"use client";

/**
 * useTapGuard — tells a genuine tap apart from a swipe on a natively-scrolling
 * strip (CSS scroll-snap carousels).
 *
 * Browsers still fire a `click` after some swipe gestures, so a plain onClick
 * on a slide would trigger mid-swipe. Snapshot the pointer position AND the
 * scroller's offset on pointerdown, then check both when the click arrives:
 *
 *   • pointer travel  — catches a drag that didn't scroll (e.g. hit the end)
 *   • scroll movement — catches an inertial swipe, where the pointer barely
 *     moves before `click` fires but the strip is already gliding
 *
 * Either signal alone misses cases, hence both. No staleness risk: a click is
 * always immediately preceded by a pointerdown on the same element.
 */

import { useRef, type RefObject } from "react";

/** Pointer travel (px) still considered a tap rather than a drag. */
const MOVE_TOLERANCE = 8;
/** Scroll movement (px) still considered "didn't scroll". */
const SCROLL_TOLERANCE = 4;

type PointerLike = { clientX: number; clientY: number };

export function useTapGuard(scrollerRef: RefObject<HTMLElement | null>) {
  const start = useRef({ x: 0, y: 0, scrollLeft: 0 });

  function onPointerDown(e: PointerLike) {
    start.current = {
      x: e.clientX,
      y: e.clientY,
      scrollLeft: scrollerRef.current?.scrollLeft ?? 0,
    };
  }

  function wasTap(e: PointerLike) {
    const moved =
      Math.abs(e.clientX - start.current.x) > MOVE_TOLERANCE ||
      Math.abs(e.clientY - start.current.y) > MOVE_TOLERANCE;
    const scrolled =
      Math.abs(
        (scrollerRef.current?.scrollLeft ?? 0) - start.current.scrollLeft,
      ) > SCROLL_TOLERANCE;
    return !moved && !scrolled;
  }

  return { onPointerDown, wasTap };
}