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 * modification, are permitted provided that the following conditions are met:
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 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
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 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Reflection;
using System.Xml;
using log4net;
using OpenMetaverse;
using OpenSim.Framework;
using OpenSim.Region.Framework.Interfaces;
using OpenSim.Region.Framework.Scenes;

namespace OpenSim.Region.Framework.Scenes.Serialization
{
    /// <summary>
    /// Serialize and deserialize coalesced scene objects.
    /// </summary>
    public class CoalescedSceneObjectsSerializer
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        /// <summary>
        /// Serialize coalesced objects to Xml
        /// </summary>
        /// <param name="coa"></param>
        /// <param name="doScriptStates">
        /// If true then serialize script states.  This will halt any running scripts
        /// </param>
        /// <returns></returns>
        public static string ToXml(CoalescedSceneObjects coa)
        {
            return ToXml(coa, true);
        }

        /// <summary>
        /// Serialize coalesced objects to Xml
        /// </summary>
        /// <param name="coa"></param>
        /// <param name="doScriptStates">
        /// If true then serialize script states.  This will halt any running scripts
        /// </param>
        /// <returns></returns>
        public static string ToXml(CoalescedSceneObjects coa, bool doScriptStates)
        {
            using (StringWriter sw = new StringWriter())
            {
                using (XmlTextWriter writer = new XmlTextWriter(sw))
                {
                    Vector3 size;

                    List<SceneObjectGroup> coaObjects = coa.Objects;

//                    m_log.DebugFormat(
//                        "[COALESCED SCENE OBJECTS SERIALIZER]: Writing {0} objects for coalesced object",
//                        coaObjects.Count);

                    // This is weak - we're relying on the set of coalesced objects still being identical
                    Vector3[] offsets = coa.GetSizeAndOffsets(out size);

                    writer.WriteStartElement("CoalescedObject");

                    writer.WriteAttributeString("x", size.X.ToString(Culture.FormatProvider));
                    writer.WriteAttributeString("y", size.Y.ToString(Culture.FormatProvider));
                    writer.WriteAttributeString("z", size.Z.ToString(Culture.FormatProvider));

                    // Embed the offsets into the group XML
                    for (int i = 0; i < coaObjects.Count; i++)
                    {
                        SceneObjectGroup obj = coaObjects[i];

//                        m_log.DebugFormat(
//                            "[COALESCED SCENE OBJECTS SERIALIZER]: Writing offset for object {0}, {1}",
//                            i, obj.Name);

                        writer.WriteStartElement("SceneObjectGroup");
                        writer.WriteAttributeString("offsetx", offsets[i].X.ToString(Culture.FormatProvider));
                        writer.WriteAttributeString("offsety", offsets[i].Y.ToString(Culture.FormatProvider));
                        writer.WriteAttributeString("offsetz", offsets[i].Z.ToString(Culture.FormatProvider));

                        SceneObjectSerializer.ToOriginalXmlFormat(obj, writer, doScriptStates);

                        writer.WriteEndElement(); // SceneObjectGroup
                    }

                    writer.WriteEndElement(); // CoalescedObject
                }

                string output = sw.ToString();

//                Console.WriteLine(output);

                return output;
            }
        }

        public static bool TryFromXml(string xml, out CoalescedSceneObjects coa)
        {
//            m_log.DebugFormat("[COALESCED SCENE OBJECTS SERIALIZER]: TryFromXml() deserializing {0}", xml);

            coa = null;

            try
            {
                // Quickly check if this is a coalesced object, without fully parsing the XML
                using (StringReader sr = new StringReader(xml))
                {
                    using (XmlTextReader reader = new XmlTextReader(sr))
                    {
                        reader.ProhibitDtd = true;

                        reader.MoveToContent(); // skip possible xml declaration

                        if (reader.Name != "CoalescedObject")
                        {
    //                        m_log.DebugFormat(
    //                            "[COALESCED SCENE OBJECTS SERIALIZER]: TryFromXml() root element was {0} so returning false",
    //                            reader.Name);

                            return false;
                        }
                    }
                }

                XmlDocument doc = new XmlDocument();
                doc.XmlResolver=null;
                doc.LoadXml(xml);
                XmlElement e = (XmlElement)doc.SelectSingleNode("/CoalescedObject");
                if (e == null)
                    return false;

                coa = new CoalescedSceneObjects(UUID.Zero);

                XmlNodeList groups = e.SelectNodes("SceneObjectGroup");
                int i = 0;

                foreach (XmlNode n in groups)
                {
                    SceneObjectGroup so = SceneObjectSerializer.FromOriginalXmlFormat(n.OuterXml);
                    if (so != null)
                    {
                        coa.Add(so);
                    }
                    else
                    {
                        // XXX: Possibly we should fail outright here rather than continuing if a particular component of the
                        // coalesced object fails to load.
                        m_log.WarnFormat(
                            "[COALESCED SCENE OBJECTS SERIALIZER]: Deserialization of xml for component {0} failed.  Continuing.",
                            i);
                    }

                    i++;
                }
            }
            catch (Exception e)
            {
                m_log.Error("[COALESCED SCENE OBJECTS SERIALIZER]: Deserialization of xml failed ",  e);
                Util.LogFailedXML("[COALESCED SCENE OBJECTS SERIALIZER]:", xml);
                return false;
            }

            return true;
        }
    }
}
