import { API_URL } from "./config";

/**
 * Simple API client that centralizes fetch configuration.
 * All requests include credentials and proper headers.
 */

export class ApiError extends Error {
  constructor(
    message: string,
    public status: number,
    public data?: unknown
  ) {
    super(message);
    this.name = "ApiError";
  }
}

async function request<T>(
  endpoint: string,
  options: RequestInit = {}
): Promise<T> {
  const url = `${API_URL}${endpoint}`;
  
  const headers: Record<string, string> = {
    ...(options.headers as Record<string, string>),
  };
  
  if (options.body && typeof options.body === "string") {
    headers["Content-Type"] = "application/json";
  }
  
  const res = await fetch(url, {
    ...options,
    headers,
    credentials: "include",
  });
  
  if (!res.ok) {
    let data: unknown;
    try {
      data = await res.json();
    } catch {
      // Response wasn't JSON
    }
    throw new ApiError(
      `Request failed: ${res.status}`,
      res.status,
      data
    );
  }
  
  return res.json();
}

export const api = {
  get<T>(endpoint: string): Promise<T> {
    return request<T>(endpoint);
  },
  
  post<T>(endpoint: string, body?: unknown): Promise<T> {
    return request<T>(endpoint, {
      method: "POST",
      body: body ? JSON.stringify(body) : undefined,
    });
  },
  
  put<T>(endpoint: string, body?: unknown): Promise<T> {
    return request<T>(endpoint, {
      method: "PUT",
      body: body ? JSON.stringify(body) : undefined,
    });
  },
};