"use client";

import Link from "next/link";
import { useCallback, useEffect, useRef, useState } from "react";

/**
 * Horizontal, scroll-snap slider for the home page "latest news" row. Keeps the
 * exact article-card markup from the server page; the cards are passed in as a
 * pre-shaped list so this client component carries no prisma/i18n dependency.
 * Prev/next buttons scroll the snap track by one viewport-ish step and disable
 * themselves at the ends.
 */
export type SliderArticle = {
  slug: string;
  title: string;
  image: string;
  excerpt: string;
};

export function ArticleSlider({ articles }: { articles: SliderArticle[] }) {
  const trackRef = useRef<HTMLDivElement>(null);
  const [atStart, setAtStart] = useState(true);
  const [atEnd, setAtEnd] = useState(false);

  const updateEdges = useCallback(() => {
    const el = trackRef.current;
    if (!el) return;
    const maxScroll = el.scrollWidth - el.clientWidth;
    setAtStart(el.scrollLeft <= 1);
    setAtEnd(el.scrollLeft >= maxScroll - 1);
  }, []);

  useEffect(() => {
    updateEdges();
    window.addEventListener("resize", updateEdges);
    return () => window.removeEventListener("resize", updateEdges);
  }, [updateEdges]);

  const scrollByDir = useCallback((dir: 1 | -1) => {
    const el = trackRef.current;
    if (!el) return;
    // Step by roughly one card width (incl. gap) so snapping lands cleanly.
    const step = Math.max(el.clientWidth * 0.8, 260);
    el.scrollBy({ left: dir * step, behavior: "smooth" });
  }, []);

  return (
    <div style={{ position: "relative" }}>
      <button
        type="button"
        aria-label="Previous"
        onClick={() => scrollByDir(-1)}
        disabled={atStart}
        className="article-slider-nav"
        style={{ left: "-0.6rem", opacity: atStart ? 0.35 : 1 }}
      >
        ‹
      </button>

      <div
        ref={trackRef}
        onScroll={updateEdges}
        style={{
          display: "flex",
          gap: "1rem",
          overflowX: "auto",
          scrollSnapType: "x mandatory",
          scrollbarWidth: "none",
          paddingBottom: "0.25rem",
        }}
      >
        {articles.map((a) => (
          <article
            key={a.slug}
            className="card hover"
            style={{
              padding: 0,
              overflow: "hidden",
              flex: "0 0 auto",
              width: "clamp(220px, 70vw, 280px)",
              scrollSnapAlign: "start",
            }}
          >
            {a.image ? (
              // biome-ignore lint/performance/noImgElement: external article image
              <img className="article-img" src={a.image} alt="" />
            ) : (
              <div className="article-img" />
            )}
            <div style={{ padding: "0.85rem" }}>
              <h3 style={{ margin: "0 0 0.3rem", fontSize: "1rem" }}>
                <Link href={`/news/${a.slug}`}>{a.title}</Link>
              </h3>
              <p className="muted" style={{ margin: 0 }}>
                {a.excerpt}
              </p>
            </div>
          </article>
        ))}
      </div>

      <button
        type="button"
        aria-label="Next"
        onClick={() => scrollByDir(1)}
        disabled={atEnd}
        className="article-slider-nav"
        style={{ right: "-0.6rem", opacity: atEnd ? 0.35 : 1 }}
      >
        ›
      </button>

      <style>{`
        .article-slider-nav {
          position: absolute;
          top: 50%;
          transform: translateY(-50%);
          z-index: 2;
          width: 2.4rem;
          height: 2.4rem;
          border-radius: 999px;
          border: 1px solid var(--border);
          background: var(--color-surface);
          color: var(--color-text);
          box-shadow: var(--shadow-card);
          font-size: 1.4rem;
          line-height: 1;
          cursor: pointer;
          display: flex;
          align-items: center;
          justify-content: center;
          transition: opacity 0.15s ease, box-shadow 0.15s ease;
        }
        .article-slider-nav:hover:not(:disabled) {
          box-shadow: var(--shadow-card-hover);
        }
        .article-slider-nav:disabled {
          cursor: default;
        }
      `}</style>
    </div>
  );
}