source: branches/HeuristicLab.Problems.GrammaticalOptimization/SharpVectorCss/Css/CssXmlElement.cs @ 13918

using System;
using System.Xml;

using SharpVectors.Dom.Stylesheets;

namespace SharpVectors.Dom.Css
{
  public delegate void NodeChangeHandler(Object src, XmlNodeChangedEventArgs args);
  public delegate void CssChangeHandler();
  
  public class CssXmlElement : Element, IElementCssInlineStyle
  {
    #region Constructors

    public CssXmlElement(string prefix, string localname, string ns, 
            CssXmlDocument doc) : base(prefix, localname, ns, doc) 
    {
    }

    #endregion

    #region Style attribute

    private ICssStyleDeclaration style;

    public ICssStyleDeclaration Style
    {
      get
      {
        if(style == null)
        {
          style = new CssStyleDeclaration(GetAttribute("style", String.Empty), null, false, CssStyleSheetType.Inline);
        }
        return style;
      }
    }

    #endregion

    #region GetComputedStyle
    
        protected ICssStyleDeclaration cachedCSD;
    
        public virtual ICssStyleDeclaration GetComputedStyle(string pseudoElt)
    {
      if(cachedCSD == null)
      {
        CssCollectedStyleDeclaration csd = new CssCollectedStyleDeclaration(this);
        MediaList currentMedia = OwnerDocument.Media;

        if(OwnerDocument.UserAgentStyleSheet != null)
        {
          OwnerDocument.UserAgentStyleSheet.GetStylesForElement(this, pseudoElt, currentMedia, csd);
        }
        ((StyleSheetList)OwnerDocument.StyleSheets).GetStylesForElement(this, pseudoElt, csd);

        ((CssStyleDeclaration)Style).GetStylesForElement(csd, 0);

        if(OwnerDocument.UserStyleSheet != null)
        {
          OwnerDocument.UserStyleSheet.GetStylesForElement(this, pseudoElt, currentMedia, csd);
        }

        cachedCSD = csd;
      }
      return cachedCSD;
    }

    public virtual string GetComputedStringValue(string propertyName, string pseudoElt)
    {
      ICssStyleDeclaration csd = GetComputedStyle(pseudoElt);
      return csd.GetPropertyValue(propertyName);

    }

    public virtual ICssValue GetComputedCssValue(string propertyName, string pseudoElt)
    {
      ICssStyleDeclaration csd = GetComputedStyle(pseudoElt);
      return csd.GetPropertyCssValue(propertyName);

    }

    #endregion

    #region OwnerDocument

    public new CssXmlDocument OwnerDocument
    {
      get
      {
        return (CssXmlDocument)base.OwnerDocument;
      }
    }

    #endregion

    #region Supports

    public override bool Supports(string feature, string version)
    {
      if ((feature == "StyleSheets" || feature == "CSS" ) && version == "2.0")
      {
        return true;
      }
            
      return base.Supports(feature, version);
    }

    #endregion

    #region Update handling
    public virtual void CssInvalidate()
    {
      // TODO: why is this being called during load?
      foreach(XmlNode child in ChildNodes)
      {
        if (child is CssXmlElement)
         ((CssXmlElement)child).CssInvalidate();
      }

      // Kill the cache
      cachedCSD = null;
      
      // Notify
      FireCssChange();
    }

    /// <summary>
    /// Called when this element is changing in one of the following ways
    /// <list type="">
    /// <item>Text child added/removed/changed</item>
    /// <item>Element moved in the tree</item>
    /// </list>
    /// </summary>
    public virtual void ElementChange(Object src, XmlNodeChangedEventArgs args)
    {
      // Invalidate the CSS, the cascade for the CSS heirarchy will need to be recomputed
      CssInvalidate();  
      
      // Notify any listeners
      FireElementChange(src, args);
      FireParentNodeChange(src, args, false);
      FireChildNodeChange(src, args, false);
    }
    
    /// <summary>
    /// Called when any parent element is changing. If an element is moved the CSS heirarchy for that element 
    /// will need to change.
    /// </summary>
    public virtual void ParentNodeChange(Object src, XmlNodeChangedEventArgs args)
    {
      FireParentNodeChange(src, args, true);
    }

    /// <summary>
    /// Called when any attribute is changing. This is typically triggered by calls to 
    /// setAttribute() and should only be called from the CssXmlDocument.
    /// </summary>
    /// <see cref="CssXmlDocument"/>
    public virtual void AttributeChange(Object src, XmlNodeChangedEventArgs args)
    {
      // Invalidate the CSS, the cascade for the CSS heirarchy will need to be recomputed
      // We do this before and after the change because we need to invalidate the old and new locations
      CssInvalidate();  

      XmlAttribute attribute = src as XmlAttribute;

      if(attribute != null)
      {
        HandleAttributeChange(attribute);
      }
    
      // Notify any listeners
      FireAttributeChange(src, args);
      FireParentNodeChange(src, args, false);
      FireChildNodeChange(src, args, false);

      // Invalidate the CSS, the cascade for the CSS heirarchy will need to be recomputed
      CssInvalidate();  
    }

    /// <summary>
    /// This function allows each element to handle it's own behaviors for
    /// attribute changing. By default, the cached computed style is invalidated
    /// because most attributes refer to style properties.
    /// </summary>
    /// <param name="attribute">The attribute that is changing.</param>
    public virtual void HandleAttributeChange(XmlAttribute attribute) 
    {
      if(attribute.NamespaceURI.Length == 0)
      {
        switch (attribute.LocalName)
        {
          case "style":
            style = null;
            break;
        }
      }             
    }

    /// <summary>
    /// Called when any child node is changing. If an element is moved the CSS heirarchy for that element 
    /// will need to change. This is mainly useful when one of the child nodes parent is a 
    /// referenced node (for example in a &lt;use&gt; element.
    /// </summary>
    public virtual void ChildNodeChange(Object src, XmlNodeChangedEventArgs args)
    {
      FireChildNodeChange(src, args, true);
    }

    protected void FireCssChange() 
    {
      if (cssChangeHandler != null)
      {
        cssChangeHandler();
      }
    }

    protected void FireAttributeChange(Object src, XmlNodeChangedEventArgs args) 
    {
      if (attributeChangeHandler != null)
      {
        attributeChangeHandler(src, args);
      }
    }

    protected void FireElementChange(Object src, XmlNodeChangedEventArgs args) 
    {
      if (elementChangeHandler != null)
      {
        elementChangeHandler(src, args);
      }
    }

    protected void FireParentNodeChange(Object src, XmlNodeChangedEventArgs args, bool fireEvent)
    {
      if (fireEvent && parentNodeChangeHandler != null)
      {
        parentNodeChangeHandler(src, args);
      }

      foreach(XmlNode child in ChildNodes)
      {
        if (child.NodeType != XmlNodeType.Element) continue;
        
        CssXmlElement cssChild = child as CssXmlElement;
        
        if(cssChild != null)
        {
          cssChild.ParentNodeChange(src, args);
        }
      }
    }

    protected void FireChildNodeChange(Object src, XmlNodeChangedEventArgs args, bool fireEvent)
    {
      if (fireEvent && childNodeChangeHandler != null)
      {
        childNodeChangeHandler(src, args);
      }
      
      CssXmlElement cssParent = ParentNode as CssXmlElement;
        
      if(cssParent != null)
      {
        cssParent.ChildNodeChange(src, args);
      }
    }

    public virtual event NodeChangeHandler attributeChangeHandler;
    public virtual event NodeChangeHandler elementChangeHandler;
    public virtual event NodeChangeHandler parentNodeChangeHandler;
    public virtual event NodeChangeHandler childNodeChangeHandler;
    public virtual event CssChangeHandler cssChangeHandler;

    #endregion
  }
}