import type { CreateRoomInput, CreatedRoom, RoomView } from '@ai-rendezvous/core';

export class ApiError extends Error {
  constructor(readonly status: number, readonly code: string, message: string) {
    super(message);
  }
}

/**
 * Thin client for the AI Rendezvous HTTP API. Uses only fetch — no harness
 * assumptions, suitable for integrations in any Node-based environment.
 */
export class RendezvousClient {
  constructor(
    readonly baseUrl: string,
    readonly token?: string,
  ) {}

  private async request<T>(method: string, path: string, body?: unknown): Promise<T> {
    const res = await fetch(`${this.baseUrl}${path}`, {
      method,
      headers: {
        'content-type': 'application/json',
        ...(this.token ? { authorization: `Bearer ${this.token}` } : {}),
      },
      body: body === undefined ? undefined : JSON.stringify(body),
    });
    const text = await res.text();
    const data = text ? JSON.parse(text) : {};
    if (!res.ok) {
      const err = (data as { error?: { code?: string; message?: string } }).error ?? {};
      throw new ApiError(res.status, err.code ?? 'unknown', err.message ?? res.statusText);
    }
    return data as T;
  }

  createRoom(input: CreateRoomInput): Promise<CreatedRoom> {
    return this.request<CreatedRoom>('POST', '/api/rooms', input);
  }

  getRoom(roomId: string): Promise<RoomView> {
    return this.request<RoomView>('GET', `/api/rooms/${roomId}`);
  }

  join(roomId: string): Promise<{ joined: boolean; participants: { role: string; joined_at: string | null }[] }> {
    return this.request('POST', `/api/rooms/${roomId}/join`, {});
  }

  postMessage(roomId: string, content: string): Promise<unknown> {
    return this.request('POST', `/api/rooms/${roomId}/messages`, { content });
  }

  ask(
    roomId: string,
    question: string,
    opts: { blocking?: boolean; addressed_to_participant_id?: string } = {},
  ): Promise<unknown> {
    return this.request('POST', `/api/rooms/${roomId}/questions`, {
      question,
      blocking: opts.blocking ?? true,
      ...(opts.addressed_to_participant_id
        ? { addressed_to_participant_id: opts.addressed_to_participant_id }
        : {}),
    });
  }

  resolve(roomId: string, questionId: string, resolution: string): Promise<unknown> {
    return this.request('POST', `/api/rooms/${roomId}/questions/${questionId}/resolve`, { resolution });
  }

  proposeContract(roomId: string, markdown: string): Promise<{ version: number }> {
    return this.request('PUT', `/api/rooms/${roomId}/contract`, { markdown });
  }

  agree(roomId: string): Promise<{
    agreed_contract_version: number;
    room_status: string;
    everyone_agreed: boolean;
  }> {
    return this.request('POST', `/api/rooms/${roomId}/agree`, {});
  }

  async finalMarkdown(roomId: string): Promise<string> {
    const res = await fetch(`${this.baseUrl}/api/rooms/${roomId}/final.md`, {
      headers: this.token ? { authorization: `Bearer ${this.token}` } : {},
    });
    if (!res.ok) throw new ApiError(res.status, 'unknown', await res.text());
    return res.text();
  }

  async inviteMarkdown(inviteUrl: string): Promise<string> {
    const res = await fetch(`${inviteUrl}.md`);
    if (!res.ok) throw new ApiError(res.status, 'unknown', await res.text());
    return res.text();
  }

  /** Client for a specific participant. */
  as(token: string): RendezvousClient {
    return new RendezvousClient(this.baseUrl, token);
  }
}