//------------------------------------------------------------------------------
// <copyright file="XmlText.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>                                                                
// <owner current="true" primary="true">Microsoft</owner>
//------------------------------------------------------------------------------

namespace System.Xml 
{
    using System;
    using System.Text;
    using System.Diagnostics;
    using System.Xml.XPath;

    // Represents the text content of an element or attribute.
    public class XmlText : XmlCharacterData {
        internal XmlText( string strData ): this( strData, null ) {
        }

        protected internal XmlText( string strData, XmlDocument doc ): base( strData, doc ) {
        }

        // Gets the name of the node.
        public override String Name { 
            get { 
                return OwnerDocument.strTextName;
            }
        }

        // Gets the name of the current node without the namespace prefix.
        public override String LocalName { 
            get { 
                return OwnerDocument.strTextName;
            }
        }

        // Gets the type of the current node.
        public override XmlNodeType NodeType {
            get { 
                return XmlNodeType.Text;
            }
        }

        public override XmlNode ParentNode {
            get {
                switch (parentNode.NodeType) {
                    case XmlNodeType.Document:
                        return null;
                    case XmlNodeType.Text:
                    case XmlNodeType.CDATA:
                    case XmlNodeType.Whitespace:
                    case XmlNodeType.SignificantWhitespace:
                        XmlNode parent = parentNode.parentNode;
                        while (parent.IsText) {
                            parent = parent.parentNode;
                        }
                        return parent; 
                    default:
                        return parentNode;
                }
            }
        }

        // Creates a duplicate of this node.
        public override XmlNode CloneNode(bool deep) {
            Debug.Assert( OwnerDocument != null );
            return OwnerDocument.CreateTextNode( Data );
        }

        public override String Value {
            get { 
                return Data;
            }

            set { 
                Data = value;
                XmlNode parent = parentNode;
                if ( parent != null && parent.NodeType == XmlNodeType.Attribute ) {
                    XmlUnspecifiedAttribute attr = parent as XmlUnspecifiedAttribute;
                    if ( attr != null && !attr.Specified ) {
                        attr.SetSpecified( true );
                    }
                }
            }
        }

        // Splits the node into two nodes at the specified offset, keeping
        // both in the tree as siblings.
        public virtual XmlText SplitText(int offset) {
            XmlNode parentNode = this.ParentNode;
            int length = this.Length;
            if( offset > length )
                throw new ArgumentOutOfRangeException( "offset" );
            //if the text node is out of the living tree, throw exception.
            if ( parentNode == null )
                throw new InvalidOperationException(Res.GetString(Res.Xdom_TextNode_SplitText)); 
            
            int count = length - offset;
            String splitData = Substring(offset, count);
            DeleteData(offset, count);
            XmlText newTextNode = OwnerDocument.CreateTextNode(splitData);
            parentNode.InsertAfter(newTextNode, this);
            return newTextNode;
        }

        // Saves the node to the specified XmlWriter.
        public override void WriteTo(XmlWriter w) {
            w.WriteString(Data);
        }

        // Saves all the children of the node to the specified XmlWriter.
        public override void WriteContentTo(XmlWriter w) {
            // Intentionally do nothing
        }

        internal override XPathNodeType XPNodeType { 
            get { 
                return XPathNodeType.Text; 
            } 
        }

        internal override bool IsText {
            get {
                return true;
            }
        }

        public override XmlNode PreviousText {
            get {
                if (parentNode.IsText) {
                    return parentNode;
                }
                return null;
            }
        }
    }
}