org.dominokit.domino.ui.dialogs.DefaultZIndexManager Maven / Gradle / Ivy

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/*
 * Copyright © 2019 Dominokit
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.dominokit.domino.ui.dialogs;

import static java.util.Objects.isNull;
import static java.util.Objects.nonNull;
import static org.dominokit.domino.ui.utils.ElementsFactory.elements;

import java.util.ArrayList;
import java.util.Deque;
import java.util.LinkedList;
import java.util.List;
import java.util.Optional;
import org.dominokit.domino.ui.config.HasComponentConfig;
import org.dominokit.domino.ui.config.ZIndexConfig;
import org.dominokit.domino.ui.utils.IsPopup;

/**
 * Default implementation of the {@link ZIndexManager} for managing z-index values of popups and
 * modals. It provides utilities for handling stacking order to ensure the correct display of
 * overlay components.
 *
 * Usage:
 *
 * 
 * DefaultZIndexManager.INSTANCE.onPopupOpen(somePopup);
 * 
 */
public class DefaultZIndexManager implements ZIndexManager, HasComponentConfig {

  /** A singleton instance of {@link DefaultZIndexManager}. */
  public static final ZIndexManager INSTANCE = new DefaultZIndexManager();

  private Integer currentZIndex;
  private static Deque> modals = new LinkedList<>();

  private final List listeners = new ArrayList<>();

  /**
   * Calculates and returns the next z-index value.
   *
   * @return the next z-index value
   */
  @Override
  public Integer getNextZIndex() {
    if (isNull(currentZIndex)) {
      this.currentZIndex = getConfig().getInitialZIndex();
    }
    currentZIndex += getConfig().getzIndexIncrement();
    return currentZIndex;
  }

  /**
   * Handler for when a popup is opened. Adjusts z-index values and ensures modals are correctly
   * stacked.
   *
   * @param popup the popup that was opened
   */
  @Override
  public void onPopupOpen(IsPopup popup) {
    if (popup.isModal()) {
      Integer nextZIndex = getNextZIndex();
      ModalBackDrop.INSTANCE.setZIndex(nextZIndex);
      if (!ModalBackDrop.INSTANCE.isAttached()) {
        elements.body().appendChild(ModalBackDrop.INSTANCE);
      }
      modals.push(popup);
    }

    Integer next = getNextZIndex();
    popup.setZIndex(next);
    listeners.forEach(
        listener -> listener.onZIndexChange(new ZIndexListener.ZIndexInfo(popup, modals)));
  }

  /**
   * Handler for when a popup is closed. Adjusts z-index values and updates modal stacking.
   *
   * @param popup the popup that was closed
   */
  @Override
  public void onPopupClose(IsPopup popup) {
    if (popup.isModal()) {
      modals.remove(popup);
      if (!modals.isEmpty()) {
        Integer backdropZIndex = getNextZIndex();
        ModalBackDrop.INSTANCE.setZIndex(backdropZIndex);
        Integer modalZIndex = getNextZIndex();
        modals.peek().setZIndex(modalZIndex);
        listeners.forEach(
            listener ->
                listener.onZIndexChange(new ZIndexListener.ZIndexInfo(modals.peek(), modals)));
      } else {
        ModalBackDrop.INSTANCE.remove();
      }
    }
  }

  /**
   * Returns the top level modal if any.
   *
   * @return an {@link Optional} containing the top level modal, or empty if none exists
   */
  @Override
  public Optional> getTopLevelModal() {
    return Optional.ofNullable(modals.peek());
  }

  /**
   * Adds a listener to be notified of z-index changes.
   *
   * @param listener the {@link ZIndexListener} to add
   */
  @Override
  public void addZIndexListener(ZIndexListener listener) {
    if (nonNull(listener)) {
      listeners.add(listener);
    }
  }

  /**
   * Removes a z-index change listener.
   *
   * @param listener the {@link ZIndexListener} to remove
   */
  @Override
  public void removeZIndexListener(ZIndexListener listener) {
    if (nonNull(listener)) {
      listeners.remove(listener);
    }
  }
}