/**
 * Server-side fetch from the FlatRender Admin API.
 *
 * All functions return hardcoded fallback data when:
 *  - ADMIN_API_URL is not set, or
 *  - The admin service is unreachable.
 *
 * This means the Next.js app works standalone with no admin service running.
 */

const BASE = process.env.ADMIN_API_URL?.replace(/\/$/, "");

export interface AdminCategory {
  id: string;
  name: string;
  slug: string;
  description?: string;
  iconUrl?: string;
  type: "video" | "image" | "both";
  sortOrder: number;
  projectCount: number;
}

export interface AdminProject {
  id: string;
  title: string;
  slug: string;
  description?: string;
  type: "video" | "image";
  status: string;
  categoryId?: string;
  categoryName?: string;
  coverImageUrl?: string;
  previewVideoUrl?: string;
  tags: string[];
  metaJson?: string;
  sortOrder: number;
  mediaCount: number;
  createdAt: string;
  updatedAt: string;
}

export interface AdminProjectsResponse {
  total: number;
  page: number;
  pageSize: number;
  items: AdminProject[];
}

// ── Fetch helpers ─────────────────────────────────────────────────────────────

async function safeFetch<T>(url: string): Promise<T | null> {
  if (!BASE) return null;
  try {
    const res = await fetch(url, {
      next: { revalidate: 60 }, // cache for 60 s (ISR)
      headers: { Accept: "application/json" },
    });
    if (!res.ok) return null;
    return res.json() as Promise<T>;
  } catch {
    return null;
  }
}

// ── Public API ────────────────────────────────────────────────────────────────

export async function fetchCategories(
  type?: "video" | "image"
): Promise<AdminCategory[]> {
  const qs = type ? `?type=${type}` : "";
  return (
    (await safeFetch<AdminCategory[]>(`${BASE}/api/public/categories${qs}`)) ??
    []
  );
}

export async function fetchProjects(opts?: {
  type?: "video" | "image";
  categorySlug?: string;
  search?: string;
  page?: number;
  pageSize?: number;
}): Promise<AdminProjectsResponse> {
  const params = new URLSearchParams();
  if (opts?.type) params.set("type", opts.type);
  if (opts?.categorySlug) params.set("categorySlug", opts.categorySlug);
  if (opts?.search) params.set("search", opts.search);
  if (opts?.page) params.set("page", String(opts.page));
  if (opts?.pageSize) params.set("pageSize", String(opts.pageSize));

  const qs = params.size ? `?${params}` : "";
  return (
    (await safeFetch<AdminProjectsResponse>(
      `${BASE}/api/public/projects${qs}`
    )) ?? { total: 0, page: 1, pageSize: 20, items: [] }
  );
}

export async function fetchProject(slug: string): Promise<AdminProject | null> {
  return safeFetch<AdminProject>(`${BASE}/api/public/projects/${slug}`);
}

/** True when admin API is configured and reachable. */
export async function isAdminApiAvailable(): Promise<boolean> {
  if (!BASE) return false;
  try {
    const res = await fetch(`${BASE}/api/public/categories`, {
      next: { revalidate: 30 },
    });
    return res.ok;
  } catch {
    return false;
  }
}