// ============================================================
// HTTP API 客户端
// 职责：封装 REST API 请求（auth、conversations 等）
// ============================================================

const API_BASE = "/api";

interface ApiResponse<T> {
  data?: T;
  error?: { code: string; message: string };
  status: number;
}

async function request<T>(
  path: string,
  options: RequestInit = {}
): Promise<ApiResponse<T>> {
  const url = `${API_BASE}${path}`;
  const headers: Record<string, string> = {
    "Content-Type": "application/json",
    ...(options.headers as Record<string, string>),
  };

  try {
    const res = await fetch(url, { ...options, headers });
    const status = res.status;

    if (res.status === 204) {
      return { status };
    }

    const body = await res.json();

    if (!res.ok) {
      return {
        error: { code: body.error || "UNKNOWN", message: body.message || "请求失败" },
        status,
      };
    }

    return { data: body as T, status };
  } catch (err) {
    return {
      error: { code: "NETWORK_ERROR", message: "网络连接失败，请检查网络" },
      status: 0,
    };
  }
}

function authHeaders(accessToken: string): Record<string, string> {
  return { Authorization: `Bearer ${accessToken}` };
}

// ---- Auth API ----

export interface AuthUser {
  id: string;
  username: string;
  created_at: string;
}

export interface AuthResponse {
  user: AuthUser;
  access_token: string;
  refresh_token: string;
}

export async function register(
  username: string,
  password: string
): Promise<ApiResponse<AuthResponse>> {
  return request<AuthResponse>("/auth/register", {
    method: "POST",
    body: JSON.stringify({ username, password }),
  });
}

export async function login(
  username: string,
  password: string
): Promise<ApiResponse<AuthResponse>> {
  return request<AuthResponse>("/auth/login", {
    method: "POST",
    body: JSON.stringify({ username, password }),
  });
}

export async function refreshToken(
  refresh_token: string
): Promise<ApiResponse<AuthResponse>> {
  return request<AuthResponse>("/auth/refresh", {
    method: "POST",
    body: JSON.stringify({ refresh_token }),
  });
}

export async function logout(
  accessToken: string,
  refreshToken: string
): Promise<ApiResponse<{ message: string }>> {
  return request<{ message: string }>("/auth/logout", {
    method: "POST",
    headers: authHeaders(accessToken),
    body: JSON.stringify({ refresh_token: refreshToken }),
  });
}