Metronome

import { useId } from 'react';

const css = `
  @keyframes radio-metronome-swing { from { transform: rotate(-26deg); } to { transform: rotate(26deg); } }
  @keyframes radio-metronome-beat { 0% { opacity: 1; box-shadow: 0 0 8px light-dark(#373a40, #f1f2f3); } 40%, 100% { opacity: 0.25; box-shadow: none; } }
  .radio-metronome { --radio-metronome-t: 1s; --radio-metronome-w: 8px; --radio-metronome-k: 0; display: flex; align-items: center; gap: 18px; }
  .radio-metronome:has(.radio-metronome__input[value='andante']:checked) { --radio-metronome-t: 0.625s; --radio-metronome-w: 22px; --radio-metronome-k: 1; }
  .radio-metronome:has(.radio-metronome__input[value='presto']:checked) { --radio-metronome-t: 0.357s; --radio-metronome-w: 38px; --radio-metronome-k: 2; }
  .radio-metronome__body { position: relative; width: 64px; height: 90px; }
  .radio-metronome__case {
    position: absolute;
    inset: 0;
    clip-path: polygon(32% 0, 68% 0, 100% 100%, 0 100%);
    background: linear-gradient(light-dark(#cbced3, #393c41), light-dark(#dbdde1, #2e3035));
  }
  .radio-metronome__face {
    position: absolute;
    left: 22px;
    top: 12px;
    width: 20px;
    height: 62px;
    background: repeating-linear-gradient(transparent 0 7px, light-dark(#6d7179, #7d8087) 7px 8px), light-dark(#ebedf0, #232529);
    clip-path: polygon(20% 0, 80% 0, 100% 100%, 0 100%);
  }
  .radio-metronome__arm {
    position: absolute;
    left: 31px;
    bottom: 12px;
    width: 2px;
    height: 70px;
    border-radius: 1px;
    background: light-dark(#42454c, #e5e6e9);
    transform-origin: 50% 100%;
    animation: radio-metronome-swing var(--radio-metronome-t) ease-in-out infinite alternate;
  }
  .radio-metronome__weight {
    position: absolute;
    left: -5px;
    top: var(--radio-metronome-w);
    width: 12px;
    height: 9px;
    background: light-dark(#50535b, #c6c8cd);
    clip-path: polygon(20% 0, 80% 0, 100% 100%, 0 100%);
    transition: top 0.4s cubic-bezier(0.3, 1.3, 0.5, 1);
  }
  .radio-metronome__beat {
    position: absolute;
    left: 29px;
    top: 4px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: light-dark(#373a40, #f1f2f3);
    animation: radio-metronome-beat var(--radio-metronome-t) ease-out infinite;
  }
  .radio-metronome__side { display: grid; gap: 10px; }
  .radio-metronome__bpm { height: 22px; overflow: hidden; }
  .radio-metronome__bpm-strip { display: grid; transform: translateY(calc(var(--radio-metronome-k) * -22px)); transition: transform 0.35s cubic-bezier(0.3, 1.3, 0.5, 1); }
  .radio-metronome__bpm-strip span { height: 22px; color: light-dark(#373a40, #f1f2f3); font-size: 18px; font-weight: 600; line-height: 22px; font-variant-numeric: tabular-nums; }
  .radio-metronome__bpm-strip small { color: light-dark(#5f626a, #a7abb2); font-size: 10px; font-weight: 400; }
  .radio-metronome__opts { display: grid; gap: 2px; }
  .radio-metronome__opt {
    position: relative;
    padding: 4px 10px;
    border-radius: 6px;
    color: light-dark(#5f626a, #a7abb2);
    font-size: 12px;
    font-weight: 600;
    font-style: italic;
    cursor: pointer;
    transition: color 0.2s, background-color 0.2s;
  }
  .radio-metronome__opt:hover { color: light-dark(#42454c, #e5e6e9); }
  .radio-metronome__input { position: absolute; width: 1px; height: 1px; margin: 0; opacity: 0; }
  .radio-metronome__opt:has(.radio-metronome__input:focus-visible) { outline: 2px solid light-dark(#5f626a, #a7abb2); outline-offset: 1px; }
  .radio-metronome__opt:has(.radio-metronome__input:checked) { background: light-dark(#ebedf0, #232529); color: light-dark(#373a40, #f1f2f3); }
  @media (prefers-reduced-motion: reduce) {
    .radio-metronome * { animation: none !important; transition-duration: 0.01s !important; }
  }
`;

const TEMPI = [
  { value: 'largo', label: 'Largo', bpm: 60 },
  { value: 'andante', label: 'Andante', bpm: 96 },
  { value: 'presto', label: 'Presto', bpm: 168 },
];

export function MetronomeRadio() {
  const name = useId();
  return (
    <>
      <style>
        {css}
      </style>
      <div className="radio-metronome">
        <span className="radio-metronome__body" aria-hidden="true">
          <span className="radio-metronome__case" />
          <span className="radio-metronome__face" />
          <span className="radio-metronome__beat" />
          <span className="radio-metronome__arm">
            <span className="radio-metronome__weight" />
          </span>
        </span>
        <div className="radio-metronome__side">
          <span className="radio-metronome__bpm" aria-hidden="true">
            <span className="radio-metronome__bpm-strip">
              {TEMPI.map((t) => (
                <span key={t.value}>
                  {t.bpm} <small>BPM</small>
                </span>
              ))}
            </span>
          </span>
          <div className="radio-metronome__opts" role="radiogroup" aria-label="Tempo">
            {TEMPI.map((t, i) => (
              <label key={t.value} className="radio-metronome__opt">
                <input className="radio-metronome__input" type="radio" name={name} value={t.value} defaultChecked={i === 0} />
                {t.label}
              </label>
            ))}
          </div>
        </div>
      </div>
    </>
  );
}