/*
 * Copyright 2010 Google Inc.
 * 
 * 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 com.google.gwt.uibinder.elementparsers;

import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.core.ext.typeinfo.JClassType;
import com.google.gwt.uibinder.rebind.UiBinderWriter;
import com.google.gwt.uibinder.rebind.XMLElement;

/**
 * Parses {@link com.google.gwt.user.client.ui.AbsolutePanel AbsolutePanel}
 * widgets.
 */
public class AbsolutePanelParser implements ElementParser {

  private static final String AT = "at";

  public void parse(XMLElement elem, String fieldName, JClassType type,
      UiBinderWriter writer) throws UnableToCompleteException {

    // Parse children.
    for (XMLElement child : elem.consumeChildElements()) {
      // Parse position element.
      if (isPositionElement(elem, child)) {
        // Parse position.
        String left = child.consumeRequiredIntAttribute("left");
        String top = child.consumeRequiredIntAttribute("top");
        // Add child widget.
        XMLElement widgetElem = child.consumeSingleChildElement();
        String widgetFieldName = writer.parseElementToField(widgetElem);
        writer.addStatement("%1$s.add(%2$s, %3$s, %4$s);", fieldName,
            widgetFieldName, left, top);
        continue;
      }

      // Parse Widget.
      if (writer.isWidgetElement(child)) {
        String widgetFieldName = writer.parseElementToField(child);
        writer.addStatement("%1$s.add(%2$s);", fieldName, widgetFieldName);
        continue;
      }

      // die
      writer.die(child, "Expecting only <%s:%s> or widget children in %s",
          elem.getPrefix(), AT, elem);
    }
  }

  private boolean isPositionElement(XMLElement parent, XMLElement child) {
    if (!parent.getNamespaceUri().equals(child.getNamespaceUri())) {
      return false;
    }
    if (!AT.equals(child.getLocalName())) {
      return false;
    }
    return true;
  }
}