import { useState, useMemo } from "react";
import { ArrowUpRight } from "lucide-react";
import type { NewsResponse, NewsArticle } from "../api";

interface NewsGridProps {
  data: NewsResponse;
}

const CATEGORIES = [
  { key: "all", label: "Alle" },
  { key: "tech", label: "Tech" },
  { key: "wirtschaft", label: "Wirtschaft" },
  { key: "politik", label: "Politik" },
  { key: "allgemein", label: "Allgemein" },
] as const;

const SOURCE_COLORS: Record<string, string> = {
  heise: "border-gold/40 text-gold bg-gold/5",
  golem: "border-azure/40 text-azure bg-azure/5",
  spiegel: "border-cherry/40 text-cherry bg-cherry/5",
  tagesschau: "border-azure/40 text-azure bg-azure/5",
  zeit: "border-base-400 text-base-700 bg-base-200",
  faz: "border-mint/40 text-mint bg-mint/5",
  welt: "border-iris/40 text-iris bg-iris/5",
  t3n: "border-iris/40 text-iris bg-iris/5",
  default: "border-gold/30 text-gold-muted bg-gold/5",
};

function sourceColor(source: string): string {
  const key = source.toLowerCase();
  for (const [prefix, cls] of Object.entries(SOURCE_COLORS)) {
    if (key.includes(prefix)) return cls;
  }
  return SOURCE_COLORS.default;
}

function relativeTime(isoDate: string): string {
  try {
    const date = new Date(isoDate);
    if (isNaN(date.getTime())) return "";
    const diff = Date.now() - date.getTime();
    const seconds = Math.floor(diff / 1_000);
    const minutes = Math.floor(seconds / 60);
    const hours = Math.floor(minutes / 60);
    const days = Math.floor(hours / 24);

    if (seconds < 60) return "gerade eben";
    if (minutes < 60) return `vor ${minutes} Min.`;
    if (hours < 24) return hours === 1 ? "vor 1 Stunde" : `vor ${hours} Stunden`;
    if (days === 1) return "gestern";
    if (days < 7) return `vor ${days} Tagen`;
    return date.toLocaleDateString("de-DE", { day: "2-digit", month: "short" });
  } catch {
    return "";
  }
}

export default function NewsGrid({ data }: NewsGridProps) {
  const [activeCategory, setActiveCategory] = useState<string>("all");

  const filteredArticles = useMemo(() => {
    if (!data?.articles) return [];
    if (activeCategory === "all") return data.articles;
    return data.articles.filter(
      (a) => a.category?.toLowerCase() === activeCategory
    );
  }, [data, activeCategory]);

  if (!data?.articles) return null;

  return (
    <div className="animate-fade-in">
      {/* Section header */}
      <div className="section-label">
        <span className="section-number">04</span>
        <h2 className="section-title">Nachrichten</h2>
        <span className="section-rule" />
        <span className="text-xs font-mono text-base-500">{filteredArticles.length}</span>
      </div>

      {/* Category tabs */}
      <div className="flex gap-1 flex-wrap mb-5">
        {CATEGORIES.map((cat) => (
          <button
            key={cat.key}
            onClick={() => setActiveCategory(cat.key)}
            className={`tab-btn ${activeCategory === cat.key ? "active" : ""}`}
          >
            {cat.label}
          </button>
        ))}
      </div>

      {/* Articles grid */}
      {filteredArticles.length === 0 ? (
        <div className="deck-card p-8 text-center text-base-500 text-sm">
          Keine Artikel in dieser Kategorie.
        </div>
      ) : (
        <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 gap-px bg-base-300">
          {filteredArticles.map((article) => (
            <ArticleCard key={article.id} article={article} />
          ))}
        </div>
      )}
    </div>
  );
}

function ArticleCard({ article }: { article: NewsArticle }) {
  return (
    <a
      href={article.url}
      target="_blank"
      rel="noopener noreferrer"
      className="group block bg-base-50 p-4 hover:bg-base-100 transition-colors relative"
    >
      <div className="flex items-center justify-between mb-3">
        <span className={`tag ${sourceColor(article.source)}`}>
          {article.source}
        </span>
        <ArrowUpRight className="w-3 h-3 text-base-400 opacity-0 group-hover:opacity-100 transition-opacity" />
      </div>

      <h3 className="text-sm font-medium text-base-800 leading-snug line-clamp-2 group-hover:text-base-900 transition-colors">
        {article.title}
      </h3>

      <div className="flex items-center gap-3 mt-3 pt-3 border-t border-base-200">
        {article.category && (
          <span className="text-[9px] font-mono text-base-500 uppercase tracking-wider">
            {article.category}
          </span>
        )}
        <span className="text-[9px] font-mono text-base-500 ml-auto">
          {relativeTime(article.published_at)}
        </span>
      </div>
    </a>
  );
}