import { useMutation } from "@tanstack/react-query";
import { BlossomUploader } from '@nostrify/nostrify/uploaders';

import { useCurrentUser } from "./useCurrentUser";

/**
 * Two Blossom hosts. `BlossomUploader` signs ONE auth event and PUTs to every
 * server in parallel, resolving with the first success — so the same bytes
 * normally land on both from a single signature (no double Amber prompt). We then
 * record a mirror URL on the returned tags so photo redundancy is explicit in the
 * event; the read side also derives it from the sha256 (lib/imageFallback).
 */
const UPLOAD_SERVERS = ['https://blossom.primal.net/', 'https://blossom.band/'];

function hostOf(url: string): string {
  try {
    return new URL(url).hostname;
  } catch {
    return '';
  }
}

export function useUploadFile() {
  const { user } = useCurrentUser();

  return useMutation({
    mutationFn: async (file: File) => {
      if (!user) {
        throw new Error('Must be logged in to upload files');
      }

      const uploader = new BlossomUploader({
        servers: UPLOAD_SERVERS,
        signer: user.signer,
      });

      const tags = await uploader.upload(file);

      // Remember the mirror copy of the same blob. Blossom is content-addressed,
      // so `<other-host>/<sha256>` is the same file.
      const primaryUrl = tags[0]?.[1];
      const sha = tags.find(([name]) => name === 'x')?.[1];
      if (primaryUrl && sha) {
        const primaryHost = hostOf(primaryUrl);
        const mirror = UPLOAD_SERVERS.find((s) => hostOf(s) !== primaryHost);
        if (mirror) tags.push(['fallback', `${mirror.replace(/\/+$/, '')}/${sha}`]);
      }

      return tags;
    },
  });
}