import { Link } from "@remix-run/react";
import { useRef, useState, useEffect, useCallback } from "react";
import { motion } from "framer-motion";
import { ChevronLeft, ChevronRight, Package, ShoppingBag } from "lucide-react";
import { Skeleton } from "./ui/skeleton";
import { ErrorState } from "./UiProvider";

interface HorizontalCollection {
  id?: string;
  title?: string;
  description?: string | null;
  coverImageUrl?: string | null;
  productCount?: number;
}

const HorizontalCollectionsList = ({
  collections,
  isLoading,
  isError,
  refetch,
  showViewAllButton = false,
}: {
  collections: HorizontalCollection[];
  isLoading: boolean;
  isError: boolean;
  refetch: () => void;
  showViewAllButton?: boolean;
}) => {
  const scrollContainerRef = useRef<HTMLDivElement>(null);
  const [showLeftButton, setShowLeftButton] = useState(false);
  const [showRightButton, setShowRightButton] = useState(false);
  const [currentPage, setCurrentPage] = useState(0);

  const totalPages = collections.length;

  // Helper function to calculate card width consistently
  const getCardWidth = useCallback(() => {
    // Same calculation as scrollToNext/scrollToPrev: 85vw (max 300px) + 16px gap
    return Math.min(window.innerWidth * 0.85, 300) + 16;
  }, []);

  const checkScrollButtons = useCallback(() => {
    if (!scrollContainerRef.current) return;

    const { scrollLeft, scrollWidth, clientWidth } = scrollContainerRef.current;

    // Calculate max scroll position
    const maxScroll = scrollWidth - clientWidth;

    // For RTL, scrollLeft might be negative or start from max
    // Check if we can scroll in each direction
    const canScrollRight = Math.abs(scrollLeft) > 100;
    const canScrollLeft = Math.abs(scrollLeft) < maxScroll - 100;

    setShowRightButton(canScrollRight);
    setShowLeftButton(canScrollLeft);

    // Calculate card width using the same logic as scroll functions
    const cardWidth = getCardWidth();

    // Calculate current page based on scroll position
    const page = Math.round(Math.abs(scrollLeft) / cardWidth);
    setCurrentPage(Math.min(page, collections.length - 1));
  }, [collections.length, getCardWidth]);

  useEffect(() => {
    // Small delay to ensure content is rendered
    const timer = setTimeout(() => {
      checkScrollButtons();
    }, 100);

    const container = scrollContainerRef.current;
    if (container) {
      container.addEventListener("scroll", checkScrollButtons);
      window.addEventListener("resize", checkScrollButtons);
      return () => {
        container.removeEventListener("scroll", checkScrollButtons);
        window.removeEventListener("resize", checkScrollButtons);
      };
    }
    return () => clearTimeout(timer);
  }, [collections, checkScrollButtons]);

  const scrollToNext = () => {
    if (!scrollContainerRef.current) return;
    const container = scrollContainerRef.current;
    const cardWidth = getCardWidth();
    container.scrollBy({ left: cardWidth, behavior: "smooth" });
  };

  const scrollToPrev = () => {
    if (!scrollContainerRef.current) return;
    const container = scrollContainerRef.current;
    const cardWidth = getCardWidth();
    container.scrollBy({ left: -cardWidth, behavior: "smooth" });
  };

  if (isLoading) {
    return <HorizontalSkeleton />;
  }

  if (isError) {
    return (
      <div className="px-4">
        <ErrorState onRetry={refetch} />
      </div>
    );
  }

  if (collections.length === 0) {
    return null;
  }

  return (
    <div className="w-full flex flex-col gap-3">
      {/* Scroll Container */}
      <div
        ref={scrollContainerRef}
        className="w-full overflow-x-auto scrollbar-hide snap-x snap-mandatory px-4 lg:overflow-visible lg:px-0"
      >
        <div
          className="flex lg:grid lg:grid-cols-4 lg:gap-4 lg:!w-full"
          style={{ width: "max-content" }}
        >
          {collections.map((collection, index) => (
            <Link
              key={collection.id || index}
              to={`/collection/${collection.id}`}
              className="flex flex-col pr-2 md:pr-4 snap-start group lg:!w-auto lg:!max-w-none lg:pr-0"
              style={{ width: "calc(85vw)", maxWidth: "300px" }}
            >
              <div className="flex flex-col gap-3 p-3 bg-WHITE2 rounded-2xl border border-inner-border hover:border-gray-300 transition-all duration-300 hover:shadow-lg h-full">
                {/* Collection Image */}
                <div className="relative overflow-hidden rounded-xl w-full h-64 lg:h-auto lg:aspect-[3/4] bg-gray-100">
                  {collection.coverImageUrl ? (
                    <img
                      src={collection.coverImageUrl}
                      alt={collection.title || "Collection"}
                      className="w-full h-full object-cover group-hover:scale-105 transition-transform duration-500"
                    />
                  ) : (
                    <div className="w-full h-full flex items-center justify-center bg-WHITE2">
                      <Package size={48} className="text-GRAY" />
                    </div>
                  )}

                  {/* Product Count Badge */}
                  {collection.productCount !== undefined && (
                    <div className="absolute bottom-2 left-2">
                      <div className="flex items-center gap-1.5 bg-white/95 backdrop-blur-sm px-2.5 py-1 rounded-full shadow-md">
                        <ShoppingBag size={12} className="text-black" />
                        <span className="text-R12 text-black font-bold">
                          {collection.productCount} محصول
                        </span>
                      </div>
                    </div>
                  )}
                </div>

                {/* Collection Info */}
                <div className="flex flex-col gap-1.5">
                  <h3 className="text-B14 font-bold text-black line-clamp-2">
                    {collection.title || "بدون عنوان"}
                  </h3>

                  {collection.description && (
                    <p className="text-R12 text-GRAY line-clamp-2">
                      {collection.description}
                    </p>
                  )}
                </div>
              </div>
            </Link>
          ))}

          {/* View All Button Card */}
          {showViewAllButton && (
            <Link
              to="/collections"
              className="flex flex-col pr-2 md:pr-4 snap-start group lg:!w-auto lg:!max-w-none lg:pr-0"
              style={{ width: "calc(85vw)", maxWidth: "300px" }}
            >
              <div className="flex flex-col items-center justify-center gap-3 p-3 bg-gradient-to-br from-black to-gray-800 rounded-2xl border border-inner-border hover:border-gray-600 transition-all duration-300 hover:shadow-lg h-full min-h-[304px]">
                <div className="flex flex-col items-center justify-center gap-3">
                  <div className="w-16 h-16 rounded-full bg-white/10 flex items-center justify-center group-hover:scale-110 transition-transform duration-300">
                    <Package size={32} className="text-white" />
                  </div>
                  <div className="flex flex-col items-center gap-2">
                    <h3 className="text-B16 font-bold text-white text-center">
                      مشاهده همه کالکشن‌ها
                    </h3>
                    <p className="text-R12 text-white/70 text-center">
                      کاوش در کالکشن‌های بیشتر
                    </p>
                  </div>
                  <div className="flex items-center gap-2 mt-2 text-white group-hover:gap-3 transition-all duration-300">
                    <span className="text-R14 font-bold">مشاهده همه</span>
                    <ChevronLeft
                      size={18}
                      className="group-hover:translate-x-[-4px] transition-transform duration-300"
                    />
                  </div>
                </div>
              </div>
            </Link>
          )}
        </div>
      </div>
      {/* Navigation Buttons Row (mobile only) */}
      {collections.length > 1 && (
        <div className="flex items-center justify-center gap-3 px-4 lg:hidden">
          <motion.button
            whileHover={!showRightButton ? {} : { scale: 1.1 }}
            whileTap={!showRightButton ? {} : { scale: 0.95 }}
            transition={{ type: "spring", stiffness: 400, damping: 25 }}
            onClick={scrollToNext}
            disabled={!showRightButton}
            aria-label="Next collections"
          >
            <ChevronRight
              size={20}
              className={showRightButton ? "text-BLACK" : "text-GRAY"}
            />
          </motion.button>

          {/* Dots indicator */}
          <div className="flex gap-1.5">
            {Array.from({ length: totalPages }).map((_, i) => (
              <div
                key={i}
                className={`h-1.5 rounded-full transition-all duration-300 ${
                  i === currentPage ? "w-6 bg-BLACK" : "w-1.5 bg-GRAY3"
                }`}
              />
            ))}
          </div>

          <motion.button
            whileHover={!showLeftButton ? {} : { scale: 1.1 }}
            whileTap={!showLeftButton ? {} : { scale: 0.95 }}
            transition={{ type: "spring", stiffness: 400, damping: 25 }}
            onClick={scrollToPrev}
            disabled={!showLeftButton}
            aria-label="Previous collections"
          >
            <ChevronLeft
              size={20}
              className={showLeftButton ? "text-BLACK" : "text-GRAY"}
            />
          </motion.button>
        </div>
      )}
    </div>
  );
};

const HorizontalSkeleton = () => {
  return (
    <div className="w-full overflow-x-auto scrollbar-hide">
      <div className="flex" style={{ width: "max-content" }}>
        {Array(4)
          .fill(1)
          .map((_, index) => (
            <div
              key={index}
              className="flex flex-col pr-2 md:pr-4 snap-start group"
              style={{ width: "calc(85vw)", maxWidth: "300px" }}
            >
              <div className="flex flex-col gap-3 p-3 bg-WHITE2 rounded-2xl border border-inner-border">
                <Skeleton className="w-full h-64 rounded-xl" />
                <Skeleton className="w-3/4 h-4" />
                <Skeleton className="w-full h-3" />
              </div>
            </div>
          ))}
      </div>
    </div>
  );
};

export default HorizontalCollectionsList;