const test = require('node:test');
const assert = require('node:assert/strict');

const {
  buildScrollRequestKey,
  getSectionTargetTop,
  resolveAnchorScrollAction,
  resolveActiveSectionIndex,
} = require('../../src/pages/index/utils/gxnlpt-scroll-helpers.js');

test('buildScrollRequestKey builds stable request keys', () => {
  assert.equal(buildScrollRequestKey('content-1', 2), 'content-1::2');
  assert.equal(buildScrollRequestKey('content-1'), 'content-1::na');
});

test('getSectionTargetTop uses offsetTop chain instead of viewport coordinates', () => {
  const scrollRoot = { offsetTop: 0 };
  const mid = { offsetTop: 120, offsetParent: scrollRoot };
  const target = { offsetTop: 260, offsetParent: mid };

  assert.equal(getSectionTargetTop(target, scrollRoot, 24), 356);
  assert.equal(getSectionTargetTop(target, scrollRoot, 0), 380);
});

test('resolveAnchorScrollAction skips duplicate or near-target scrolls', () => {
  assert.equal(
    resolveAnchorScrollAction({
      currentTop: 198,
      targetTop: 200,
      pendingRequestKey: '',
      nextRequestKey: 'content-1::0',
      suppressSectionObserver: false,
    }),
    'skip-near-target'
  );

  assert.equal(
    resolveAnchorScrollAction({
      currentTop: 0,
      targetTop: 320,
      pendingRequestKey: 'content-2::1',
      nextRequestKey: 'content-2::1',
      suppressSectionObserver: true,
    }),
    'skip-duplicate-pending'
  );
});

test('resolveActiveSectionIndex uses scrollTop-based coordinates for active tab', () => {
  const sectionTops = [
    { index: 0, top: 0 },
    { index: 1, top: 420 },
    { index: 2, top: 860 },
  ];

  assert.equal(
    resolveActiveSectionIndex({
      sectionTops,
      currentTop: 0,
      anchorOffset: 96,
      defaultIndex: 0,
    }),
    0
  );

  assert.equal(
    resolveActiveSectionIndex({
      sectionTops,
      currentTop: 360,
      anchorOffset: 96,
      defaultIndex: 0,
    }),
    1
  );

  assert.equal(
    resolveActiveSectionIndex({
      sectionTops,
      currentTop: 820,
      anchorOffset: 96,
      defaultIndex: 0,
    }),
    2
  );
});