// Browser-direct Blossom (BUD-02) upload: hash locally, sign the kind-24242
// authorization with the user's NIP-07 extension, PUT straight to the blossom
// server. The file never transits podsteadr.

import { nip07 } from './nip07';

export async function sha256File(file: File, onProgress?: (frac: number) => void): Promise<string> {
  // crypto.subtle needs the whole buffer; fine for podcast-sized mp4s (~2 GB cap).
  const buf = await file.arrayBuffer();
  onProgress?.(0.5);
  const digest = await crypto.subtle.digest('SHA-256', buf);
  onProgress?.(1);
  return [...new Uint8Array(digest)].map((b) => b.toString(16).padStart(2, '0')).join('');
}

export interface BlossomUpload {
  sha256: string;
  size: number;
  url: string;
}

export async function uploadToBlossom(
  blossomUrl: string,
  file: File,
  sha256: string,
  onProgress?: (frac: number) => void,
): Promise<BlossomUpload> {
  const now = Math.floor(Date.now() / 1000);
  const auth = await nip07().signEvent({
    kind: 24242,
    created_at: now,
    content: `Upload ${file.name}`,
    tags: [
      ['t', 'upload'],
      ['x', sha256],
      ['expiration', String(now + 600)],
    ],
  });

  const base = blossomUrl.replace(/\/+$/, '');
  // XHR instead of fetch for upload progress events.
  await new Promise<void>((resolve, reject) => {
    const xhr = new XMLHttpRequest();
    xhr.open('PUT', `${base}/upload`);
    xhr.setRequestHeader('authorization', `Nostr ${btoa(JSON.stringify(auth))}`);
    xhr.setRequestHeader('content-type', file.type || 'video/mp4');
    xhr.upload.onprogress = (e) => {
      if (e.lengthComputable) onProgress?.(e.loaded / e.total);
    };
    xhr.onload = () => {
      if (xhr.status >= 200 && xhr.status < 300) resolve();
      else reject(new Error(`blossom upload failed: ${xhr.status} ${xhr.responseText.slice(0, 200)}`));
    };
    xhr.onerror = () => reject(new Error('blossom upload failed: network error'));
    xhr.send(file);
  });

  return { sha256, size: file.size, url: `${base}/${sha256}` };
}

/** Read the media duration (seconds) from a local file, for itunes:duration. */
export function probeDuration(file: File): Promise<number | null> {
  return new Promise((resolve) => {
    const el = document.createElement('video');
    el.preload = 'metadata';
    el.onloadedmetadata = () => {
      URL.revokeObjectURL(el.src);
      resolve(Number.isFinite(el.duration) ? Math.round(el.duration) : null);
    };
    el.onerror = () => {
      URL.revokeObjectURL(el.src);
      resolve(null);
    };
    el.src = URL.createObjectURL(file);
  });
}