import { MutableRefObject } from 'react';

import { MenuDirection } from '../types';
import { getPositionHelpers } from './getPositionHelpers';
import { placeArrowVertical } from './placeArrowVertical';

export interface placeLeftorRightParams {
  anchorRect: DOMRect;
  placeLeftorRightY: number;
  placeLeftX: number;
  placeRightX: number;
  arrowRef: MutableRefObject<HTMLElement | null>;
  arrow?: boolean;
  direction: MenuDirection;
  position: 'auto' | 'anchor' | 'initial';
}

export const placeLeftorRight = (
  props: ReturnType<typeof getPositionHelpers> & placeLeftorRightParams,
): { arrowY: number | undefined; x: number; y: number; computedDirection: MenuDirection } => {
  const {
    anchorRect,
    containerRect,
    menuRect,
    placeLeftorRightY,
    placeLeftX,
    placeRightX,
    getLeftOverflow,
    getRightOverflow,
    confineHorizontally,
    confineVertically,
    arrowRef,
    arrow,
    direction,
    position,
  } = props;
  let computedDirection = direction;
  let y = placeLeftorRightY;
  if (position !== 'initial') {
    y = confineVertically(y);
    if (position === 'anchor') {
      // restrict menu to the edge of anchor element
      y = Math.min(y, anchorRect.bottom - containerRect.top);
      y = Math.max(y, anchorRect.top - containerRect.top - menuRect.height);
    }
  }

  let x, leftOverflow, rightOverflow;
  if (computedDirection === 'left') {
    x = placeLeftX;

    if (position !== 'initial') {
      // if menu overflows to the left,
      // try to reposition it to the right of the anchor.
      leftOverflow = getLeftOverflow(x);
      if (leftOverflow < 0) {
        // if menu overflows to the right after repositioning,
        // choose a side which has less overflow
        rightOverflow = getRightOverflow(placeRightX);
        if (rightOverflow <= 0 || -leftOverflow > rightOverflow) {
          x = placeRightX;
          computedDirection = 'right';
        }
      }
    }
  } else {
    // Opposite logic to the 'left' direction above
    x = placeRightX;

    if (position !== 'initial') {
      rightOverflow = getRightOverflow(x);
      if (rightOverflow > 0) {
        leftOverflow = getLeftOverflow(placeLeftX);
        if (leftOverflow >= 0 || -leftOverflow < rightOverflow) {
          x = placeLeftX;
          computedDirection = 'left';
        }
      }
    }
  }

  if (position === 'auto') x = confineHorizontally(x);
  const arrowY = arrow
    ? placeArrowVertical({
        menuY: y,
        arrowRef,
        anchorRect,
        containerRect,
        menuRect,
      })
    : undefined;
  return { arrowY, x, y, computedDirection };
};