// One System content helper — v1 (https://copilot.onesystemcrm.com/developers)
//
// Copy this file into your project as onesystem/content.ts. It loads the site's editable content (texts, links,
// images, Google titles) from One System, so the business can change it by chat with a preview and Undo.
// If One System doesn't answer quickly, the copy built into your site (public/onesystem-content.json) is used,
// so pages never go blank. Works in the browser (React / Vite) and on the server (Next.js).

export type ContentItem = { value: string; label?: string; type?: string; page?: string };
export type ContentFile = { version: 1; pages?: { path: string; name: string }[]; fields: Record<string, ContentItem> };
export type Content = Record<string, string>;

export const ONESYSTEM_API = "https://copilot.onesystemcrm.com";
const SITE_ID = /^os_[a-z0-9]{10}$/;
const TOKEN = /^[A-Za-z0-9_-]{20,100}$/;

/** The values built into the site (the fallback). */
export function bundledValues(file: ContentFile): Content {
  const out: Content = {};
  for (const [key, item] of Object.entries(file.fields ?? {})) out[key] = typeof item?.value === "string" ? item.value : "";
  return out;
}

/** The preview token in the address bar (?os_preview=…), only in the browser. */
export function previewToken(search?: string): string | null {
  const s = search ?? (typeof window === "undefined" ? "" : window.location.search);
  const t = new URLSearchParams(s).get("os_preview");
  return t && TOKEN.test(t) ? t : null;
}

export type LoadOptions = {
  /** The Site ID from One System (Settings → Website), e.g. import.meta.env.VITE_ONESYSTEM_SITE or process.env.NEXT_PUBLIC_ONESYSTEM_SITE */
  site?: string;
  /** Your public/onesystem-content.json (imported), used as the fallback and to know which items exist */
  file: ContentFile;
  /** A preview token: shows a change that is waiting for the owner's approval */
  preview?: string | null;
  /** How long to wait for One System before using the built-in copy (default 1500 ms) */
  timeoutMs?: number;
  /** Next.js: e.g. { next: { revalidate: 30 } } */
  init?: RequestInit & { next?: { revalidate?: number | false; tags?: string[] } };
  api?: string;
};

/** The live content (or the built-in copy when One System can't be reached). Never throws. */
export async function loadContent(opts: LoadOptions): Promise<Content> {
  const fallback = bundledValues(opts.file);
  if (!opts.site || !SITE_ID.test(opts.site)) return fallback;
  const preview = opts.preview && TOKEN.test(opts.preview) ? opts.preview : null;
  const url = `${(opts.api ?? ONESYSTEM_API).replace(/\/+$/, "")}/api/site-content/${opts.site}${preview ? `?preview=${encodeURIComponent(preview)}` : ""}`;
  const ctl = typeof AbortController === "undefined" ? undefined : new AbortController();
  const timer = setTimeout(() => ctl?.abort(), opts.timeoutMs ?? 1500);
  try {
    const init: RequestInit & { next?: unknown } = { ...opts.init, signal: ctl?.signal };
    if (preview) { init.cache = "no-store"; delete init.next; }
    const res = await fetch(url, init);
    if (!res.ok) return fallback;
    const body = (await res.json()) as { values?: Record<string, unknown> };
    const live: Content = {};
    for (const [key, value] of Object.entries(body?.values ?? {})) if (typeof value === "string" && key in fallback) live[key] = value;
    return { ...fallback, ...live };
  } catch {
    return fallback;
  } finally {
    clearTimeout(timer);
  }
}