/**
 * cnClient.ts
 * -------------
 * Fetches Computer Networks topic data from the Go backend.
 */

const API_BASE = '';

export interface CNTopic {
  id: string;
  chapter_no: number;
  chapter_name: string;
  subtitle: string;
  level: string;
  topics: string[];
}

export interface CNTopicContent extends CNTopic {
  content: any; // Using any to match the dynamic bson.M structure
}

/**
 * Fetches all Computer Networks topics (chapter_no, chapter_name, etc).
 */
export async function fetchCNTopics(): Promise<CNTopic[]> {
  const res = await fetch(`${API_BASE}/api/cn/topics`, {
    method: 'GET',
    headers: { 'Content-Type': 'application/json' },
  });

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

  const data = await res.json() as { topics: CNTopic[] };
  return data.topics ?? [];
}

/**
 * Fetches full content for a specific Computer Networks chapter.
 */
export async function fetchCNTopicContent(chapterNo: number): Promise<CNTopicContent> {
  const res = await fetch(`${API_BASE}/api/cn/topics/${chapterNo}`, {
    method: 'GET',
    headers: { 'Content-Type': 'application/json' },
  });

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

  return await res.json() as CNTopicContent;
}