// Banner serving — source of truth is bb.banner_creatives in Supabase.
// The DB query is date-gated (status=active AND start<=NOW<=end) and the
// result is cached in-process for 5 minutes. A hardcoded fallback keeps
// the site rendering banners if Supabase is unreachable during a deploy
// or during the initial module load.
//
// Public helpers (rotateAll, pickAds) are SYNCHRONOUS so existing client
// component callsites keep working. They read from a module-level cache
// that is primed on first import and refreshed asynchronously after the
// TTL expires.

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

export interface Ad {
  slug?: string;
  label: string;
  size: "300x250" | "300x600" | "728x90";
  src: string;
  alt: string;
  click_url?: string;
}

const SUPABASE_URL = process.env.NEXT_PUBLIC_SUPABASE_URL!;
const SUPABASE_ANON = process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!;
const SCHEMA = process.env.NEXT_PUBLIC_SUPABASE_SCHEMA || "bb";

const CACHE_TTL_MS = 5 * 60 * 1000;
type CacheRow = { rows: Ad[]; loadedAt: number };
let CACHE: CacheRow | null = null;
let REFRESH_IN_FLIGHT: Promise<void> | null = null;

const FALLBACK: Ad[] = [
  { slug: "liveu-728x90", label: "LiveU 728x90", size: "728x90",
    src: "/legacy/ads/728-x-90-pxEN.gif",
    alt: "LiveU 728x90", click_url: "https://bit.ly/4ghXVeq" },
  { slug: "blackmagic-davinci-resolve-300x600",
    label: "Blackmagic DaVinci Resolve 20", size: "300x600",
    src: "/legacy/ads/Davinci-Resolve-20_300x600.jpg",
    alt: "Blackmagic Design DaVinci Resolve 20",
    click_url: "http://bmd.link/mRNsKu" },
  { slug: "studio-hero-300x250", label: "Studio Hero", size: "300x250",
    src: "/legacy/ads/Studio-Hero-for-Broadcast-Beat.png",
    alt: "Studio Suite — Studio Hero", click_url: "http://www.TheStudioHero.com" },
  { slug: "magewell-pro-convert-300x250", label: "Magewell Pro-Convert", size: "300x250",
    src: "/legacy/ads/Magewell_Pro-Convert-IP-to-HDMI_Sports_NAB2026.gif",
    alt: "Magewell Pro-Convert IP to HDMI",
    click_url: "https://www.magewell.com" },
  { slug: "liveu-payg-300x250", label: "LiveU PAYG", size: "300x250",
    src: "/legacy/ads/PAYG-300x250-1.gif",
    alt: "LiveU Pay-As-You-Go", click_url: "https://bit.ly/4ghXVeq" },
  { slug: "aja-colorbox-300x250", label: "AJA ColorBox", size: "300x250",
    src: "/legacy/ads/aja_2025_colorbox_og_colorbox_300x250_en-2.gif",
    alt: "AJA ColorBox", click_url: "https://www.aja.com" },
  { slug: "zixi-300x250", label: "Zixi", size: "300x250",
    src: "/legacy/ads/Zixi_Ads_300x250.png",
    alt: "Zixi", click_url: "https://zixi.com/" },
  { slug: "telycam-300x250", label: "Telycam MixOne / ExploreXE", size: "300x250",
    src: "/legacy/ads/Telycam_Broadcast Beat_300x250_MixOne-ExploreXE_with_NAB2026_2f30157f.gif",
    alt: "Telycam MixOne / ExploreXE — NAB 2026", click_url: "https://telycam.com/" },
  { slug: "lectrosonics-300x250", label: "Lectrosonics", size: "300x250",
    src: "/legacy/ads/300x250-banner-Our-Story-film_resize.jpg",
    alt: "Lectrosonics Our Story", click_url: "https://www.lectrosonics.com/" },
];

interface DbRow {
  slug: string;
  name: string;
  image_path: string;
  click_url: string | null;
  size: "300x250" | "300x600" | "728x90";
}

async function loadFromDb(): Promise<Ad[]> {
  if (!SUPABASE_URL || !SUPABASE_ANON) return FALLBACK;
  try {
    const sb = createClient(SUPABASE_URL, SUPABASE_ANON, {
      db: { schema: SCHEMA as "public" },
      auth: { persistSession: false },
    });
    const nowIso = new Date().toISOString();
    const { data, error } = await sb
      .from("banner_creatives")
      .select("slug,name,image_path,click_url,size,start_date,end_date,status")
      .eq("status", "active")
      .or(`start_date.is.null,start_date.lte.${nowIso}`)
      .or(`end_date.is.null,end_date.gte.${nowIso}`);
    if (error || !data || data.length === 0) {
      if (typeof console !== "undefined") {
        console.warn("[ads] db query empty/error, using fallback:", error?.message || "no rows");
      }
      return FALLBACK;
    }
    return (data as DbRow[]).map((r) => ({
      slug: r.slug,
      label: r.name,
      size: r.size,
      src: r.image_path,
      alt: r.name,
      click_url: r.click_url || undefined,
    }));
  } catch (err: any) {
    if (typeof console !== "undefined") {
      console.warn("[ads] db query threw, using fallback:", err?.message);
    }
    return FALLBACK;
  }
}

function triggerRefresh(): void {
  if (REFRESH_IN_FLIGHT) return;
  REFRESH_IN_FLIGHT = loadFromDb()
    .then((rows) => {
      CACHE = { rows, loadedAt: Date.now() };
    })
    .catch(() => {
      // Failures stay logged via loadFromDb; keep CACHE as-is.
    })
    .finally(() => {
      REFRESH_IN_FLIGHT = null;
    });
}

function readCachedAds(): Ad[] {
  if (!CACHE) {
    triggerRefresh();
    return FALLBACK;
  }
  if (Date.now() - CACHE.loadedAt > CACHE_TTL_MS) {
    // Stale — kick off a background refresh but serve the stale snapshot.
    triggerRefresh();
  }
  return CACHE.rows;
}

export function shuffle<T>(arr: T[]): T[] {
  const out = arr.slice();
  for (let i = out.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [out[i], out[j]] = [out[j], out[i]];
  }
  return out;
}

export function rotateAll(size: Ad["size"], exclude: Set<string> = new Set()): Ad[] {
  const pool = readCachedAds().filter((a) => a.size === size);
  const key = (a: Ad) => a.src ?? a.label;
  return shuffle(pool.filter((a) => !exclude.has(key(a))));
}

export function pickAds(
  size: Ad["size"],
  n: number,
  exclude: Set<string> = new Set()
): Ad[] {
  const all = rotateAll(size, exclude);
  return all.slice(0, Math.min(n, all.length));
}

// Sync exports for callers that still want the bare arrays. These also
// read the cache (so live edits surface) but fall back to FALLBACK.
export const ADS_728X90: Ad[] = (() => readCachedAds().filter((a) => a.size === "728x90"))();
export const ADS_300X250: Ad[] = (() => readCachedAds().filter((a) => a.size === "300x250"))();
export const FIXED_300X600: Ad | null = (() => readCachedAds().find((a) => a.size === "300x600") || null)();

// Prime the cache once at module load.
triggerRefresh();
