import { ATTACHMENT_STALLED_DOWNLOAD_THRESHOLD_MS, shouldResetStalledAttachmentDownload } from './attachment-autodownload.rules';

const NOW_MS = 1_750_000_000_000;

describe('attachment autodownload rules', () => {
  it('does not reset an actively transferring download with recent chunk progress', () => {
    // Regression: the pending-request marker is deleted on the first received
    // chunk, so an in-flight multi-chunk transfer has receivedBytes > 0 and no
    // pending request - it must NOT be treated as stalled while chunks flow.
    expect(shouldResetStalledAttachmentDownload({
      available: false,
      receivedBytes: 128,
      lastUpdateMs: NOW_MS - 100
    }, false, NOW_MS)).toBe(false);
  });

  it('resets partial downloads with no progress past the stall threshold', () => {
    expect(shouldResetStalledAttachmentDownload({
      available: false,
      receivedBytes: 128,
      lastUpdateMs: NOW_MS - ATTACHMENT_STALLED_DOWNLOAD_THRESHOLD_MS - 1
    }, false, NOW_MS)).toBe(true);
  });

  it('treats partial downloads without a progress timestamp as stalled', () => {
    expect(shouldResetStalledAttachmentDownload({
      available: false,
      receivedBytes: 128
    }, false, NOW_MS)).toBe(true);
  });

  it('never resets downloads with a pending request or already available', () => {
    expect(shouldResetStalledAttachmentDownload({
      available: false,
      receivedBytes: 128,
      lastUpdateMs: NOW_MS - ATTACHMENT_STALLED_DOWNLOAD_THRESHOLD_MS - 1
    }, true, NOW_MS)).toBe(false);

    expect(shouldResetStalledAttachmentDownload({
      available: true,
      receivedBytes: 128,
      lastUpdateMs: NOW_MS - ATTACHMENT_STALLED_DOWNLOAD_THRESHOLD_MS - 1
    }, false, NOW_MS)).toBe(false);
  });

  it('never resets downloads that have not received any bytes', () => {
    expect(shouldResetStalledAttachmentDownload({
      available: false,
      receivedBytes: 0
    }, false, NOW_MS)).toBe(false);
  });
});