/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.apache.myfaces.tobago.internal.component;
  
  import org.apache.myfaces.tobago.component.RendererTypes;
  import org.apache.myfaces.tobago.component.Tags;
  import org.apache.myfaces.tobago.component.Visual;
  import org.apache.myfaces.tobago.layout.AlignItems;
  import org.apache.myfaces.tobago.layout.Measure;
  import org.apache.myfaces.tobago.layout.MeasureList;
  import org.apache.myfaces.tobago.util.ComponentUtils;
  
  import javax.faces.component.UIComponent;
  import javax.faces.context.FacesContext;
  import javax.faces.event.ComponentSystemEvent;
  import javax.faces.event.ListenerFor;
  import javax.faces.event.PostAddToViewEvent;
  
  /**
   * {@link org.apache.myfaces.tobago.internal.taglib.component.FlexLayoutTagDeclaration}
   *
   * @since 3.0.0
   */
  @ListenerFor(systemEventClass = PostAddToViewEvent.class)
  public abstract class AbstractUIFlexLayout extends AbstractUILayoutBase {
  
    public static final String COMPONENT_FAMILY = "org.apache.myfaces.tobago.FlexLayout";
  
    @Override
    public void processEvent(final ComponentSystemEvent event) {
  
      if (event instanceof PostAddToViewEvent) {
        final FacesContext facesContext = getFacesContext();
  
        final boolean horizontal = isHorizontal();
  
        MeasureList tokens = horizontal ? getColumns() : getRows();
        if (tokens == null) {
          tokens = new MeasureList();
          tokens.add(Measure.AUTO);
        }
  
        if (tokens.getSize() > 0) {
          int i = 0;
  
          for (final UIComponent child : getChildren()) {
            if (child instanceof Visual) {
              if (i >= tokens.getSize()) {
                i = 0;
              }
              final Measure token = tokens.get(i++);
              final Measure.Unit unit = token.getUnit();
              if (unit != Measure.Unit.AUTO) {
                AbstractUIStyle style = ComponentUtils.findChild(child, AbstractUIStyle.class);
                if (style == null) {
                  style = (AbstractUIStyle) facesContext.getApplication().createComponent(
                      facesContext, Tags.style.componentType(), RendererTypes.Style.name());
                  style.setTransient(true);
                  child.getChildren().add(style);
                }
                if (unit == Measure.Unit.FR) {
                  final float factor = token.getValue();
                  style.setFlexGrow(factor);
                  style.setFlexShrink(0);
                  style.setFlexBasis(Measure.ZERO);
  //                style.setFlexBasis(Measure.AUTO); // is unbalanced when mixing e.g. <p> with <textarea>
                } else {
                  if (horizontal) {
                    style.setWidth(token);
                  } else {
                    style.setHeight(token);
                  }
                }
              }
            }
          }
        }
      }
    }
  
    public abstract MeasureList getColumns();
  
   public abstract MeasureList getRows();
 
   public abstract AlignItems getAlignItems();
 
   public boolean isHorizontal() {
     return getRows() == null;
   }
 }