import { createFileRoute, useNavigate, useSearch } from '@tanstack/react-router'
import { useState, useEffect, useMemo, useRef, useCallback } from 'react'
import Fuse from 'fuse.js'
import { useAllProducts } from '../hooks/prominent-api-hooks'
import { SearchBar } from 'web-components'
import { ProductCard } from '../components/ProductCard'
import { SearchX, Loader2, ChevronLeft } from 'lucide-react'
import { AppLayout } from '../components/AppLayout'
import AddToCartDialog from '../components/AddToCartDialog'
import { useCartStore } from '../lib/stores/cart-store'

export const Route = createFileRoute('/home/search')({
  component: SearchPage,
  validateSearch: (search: Record<string, string>) => ({
    q: search.q || '',
  }),
})

// Debounce hook for search
function useDebounce<T>(value: T, delay: number): T {
  const [debouncedValue, setDebouncedValue] = useState<T>(value)

  useEffect(() => {
    const timer = setTimeout(() => {
      setDebouncedValue(value)
    }, delay)

    return () => {
      clearTimeout(timer)
    }
  }, [value, delay])

  return debouncedValue
}

function SearchPage() {
  const navigate = useNavigate()
  const { q } = useSearch({ from: '/home/search' })
  const [inputQuery, setInputQuery] = useState(q)
  const searchInputRef = useRef<HTMLInputElement>(null)
  const { setAddedToCartProduct } = useCartStore()

  // Debounce the search query for automatic search
  const debouncedQuery = useDebounce(inputQuery, 300)

  // Focus search input on mount
  useEffect(() => {
    requestAnimationFrame(() => {
      searchInputRef.current?.focus()
    })
  }, [])

  const { data: productsData, isLoading, error, refetch } = useAllProducts()
  const allProducts = productsData?.products || []

  // Client-side search filtering using Fuse.js
  const products = useMemo(() => {
    if (!debouncedQuery.trim()) return allProducts

    const fuse = new Fuse(allProducts, {
      keys: ['name', 'shortDescription'],
      threshold: 0.3,
      includeScore: true,
      shouldSort: true,
    })

    const fuseResults = fuse.search(debouncedQuery)
    return fuseResults.map((result) => result.item)
  }, [allProducts, debouncedQuery])

  const handleSearch = useCallback(() => {
    // Search is now automatic via debounce, but keep this for manual submit
    // Update URL with search query
    navigate({
      to: '/home/search',
      search: { q: inputQuery },
    })
  }, [inputQuery, navigate])

  const handleProductPress = (id: number) => {
    navigate({
      to: '/home/product/$id',
      params: { id: String(id) },
    })
  }

  const handleAddToCart = (product: any) => {
    setAddedToCartProduct({ productId: product.id, product })
  }

  if (isLoading) {
    return (
      <AppLayout>
        <div className="flex min-h-full flex-1 items-center justify-center">
          <Loader2 className="h-8 w-8 animate-spin text-brand-500" />
          <p className="ml-2 font-medium text-gray-500">Loading products...</p>
        </div>
      </AppLayout>
    )
  }

  if (error) {
    return (
      <AppLayout>
        <div className="flex min-h-full flex-1 flex-col items-center justify-center px-4">
          <SearchX className="h-16 w-16 text-gray-300" />
          <p className="mt-4 text-lg font-medium text-gray-900">Failed to load products</p>
          <button
            onClick={() => refetch()}
            className="mt-4 rounded-lg bg-brand-600 px-4 py-2 font-medium text-white transition-colors hover:bg-brand-700"
          >
            Retry
          </button>
        </div>
      </AppLayout>
    )
  }

  return (
    <AppLayout>
      <div className="flex min-h-full flex-1 flex-col bg-gray-50">
        {/* Search Header */}
        <div className="sticky top-0 z-10 border-b border-gray-100 bg-white px-4 pb-4 pt-4">
          <div className="mx-auto flex w-full max-w-7xl items-center gap-3">
            <button
              onClick={() => navigate({ to: '/home' })}
              className="flex h-10 w-10 shrink-0 items-center justify-center rounded-lg bg-gray-50 text-gray-700 transition-colors hover:bg-gray-100"
              aria-label="Back to home"
            >
              <ChevronLeft className="h-5 w-5" />
            </button>
            <div className="flex-1">
              <SearchBar
                ref={searchInputRef}
                placeholder="Search products..."
                value={inputQuery}
                onChange={setInputQuery}
                onSearch={handleSearch}
              />
            </div>
          </div>
          <div className="mx-auto mt-3 flex w-full max-w-7xl flex-row items-center justify-between">
            <p className="text-lg font-bold text-gray-900">
              {debouncedQuery ? `Search Results for "${debouncedQuery}"` : 'All Products'}
            </p>
            <p className="text-sm text-gray-500">{products.length} items</p>
          </div>
        </div>

        {/* Products Grid */}
        <div className="mx-auto w-full max-w-7xl flex-1 p-4">
          {products.length === 0 ? (
            <div className="flex flex-1 flex-col items-center justify-center px-4 py-12">
              <SearchX className="h-16 w-16 text-gray-300" />
              <p className="mt-4 text-center text-lg font-medium text-gray-500">
                No products found
              </p>
              {debouncedQuery && (
                <p className="mt-2 text-center text-gray-400">
                  Try adjusting your search for "{debouncedQuery}"
                </p>
              )}
            </div>
          ) : (
            <div className="grid grid-cols-2 gap-3 md:grid-cols-3 lg:grid-cols-4 xl:grid-cols-5">
              {products.map((product: any) => (
                <ProductCard
                  key={product.id}
                  item={product}
                  onPress={() => handleProductPress(product.id)}
                  showDeliveryInfo={false}
                  miniView={true}
                  useAddToCartDialog={true}
                />
              ))}
            </div>
          )}
        </div>
      </div>

      <AddToCartDialog />
    </AppLayout>
  )
}