/**********************************************
    * Copyright (C) 2011 Lukas Laag
    * This file is part of svgreal.
    * 
    * svgreal is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    * 
   * svgreal 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 General Public License for more details.
   * 
   * You should have received a copy of the GNU General Public License
   * along with svgreal.  If not, see http://www.gnu.org/licenses/
   **********************************************/
  package org.vectomatic.svg.edit.client.model;
  
  import org.vectomatic.dom.svg.OMSVGStyle;
  import org.vectomatic.dom.svg.impl.SVGElement;
  import org.vectomatic.svg.edit.client.command.IFactoryInstantiator;
  
  /**
   * Metadata class based on CSS properties
   * @author laaglu
   * @param <T>
   * The CSS property type
   */
  public class CssMetadata<T> extends MetadataBase<T, SVGElement>  {
  	protected IConverter<String, T> converter;
  	protected T defaultValue;
  	
  	public CssMetadata(String propertyName, String description, IFieldFactory fieldFactory, IConverter<String, T> converter, T defaultValue, IFactoryInstantiator<?> factory, IValidator<T, SVGElement> validator) {
  		super(propertyName, description, fieldFactory, factory, validator);
  		this.defaultValue = defaultValue;
  		this.converter = converter;
  	}
  	
  	@Override
  	public T get(SVGElement element) {
  		OMSVGStyle style = element.getStyle().cast();
  		String value = style.getSVGProperty(propertyName);
  		if (value == null || value.length() == 0) {
  			value = element.getAttribute(propertyName);
  		}
  		if (value == null || value.length() == 0) {
  			return defaultValue;
  		}
  		return converter.sourceToDest(value);
  	}
  	
  	@Override
  	public T set(SVGElement element, T value) {
  		String str = converter.destToSource(value);
  		if (str == null || str.length() == 0) {
  			// This is to deal with CSS properties which are inherited
  			// Setting the value to "" or null means the property should
  			// be inherited
  			return remove(element);
  		}
  		OMSVGStyle style = element.getStyle().cast();
  		T oldValue = get(element);
  		style.setSVGProperty(propertyName, str);
  		element.removeAttribute(propertyName);
  		return oldValue;
  	}
  	
  	@Override
  	public T remove(SVGElement element) {
  		OMSVGStyle style = element.getStyle().cast();
  		T oldValue = converter.sourceToDest(style.getSVGProperty(propertyName));
  		style.clearSVGProperty(propertyName);
  		if (oldValue == null) {
  			oldValue = converter.sourceToDest(element.getAttribute(propertyName));
  		}
  		element.removeAttribute(propertyName);
  		return oldValue;
  	}
  	
  	public T getDefaultValue() {
  		return defaultValue;
  	}
  	
  	@Override
  	public String toString() {
  		StringBuilder builder = new StringBuilder("CSSMetadata(");
  		builder.append(propertyName);
  		builder.append(", ");
  		builder.append(propertyName);
  		builder.append(")");
  		return builder.toString();
  	}
  }