import db from "../../db.server";

const MAX_BYTES = 5 * 1024 * 1024; // 5 MB cap
const STALE_AFTER_MS = 24 * 60 * 60 * 1000; // re-fetch once a day at most

/**
 * Returns a `data:` URL for the shop's logo bytes, fetching from the
 * configured URL on first use (or when stale) and persisting to the
 * `LogoCache` table for subsequent renders.
 */
export async function getLogoDataUrl(
  shopDomain: string,
  logoUrl: string,
): Promise<string | undefined> {
  if (!logoUrl) return undefined;

  const cached = await db.logoCache.findUnique({ where: { shopDomain } });
  const isFresh =
    cached &&
    cached.sourceUrl === logoUrl &&
    Date.now() - cached.fetchedAt.getTime() < STALE_AFTER_MS;

  if (isFresh && cached) {
    return toDataUrl(cached.bytes, cached.contentType);
  }

  let response: Response;
  try {
    response = await fetch(logoUrl);
  } catch (err) {
    console.warn(`Logo fetch failed for ${shopDomain}:`, err);
    return cached ? toDataUrl(cached.bytes, cached.contentType) : undefined;
  }
  if (!response.ok) {
    console.warn(`Logo fetch HTTP ${response.status} for ${shopDomain}`);
    return cached ? toDataUrl(cached.bytes, cached.contentType) : undefined;
  }

  const arrayBuf = await response.arrayBuffer();
  if (arrayBuf.byteLength > MAX_BYTES) {
    console.warn(`Logo too large (${arrayBuf.byteLength} bytes) — skipping cache.`);
    return undefined;
  }
  const bytes = Buffer.from(arrayBuf);
  const contentType = response.headers.get("content-type") || guessContentType(logoUrl);
  const etag = response.headers.get("etag") || "";

  await db.logoCache.upsert({
    where: { shopDomain },
    create: { shopDomain, sourceUrl: logoUrl, bytes, contentType, etag },
    update: { sourceUrl: logoUrl, bytes, contentType, etag, fetchedAt: new Date() },
  });

  return toDataUrl(bytes, contentType);
}

function toDataUrl(bytes: Buffer | Uint8Array, contentType: string): string {
  const buf = Buffer.isBuffer(bytes) ? bytes : Buffer.from(bytes);
  return `data:${contentType};base64,${buf.toString("base64")}`;
}

function guessContentType(url: string): string {
  const lower = url.toLowerCase();
  if (lower.endsWith(".jpg") || lower.endsWith(".jpeg")) return "image/jpeg";
  if (lower.endsWith(".webp")) return "image/webp";
  return "image/png";
}