'use client';
import { useEffect, useState, useMemo } from 'react';

// Core columns for performance and usability
const columns = [
  'uuid',
  'sku',
  'brandName',
  'productName',
  'department',
  'category',
  'subcategory',
  'retailPrice',
  'salePrice',
  'imageUrl',
];

export default function AdminProductsPage() {
  const [products, setProducts] = useState<any[]>([]);
  const [total, setTotal] = useState(0);
  const [page, setPage] = useState(1);
  const [limit, setLimit] = useState(50);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  // Filter state
  const [brand, setBrand] = useState('');
  const [department, setDepartment] = useState('');
  const [category, setCategory] = useState('');
  const [subcategory, setSubcategory] = useState('');

  useEffect(() => {
    setLoading(true);
    setError(null);
    fetch(`/api/products?page=${page}&limit=${limit}`)
      .then(res => res.json())
      .then(data => {
        setProducts(data.data || []);
        setTotal(data.total || 0);
        setLoading(false);
      })
      .catch(err => {
        setError(err.message || 'Error fetching products');
        setLoading(false);
      });
  }, [page, limit]);

  // Get unique filter options from current page's products
  const brandOptions = useMemo(() => Array.from(new Set(products.map(p => p.brandName).filter(Boolean))).sort(), [products]);
  const departmentOptions = useMemo(() => Array.from(new Set(products.map(p => p.department).filter(Boolean))).sort(), [products]);
  const categoryOptions = useMemo(() => Array.from(new Set(products.map(p => p.category).filter(Boolean))).sort(), [products]);
  const subcategoryOptions = useMemo(() => Array.from(new Set(products.map(p => p.subcategory).filter(Boolean))).sort(), [products]);

  // Filter products before rendering
  const filteredProducts = useMemo(() => {
    return products.filter(p =>
      (!brand || p.brandName === brand) &&
      (!department || p.department === department) &&
      (!category || p.category === category) &&
      (!subcategory || p.subcategory === subcategory)
    );
  }, [products, brand, department, category, subcategory]);

  // Reset to page 1 when filters change
  useEffect(() => { setPage(1); }, [brand, department, category, subcategory]);

  return (
    <div className="max-w-7xl mx-auto px-4 py-8">
      <h1 className="text-2xl font-bold mb-4">Admin Products</h1>
      {error && <div className="text-red-600 mb-4">{error}</div>}
      {/* Filters */}
      <div className="flex flex-wrap gap-4 mb-4 items-end">
        <div>
          <label className="block text-xs font-semibold mb-1">Brand</label>
          <select className="border rounded px-2 py-1 min-w-[120px]" value={brand} onChange={e => setBrand(e.target.value)}>
            <option value="">All</option>
            {brandOptions.map(opt => <option key={opt} value={opt}>{opt}</option>)}
          </select>
        </div>
        <div>
          <label className="block text-xs font-semibold mb-1">Department</label>
          <select className="border rounded px-2 py-1 min-w-[120px]" value={department} onChange={e => setDepartment(e.target.value)}>
            <option value="">All</option>
            {departmentOptions.map(opt => <option key={opt} value={opt}>{opt}</option>)}
          </select>
        </div>
        <div>
          <label className="block text-xs font-semibold mb-1">Category</label>
          <select className="border rounded px-2 py-1 min-w-[120px]" value={category} onChange={e => setCategory(e.target.value)}>
            <option value="">All</option>
            {categoryOptions.map(opt => <option key={opt} value={opt}>{opt}</option>)}
          </select>
        </div>
        <div>
          <label className="block text-xs font-semibold mb-1">Subcategory</label>
          <select className="border rounded px-2 py-1 min-w-[120px]" value={subcategory} onChange={e => setSubcategory(e.target.value)}>
            <option value="">All</option>
            {subcategoryOptions.map(opt => <option key={opt} value={opt}>{opt}</option>)}
          </select>
        </div>
      </div>
      <div className="overflow-x-auto border rounded bg-white">
        <table className="min-w-full text-sm">
          <thead>
            <tr>
              {columns.map(col => (
                <th key={col} className="px-2 py-2 border-b text-left font-semibold bg-zinc-50">{col}</th>
              ))}
            </tr>
          </thead>
          <tbody>
            {loading ? (
              <tr><td colSpan={columns.length} className="text-center py-8">Loading...</td></tr>
            ) : filteredProducts.length === 0 ? (
              <tr><td colSpan={columns.length} className="text-center py-8">No products found.</td></tr>
            ) : (
              filteredProducts.map((product, i) => (
                <tr key={product.uuid || i} className="border-b hover:bg-zinc-50">
                  {columns.map(col => (
                    <td key={col} className="px-2 py-1 max-w-xs truncate">
                      {col === 'imageUrl' && product[col] ? (
                        <img src={product[col]} alt="thumb" className="h-10 w-10 object-contain border rounded" />
                      ) : (
                        product[col] ?? ''
                      )}
                    </td>
                  ))}
                </tr>
              ))
            )}
          </tbody>
        </table>
      </div>
      {/* Pagination Controls */}
      <div className="flex items-center gap-4 mt-4">
        <button
          className="px-3 py-1 border rounded disabled:opacity-50"
          onClick={() => setPage(p => Math.max(1, p - 1))}
          disabled={page === 1}
        >Prev</button>
        <span>Page {page} of {Math.ceil(total / limit) || 1}</span>
        <button
          className="px-3 py-1 border rounded disabled:opacity-50"
          onClick={() => setPage(p => p + 1)}
          disabled={page * limit >= total}
        >Next</button>
        <select
          className="ml-4 border rounded px-2 py-1"
          value={limit}
          onChange={e => { setLimit(Number(e.target.value)); setPage(1); }}
        >
          {[25, 50, 100, 200].map(opt => (
            <option key={opt} value={opt}>{opt} / page</option>
          ))}
        </select>
        <span className="ml-2 text-zinc-500">Total: {total}</span>
      </div>
    </div>
  );
}