/**********************************************
    * Copyright (C) 2010 Lukas Laag
    * This file is part of lib-gwt-svg.
    * 
    * libgwtsvg is free software: you can redistribute it and/or modify
    * it under the terms of the GNU Lesser General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    * 
   * libgwtsvg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU Lesser General Public License for more details.
   * 
   * You should have received a copy of the GNU Lesser General Public License
   * along with libgwtsvg.  If not, see http://www.gnu.org/licenses/
   **********************************************/
  package com.google.gwt.uibinder.elementparsers;
  
  import org.vectomatic.dom.svg.ui.SVGWidget;
  import org.w3c.dom.Element;
  import org.w3c.dom.Node;
  
  import com.google.gwt.core.ext.UnableToCompleteException;
  import com.google.gwt.core.ext.typeinfo.JClassType;
  import com.google.gwt.uibinder.rebind.FieldManager;
  import com.google.gwt.uibinder.rebind.FieldWriter;
  import com.google.gwt.uibinder.rebind.UiBinderWriter;
  import com.google.gwt.uibinder.rebind.XMLElement;
  
  public class SvgFieldInterpreter implements XMLElement.Interpreter<String> {
  
  	private final UiBinderWriter writer;
  	private final String ancestorExpression;
  	private final Element root;
  
  	public SvgFieldInterpreter(UiBinderWriter writer, String ancestorExpression, Element root) {
  		this.writer = writer;
  		this.ancestorExpression = ancestorExpression;
  		this.root = root;
  	}
  
  	public String interpretElement(XMLElement elem) throws UnableToCompleteException {
  		String fieldName = writer.declareFieldIfNeeded(elem);
  		if (fieldName != null) {
  			JClassType type = writer.findFieldType(elem);
  			StringBuilder builder = new StringBuilder();
  			builder.append("(");
  			builder.append(type.getQualifiedSourceName());
  			builder.append(")");
  			builder.append(SVGWidget.class.getName());
  			builder.append(".getUiBinderField(");
  		    FieldManager fieldManager = writer.getFieldManager();
  			builder.append(fieldManager.convertFieldToGetter(ancestorExpression));
  			builder.append(".getSvgElement().getElement(), \"");
  			builder.append(getXpath(elem.getElement()));
  			builder.append("\")");
  			FieldWriter ancestorWriter = fieldManager.require(ancestorExpression);
  			ancestorWriter.setBuildPrecedence(1 + ancestorWriter.getBuildPrecedence());
  		    writer.setFieldInitializer(fieldName, builder.toString());
  //		    writer.addInitStatement(
  //		        "%s = (" + type.getQualifiedSourceName() + ")" + SVGWidget.class.getName() + ".getUiBinderField(%s, \"%s\");",
  //		        fieldName, ancestorExpression, getXpath(elem.getElement()));
  		    return null;
  		}
  
  		/*
  		 * Return null because we don't want to replace the dom element with any
  		 * particular string (though we may have consumed its id or gwt:field)
  		 */
  		return null;
  	}
  	
  	private String getXpath(Element element) {
  		StringBuilder buffer = new StringBuilder();
  		while (!root.isSameNode(element)) {
  			int index = 1;
  			Node sibling = element.getPreviousSibling();
  			while (sibling != null) {
  				if (sibling.getNodeType() == Node.ELEMENT_NODE) {
  					index++;
  				}
  				sibling = sibling.getPreviousSibling();
  			}
  			buffer.insert(0, "/*[" + index + "]");
  			Node node = element.getParentNode();
  			while (node.getNodeType() != Node.ELEMENT_NODE) {
  				node = node.getParentNode();
  			}
  			element = (Element)node;
  		}
  		buffer.insert(0, ".");
  		return buffer.toString();
  	}
  }