import { createClient } from "@supabase/supabase-js";

export const dynamic = "force-dynamic";
export const revalidate = 21600; // 6h

interface Article {
  title: string;
  excerpt: string | null;
  tags: string[] | null;
  published_at: string | null;
}

function detectTrends(recent: Article[], baseline: Article[]) {
  const recentCounts: Record<string, number> = {};
  for (const a of recent) for (const t of a.tags || []) {
    const k = t.toLowerCase();
    recentCounts[k] = (recentCounts[k] || 0) + 1;
  }
  const baseCounts: Record<string, number> = {};
  for (const a of baseline) for (const t of a.tags || []) {
    const k = t.toLowerCase();
    baseCounts[k] = (baseCounts[k] || 0) + 1;
  }
  const scored = Object.entries(recentCounts).map(([k, c]) => {
    const baseline_per_day = (baseCounts[k] || 0) / 30;
    const recent_per_day = c / 7;
    const lift = baseline_per_day > 0 ? recent_per_day / baseline_per_day : recent_per_day * 3;
    return { entity: k, lift, count: c };
  });
  scored.sort((a, b) => b.lift - a.lift);
  return scored.slice(0, 5);
}

function titleCase(s: string): string {
  return s.replace(/\b\w/g, (c) => c.toUpperCase());
}

export default async function TrendsSidebar() {
  const sb = createClient(
    process.env.NEXT_PUBLIC_SUPABASE_URL!,
    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!,
    {
      db: { schema: (process.env.NEXT_PUBLIC_SUPABASE_SCHEMA || "bb") as "public" },
      auth: { persistSession: false },
    }
  );

  const since7d = new Date(Date.now() - 7 * 86400000).toISOString();
  const since30d = new Date(Date.now() - 30 * 86400000).toISOString();
  const [recent, baseline] = await Promise.all([
    sb
      .from("wp_imported_posts")
      .select("title, excerpt, tags, wp_published_at")
      .eq("status", "published")
      .gte("wp_published_at", since7d)
      .order("wp_published_at", { ascending: false })
      .limit(200),
    sb
      .from("wp_imported_posts")
      .select("title, excerpt, tags, wp_published_at")
      .eq("status", "published")
      .gte("wp_published_at", since30d)
      .lt("wp_published_at", since7d)
      .order("wp_published_at", { ascending: false })
      .limit(800),
  ]);

  const recentArts: Article[] = (recent.data || []).map((r: any) => ({
    title: r.title, excerpt: r.excerpt, tags: r.tags, published_at: r.wp_published_at,
  }));
  const baselineArts: Article[] = (baseline.data || []).map((r: any) => ({
    title: r.title, excerpt: r.excerpt, tags: r.tags, published_at: r.wp_published_at,
  }));
  const trends = detectTrends(recentArts, baselineArts);

  return (
    <aside
      className="rounded p-4"
      style={{
        background: "var(--color-trends-bg, #F5EFEB)",
        color: "var(--color-trends-text, #2F4F5B)",
        borderRadius: "var(--border-radius-md, 6px)",
      }}
      aria-label="BB AI detected trends"
    >
      <div className="flex items-center justify-between mb-3">
        <h2 className="font-serif text-base font-semibold">BB AI · detected trends</h2>
        <span className="inline-flex items-center gap-1.5 text-[10px] font-mono uppercase tracking-wider opacity-70">
          <span className="bb-pulse-dot" style={{ background: "var(--color-trends-text, #2F4F5B)" }} />
          live
        </span>
      </div>

      <ul className="space-y-1.5">
        {trends.length === 0 && (
          <li className="text-xs opacity-60">No trend data yet.</li>
        )}
        {trends.map((t) => (
          <li key={t.entity} className="flex items-center justify-between text-sm">
            <span className="truncate font-serif">{titleCase(t.entity)}</span>
            <span className="font-mono text-[12px] opacity-80">
              +{Math.round((t.lift - 1) * 100) || t.count}
            </span>
          </li>
        ))}
      </ul>
    </aside>
  );
}