Scroller

import * as React from "react";
 
/**
 * A utility to compose multiple event handlers into a single event handler.
 * Call originalEventHandler first, then ourEventHandler unless prevented.
 */
function composeEventHandlers<E>(
  originalEventHandler?: (event: E) => void,
  ourEventHandler?: (event: E) => void,
  { checkForDefaultPrevented = true } = {},
) {
  return function handleEvent(event: E) {
    originalEventHandler?.(event);
 
    if (
      checkForDefaultPrevented === false ||
      !(event as unknown as Event).defaultPrevented
    ) {
      return ourEventHandler?.(event);
    }
  };
}
 
/**
 * @see https://github.com/radix-ui/primitives/blob/main/packages/react/compose-refs/src/compose-refs.tsx
 */
 
type PossibleRef<T> = React.Ref<T> | undefined;
 
/**
 * Set a given ref to a given value.
 * This utility takes care of different types of refs: callback refs and RefObject(s).
 */
function setRef<T>(ref: PossibleRef<T>, value: T) {
  if (typeof ref === "function") {
    return ref(value);
  }
 
  if (ref !== null && ref !== undefined) {
    ref.current = value;
  }
}
 
/**
 * A utility to compose multiple refs together.
 * Accepts callback refs and RefObject(s).
 */
function composeRefs<T>(...refs: PossibleRef<T>[]): React.RefCallback<T> {
  return (node) => {
    let hasCleanup = false;
    const cleanups = refs.map((ref) => {
      const cleanup = setRef(ref, node);
      if (!hasCleanup && typeof cleanup === "function") {
        hasCleanup = true;
      }
      return cleanup;
    });
 
    // React <19 will log an error to the console if a callback ref returns a
    // value. We don't use ref cleanups internally so this will only happen if a
    // user's ref callback returns a value, which we only expect if they are
    // using the cleanup functionality added in React 19.
    if (hasCleanup) {
      return () => {
        for (let i = 0; i < cleanups.length; i++) {
          const cleanup = cleanups[i];
          if (typeof cleanup === "function") {
            cleanup();
          } else {
            setRef(refs[i], null);
          }
        }
      };
    }
  };
}
 
/**
 * A custom hook that composes multiple refs.
 * Accepts callback refs and RefObject(s).
 */
function useComposedRefs<T>(...refs: PossibleRef<T>[]): React.RefCallback<T> {
  // eslint-disable-next-line react-hooks/exhaustive-deps
  return React.useCallback(composeRefs(...refs), refs);
}
 
export { composeEventHandlers, composeRefs, useComposedRefs };

"use client";
 
import { useComposedRefs } from "@/lib/composition";
import { cn } from "@/lib/utils";
import { Slot } from "@radix-ui/react-slot";
import { type VariantProps, cva } from "class-variance-authority";
import {
  ChevronDown,
  ChevronLeft,
  ChevronRight,
  ChevronUp,
} from "lucide-react";
import * as React from "react";
 
const DATA_TOP_SCROLL = "data-top-scroll";
const DATA_BOTTOM_SCROLL = "data-bottom-scroll";
const DATA_LEFT_SCROLL = "data-left-scroll";
const DATA_RIGHT_SCROLL = "data-right-scroll";
const DATA_TOP_BOTTOM_SCROLL = "data-top-bottom-scroll";
const DATA_LEFT_RIGHT_SCROLL = "data-left-right-scroll";
 
const scrollerVariants = cva("", {
  variants: {
    orientation: {
      vertical: [
        "overflow-y-auto",
        "data-[top-scroll=true]:[mask-image:linear-gradient(0deg,#000_calc(100%_-_var(--scroll-shadow-size)),transparent)]",
        "data-[bottom-scroll=true]:[mask-image:linear-gradient(180deg,#000_calc(100%_-_var(--scroll-shadow-size)),transparent)]",
        "data-[top-bottom-scroll=true]:[mask-image:linear-gradient(#000,#000,transparent_0,#000_var(--scroll-shadow-size),#000_calc(100%_-_var(--scroll-shadow-size)),transparent)]",
      ],
      horizontal: [
        "overflow-x-auto",
        "data-[left-scroll=true]:[mask-image:linear-gradient(270deg,#000_calc(100%_-_var(--scroll-shadow-size)),transparent)]",
        "data-[right-scroll=true]:[mask-image:linear-gradient(90deg,#000_calc(100%_-_var(--scroll-shadow-size)),transparent)]",
        "data-[left-right-scroll=true]:[mask-image:linear-gradient(to_right,#000,#000,transparent_0,#000_var(--scroll-shadow-size),#000_calc(100%_-_var(--scroll-shadow-size)),transparent)]",
      ],
    },
    hideScrollbar: {
      true: "[-ms-overflow-style:none] [scrollbar-width:none] [&::-webkit-scrollbar]:hidden",
      false: "",
    },
  },
  defaultVariants: {
    orientation: "vertical",
    hideScrollbar: false,
  },
});
 
type ScrollDirection = "up" | "down" | "left" | "right";
 
type ScrollVisibility = {
  [key in ScrollDirection]: boolean;
};
 
interface ScrollerProps
  extends VariantProps<typeof scrollerVariants>,
    React.ComponentPropsWithoutRef<"div"> {
  size?: number;
  offset?: number;
  asChild?: boolean;
  withNavigation?: boolean;
  scrollStep?: number;
  scrollTriggerMode?: "press" | "hover" | "click";
}
 
const Scroller = React.forwardRef<HTMLDivElement, ScrollerProps>(
  (props, forwardedRef) => {
    const {
      orientation = "vertical",
      hideScrollbar,
      className,
      size = 40,
      offset = 0,
      scrollStep = 40,
      style,
      asChild,
      withNavigation = false,
      scrollTriggerMode = "press",
      ...scrollerProps
    } = props;
 
    const containerRef = React.useRef<HTMLDivElement | null>(null);
    const composedRef = useComposedRefs(forwardedRef, containerRef);
    const [scrollVisibility, setScrollVisibility] =
      React.useState<ScrollVisibility>({
        up: false,
        down: false,
        left: false,
        right: false,
      });
 
    const onScrollBy = React.useCallback(
      (direction: ScrollDirection) => {
        const container = containerRef.current;
        if (!container) return;
 
        const scrollMap: Record<ScrollDirection, () => void> = {
          up: () => (container.scrollTop -= scrollStep),
          down: () => (container.scrollTop += scrollStep),
          left: () => (container.scrollLeft -= scrollStep),
          right: () => (container.scrollLeft += scrollStep),
        };
 
        scrollMap[direction]();
      },
      [scrollStep],
    );
 
    React.useLayoutEffect(() => {
      const container = containerRef.current;
      if (!container) return;
 
      function onScroll() {
        if (!container) return;
 
        const isVertical = orientation === "vertical";
 
        if (isVertical) {
          const scrollTop = container.scrollTop;
          const clientHeight = container.clientHeight;
          const scrollHeight = container.scrollHeight;
 
          if (withNavigation) {
            setScrollVisibility((prev) => ({
              ...prev,
              up: scrollTop > offset,
              down: scrollTop + clientHeight < scrollHeight,
            }));
          }
 
          const hasTopScroll = scrollTop > offset;
          const hasBottomScroll =
            scrollTop + clientHeight + offset < scrollHeight;
          const isVerticallyScrollable = scrollHeight > clientHeight;
 
          if (hasTopScroll && hasBottomScroll && isVerticallyScrollable) {
            container.setAttribute(DATA_TOP_BOTTOM_SCROLL, "true");
            container.removeAttribute(DATA_TOP_SCROLL);
            container.removeAttribute(DATA_BOTTOM_SCROLL);
          } else {
            container.removeAttribute(DATA_TOP_BOTTOM_SCROLL);
            if (hasTopScroll) container.setAttribute(DATA_TOP_SCROLL, "true");
            else container.removeAttribute(DATA_TOP_SCROLL);
            if (hasBottomScroll && isVerticallyScrollable)
              container.setAttribute(DATA_BOTTOM_SCROLL, "true");
            else container.removeAttribute(DATA_BOTTOM_SCROLL);
          }
        }
 
        const scrollLeft = container.scrollLeft;
        const clientWidth = container.clientWidth;
        const scrollWidth = container.scrollWidth;
 
        if (withNavigation) {
          setScrollVisibility((prev) => ({
            ...prev,
            left: scrollLeft > offset,
            right: scrollLeft + clientWidth < scrollWidth,
          }));
        }
 
        const hasLeftScroll = scrollLeft > offset;
        const hasRightScroll = scrollLeft + clientWidth + offset < scrollWidth;
        const isHorizontallyScrollable = scrollWidth > clientWidth;
 
        if (hasLeftScroll && hasRightScroll && isHorizontallyScrollable) {
          container.setAttribute(DATA_LEFT_RIGHT_SCROLL, "true");
          container.removeAttribute(DATA_LEFT_SCROLL);
          container.removeAttribute(DATA_RIGHT_SCROLL);
        } else {
          container.removeAttribute(DATA_LEFT_RIGHT_SCROLL);
          if (hasLeftScroll) container.setAttribute(DATA_LEFT_SCROLL, "true");
          else container.removeAttribute(DATA_LEFT_SCROLL);
          if (hasRightScroll && isHorizontallyScrollable)
            container.setAttribute(DATA_RIGHT_SCROLL, "true");
          else container.removeAttribute(DATA_RIGHT_SCROLL);
        }
      }
 
      onScroll();
      container.addEventListener("scroll", onScroll);
      window.addEventListener("resize", onScroll);
 
      return () => {
        container.removeEventListener("scroll", onScroll);
        window.removeEventListener("resize", onScroll);
      };
    }, [orientation, offset, withNavigation]);
 
    const composedStyle = React.useMemo<React.CSSProperties>(
      () => ({
        "--scroll-shadow-size": `${size}px`,
        ...style,
      }),
      [size, style],
    );
 
    const activeDirections = withNavigation
      ? React.useMemo<ScrollDirection[]>(
          () =>
            orientation === "vertical" ? ["up", "down"] : ["left", "right"],
          [orientation],
        )
      : [];
 
    const Comp = asChild ? Slot : "div";
 
    const ScrollerImpl = (
      <Comp
        {...scrollerProps}
        ref={composedRef}
        style={composedStyle}
        className={cn(
          scrollerVariants({ orientation, hideScrollbar, className }),
        )}
      />
    );
 
    if (withNavigation) {
      return (
        <div className="relative w-full">
          {activeDirections.map(
            (direction) =>
              scrollVisibility[direction] && (
                <ScrollButton
                  key={direction}
                  direction={direction}
                  onClick={() => onScrollBy(direction)}
                  triggerMode={scrollTriggerMode}
                />
              ),
          )}
          {ScrollerImpl}
        </div>
      );
    }
 
    return ScrollerImpl;
  },
);
Scroller.displayName = "Scroller";
 
const scrollButtonVariants = cva(
  "absolute z-10 transition-opacity [&>svg]:size-4 [&>svg]:opacity-80 hover:[&>svg]:opacity-100",
  {
    variants: {
      direction: {
        up: "-translate-x-1/2 top-2 left-1/2",
        down: "-translate-x-1/2 bottom-2 left-1/2",
        left: "-translate-y-1/2 top-1/2 left-2",
        right: "-translate-y-1/2 top-1/2 right-2",
      },
    },
    defaultVariants: {
      direction: "up",
    },
  },
);
 
const directionToIcon: Record<ScrollDirection, React.ElementType> = {
  up: ChevronUp,
  down: ChevronDown,
  left: ChevronLeft,
  right: ChevronRight,
} as const;
 
interface ScrollButtonProps extends React.ComponentPropsWithoutRef<"button"> {
  direction: ScrollDirection;
  triggerMode?: "press" | "hover" | "click";
}
 
const ScrollButton = React.forwardRef<HTMLButtonElement, ScrollButtonProps>(
  (props, forwardedRef) => {
    const {
      direction,
      className,
      triggerMode = "press",
      onClick,
      ...buttonProps
    } = props;
 
    const [autoScrollTimer, setAutoScrollTimer] = React.useState<number | null>(
      null,
    );
 
    const onAutoScrollStart = React.useCallback(
      (event?: React.MouseEvent<HTMLButtonElement>) => {
        if (autoScrollTimer !== null) return;
 
        if (triggerMode === "press") {
          const timer = window.setInterval(onClick ?? (() => {}), 50);
          setAutoScrollTimer(timer);
        } else if (triggerMode === "hover") {
          const timer = window.setInterval(() => {
            if (event) onClick?.(event);
          }, 50);
          setAutoScrollTimer(timer);
        }
      },
      [autoScrollTimer, onClick, triggerMode],
    );
 
    const onAutoScrollStop = React.useCallback(() => {
      if (autoScrollTimer === null) return;
 
      window.clearInterval(autoScrollTimer);
      setAutoScrollTimer(null);
    }, [autoScrollTimer]);
 
    const eventHandlers = React.useMemo(() => {
      const triggerModeHandlers: Record<
        NonNullable<ScrollerProps["scrollTriggerMode"]>,
        React.ComponentPropsWithoutRef<"button">
      > = {
        press: {
          onPointerDown: onAutoScrollStart,
          onPointerUp: onAutoScrollStop,
          onPointerLeave: onAutoScrollStop,
          onClick: () => {},
        },
        hover: {
          onPointerEnter: onAutoScrollStart,
          onPointerLeave: onAutoScrollStop,
          onClick: () => {},
        },
        click: {
          onClick,
        },
      } as const;
 
      return triggerModeHandlers[triggerMode] ?? {};
    }, [triggerMode, onAutoScrollStart, onAutoScrollStop, onClick]);
 
    React.useEffect(() => {
      return () => onAutoScrollStop();
    }, [onAutoScrollStop]);
 
    const Icon = directionToIcon[direction];
 
    return (
      <button
        type="button"
        {...buttonProps}
        {...eventHandlers}
        ref={forwardedRef}
        className={cn(scrollButtonVariants({ direction, className }))}
      >
        <Icon />
      </button>
    );
  },
);
ScrollButton.displayName = "ScrollButton";
 
export { Scroller };