MotionThumb.tsx

import useLayoutEffect from '@rc-component/util/lib/hooks/useLayoutEffect';
import { composeRef } from '@rc-component/util/lib/ref';
import classNames from 'classnames';
import CSSMotion from 'rc-motion';
import * as React from 'react';
import type { SegmentedValue } from '.';

type ThumbReact = {
  left: number;
  right: number;
  width: number;
  top: number;
  bottom: number;
  height: number;
} | null;

export interface MotionThumbInterface {
  containerRef: React.RefObject<HTMLDivElement>;
  value: SegmentedValue;
  getValueIndex: (value: SegmentedValue) => number;
  prefixCls: string;
  motionName: string;
  onMotionStart: VoidFunction;
  onMotionEnd: VoidFunction;
  direction?: 'ltr' | 'rtl';
  vertical?: boolean;
}

const calcThumbStyle = (
  targetElement: HTMLElement | null | undefined,
  vertical?: boolean,
): ThumbReact => {
  if (!targetElement) return null;

  const style: ThumbReact = {
    left: targetElement.offsetLeft,
    right:
      (targetElement.parentElement!.clientWidth as number) -
      targetElement.clientWidth -
      targetElement.offsetLeft,
    width: targetElement.clientWidth,
    top: targetElement.offsetTop,
    bottom:
      (targetElement.parentElement!.clientHeight as number) -
      targetElement.clientHeight -
      targetElement.offsetTop,
    height: targetElement.clientHeight,
  };

  if (vertical) {
    // Adjusts positioning and size for vertical layout by setting horizontal properties to 0 and using vertical properties from the style object.
    return {
      left: 0,
      right: 0,
      width: 0,
      top: style.top,
      bottom: style.bottom,
      height: style.height,
    };
  }

  return {
    left: style.left,
    right: style.right,
    width: style.width,
    top: 0,
    bottom: 0,
    height: 0,
  };
};

const toPX = (value: number | undefined): string | undefined =>
  value !== undefined ? `${value}px` : undefined;

export default function MotionThumb(props: MotionThumbInterface) {
  const {
    prefixCls,
    containerRef,
    value,
    getValueIndex,
    motionName,
    onMotionStart,
    onMotionEnd,
    direction,
    vertical = false,
  } = props;

  const thumbRef = React.useRef<HTMLDivElement>(null);
  const [prevValue, setPrevValue] = React.useState(value);

  // =========================== Effect ===========================
  const findValueElement = (val: SegmentedValue) => {
    const index = getValueIndex(val);
    const ele = containerRef.current?.querySelectorAll<HTMLDivElement>(
      `.${prefixCls}-item`,
    )[index];
    return ele?.offsetParent && ele;
  };

  const [prevStyle, setPrevStyle] = React.useState<ThumbReact>(null);
  const [nextStyle, setNextStyle] = React.useState<ThumbReact>(null);

  useLayoutEffect(() => {
    if (prevValue !== value) {
      const prev = findValueElement(prevValue);
      const next = findValueElement(value);

      const calcPrevStyle = calcThumbStyle(prev, vertical);
      const calcNextStyle = calcThumbStyle(next, vertical);

      setPrevValue(value);
      setPrevStyle(calcPrevStyle);
      setNextStyle(calcNextStyle);

      if (prev && next) {
        onMotionStart();
      } else {
        onMotionEnd();
      }
    }
  }, [value]);

  const thumbStart = React.useMemo(() => {
    if (vertical) {
      return toPX(prevStyle?.top ?? 0);
    }

    if (direction === 'rtl') {
      return toPX(-(prevStyle?.right as number));
    }

    return toPX(prevStyle?.left as number);
  }, [vertical, direction, prevStyle]);

  const thumbActive = React.useMemo(() => {
    if (vertical) {
      return toPX(nextStyle?.top ?? 0);
    }

    if (direction === 'rtl') {
      return toPX(-(nextStyle?.right as number));
    }

    return toPX(nextStyle?.left as number);
  }, [vertical, direction, nextStyle]);

  // =========================== Motion ===========================
  const onAppearStart = () => {
    if (vertical) {
      return {
        transform: 'translateY(var(--thumb-start-top))',
        height: 'var(--thumb-start-height)',
      };
    }

    return {
      transform: 'translateX(var(--thumb-start-left))',
      width: 'var(--thumb-start-width)',
    };
  };

  const onAppearActive = () => {
    if (vertical) {
      return {
        transform: 'translateY(var(--thumb-active-top))',
        height: 'var(--thumb-active-height)',
      };
    }

    return {
      transform: 'translateX(var(--thumb-active-left))',
      width: 'var(--thumb-active-width)',
    };
  };

  const onVisibleChanged = () => {
    setPrevStyle(null);
    setNextStyle(null);
    onMotionEnd();
  };

  // =========================== Render ===========================
  // No need motion when nothing exist in queue
  if (!prevStyle || !nextStyle) {
    return null;
  }

  return (
    <CSSMotion
      visible
      motionName={motionName}
      motionAppear
      onAppearStart={onAppearStart}
      onAppearActive={onAppearActive}
      onVisibleChanged={onVisibleChanged}
    >
      {({ className: motionClassName, style: motionStyle }, ref) => {
        const mergedStyle = {
          ...motionStyle,
          '--thumb-start-left': thumbStart,
          '--thumb-start-width': toPX(prevStyle?.width),
          '--thumb-active-left': thumbActive,
          '--thumb-active-width': toPX(nextStyle?.width),
          '--thumb-start-top': thumbStart,
          '--thumb-start-height': toPX(prevStyle?.height),
          '--thumb-active-top': thumbActive,
          '--thumb-active-height': toPX(nextStyle?.height),
        } as React.CSSProperties;

        // It's little ugly which should be refactor when @umi/test update to latest jsdom
        const motionProps = {
          ref: composeRef(thumbRef, ref),
          style: mergedStyle,
          className: classNames(`${prefixCls}-thumb`, motionClassName),
        };

        if (process.env.NODE_ENV === 'test') {
          (motionProps as any)['data-test-style'] = JSON.stringify(mergedStyle);
        }

        return <div {...motionProps} />;
      }}
    </CSSMotion>
  );
}