 py-16 text-center">
        <h1 className="text-2xl font-bold mb-4">Your Cart</h1>
        <p className="text-muted-foreground mb-8">Your cart is empty.</p>
        <a href="/products" className="text-primary hover:underline">
          Continue Shopping
        </a>
      </div>
    );
  }

  return (
    <div className="container mx-auto px-4 py-8">
      <h1 className="text-2xl font-bold mb-8">Your Cart</h1>

      <div className="grid md:grid-cols-3 gap-8">
        <div className="md:col-span-2 space-y-4">
          {cart.items.map((item) => (
            <div
              key={item.id}
              className="flex items-center gap-4 p-4 border rounded-lg"
            >
              <div className="w-20 h-20 bg-muted rounded" />
              <div className="flex-1">
                <h3 className="font-semibold">{item.product_name}</h3>
                {item.variant && (
                  <p className="text-sm text-muted-foreground">
                    Variant: {item.variant}
                  </p>
                )}
                <p className="text-sm">Qty: {item.quantity}</p>
              </div>
              <div className="text-right">
                <p className="font-bold">${item.subtotal.toFixed(2)}</p>
              </div>
            </div>
          ))}
        </div>

        <div className="border rounded-lg p-6 h-fit">
          <h2 className="font-bold mb-4">Order Summary</h2>
          <div className="space-y-2 mb-4">
            <div className="flex justify-between">
              <span>Subtotal</span>
              <span>${cart.subtotal.toFixed(2)}</span>
            </div>
            <div className="flex justify-between text-muted-foreground">
              <span>Shipping</span>
              <span>Calculated at checkout</span>
            </div>
          </div>
          <div className="border-t pt-4 mb-4">
            <div className="flex justify-between font-bold">
              <span>Total</span>
              <span>${cart.subtotal.toFixed(2)}</span>
            </div>
          </div>
          <button
            onClick={handleCheckout}
            disabled={checkingOut}
            className="w-full bg-primary text-primary-foreground py-3 rounded-md font-medium hover:bg-primary/90 disabled:opacity-50"
          >
            {checkingOut ? "Redirecting..." : "Checkout"}
          </button>
        </div>
      </div>
    </div>
  );
}