DreamKnob/packages/dreamknob/src/skins/TransportButton.tsx

import * as React from 'react';
import { panelButtonChrome, useKnobTheme } from '../core/theme';

export type TransportKind =
  | 'play'
  | 'pause'
  | 'stop'
  | 'record'
  | 'rewind'
  | 'forward'
  | 'panic';

export interface TransportButtonProps {
  kind: TransportKind;
  /** Engaged/lit state (playing, armed, recording). Reflects app state. */
  active?: boolean;
  onClick?: () => void;
  /** Pulse the glyph while active (auto-on for `record`). Reduced-motion aware. */
  blink?: boolean;
  /** Override the glyph/LED color. Defaults per kind (play green, record red…). */
  color?: string;
  /** Button size in px (square). Default: 38. */
  size?: number;
  disabled?: boolean;
  className?: string;
  style?: React.CSSProperties;
  'aria-label'?: string;
}

const LABEL: Record<TransportKind, string> = {
  play: 'Play',
  pause: 'Pause',
  stop: 'Stop',
  record: 'Record',
  rewind: 'Rewind',
  forward: 'Forward',
  panic: 'Panic — all notes off',
};

/** Glyph in a 24×24 box, filled with `currentColor`. */
const Glyph: React.FC<{ kind: TransportKind }> = ({ kind }) => {
  switch (kind) {
    case 'play':
      return <path d="M8 5.5 L19 12 L8 18.5 Z" />;
    case 'pause':
      return (
        <>
          <rect x="7" y="5.5" width="3.6" height="13" rx="1" />
          <rect x="13.4" y="5.5" width="3.6" height="13" rx="1" />
        </>
      );
    case 'stop':
      return <rect x="6.5" y="6.5" width="11" height="11" rx="1.5" />;
    case 'record':
      return <circle cx="12" cy="12" r="5.2" />;
    case 'rewind':
      return (
        <>
          <path d="M11.5 6 L11.5 18 L4 12 Z" />
          <path d="M20 6 L20 18 L12.5 12 Z" />
        </>
      );
    case 'forward':
      return (
        <>
          <path d="M4 6 L11.5 12 L4 18 Z" />
          <path d="M12.5 6 L20 12 L12.5 18 Z" />
        </>
      );
    case 'panic':
      return (
        <>
          <rect x="10.6" y="5" width="2.8" height="8.4" rx="1.4" />
          <circle cx="12" cy="17.4" r="1.7" />
        </>
      );
  }
};

/**
 * A record / play / stop / pause / panic transport button, styled to sit
 * alongside dreamknob controls. `active` lights it; `record` blinks while
 * armed. Reduced-motion aware.
 */
export const TransportButton = React.forwardRef<HTMLButtonElement, TransportButtonProps>(
  function TransportButton(
    { kind, active = false, onClick, blink, color, size = 38, disabled = false, className, style, ...aria },
    ref,
  ) {
    const theme = useKnobTheme();
    const [focusVisible, setFocusVisible] = React.useState(false);
    const glyphRef = React.useRef<SVGSVGElement>(null);
    const chrome = panelButtonChrome(theme.scheme, active);

    const accent =
      color ??
      (kind === 'record' || kind === 'panic'
        ? theme.zoneHot
        : kind === 'play'
          ? theme.zoneGood
          : kind === 'pause'
            ? theme.zoneWarn
            : theme.text);
    const lit = active ? accent : theme.label;
    const shouldBlink = (blink ?? kind === 'record') && active;

    React.useEffect(() => {
      const el = glyphRef.current;
      if (!el || !shouldBlink) return;
      if (typeof window !== 'undefined' && window.matchMedia?.('(prefers-reduced-motion: reduce)').matches)
        return;
      const anim = el.animate([{ opacity: 1 }, { opacity: 0.3 }], {
        duration: 560,
        iterations: Infinity,
        direction: 'alternate',
        easing: 'ease-in-out',
      });
      return () => anim.cancel();
    }, [shouldBlink]);

    return (
      <button
        ref={ref}
        type="button"
        aria-label={aria['aria-label'] ?? LABEL[kind]}
        aria-pressed={active}
        disabled={disabled}
        data-active={active ? '' : undefined}
        data-kind={kind}
        data-focus-visible={focusVisible ? '' : undefined}
        className={className}
        onClick={onClick}
        onFocus={e => {
          try {
            setFocusVisible(e.currentTarget.matches(':focus-visible'));
          } catch {
            setFocusVisible(true);
          }
        }}
        onBlur={() => setFocusVisible(false)}
        style={{
          display: 'inline-flex',
          alignItems: 'center',
          justifyContent: 'center',
          width: size,
          height: size,
          padding: 0,
          borderRadius: 8,
          border: chrome.border,
          background: chrome.background,
          boxShadow: `${chrome.boxShadow}${
            active ? `, 0 0 ${size * 0.28}px ${accent}55` : ''
          }${focusVisible ? `, 0 0 0 2px ${theme.focusRing}` : ''}`,
          outline: 'none',
          cursor: disabled ? 'not-allowed' : 'pointer',
          opacity: disabled ? 0.45 : 1,
          touchAction: 'manipulation',
          transition: 'background 80ms, box-shadow 80ms',
          ...style,
        }}
      >
        <svg
          ref={glyphRef}
          width={size * 0.55}
          height={size * 0.55}
          viewBox="0 0 24 24"
          fill={lit}
          style={{
            display: 'block',
            filter: active ? `drop-shadow(0 0 ${size * 0.12}px ${accent})` : undefined,
            transition: 'fill 80ms',
          }}
          aria-hidden="true"
        >
          <Glyph kind={kind} />
        </svg>
      </button>
    );
  },
);