import { useLocation } from "wouter";
import { useAuth } from "@/hooks/use-auth";
import { useCart } from "@/hooks/use-cart";
import Header from "@/components/layout/header";
import { ShoppingCart, Plus, Minus, Trash2, ArrowLeft } from "lucide-react";
import { useToast } from "@/hooks/use-toast";
import { useState } from "react";

export default function Cart() {
  const [, setLocation] = useLocation();
  const { user, isLoading } = useAuth();
  const [searchQuery, setSearchQuery] = useState("");
  const { items, itemCount, subtotal, tax, total, updateQuantity, removeItem } = useCart();
  const { toast } = useToast();

  // Show loading while authentication is being verified
  if (isLoading) {
    return (
      <div className="min-h-screen bg-gray-50 flex items-center justify-center">
        <div className="text-center">
          <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-primary mx-auto mb-4"></div>
          <p className="text-gray-600">Loading...</p>
        </div>
      </div>
    );
  }

  // Redirect if not authenticated after loading completes
  if (!user) {
    setLocation('/auth');
    return null;
  }

  const handleUpdateQuantity = async (id: string, newQuantity: number) => {
    if (newQuantity < 1) return;
    try {
      await updateQuantity(id, newQuantity);
    } catch (error) {
      toast({
        variant: "destructive",
        title: "Error",
        description: "Failed to update quantity.",
      });
    }
  };

  const handleRemoveItem = async (id: string) => {
    try {
      await removeItem(id);
      toast({
        title: "Item removed",
        description: "Item has been removed from your cart.",
      });
    } catch (error) {
      toast({
        variant: "destructive",
        title: "Error",
        description: "Failed to remove item.",
      });
    }
  };

  const handleCheckout = () => {
    setLocation('/checkout');
  };

  return (
    <div className="min-h-screen bg-gray-50">
      <Header searchQuery={searchQuery} setSearchQuery={setSearchQuery} />

      <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 py-8" data-testid="cart-page">
        {/* Back Button */}
        <div className="mb-6">
          <button
            onClick={() => setLocation('/')}
            className="flex items-center text-gray-600 hover:text-gray-900 px-3 py-2 rounded-md transition-colors"
            data-testid="back-to-home"
          >
            <ArrowLeft className="h-4 w-4 mr-2" />
            Continue Shopping
          </button>
        </div>

        {/* Header */}
        <div className="mb-8">
          <h1 className="text-3xl font-bold text-gray-900" data-testid="cart-title">
            Shopping Cart
          </h1>
          <p className="text-gray-600 mt-2">
            {itemCount > 0 ? `${itemCount} item${itemCount > 1 ? 's' : ''} in your cart` : 'Your cart is empty'}
          </p>
        </div>

        {/* Cart Content */}
        <div className="grid grid-cols-1 lg:grid-cols-3 gap-8">
          {/* Cart Items */}
          <div className="lg:col-span-2">
            <section className="bg-white rounded-lg shadow-sm border border-gray-200">
              <header className="px-6 py-4 border-b border-gray-200">
                <h2 className="text-lg font-semibold text-gray-900 flex items-center">
                  <ShoppingCart className="h-5 w-5 mr-2" />
                  Cart Items
                </h2>
              </header>
              <div className="p-6">
                {items.length === 0 ? (
                  <div className="text-center py-12" data-testid="empty-cart">
                    <ShoppingCart className="h-16 w-16 text-gray-400 mx-auto mb-4" />
                    <h3 className="text-lg font-medium text-gray-900 mb-2">Your cart is empty</h3>
                    <p className="text-gray-500 mb-6">Add some items to get started!</p>
                    <button
                      onClick={() => setLocation('/')}
                      className="inline-flex items-center px-4 py-2 bg-primary text-primary-foreground font-medium rounded-md hover:bg-primary/90 transition-all"
                      data-testid="start-shopping"
                    >
                      Start Shopping
                    </button>
                  </div>
                ) : (
                  <div className="space-y-4" data-testid="cart-items">
                    {items.map((item) => (
                      <article 
                        key={item.id} 
                        className="flex flex-col sm:flex-row sm:items-center gap-4 p-4 border border-gray-200 rounded-lg hover:shadow-md transition-shadow"
                        data-testid={`cart-item-${item.id}`}
                      >
                        {/* Product Image */}
                        <div className="w-20 h-20 sm:w-24 sm:h-24 bg-gray-100 rounded-lg overflow-hidden flex-shrink-0 mx-auto sm:mx-0">
                          {item.product?.images && item.product.images.length > 0 ? (
                            <img
                              src={item.product.images[0]}
                              alt={item.product.title}
                              className="w-full h-full object-cover"
                              data-testid={`cart-item-image-${item.id}`}
                            />
                          ) : (
                            <div className="w-full h-full bg-gray-200 flex items-center justify-center">
                              <span className="text-xs text-gray-400">No Image</span>
                            </div>
                          )}
                        </div>

                        {/* Product Details */}
                        <div className="flex-1 space-y-2">
                          <h3 className="font-medium text-gray-900 text-lg" data-testid={`cart-item-title-${item.id}`}>
                            {item.product?.title || 'Unknown Product'}
                          </h3>
                          <p className="text-sm text-gray-500" data-testid={`cart-item-seller-${item.id}`}>
                            Sold by {item.product?.store?.name || item.product?.seller?.username || 'Unknown Seller'}
                          </p>
                          <p className="text-xl font-bold text-primary" data-testid={`cart-item-price-${item.id}`}>
                            ₹{item.product ? parseFloat(item.product.price).toFixed(2) : '0.00'}
                          </p>
                        </div>

                        {/* Quantity Controls and Remove */}
                        <div className="flex flex-col sm:flex-row items-center gap-4">
                          {/* Quantity Controls */}
                          <div className="flex items-center space-x-3">
                            <button
                              className="flex items-center justify-center w-8 h-8 text-gray-700 bg-white border border-gray-300 rounded-md hover:bg-gray-50 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
                              onClick={() => handleUpdateQuantity(item.id, item.quantity - 1)}
                              disabled={item.quantity <= 1}
                              data-testid={`cart-decrease-${item.id}`}
                            >
                              <Minus className="h-4 w-4" />
                            </button>
                            
                            <span className="text-lg font-medium w-12 text-center" data-testid={`cart-quantity-${item.id}`}>
                              {item.quantity}
                            </span>
                            
                            <button
                              className="flex items-center justify-center w-8 h-8 text-gray-700 bg-white border border-gray-300 rounded-md hover:bg-gray-50 transition-colors"
                              onClick={() => handleUpdateQuantity(item.id, item.quantity + 1)}
                              data-testid={`cart-increase-${item.id}`}
                            >
                              <Plus className="h-4 w-4" />
                            </button>
                          </div>

                          {/* Remove Button */}
                          <button
                            className="flex items-center justify-center px-4 py-2 text-sm font-medium text-red-500 bg-white border border-red-300 rounded-md hover:bg-red-50 hover:text-red-700 transition-colors"
                            onClick={() => handleRemoveItem(item.id)}
                            data-testid={`cart-remove-${item.id}`}
                          >
                            <Trash2 className="h-4 w-4 mr-2" />
                            Remove
                          </button>
                        </div>
                      </article>
                    ))}
                  </div>
                )}
              </div>
            </section>
          </div>

          {/* Order Summary */}
          {items.length > 0 && (
            <div className="lg:col-span-1">
              <section className="bg-white rounded-lg shadow-sm border border-gray-200 sticky top-8">
                <header className="px-6 py-4 border-b border-gray-200">
                  <h2 className="text-lg font-semibold text-gray-900">Order Summary</h2>
                </header>
                <div className="p-6">
                  <div className="space-y-3 mb-6" data-testid="cart-summary">
                    <div className="flex justify-between text-sm">
                      <span className="text-gray-600">Subtotal ({itemCount} items):</span>
                      <span className="text-gray-900" data-testid="cart-subtotal">
                        ₹{subtotal.toFixed(2)}
                      </span>
                    </div>
                    <div className="flex justify-between text-sm">
                      <span className="text-gray-600">Shipping:</span>
                      <span className="text-green-600" data-testid="cart-shipping">Free</span>
                    </div>
                    <div className="flex justify-between text-sm">
                      <span className="text-gray-600">Tax:</span>
                      <span className="text-gray-900" data-testid="cart-tax">
                        ₹{tax.toFixed(2)}
                      </span>
                    </div>
                    <div className="border-t border-gray-200 pt-3">
                      <div className="flex justify-between text-lg font-bold">
                        <span className="text-gray-900">Total:</span>
                        <span className="text-gray-900" data-testid="cart-total">
                          ₹{total.toFixed(2)}
                        </span>
                      </div>
                    </div>
                  </div>

                  <div className="space-y-3">
                    <button
                      className="w-full px-4 py-3 bg-primary text-primary-foreground font-medium rounded-md hover:bg-primary/90 transition-all"
                      onClick={handleCheckout}
                      data-testid="checkout-button"
                    >
                      Proceed to Checkout
                    </button>
                    <button
                      className="w-full px-4 py-2 text-gray-700 bg-white border border-gray-300 rounded-md hover:bg-gray-50 transition-colors"
                      onClick={() => setLocation('/')}
                      data-testid="continue-shopping"
                    >
                      Continue Shopping
                    </button>
                  </div>
                </div>
              </section>
            </div>
          )}
        </div>
      </div>
    </div>
  );
}