'use strict';

// ---------------------------------------------------------------------------
// Encrypted wallpaper
// ---------------------------------------------------------------------------

async function uploadBackground(file) {
  if (!file) return;
  const allowedTypes = ['image/jpeg', 'image/png', 'image/webp'];
  if (!allowedTypes.includes(file.type)) {
    await customAlert('Nur JPEG-, PNG- oder WebP-Bilder sind erlaubt.');
    return;
  }
  if (file.size > DIORA_CONFIG.bgMaxBytes) {
    await customAlert(`Das Bild darf höchstens ${DIORA_CONFIG.bgMaxBytes / 1024 / 1024} MB groß sein.`);
    return;
  }

  const key = await getOrCreateEncKey();
  const buf = await file.arrayBuffer();
  const {iv, ciphertext} = await encryptBytes(key, buf);

  const res = await fetch('/accounts/background/upload/', {
    method: 'POST',
    headers: {'Content-Type': 'application/json', 'X-CSRFToken': getCsrfToken()},
    body: JSON.stringify({iv, ciphertext, mime_type: file.type, file_size: file.size}),
  });
  const data = await res.json();
  if (!data.ok) throw new Error(data.error || 'upload failed');
}

async function applyEncryptedBackground() {
  if (typeof ENCRYPTED_BG === 'undefined' || !ENCRYPTED_BG.ciphertext) return;
  try {
    const key = await getOrCreateEncKey();
    const plain = await decryptBytes(key, ENCRYPTED_BG.iv, ENCRYPTED_BG.ciphertext);
    const blob = new Blob([plain], {type: ENCRYPTED_BG.mime || 'image/jpeg'});
    const url = URL.createObjectURL(blob);
    document.body.style.backgroundImage = `url('${url}')`;
    const contrastBtn = document.getElementById('contrast-toggle');
    if (contrastBtn) contrastBtn.hidden = false; // only with a picture behind the page
    document.body.style.backgroundSize = 'cover';
    document.body.style.backgroundPosition = 'center';
    document.body.style.backgroundAttachment = 'fixed';

    // Analyze brightness for accent/scheme
    analyzeBackground(url).then(({bright, bgLuminance}) => {
      setScheme(bright);
      applyAccent(pickBestAccent(bgLuminance));
    });
  } catch (e) {
    console.warn('Could not decrypt background:', e);
  }
}