// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
/*++
                                                                              
                                                              
                                                                              
    Abstract:
        This file contains the definition  and implementation
        for the XpsResource class.  This class acts as the
        base class for all resources that can be added to a
        Xps package.
                
 
--*/
using System.IO;
using System.IO.Packaging;
 
namespace System.Windows.Xps.Packaging
{
    /// <summary>
    /// Base class for all Xps Resources
    /// </summary>
    /// <exception cref="ArgumentNullException">part is null.</exception>
    public class XpsResource : XpsPartBase, INode, IDisposable
    {
        #region Constructors
 
        internal
        XpsResource(
            XpsManager    xpsManager,
            INode           parent,
            PackagePart     part
            )
            : base(xpsManager)
        {
            ArgumentNullException.ThrowIfNull(part);
 
            this.Uri = part.Uri;
 
            _parentNode = parent;
            _metroPart = part;
 
            _partEditor = new PartEditor(_metroPart);
        }
 
        #endregion Constructors
 
        #region Public methods
 
        /// <summary>
        /// This method retrieves the relative Uri for this resource
        /// based on a supplied absolute resource.
        /// </summary>
        /// <param name="inUri">
        /// Absolute Uri used for conversion.
        /// </param>
        /// <returns>
        /// A Uri to this resource relative to the supplied resource.
        /// </returns>
        public
        Uri
        RelativeUri(
            Uri inUri
            )
        {
            ArgumentNullException.ThrowIfNull(inUri);
            return new Uri(XpsManager.MakeRelativePath(this.Uri, inUri), UriKind.Relative);
        }
 
        /// <summary>
        /// This method retrieves a reference to the Stream that can
        /// be used to read and/or write data to/from this resource
        /// within the Metro package.
        /// </summary>
        /// <returns>
        /// A reference to a writable/readable stream.
        /// </returns>
        public
        virtual
        Stream
        GetStream(
            )
        {
            return _partEditor.DataStream;
        }
 
        /// <summary>
        /// This method commits all changes for this resource
        /// </summary>
        public
        void
        Commit(
            )
        {
            CommitInternal();
        }
 
        /// <summary>
        /// This method closes this resource part and frees all
        /// associated memory.
        /// </summary>
        internal
        override
        void
        CommitInternal()
        {
            if (_partEditor != null)
            {
                _partEditor.Close();
 
                _partEditor = null;
                _metroPart = null;
                _parentNode = null;
            }
        }
 
        #endregion Public methods
 
        #region Private data
 
        private INode _parentNode;
        private PackagePart _metroPart;
 
        private PartEditor _partEditor;
 
        #endregion Private data
 
        #region INode implementation
 
        void
        INode.Flush(
            )
        {
            //
            // Flush the part editor
            //
            _partEditor?.Flush();
        }
 
        void
        INode.CommitInternal()
        {
            CommitInternal();
        }
 
 
        PackagePart
        INode.GetPart(
            )
        {
            return _metroPart;
        }
 
        #endregion INode implementation
 
        #region IDisposable implementation
 
        void
        IDisposable.Dispose()
        {
            _partEditor?.Close();
 
            GC.SuppressFinalize(this);
        }
 
        #endregion IDisposable implementation
    }
}