import type { Task, Handoff, Decision, Memory, Message, ActivityItem } from '../core/schema.js';
import type { IndexEntry } from '../core/index.js';
import type { InboxMessage } from '../core/services/messageService.js';
import type { TaskLogEntry } from '../core/services/taskLogService.js';

export class RemoteError extends Error {
  constructor(public status: number, message: string) {
    super(message);
  }
}

async function request<T>(baseUrl: string, method: string, path: string, body?: unknown): Promise<T> {
  const url = `${baseUrl}${path}`;
  let res: Response;
  try {
    res = await fetch(url, {
      method,
      headers: body ? { 'Content-Type': 'application/json' } : undefined,
      body: body ? JSON.stringify(body) : undefined,
    });
  } catch (err) {
    const message = err instanceof Error ? err.message : String(err);
    throw new RemoteError(0, `Cannot reach AgentHub server at ${baseUrl}: ${message}`);
  }

  const text = await res.text();
  if (!res.ok) {
    throw new RemoteError(res.status, text || `HTTP ${res.status}`);
  }
  if (!text) {
    throw new RemoteError(res.status, 'Empty response from server');
  }
  return JSON.parse(text) as T;
}

export const remoteClient = {
  async getStatus(baseUrl: string): Promise<string> {
    return request<{ body: string }>(baseUrl, 'GET', '/status').then((r) => r.body);
  },

  async announce(baseUrl: string, agent: string, role?: string, action: 'joined' | 'left' = 'joined'): Promise<void> {
    await request<{ ok: boolean }>(baseUrl, 'POST', '/announce', { agent, role, action });
  },

  async updateStatus(baseUrl: string): Promise<string> {
    return request<{ body: string }>(baseUrl, 'POST', '/status/update').then((r) => r.body);
  },

  async createTask(baseUrl: string, options: Partial<Task>): Promise<Task> {
    return request<Task>(baseUrl, 'POST', '/tasks', options);
  },

  async listTasks(baseUrl: string, filters?: { status?: string; role?: string }): Promise<IndexEntry[]> {
    const params = new URLSearchParams((filters ?? {}) as Record<string, string>);
    const qs = params.toString();
    return request<IndexEntry[]>(baseUrl, 'GET', `/tasks${qs ? '?' + qs : ''}`);
  },

  async getTask(baseUrl: string, id: string): Promise<{ task: Task; body: string }> {
    return request<{ task: Task; body: string }>(baseUrl, 'GET', `/tasks/${id}`);
  },

  async claimTask(baseUrl: string, id: string, agentName: string): Promise<Task> {
    return request<Task>(baseUrl, 'PATCH', `/tasks/${id}`, { status: 'in_progress', assignedTo: agentName });
  },

  async doneTask(
    baseUrl: string,
    id: string,
    meta?: { tokens?: number; duration?: number; by?: string },
  ): Promise<Task> {
    return request<Task>(baseUrl, 'PATCH', `/tasks/${id}`, {
      status: 'done',
      doneTokens: meta?.tokens,
      doneDuration: meta?.duration,
      doneBy: meta?.by,
    });
  },

  async assignTask(baseUrl: string, id: string, agentName: string): Promise<Task> {
    return request<Task>(baseUrl, 'PATCH', `/tasks/${id}`, { assignedTo: agentName });
  },

  async reviewTask(baseUrl: string, id: string): Promise<Task> {
    return request<Task>(baseUrl, 'PATCH', `/tasks/${id}`, { status: 'review' });
  },

  async reopenTask(baseUrl: string, id: string): Promise<Task> {
    return request<Task>(baseUrl, 'PATCH', `/tasks/${id}`, { status: 'open' });
  },

  async getTaskActivity(baseUrl: string, id: string): Promise<ActivityItem[]> {
    return request<ActivityItem[]>(baseUrl, 'GET', `/tasks/${id}/activity`);
  },

  async appendTaskLog(
    baseUrl: string,
    id: string,
    entry: { text: string; agent?: string; level?: string },
  ): Promise<TaskLogEntry> {
    return request<TaskLogEntry>(baseUrl, 'POST', `/tasks/${id}/log`, entry);
  },

  async createHandoff(baseUrl: string, options: Partial<Handoff>): Promise<Handoff> {
    return request<Handoff>(baseUrl, 'POST', '/handoffs', options);
  },

  async listHandoffs(baseUrl: string): Promise<IndexEntry[]> {
    return request<IndexEntry[]>(baseUrl, 'GET', '/handoffs');
  },

  async getHandoff(baseUrl: string, id: string): Promise<{ handoff: Handoff; body: string }> {
    return request<{ handoff: Handoff; body: string }>(baseUrl, 'GET', `/handoffs/${id}`);
  },

  async createDecision(baseUrl: string, options: Partial<Decision>): Promise<Decision> {
    return request<Decision>(baseUrl, 'POST', '/decisions', options);
  },

  async listDecisions(baseUrl: string): Promise<IndexEntry[]> {
    return request<IndexEntry[]>(baseUrl, 'GET', '/decisions');
  },

  async addMemory(baseUrl: string, options: Partial<Memory>): Promise<Memory> {
    return request<Memory>(baseUrl, 'POST', '/memory', options);
  },

  async searchMemory(baseUrl: string, query: string): Promise<IndexEntry[]> {
    return request<IndexEntry[]>(baseUrl, 'GET', `/memory/search?q=${encodeURIComponent(query)}`);
  },

  async listMemory(baseUrl: string): Promise<IndexEntry[]> {
    return request<IndexEntry[]>(baseUrl, 'GET', '/memory');
  },

  async sendMessage(baseUrl: string, options: Partial<Message>): Promise<Message> {
    return request<Message>(baseUrl, 'POST', '/messages', options);
  },

  async getInbox(baseUrl: string, agent: string, unreadOnly = false): Promise<InboxMessage[]> {
    const q = `?agent=${encodeURIComponent(agent)}${unreadOnly ? '&unread=1' : ''}`;
    return request<InboxMessage[]>(baseUrl, 'GET', `/messages${q}`);
  },

  async markMessageRead(baseUrl: string, id: string): Promise<Message> {
    return request<Message>(baseUrl, 'POST', `/messages/${id}/read`);
  },

  async ackMessage(baseUrl: string, id: string, by?: string): Promise<Message> {
    return request<Message>(baseUrl, 'POST', `/messages/${id}/ack`, by ? { by } : undefined);
  },

  async getMessage(baseUrl: string, id: string): Promise<{ message: Message; body: string }> {
    return request<{ message: Message; body: string }>(baseUrl, 'GET', `/messages/${id}`);
  },

  async delegate(baseUrl: string, auto: boolean): Promise<{ suggestion?: { task: IndexEntry; role: string; preferredAgent: string }; handoff?: Handoff }> {
    return request<{ suggestion?: { task: IndexEntry; role: string; preferredAgent: string }; handoff?: Handoff }>(baseUrl, 'POST', `/delegate?auto=${auto}`);
  },
};