import { getAccessToken, setAccessToken } from './token-store';
import { refreshRequest } from './api';

const API_URL = process.env.NEXT_PUBLIC_API_URL ?? 'http://localhost:3001/api/v1';

export class ApiError extends Error {
  status: number;

  constructor(status: number, message: string) {
    super(message);
    this.status = status;
  }
}

async function rawFetch(path: string, init: RequestInit): Promise<Response> {
  const token = getAccessToken();
  return fetch(`${API_URL}${path}`, {
    ...init,
    credentials: 'include',
    headers: {
      'Content-Type': 'application/json',
      ...(token ? { Authorization: `Bearer ${token}` } : {}),
      ...init.headers,
    },
  });
}

export interface BlobDownload {
  blob: Blob;
  filename: string;
}

function filenameFromContentDisposition(header: string | null, fallback: string): string {
  const match = header ? /filename="([^"]+)"/.exec(header) : null;
  return match?.[1] ?? fallback;
}

export async function apiFetchBlob(path: string, fallbackFilename: string): Promise<BlobDownload> {
  let response = await rawFetch(path, {});

  if (response.status === 401) {
    const refreshed = await refreshRequest();
    if (refreshed) {
      setAccessToken(refreshed.accessToken);
      response = await rawFetch(path, {});
    }
  }

  if (!response.ok) {
    throw new ApiError(response.status, 'Export fehlgeschlagen');
  }

  const blob = await response.blob();
  const filename = filenameFromContentDisposition(
    response.headers.get('Content-Disposition'),
    fallbackFilename,
  );
  return { blob, filename };
}

export async function apiFetch<T>(path: string, init: RequestInit = {}): Promise<T> {
  let response = await rawFetch(path, init);

  if (response.status === 401) {
    const refreshed = await refreshRequest();
    if (refreshed) {
      setAccessToken(refreshed.accessToken);
      response = await rawFetch(path, init);
    }
  }

  if (!response.ok) {
    const body: unknown = await response.json().catch(() => ({}));
    const message =
      typeof body === 'object' && body !== null && 'message' in body
        ? String((body as { message: unknown }).message)
        : 'Request failed';
    throw new ApiError(response.status, message);
  }

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

  return response.json() as Promise<T>;
}