/*
    * 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.facelets;
  
  import org.apache.myfaces.tobago.component.Attributes;
  import org.apache.myfaces.tobago.component.Position;
  import org.apache.myfaces.tobago.layout.Measure;
  
  import javax.el.ValueExpression;
  import javax.faces.component.UIComponent;
  import javax.faces.view.facelets.FaceletContext;
  import javax.faces.view.facelets.MetaRule;
  import javax.faces.view.facelets.Metadata;
  import javax.faces.view.facelets.MetadataTarget;
  import javax.faces.view.facelets.TagAttribute;
  
  public class PositionRule extends MetaRule {
    
    public static final PositionRule INSTANCE = new PositionRule();
  
    public Metadata applyRule(String name, TagAttribute attribute, MetadataTarget metadataTarget) {
      if (Attributes.LEFT.equals(name)) {
        return new LeftMapper(attribute);
      }
      if (Attributes.TOP.equals(name)) {
        return new TopMapper(attribute);
      }
      return null;
    }
  
    static final class LeftMapper extends Metadata {
      private final TagAttribute attribute;
  
      LeftMapper(TagAttribute attribute) {
        this.attribute = attribute;
      }
  
      public void applyMetadata(FaceletContext ctx, Object instance) {
        if (attribute.isLiteral()) {
          ((Position) instance).setLeft(Measure.parse(attribute.getValue()));
        } else {
          ValueExpression expression = attribute.getValueExpression(ctx, Object.class);
          ((UIComponent) instance).setValueExpression(Attributes.LEFT, expression);
        }
      }
    }
  
    static final class TopMapper extends Metadata {
      private final TagAttribute attribute;
  
      TopMapper(TagAttribute attribute) {
        this.attribute = attribute;
      }
  
      public void applyMetadata(FaceletContext ctx, Object instance) {
        if (attribute.isLiteral()) {
           ((Position) instance).setTop(Measure.parse(attribute.getValue()));
        } else {
          ValueExpression expression = attribute.getValueExpression(ctx, Object.class);
          ((UIComponent) instance).setValueExpression(Attributes.TOP, expression);
        }
      }
    }
  }