'use strict';

/**
 * WAVE D1 motion primitives.
 *
 * The property that matters most here is not how they look — it is that they
 * never withhold content. A reveal primitive that hides a row until an observer
 * fires will, on any browser or preference where the observer never fires, hide
 * the row forever.
 */

const m = require('../../web/src/lib/motion');

describe('reduced motion is honoured, not softened', () => {
  it('assumes reduced motion server-side', () => {
    expect(m.prefersReducedMotion()).toBe(true);
  });

  it('nudge does nothing and returns a no-op cleanup', () => {
    const el = { style: {} };
    const stop = m.nudge(el);
    expect(el.style.transform).toBeUndefined();
    expect(typeof stop).toBe('function');
    expect(() => stop()).not.toThrow();
  });

  it('boot stagger collapses to zero delay AND forces opacity', () => {
    // Not just delay 0: if a CSS animation supplies the opacity, skipping the
    // animation without forcing opacity leaves the row invisible.
    expect(m.bootStagger(9)).toEqual({ animationDelay: '0ms', opacity: 1 });
  });

  it('reveal fires IMMEDIATELY rather than waiting for an observer', () => {
    const el = {}; let revealed = null;
    m.revealOnIntersect(el, (x) => { revealed = x; });
    expect(revealed).toBe(el);
  });
});

describe('the stagger cannot make content late', () => {
  it('is capped, so a long board does not delay its tail', () => {
    // Uncapped, row 40 would wait 1.1s and the stagger becomes the latency it
    // exists to disguise.
    const orig = m.prefersReducedMotion;
    expect(m.STAGGER_CAP_MS).toBeLessThanOrEqual(300);
    expect(m.STAGGER_STEP_MS * 40).toBeGreaterThan(m.STAGGER_CAP_MS);
  });

  it('the nudge is short enough to read as acknowledgement, not latency', () => {
    expect(m.NUDGE_MS).toBeLessThanOrEqual(220);
  });
});

describe('row hover is pointer-only by construction', () => {
  it('exposes handlers rather than CSS, so touch cannot stick a hover state', () => {
    const h = m.rowHover();
    expect(typeof h.onMouseEnter).toBe('function');
    expect(typeof h.onMouseLeave).toBe('function');
  });

  it('clears the tint it set, never leaving a row highlighted', () => {
    const el = { style: { background: '' } };
    const h = m.rowHover();
    h.onMouseEnter({ currentTarget: el });
    expect(el.style.background).toBeTruthy();
    h.onMouseLeave({ currentTarget: el });
    expect(el.style.background).toBe('');
  });

  it('survives a missing currentTarget rather than throwing mid-render', () => {
    const h = m.rowHover();
    expect(() => h.onMouseEnter({})).not.toThrow();
    expect(() => h.onMouseLeave({})).not.toThrow();
  });
});

describe('no observer leak', () => {
  it('reveal returns an unobserve function in every path', () => {
    expect(typeof m.revealOnIntersect(null, () => {})).toBe('function');
    expect(typeof m.revealOnIntersect({}, () => {})).toBe('function');
  });
});