/** A rectangle measured in viewport CSS pixels. */
export interface OriginRect {
  /** Distance from the viewport's top edge in CSS pixels. */
  top: number;
  /** Distance from the viewport's left edge in CSS pixels. */
  left: number;
  /** Rectangle width in CSS pixels. */
  width: number;
  /** Rectangle height in CSS pixels. */
  height: number;
}

/** Clamp a value to the inclusive unit range `0..1`. */
export function clamp01(value: number): number {
  return Math.max(0, Math.min(1, value));
}

/** Clamp a value to the inclusive range `min..max`. */
export function clamp(value: number, min: number, max: number): number {
  return Math.max(min, Math.min(max, value));
}

/** Measure an element's viewport bounds as a plain, serializable rectangle. */
export function measureRect(element: Element): OriginRect {
  const { top, left, width, height } = element.getBoundingClientRect();
  return { top, left, width, height };
}

/** Bounds of the browser window, or a unit rectangle outside a browser. */
export function windowRect(): OriginRect {
  const browser = typeof window !== "undefined";
  return {
    top: 0,
    left: 0,
    width: browser ? window.innerWidth : 1,
    height: browser ? window.innerHeight : 1,
  };
}

/**
 * Whether animation should resolve immediately.
 *
 * True outside a browser, when `requestAnimationFrame` is unavailable, or when
 * the user prefers reduced motion.
 */
export function prefersReducedMotion(): boolean {
  return (
    typeof window === "undefined" ||
    !window.requestAnimationFrame ||
    Boolean(window.matchMedia?.("(prefers-reduced-motion: reduce)").matches)
  );
}