/* Service worker: performs downloads via the extension's own downloads API.
 *
 * A content script (page context) may auto-download only ONE file before Chrome
 * blocks the rest behind a "multiple downloads" guard. Routing each batch
 * through chrome.downloads here sidesteps that: every part downloads
 * immediately and appears in Chrome's download tray.
 *
 * Service workers cannot call URL.createObjectURL, so the content script makes
 * the blob URL and sends it here. A data: URL is accepted as a fallback for the
 * same reason, though large ones are less reliable — hence blob first.
 */
chrome.runtime.onMessage.addListener(function (msg, sender, sendResponse) {
  if (!msg || msg.type !== 'download' || !msg.url) return;
  try {
    chrome.downloads.download(
      { url: msg.url, filename: msg.filename, saveAs: false, conflictAction: 'uniquify' },
      function (id) {
        var err = chrome.runtime.lastError;
        sendResponse({ ok: !err && id != null, error: err && err.message });
      }
    );
  } catch (e) {
    sendResponse({ ok: false, error: String(e) });
  }
  return true; // keep the message channel open for the async sendResponse
});