import { ApiError, toApiError } from "./errors";

const API_BASE_URL = (import.meta.env.VITE_API_BASE_URL as string | undefined)?.trim() || "http://localhost:3001";

function buildUrl(path: string): string {
  const normalizedPath = path.startsWith("/") ? path : `/${path}`;
  return `${API_BASE_URL}${normalizedPath}`;
}

async function parseResponseBody(response: Response): Promise<unknown> {
  const contentType = response.headers.get("content-type") ?? "";
  if (!contentType.includes("application/json")) {
    return null;
  }

  try {
    return await response.json();
  } catch {
    return null;
  }
}

export async function requestJson<T>(path: string, init?: RequestInit): Promise<T> {
  try {
    const response = await fetch(buildUrl(path), {
      ...init,
      headers: {
        "Content-Type": "application/json",
        ...(init?.headers ?? {}),
      },
    });

    if (response.status === 204) {
      return undefined as T;
    }

    const payload = await parseResponseBody(response);

    if (!response.ok) {
      throw toApiError(response.status, payload);
    }

    return payload as T;
  } catch (error) {
    if (error instanceof ApiError) {
      throw error;
    }

    throw new ApiError({
      code: "network_error",
      status: null,
      message: "Не удалось связаться с сервером.",
    });
  }
}