"use client";

import { useState, useEffect, useMemo } from "react";
import { Card } from "@/components/ui/card";
import { Input } from "@/components/ui/input";
import { Button } from "@/components/ui/button";
import { formatCurrency, cn } from "@/lib/utils";

interface Category {
  id: string;
  name: string;
  description: string | null;
  _count: {
    products: number;
  };
}

interface Product {
  id: string;
  name: string;
  description: string | null;
  sku: string | null;
  price: number;
  stock: number;
  minStock: number;
  trackStock: boolean;
  image: string | null;
  lowStock: boolean;
  category: {
    id: string;
    name: string;
  };
}

interface ProductGridProps {
  siteId: string;
  onAddToCart: (product: Product) => void;
}

export function ProductGrid({ siteId, onAddToCart }: ProductGridProps) {
  const [products, setProducts] = useState<Product[]>([]);
  const [categories, setCategories] = useState<Category[]>([]);
  const [selectedCategory, setSelectedCategory] = useState<string | null>(null);
  const [searchQuery, setSearchQuery] = useState("");
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  // Fetch categories
  useEffect(() => {
    async function fetchCategories() {
      try {
        const response = await fetch("/api/products/categories");
        if (!response.ok) {
          throw new Error("Error al cargar categorias");
        }
        const data = await response.json();
        setCategories(data);
      } catch (err) {
        console.error("Error fetching categories:", err);
      }
    }

    fetchCategories();
  }, []);

  // Fetch products
  useEffect(() => {
    async function fetchProducts() {
      setLoading(true);
      setError(null);
      try {
        const params = new URLSearchParams({ siteId, isActive: "true" });
        if (selectedCategory) {
          params.append("categoryId", selectedCategory);
        }
        if (searchQuery) {
          params.append("search", searchQuery);
        }

        const response = await fetch(`/api/products?${params.toString()}`);
        if (!response.ok) {
          throw new Error("Error al cargar productos");
        }
        const data = await response.json();
        setProducts(data);
      } catch (err) {
        setError(err instanceof Error ? err.message : "Error desconocido");
      } finally {
        setLoading(false);
      }
    }

    // Debounce search
    const timeoutId = setTimeout(fetchProducts, searchQuery ? 300 : 0);
    return () => clearTimeout(timeoutId);
  }, [siteId, selectedCategory, searchQuery]);

  // Filter products based on category and search
  const filteredProducts = useMemo(() => {
    return products;
  }, [products]);

  const handleProductClick = (product: Product) => {
    if (product.trackStock && product.stock <= 0) {
      return; // Cannot add out of stock products
    }
    onAddToCart(product);
  };

  return (
    <div className="flex flex-col h-full">
      {/* Search Input */}
      <div className="mb-4">
        <Input
          type="text"
          placeholder="Buscar productos..."
          value={searchQuery}
          onChange={(e) => setSearchQuery(e.target.value)}
          className="w-full"
        />
      </div>

      {/* Category Tabs */}
      <div className="flex gap-2 mb-4 overflow-x-auto pb-2">
        <Button
          variant={selectedCategory === null ? "default" : "outline"}
          size="sm"
          onClick={() => setSelectedCategory(null)}
        >
          Todos
        </Button>
        {categories.map((category) => (
          <Button
            key={category.id}
            variant={selectedCategory === category.id ? "default" : "outline"}
            size="sm"
            onClick={() => setSelectedCategory(category.id)}
            className="whitespace-nowrap"
          >
            {category.name}
          </Button>
        ))}
      </div>

      {/* Loading State */}
      {loading && (
        <div className="flex-1 flex items-center justify-center">
          <div className="text-center">
            <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-primary mx-auto mb-2"></div>
            <p className="text-primary-500">Cargando productos...</p>
          </div>
        </div>
      )}

      {/* Error State */}
      {error && !loading && (
        <div className="flex-1 flex items-center justify-center">
          <div className="text-center text-red-500">
            <p>{error}</p>
            <Button
              variant="outline"
              size="sm"
              className="mt-2"
              onClick={() => setSearchQuery("")}
            >
              Reintentar
            </Button>
          </div>
        </div>
      )}

      {/* Empty State */}
      {!loading && !error && filteredProducts.length === 0 && (
        <div className="flex-1 flex items-center justify-center">
          <div className="text-center text-primary-500">
            <p>No se encontraron productos</p>
            {searchQuery && (
              <Button
                variant="outline"
                size="sm"
                className="mt-2"
                onClick={() => setSearchQuery("")}
              >
                Limpiar busqueda
              </Button>
            )}
          </div>
        </div>
      )}

      {/* Product Grid */}
      {!loading && !error && filteredProducts.length > 0 && (
        <div className="flex-1 overflow-y-auto">
          <div className="grid grid-cols-2 md:grid-cols-3 lg:grid-cols-4 gap-3">
            {filteredProducts.map((product) => {
              const isOutOfStock = product.trackStock && product.stock <= 0;
              const isLowStock = product.lowStock;

              return (
                <Card
                  key={product.id}
                  className={cn(
                    "p-4 cursor-pointer transition-all hover:shadow-md",
                    isOutOfStock && "opacity-50 cursor-not-allowed bg-gray-100",
                    isLowStock && !isOutOfStock && "border-amber-400 border-2"
                  )}
                  onClick={() => handleProductClick(product)}
                >
                  {/* Product Image Placeholder */}
                  {product.image ? (
                    <div className="w-full h-24 mb-3 rounded-md overflow-hidden">
                      <img
                        src={product.image}
                        alt={product.name}
                        className="w-full h-full object-cover"
                      />
                    </div>
                  ) : (
                    <div className="w-full h-24 mb-3 bg-primary-100 rounded-md flex items-center justify-center">
                      <span className="text-3xl text-primary-300">
                        {product.name.charAt(0).toUpperCase()}
                      </span>
                    </div>
                  )}

                  {/* Product Info */}
                  <h3 className="font-medium text-primary-800 text-sm truncate">
                    {product.name}
                  </h3>
                  <p className="text-primary-600 font-bold mt-1">
                    {formatCurrency(product.price)}
                  </p>

                  {/* Stock Indicator */}
                  {product.trackStock && (
                    <div className="mt-2">
                      {isOutOfStock ? (
                        <span className="text-xs text-red-500 font-medium">
                          Agotado
                        </span>
                      ) : isLowStock ? (
                        <span className="text-xs text-amber-600 font-medium">
                          Stock bajo: {product.stock}
                        </span>
                      ) : (
                        <span className="text-xs text-primary-400">
                          Stock: {product.stock}
                        </span>
                      )}
                    </div>
                  )}
                </Card>
              );
            })}
          </div>
        </div>
      )}
    </div>
  );
}