export interface RedditBotApiClientOptions {
  baseUrl?: string;
  token?: string;
  fetchImplementation?: typeof fetch;
}

export class RedditBotApiError extends Error {
  constructor(message: string, readonly status: number) {
    super(message);
    this.name = 'RedditBotApiError';
  }
}

export class RedditBotApiClient {
  private readonly baseUrl: string;
  private readonly token: string;
  private readonly fetchImplementation: typeof fetch;

  constructor(options: RedditBotApiClientOptions = {}) {
    this.baseUrl = (options.baseUrl ?? process.env.REDDIT_BOT_API_URL ?? 'http://127.0.0.1:3000').replace(/\/$/, '');
    this.token = options.token
      ?? process.env.REDDIT_BOT_AGENT_TOKEN
      ?? process.env.REDDIT_BOT_AGENT_CONTROL_TOKEN
      ?? process.env.REDDIT_BOT_AGENT_READ_TOKEN
      ?? process.env.WEB_DASHBOARD_TOKEN
      ?? '';
    this.fetchImplementation = options.fetchImplementation ?? fetch;
    if (!this.token) {
      throw new Error('MCP server requires REDDIT_BOT_AGENT_TOKEN or WEB_DASHBOARD_TOKEN');
    }
    new URL(this.baseUrl);
  }

  get(path: string): Promise<unknown> {
    return this.request(path);
  }

  post(path: string, body?: unknown): Promise<unknown> {
    return this.request(path, {
      method: 'POST',
      ...(body === undefined ? {} : {
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(body),
      }),
    });
  }

  private async request(path: string, init: RequestInit = {}): Promise<unknown> {
    const response = await this.fetchImplementation(`${this.baseUrl}${path}`, {
      ...init,
      headers: {
        Authorization: `Bearer ${this.token}`,
        Accept: 'application/json',
        ...init.headers,
      },
    });
    const text = await response.text();
    let payload: unknown = null;
    if (text) {
      try {
        payload = JSON.parse(text) as unknown;
      } catch {
        payload = text;
      }
    }
    if (!response.ok) {
      const message = typeof payload === 'object' && payload !== null && 'error' in payload
        && typeof payload.error === 'string'
        ? payload.error
        : `RedditBot API request failed (${response.status})`;
      throw new RedditBotApiError(message, response.status);
    }
    return payload;
  }
}