const sleep = (ms: number) => new Promise(resolve => setTimeout(resolve, ms));

export class DiscordRateLimiter {
  private readonly baseUrl: string;
  private readonly botToken: string;

  constructor(baseUrl: string, botToken: string) {
    this.baseUrl = baseUrl;
    this.botToken = botToken;
  }

  /**
   * Makes a request to the Discord API, handling rate limits automatically.
   * @param path The API endpoint path (e.g., '/channels/123/messages').
   * @param options Fetch options (method, headers, body, etc.).
   * @returns The JSON response from the Discord API.
   */
  public async request<T>(path: string, options: RequestInit = {}): Promise<T> {
    const url = `${this.baseUrl}${path}`;

    const headers: Record<string, string> = {
      'Authorization': `Bot ${this.botToken}`,
      ...(options.headers as Record<string, string>),
    };

    // Only set Content-Type to application/json if body is a string and not explicitly set
    if (typeof options.body === 'string' && !('Content-Type' in headers)) {
      headers['Content-Type'] = 'application/json';
    }

    const response = await fetch(url, { ...options, headers });

    if (response.status === 429) {
      const retryAfter = response.headers.get('Retry-After');
      const delay = retryAfter ? parseInt(retryAfter, 10) * 1000 : 1000; // Default to 1 second if header is missing

      console.warn(`Discord API rate limit hit. Retrying after ${delay / 1000} seconds.`);
      await sleep(delay);
      return this.request<T>(path, options); // Retry the request
    }

    if (!response.ok) {
      const errorData = await response.json().catch(() => ({ message: response.statusText }));
      throw new Error(`Discord API error: ${response.status} - ${errorData.message || JSON.stringify(errorData)}`);
    }

    return response.json() as Promise<T>;
  }
}