const WP_API_BASE = "";
const FETCH_TIMEOUT_MS = 15_000;

export interface WpMediaSize {
  source_url: string;
  width?: number;
  height?: number;
}

export interface WpFeaturedMedia {
  source_url: string;
  alt_text?: string;
  media_details?: {
    width?: number;
    height?: number;
    sizes?: Record<string, WpMediaSize>;
  };
}

export interface WpAuthor {
  id: number;
  name: string;
  slug?: string;
}

export interface WpPost {
  id: number;
  date: string;
  modified?: string;
  slug: string;
  title: { rendered: string };
  content: { rendered: string };
  excerpt: { rendered: string };
  featured_media: number;
  categories: number[];
  author?: number;
  _embedded?: {
    "wp:featuredmedia"?: WpFeaturedMedia[];
    author?: WpAuthor[];
  };
}

/** Returns thumbnail URL for list/card (medium) or full for single post. */
export function getFeaturedImageUrl(
  post: WpPost,
  size: "medium" | "medium_large" | "full" = "medium"
): string | null {
  const media = post._embedded?.["wp:featuredmedia"]?.[0];
  if (!media?.source_url) return null;
  const sizes = media.media_details?.sizes;
  if (sizes?.[size]?.source_url) return sizes[size].source_url;
  if (size !== "full" && sizes?.medium?.source_url) return sizes.medium.source_url;
  return media.source_url;
}

export interface WpCategory {
  id: number;
  name: string;
  slug: string;
  count: number;
}

export interface GetPostsResult {
  posts: WpPost[];
  total: number;
  totalPages: number;
}

export interface GetPostsOptions {
  page?: number;
  perPage?: number;
  search?: string;
  categoryId?: number;
  /** ترتیب بر اساس: date, modified, title, ... در وردپرس. برای اولویت دستی (menu_order) پلاگین/فیلتر در وردپرس لازم است. */
  orderby?: string;
  order?: "asc" | "desc";
}

async function fetchWithTimeout(
  url: string,
  options?: RequestInit
): Promise<Response> {
  const controller = new AbortController();
  const timeout = setTimeout(() => controller.abort(), FETCH_TIMEOUT_MS);
  try {
    const res = await fetch(url, {
      ...options,
      signal: controller.signal,
      next: { revalidate: 0 },
    });
    clearTimeout(timeout);
    return res;
  } catch (e) {
    clearTimeout(timeout);
    throw e;
  }
}

export async function getPosts(
  options: GetPostsOptions = {}
): Promise<GetPostsResult> {
  const { page = 1, perPage = 9, search, categoryId, orderby, order } = options;
  const params = new URLSearchParams();
  params.set("page", String(page));
  params.set("per_page", String(perPage));
  if (search?.trim()) params.set("search", search.trim());
  if (categoryId) params.set("categories", String(categoryId));
  if (orderby) params.set("orderby", orderby);
  if (order) params.set("order", order);
  params.set("_embed", "1");

  const url = `${WP_API_BASE}/posts?${params.toString()}`;
  const res = await fetchWithTimeout(url);

  if (!res.ok) {
    throw new Error(`WP API error: ${res.status} ${res.statusText}`);
  }

  const total = parseInt(res.headers.get("x-wp-total") ?? "0", 10);
  const totalPages = parseInt(res.headers.get("x-wp-totalpages") ?? "1", 10);
  const posts: WpPost[] = await res.json();

  return { posts, total, totalPages };
}

export async function getPostBySlug(slug: string): Promise<WpPost | null> {
  const decodedSlug = decodeURIComponent(slug);
  const params = new URLSearchParams({ slug: decodedSlug, _embed: "1" });
  const url = `${WP_API_BASE}/posts?${params.toString()}`;
  const res = await fetchWithTimeout(url);

  if (!res.ok) {
    throw new Error(`WP API error: ${res.status} ${res.statusText}`);
  }

  const posts: WpPost[] = await res.json();
  return posts.length > 0 ? posts[0] : null;
}

export async function getRelatedPosts(
  postId: number,
  categoryIds: number[],
  limit = 3
): Promise<WpPost[]> {
  const params = new URLSearchParams();
  params.set("exclude", String(postId));
  params.set("per_page", String(limit));
  params.set("_embed", "1");
  if (categoryIds.length > 0) {
    params.set("categories", String(categoryIds[0]));
  }

  const url = `${WP_API_BASE}/posts?${params.toString()}`;
  const res = await fetchWithTimeout(url);

  if (!res.ok) {
    throw new Error(`WP API error: ${res.status} ${res.statusText}`);
  }

  const posts: WpPost[] = await res.json();
  return posts;
}

export async function getCategories(): Promise<WpCategory[]> {
  const url = `${WP_API_BASE}/categories?per_page=100`;
  const res = await fetchWithTimeout(url);

  if (!res.ok) {
    throw new Error(`WP API error: ${res.status} ${res.statusText}`);
  }

  const data: WpCategory[] = await res.json();
  return data.filter((c) => c.count > 0);
}