import { useCallback, useEffect, useRef, useState } from 'react';

type Direction = 'horizontal' | 'vertical';

interface UseResizableOptions {
  direction: Direction;
  initialSize: number;
  minSize: number;
  maxSize: number;
  /** If true, the "size" represents the *second* panel (e.g. right panel width). */
  reverse?: boolean;
}

export default function useResizable({
  direction,
  initialSize,
  minSize,
  maxSize,
  reverse = false,
}: UseResizableOptions) {
  const [size, setSize] = useState(initialSize);
  const [isDragging, setIsDragging] = useState(false);
  const startPos = useRef(0);
  const startSize = useRef(0);

  const onMouseDown = useCallback(
    (e: React.MouseEvent) => {
      e.preventDefault();
      setIsDragging(true);
      startPos.current = direction === 'horizontal' ? e.clientY : e.clientX;
      startSize.current = size;
    },
    [direction, size],
  );

  useEffect(() => {
    if (!isDragging) return;

    const onMouseMove = (e: MouseEvent) => {
      const currentPos = direction === 'horizontal' ? e.clientY : e.clientX;
      const delta = currentPos - startPos.current;
      const adjust = reverse ? -delta : delta;
      const next = Math.min(maxSize, Math.max(minSize, startSize.current + adjust));
      setSize(next);
    };

    const onMouseUp = () => setIsDragging(false);

    document.addEventListener('mousemove', onMouseMove);
    document.addEventListener('mouseup', onMouseUp);
    document.body.style.cursor = direction === 'horizontal' ? 'row-resize' : 'col-resize';
    document.body.style.userSelect = 'none';

    return () => {
      document.removeEventListener('mousemove', onMouseMove);
      document.removeEventListener('mouseup', onMouseUp);
      document.body.style.cursor = '';
      document.body.style.userSelect = '';
    };
  }, [isDragging, direction, minSize, maxSize, reverse]);

  return { size, isDragging, onMouseDown };
}