svg-layout-designer-react/src/Components/Editor/Behaviors/PushBehaviors.ts

import { IContainerModel } from '../../../Interfaces/IContainerModel';
import { Orientation } from '../../../Interfaces/Orientation';
import { ReversePairwise } from '../../../utils/itertools';
import { Flex } from './FlexBehaviors';

/**
 * Try to push the siblings
 * @param container
 * @returns
 */
export function ApplyPush(container: IContainerModel, parent: IContainerModel): IContainerModel {
  if (parent.children.length <= 1) {
    return container;
  }

  const children = parent.children;
  const isHorizontal = parent.properties.orientation === Orientation.Horizontal;

  if (isHorizontal) {
    PushContainersHorizontally(container, children);
  } else {
    PushContainersVertically(container, children);
  }

  Flex(container, parent);
  return container;
}

export function PushContainersHorizontally(container: IContainerModel, children: IContainerModel[]): IContainerModel {
  const prevIndex = children.length - 2;
  const prev: IContainerModel = children[prevIndex];
  const isOverlapping = prev.properties.x + prev.properties.width > container.properties.x;
  if (!isOverlapping) {
    return container;
  }

  // find hole
  let lastContainer: IContainerModel | null = null;
  let space: number = 0;

  while (space.toFixed(2) < container.properties.width.toFixed(2)) {
    // FIXME: possible infinite loop due to floating point
    // FIXME: A fix was applied using toFixed(2).
    // FIXME: A coverture check must be done to ensure that all scenarios are covered

    const it = ReversePairwise<IContainerModel>(children.filter(child => child !== container));

    for (const { cur, next } of it) {
      const hasSpaceBetween = next.properties.x + next.properties.width < cur.properties.x;
      if (hasSpaceBetween) {
        lastContainer = cur;
        space = cur.properties.x - (next.properties.x + next.properties.width);
        break;
      }
    }

    if (lastContainer === null) {
      // no space between
      break;
    }

    const indexLastContainer = children.indexOf(lastContainer);
    for (let i = indexLastContainer; i <= children.length - 2; i++) {
      const sibling = children[i];
      sibling.properties.x -= space;
    }
  }

  const hasNoSpaceBetween = lastContainer === null;
  if (hasNoSpaceBetween) {
    // test gap between the left of the parent and the first container
    space = children[0].properties.x;
    if (space > 0) {
      for (let i = 0; i <= children.length - 2; i++) {
        const sibling = children[i];
        sibling.properties.x -= space;
      }
      return container;
    }
  }

  return container;
}

export function PushContainersVertically(container: IContainerModel, children: IContainerModel[]): IContainerModel {
  const prevIndex = children.length - 2;
  const prev: IContainerModel = children[prevIndex];
  const isOverlapping = prev.properties.y + prev.properties.height > container.properties.y;
  if (!isOverlapping) {
    return container;
  }

  // find hole
  let lastContainer: IContainerModel | null = null;
  let space: number = 0;

  while (space.toFixed(2) < container.properties.height.toFixed(2)) {
    // FIXME: possible infinite loop due to floating point
    // FIXME: A fix was applied using toFixed(2).
    // FIXME: A coverture check must be done to ensure that all scenarios are covered

    const it = ReversePairwise<IContainerModel>(children.filter(child => child !== container));

    for (const { cur, next } of it) {
      const hasSpaceBetween = next.properties.y + next.properties.height < cur.properties.y;
      if (hasSpaceBetween) {
        lastContainer = cur;
        space = cur.properties.y - (next.properties.y + next.properties.height);
        break;
      }
    }

    if (lastContainer === null) {
      // no space between
      break;
    }

    const indexLastContainer = children.indexOf(lastContainer);
    for (let i = indexLastContainer; i <= children.length - 2; i++) {
      const sibling = children[i];
      sibling.properties.y -= space;
    }
  }

  const hasNoSpaceBetween = lastContainer === null;
  if (hasNoSpaceBetween) {
    // test gap between the left of the parent and the first container
    space = children[0].properties.y;
    if (space > 0) {
      for (let i = 0; i <= children.length - 2; i++) {
        const sibling = children[i];
        sibling.properties.y -= space;
      }
      return container;
    }
  }

  return container;
}