using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Xml;

using SabreTools.Library.Data;
using SabreTools.Library.DatItems;
using SabreTools.Library.IO;
using SabreTools.Library.Tools;

namespace SabreTools.Library.DatFiles
{
    /// <summary>
    /// Represents parsing and writing of a SofwareList, M1, or MAME XML DAT
    /// </summary>
    internal class SoftwareList : DatFile
    {
        /// <summary>
        /// Constructor designed for casting a base DatFile
        /// </summary>
        /// <param name="datFile">Parent DatFile to copy from</param>
        public SoftwareList(DatFile datFile)
            : base(datFile)
        {
        }

        /// <summary>
        /// Parse an SofwareList XML DAT and return all found games and roms within
        /// </summary>
        /// <param name="filename">Name of the file to be parsed</param>
        /// <param name="indexId">Index ID for the DAT</param>
        /// <param name="keep">True if full pathnames are to be kept, false otherwise (default)</param>
        protected override void ParseFile(
            // Standard Dat parsing
            string filename,
            int indexId,

            // Miscellaneous
            bool keep)
        {
            // Prepare all internal variables
            XmlReader xtr = filename.GetXmlTextReader();

            // If we got a null reader, just return
            if (xtr == null)
                return;

            // Otherwise, read the file to the end
            try
            {
                xtr.MoveToContent();
                while (!xtr.EOF)
                {
                    // We only want elements
                    if (xtr.NodeType != XmlNodeType.Element)
                    {
                        xtr.Read();
                        continue;
                    }

                    switch (xtr.Name)
                    {
                        case "softwarelist":
                            Header.Name = (Header.Name == null ? xtr.GetAttribute("name") ?? string.Empty : Header.Name);
                            Header.Description = (Header.Description == null ? xtr.GetAttribute("description") ?? string.Empty : Header.Description);
                            if (Header.ForceMerging == MergingFlag.None)
                                Header.ForceMerging = xtr.GetAttribute("forcemerging").AsMergingFlag();

                            if (Header.ForceNodump == NodumpFlag.None)
                                Header.ForceNodump = xtr.GetAttribute("forcenodump").AsNodumpFlag();

                            if (Header.ForcePacking == PackingFlag.None)
                                Header.ForcePacking = xtr.GetAttribute("forcepacking").AsPackingFlag();

                            xtr.Read();
                            break;

                        // We want to process the entire subtree of the machine
                        case "software":
                            ReadSoftware(xtr.ReadSubtree(), filename, indexId, keep);

                            // Skip the software now that we've processed it
                            xtr.Skip();
                            break;

                        default:
                            xtr.Read();
                            break;
                    }
                }
            }
            catch (Exception ex)
            {
                Globals.Logger.Warning($"Exception found while parsing '{filename}': {ex}");

                // For XML errors, just skip the affected node
                xtr?.Read();
            }

            xtr.Dispose();
        }

        /// <summary>
        /// Read software information
        /// </summary>
        /// <param name="reader">XmlReader representing a software block</param>
        /// <param name="filename">Name of the file to be parsed</param>
        /// <param name="indexId">Index ID for the DAT</param>
        /// <param name="keep">True if full pathnames are to be kept, false otherwise (default)</param>
        private void ReadSoftware(
            XmlReader reader,

            // Standard Dat parsing
            string filename,
            int indexId,

            // Miscellaneous
            bool keep)
        {
            // If we have an empty software, skip it
            if (reader == null)
                return;

            // Otherwise, add what is possible
            reader.MoveToContent();

            bool containsItems = false;

            // Create a new machine
            MachineType machineType = MachineType.NULL;
            if (reader.GetAttribute("isbios").AsYesNo() == true)
                machineType |= MachineType.Bios;

            if (reader.GetAttribute("isdevice").AsYesNo() == true)
                machineType |= MachineType.Device;

            if (reader.GetAttribute("ismechanical").AsYesNo() == true)
                machineType |= MachineType.Mechanical;

            Machine machine = new Machine
            {
                Name = reader.GetAttribute("name"),
                Description = reader.GetAttribute("name"),
                Supported = reader.GetAttribute("supported").AsSupported(),

                CloneOf = reader.GetAttribute("cloneof") ?? string.Empty,
                Infos = new List<ListXmlInfo>(),
                SharedFeatures = new List<SoftwareListSharedFeature>(),
                DipSwitches = new List<ListXmlDipSwitch>(),

                MachineType = (machineType == MachineType.NULL ? MachineType.None : machineType),
            };

            while (!reader.EOF)
            {
                // We only want elements
                if (reader.NodeType != XmlNodeType.Element)
                {
                    reader.Read();
                    continue;
                }

                // Get the elements from the software
                switch (reader.Name)
                {
                    case "description":
                        machine.Description = reader.ReadElementContentAsString();
                        break;

                    case "year":
                        machine.Year = reader.ReadElementContentAsString();
                        break;

                    case "publisher":
                        machine.Publisher = reader.ReadElementContentAsString();
                        break;

                    case "category":
                        machine.Category = reader.ReadElementContentAsString();
                        break;

                    case "info":
                        var info = new ListXmlInfo();
                        info.Name = reader.GetAttribute("name");
                        info.Value = reader.GetAttribute("value");

                        machine.Infos.Add(info);

                        reader.Read();
                        break;

                    case "sharedfeat":
                        var sharedFeature = new SoftwareListSharedFeature();
                        sharedFeature.Name = reader.GetAttribute("name");
                        sharedFeature.Value = reader.GetAttribute("value");

                        machine.SharedFeatures.Add(sharedFeature);

                        reader.Read();
                        break;

                    case "part": // Contains all rom and disk information
                        containsItems = ReadPart(reader.ReadSubtree(), machine, filename, indexId, keep);

                        // Skip the part now that we've processed it
                        reader.Skip();
                        break;

                    default:
                        reader.Read();
                        break;
                }
            }

            // If no items were found for this machine, add a Blank placeholder
            if (!containsItems)
            {
                Blank blank = new Blank()
                {
                    Source = new Source
                    {
                        Index = indexId,
                        Name = filename,
                    },
                };

                blank.CopyMachineInformation(machine);

                // Now process and add the rom
                ParseAddHelper(blank);
            }
        }

        /// <summary>
        /// Read part information
        /// </summary>
        /// <param name="reader">XmlReader representing a part block</param>
        /// <param name="machine">Machine information to pass to contained items</param>
        /// <param name="filename">Name of the file to be parsed</param>
        /// <param name="indexId">Index ID for the DAT</param>
        /// <param name="keep">True if full pathnames are to be kept, false otherwise (default)</param>
        private bool ReadPart(
            XmlReader reader,
            Machine machine,

            // Standard Dat parsing
            string filename,
            int indexId,

            // Miscellaneous
            bool keep)
        {
            string areaname,
                partname = string.Empty,
                partinterface = string.Empty,
                areaWidth,
                areaEndinaness;
            long? areasize = null;
            var features = new List<SoftwareListFeature>();
            bool containsItems = false;

            while (!reader.EOF)
            {
                // We only want elements
                if (reader.NodeType != XmlNodeType.Element)
                {
                    if (reader.NodeType == XmlNodeType.EndElement && reader.Name == "part")
                    {
                        partname = string.Empty;
                        partinterface = string.Empty;
                        features = new List<SoftwareListFeature>();
                    }

                    if (reader.NodeType == XmlNodeType.EndElement && (reader.Name == "dataarea" || reader.Name == "diskarea"))
                        areasize = null;

                    reader.Read();
                    continue;
                }

                // Get the elements from the software
                switch (reader.Name)
                {
                    case "part":
                        partname = reader.GetAttribute("name");
                        partinterface = reader.GetAttribute("interface");
                        reader.Read();
                        break;

                    case "feature":
                        var feature = new SoftwareListFeature();
                        feature.Name = reader.GetAttribute("name");
                        feature.Value = reader.GetAttribute("value");

                        features.Add(feature);

                        reader.Read();
                        break;

                    case "dataarea":
                        areaname = reader.GetAttribute("name");
                        if (reader.GetAttribute("size") != null)
                        {
                            if (Int64.TryParse(reader.GetAttribute("size"), out long tempas))
                                areasize = tempas;
                        }

                        areaWidth = reader.GetAttribute("width");
                        areaEndinaness = reader.GetAttribute("endianness");

                        containsItems = ReadDataArea(
                            reader.ReadSubtree(),
                            machine,
                            partname,
                            partinterface,
                            features,
                            areaname,
                            areasize,
                            areaWidth,
                            areaEndinaness,
                            filename,
                            indexId,
                            keep);

                        // Skip the dataarea now that we've processed it
                        reader.Skip();
                        break;

                    case "diskarea":
                        areaname = reader.GetAttribute("name");

                        containsItems = ReadDiskArea(
                            reader.ReadSubtree(),
                            machine,
                            partname,
                            partinterface,
                            features,
                            areaname,
                            areasize,
                            filename,
                            indexId,
                            keep);

                        // Skip the diskarea now that we've processed it
                        reader.Skip();
                        break;

                    case "dipswitch":
                        // TODO: Use these dipswitches
                        var dipSwitch = new ListXmlDipSwitch();
                        dipSwitch.Name = reader.GetAttribute("name");
                        dipSwitch.Tag = reader.GetAttribute("tag");
                        dipSwitch.Mask = reader.GetAttribute("mask");

                        // Now read the internal tags
                        ReadDipSwitch(reader.ReadSubtree(), dipSwitch);

                        // Skip the dipswitch now that we've processed it
                        reader.Skip();
                        break;

                    default:
                        reader.Read();
                        break;
                }
            }

            return containsItems;
        }

        /// <summary>
        /// Read dataarea information
        /// </summary>
        /// <param name="reader">XmlReader representing a dataarea block</param>
        /// <param name="machine">Machine information to pass to contained items</param>
        /// <param name="partName">Name of the containing part</param>
        /// <param name="partInterface">Interface of the containing part</param>
        /// <param name="features">List of features from the parent part</param>
        /// <param name="areaName">Name of the containing area</param>
        /// <param name="areaSize">Size of the containing area</param>
        /// <param name="areaWidth">Byte width of the containing area</param>
        /// <param name="areaEndianness">Endianness of the containing area</param>
        /// <param name="filename">Name of the file to be parsed</param>
        /// <param name="indexId">Index ID for the DAT</param>
        /// <param name="keep">True if full pathnames are to be kept, false otherwise (default)</param>
        private bool ReadDataArea(
            XmlReader reader,
            Machine machine,
            string partName,
            string partInterface,
            List<SoftwareListFeature> features,
            string areaName,
            long? areaSize,
            string areaWidth,
            string areaEndianness,

            // Standard Dat parsing
            string filename,
            int indexId,

            // Miscellaneous
            bool keep)
        {
            string key = string.Empty;
            string temptype = reader.Name;
            bool containsItems = false;

            while (!reader.EOF)
            {
                // We only want elements
                if (reader.NodeType != XmlNodeType.Element)
                {
                    reader.Read();
                    continue;
                }

                // Get the elements from the software
                switch (reader.Name)
                {
                    case "rom":
                        containsItems = true;

                        // If the rom is continue or ignore, add the size to the previous rom
                        if (reader.GetAttribute("loadflag") == "continue" || reader.GetAttribute("loadflag") == "ignore")
                        {
                            int index = Items[key].Count - 1;
                            DatItem lastrom = Items[key][index];
                            if (lastrom.ItemType == ItemType.Rom)
                            {
                                ((Rom)lastrom).Size += Sanitizer.CleanSize(reader.GetAttribute("size"));
                            }

                            Items[key].RemoveAt(index);
                            Items[key].Add(lastrom);
                            reader.Read();
                            continue;
                        }

                        DatItem rom = new Rom
                        {
                            Name = reader.GetAttribute("name"),
                            Size = Sanitizer.CleanSize(reader.GetAttribute("size")),
                            CRC = reader.GetAttribute("crc"),
                            MD5 = reader.GetAttribute("md5"),
#if NET_FRAMEWORK
                            RIPEMD160 = reader.GetAttribute("ripemd160"),
#endif
                            SHA1 = reader.GetAttribute("sha1"),
                            SHA256 = reader.GetAttribute("sha256"),
                            SHA384 = reader.GetAttribute("sha384"),
                            SHA512 = reader.GetAttribute("sha512"),
                            Offset = reader.GetAttribute("offset"),
                            ItemStatus = reader.GetAttribute("status").AsItemStatus(),

                            PartName = partName,
                            PartInterface = partInterface,
                            Features = features,
                            AreaName = areaName,
                            AreaSize = areaSize,
                            AreaWidth = areaWidth,
                            AreaEndianness = areaEndianness,
                            Value = reader.GetAttribute("value"),
                            LoadFlag = reader.GetAttribute("loadflag"),

                            Source = new Source
                            {
                                Index = indexId,
                                Name = filename,
                            },
                        };

                        rom.CopyMachineInformation(machine);

                        // Now process and add the rom
                        key = ParseAddHelper(rom);

                        reader.Read();
                        break;

                    default:
                        reader.Read();
                        break;
                }
            }

            return containsItems;
        }

        /// <summary>
        /// Read diskarea information
        /// </summary>
        /// <param name="reader">XmlReader representing a diskarea block</param>
        /// <param name="machine">Machine information to pass to contained items</param>
        /// <param name="partname">Name of the containing part</param>
        /// <param name="partinterface">Interface of the containing part</param>
        /// <param name="features">List of features from the parent part</param>
        /// <param name="areaname">Name of the containing area</param>
        /// <param name="areasize">Size of the containing area</param>
        /// <param name="filename">Name of the file to be parsed</param>
        /// <param name="indexId">Index ID for the DAT</param>
        /// <param name="keep">True if full pathnames are to be kept, false otherwise (default)</param>
        private bool ReadDiskArea(
            XmlReader reader,
            Machine machine,
            string partname,
            string partinterface,
            List<SoftwareListFeature> features,
            string areaname,
            long? areasize,

            // Standard Dat parsing
            string filename,
            int indexId,

            // Miscellaneous
            bool keep)
        {
            string key = string.Empty;
            string temptype = reader.Name;
            bool containsItems = false;

            while (!reader.EOF)
            {
                // We only want elements
                if (reader.NodeType != XmlNodeType.Element)
                {
                    reader.Read();
                    continue;
                }

                // Get the elements from the software
                switch (reader.Name)
                {
                    case "disk":
                        containsItems = true;

                        DatItem disk = new Disk
                        {
                            Name = reader.GetAttribute("name"),
                            MD5 = reader.GetAttribute("md5"),
#if NET_FRAMEWORK
                            RIPEMD160 = reader.GetAttribute("ripemd160"),
#endif
                            SHA1 = reader.GetAttribute("sha1"),
                            SHA256 = reader.GetAttribute("sha256"),
                            SHA384 = reader.GetAttribute("sha384"),
                            SHA512 = reader.GetAttribute("sha512"),
                            ItemStatus = reader.GetAttribute("status").AsItemStatus(),
                            Writable = reader.GetAttribute("writable").AsYesNo(),

                            PartName = partname,
                            PartInterface = partinterface,
                            Features = features,
                            AreaName = areaname,
                            AreaSize = areasize,

                            Source = new Source
                            {
                                Index = indexId,
                                Name = filename,
                            },
                        };

                        disk.CopyMachineInformation(machine);

                        // Now process and add the rom
                        key = ParseAddHelper(disk);

                        reader.Read();
                        break;

                    default:
                        reader.Read();
                        break;
                }
            }

            return containsItems;
        }

        /// <summary>
        /// Read DipSwitch DipValues information
        /// </summary>
        /// <param name="reader">XmlReader representing a diskarea block</param>
        /// <param name="dipSwitch">ListXMLDipSwitch to populate</param>
        private void ReadDipSwitch(XmlReader reader, ListXmlDipSwitch dipSwitch)
        {
            // If we have an empty dipswitch, skip it
            if (reader == null)
                return;

            // Get list ready
            dipSwitch.Values = new List<ListXmlDipValue>();

            // Otherwise, add what is possible
            reader.MoveToContent();

            while (!reader.EOF)
            {
                // We only want elements
                if (reader.NodeType != XmlNodeType.Element)
                {
                    reader.Read();
                    continue;
                }

                // Get the information from the dipswitch
                switch (reader.Name)
                {
                    case "dipvalue":
                        var dipValue = new ListXmlDipValue();
                        dipValue.Name = reader.GetAttribute("name");
                        dipValue.Value = reader.GetAttribute("value");
                        dipValue.Default = reader.GetAttribute("default").AsYesNo();

                        dipSwitch.Values.Add(dipValue);

                        reader.Read();
                        break;

                    default:
                        reader.Read();
                        break;
                }
            }
        }

        /// <summary>
        /// Create and open an output file for writing direct from a dictionary
        /// </summary>
        /// <param name="outfile">Name of the file to write to</param>
        /// <param name="ignoreblanks">True if blank roms should be skipped on output, false otherwise (default)</param>
        /// <returns>True if the DAT was written correctly, false otherwise</returns>
        public override bool WriteToFile(string outfile, bool ignoreblanks = false)
        {
            try
            {
                Globals.Logger.User($"Opening file for writing: {outfile}");
                FileStream fs = FileExtensions.TryCreate(outfile);

                // If we get back null for some reason, just log and return
                if (fs == null)
                {
                    Globals.Logger.Warning($"File '{outfile}' could not be created for writing! Please check to see if the file is writable");
                    return false;
                }

                XmlTextWriter xtw = new XmlTextWriter(fs, new UTF8Encoding(false))
                {
                    Formatting = Formatting.Indented,
                    IndentChar = '\t',
                    Indentation = 1
                };

                // Write out the header
                WriteHeader(xtw);

                // Write out each of the machines and roms
                string lastgame = null;

                // Use a sorted list of games to output
                foreach (string key in Items.SortedKeys)
                {
                    List<DatItem> roms = Items[key];

                    // Resolve the names in the block
                    roms = DatItem.ResolveNames(roms);

                    for (int index = 0; index < roms.Count; index++)
                    {
                        DatItem rom = roms[index];

                        // There are apparently times when a null rom can skip by, skip them
                        if (rom.Name == null || rom.Machine.Name == null)
                        {
                            Globals.Logger.Warning("Null rom found!");
                            continue;
                        }

                        // If we have a different game and we're not at the start of the list, output the end of last item
                        if (lastgame != null && lastgame.ToLowerInvariant() != rom.Machine.Name.ToLowerInvariant())
                            WriteEndGame(xtw);

                        // If we have a new game, output the beginning of the new item
                        if (lastgame == null || lastgame.ToLowerInvariant() != rom.Machine.Name.ToLowerInvariant())
                            WriteStartGame(xtw, rom);

                        // If we have a "null" game (created by DATFromDir or something similar), log it to file
                        if (rom.ItemType == ItemType.Rom
                            && ((Rom)rom).Size == -1
                            && ((Rom)rom).CRC == "null")
                        {
                            Globals.Logger.Verbose($"Empty folder found: {rom.Machine.Name}");

                            lastgame = rom.Machine.Name;
                            continue;
                        }

                        // Now, output the rom data
                        WriteDatItem(xtw, rom, ignoreblanks);

                        // Set the new data to compare against
                        lastgame = rom.Machine.Name;
                    }
                }

                // Write the file footer out
                WriteFooter(xtw);

                Globals.Logger.Verbose("File written!" + Environment.NewLine);
                xtw.Dispose();
                fs.Dispose();
            }
            catch (Exception ex)
            {
                Globals.Logger.Error(ex.ToString());
                return false;
            }

            return true;
        }

        /// <summary>
        /// Write out DAT header using the supplied StreamWriter
        /// </summary>
        /// <param name="xtw">XmlTextWriter to output to</param>
        /// <returns>True if the data was written, false on error</returns>
        private bool WriteHeader(XmlTextWriter xtw)
        {
            try
            {
                xtw.WriteStartDocument();
                xtw.WriteDocType("softwarelist", null, "softwarelist.dtd", null);

                xtw.WriteStartElement("softwarelist");
                xtw.WriteRequiredAttributeString("name", Header.Name);
                xtw.WriteRequiredAttributeString("description", Header.Description);
                xtw.WriteOptionalAttributeString("forcepacking", Header.ForcePacking.FromPackingFlag(false));
                xtw.WriteOptionalAttributeString("forcemerging", Header.ForceMerging.FromMergingFlag(false));
                xtw.WriteOptionalAttributeString("forcenodump", Header.ForceNodump.FromNodumpFlag());

                xtw.Flush();
            }
            catch (Exception ex)
            {
                Globals.Logger.Error(ex.ToString());
                return false;
            }

            return true;
        }

        /// <summary>
        /// Write out Game start using the supplied StreamWriter
        /// </summary>
        /// <param name="xtw">XmlTextWriter to output to</param>
        /// <param name="datItem">DatItem object to be output</param>
        /// <returns>True if the data was written, false on error</returns>
        private bool WriteStartGame(XmlTextWriter xtw, DatItem datItem)
        {
            try
            {
                // No game should start with a path separator
                datItem.Machine.Name = datItem.Machine.Name.TrimStart(Path.DirectorySeparatorChar);

                // Build the state
                xtw.WriteStartElement("software");
                xtw.WriteRequiredAttributeString("name", datItem.Machine.Name);

                if (!string.Equals(datItem.Machine.Name, datItem.Machine.CloneOf, StringComparison.OrdinalIgnoreCase))
                    xtw.WriteOptionalAttributeString("cloneof", datItem.Machine.CloneOf);

                xtw.WriteOptionalAttributeString("supported", datItem.Machine.Supported.FromSupported());

                xtw.WriteOptionalElementString("description", datItem.Machine.Description);
                xtw.WriteOptionalElementString("year", datItem.Machine.Year);
                xtw.WriteOptionalElementString("publisher", datItem.Machine.Publisher);
                xtw.WriteOptionalElementString("category", datItem.Machine.Category);

                if (datItem.Machine.Infos != null && datItem.Machine.Infos.Count > 0)
                {
                    foreach (ListXmlInfo kvp in datItem.Machine.Infos)
                    {
                        xtw.WriteStartElement("info");
                        xtw.WriteRequiredAttributeString("name", kvp.Name);
                        xtw.WriteRequiredAttributeString("value", kvp.Value);
                        xtw.WriteEndElement();
                    }
                }

                if (datItem.Machine.SharedFeatures != null && datItem.Machine.SharedFeatures.Count > 0)
                {
                    foreach (SoftwareListSharedFeature kvp in datItem.Machine.SharedFeatures)
                    {
                        xtw.WriteStartElement("sharedfeat");
                        xtw.WriteRequiredAttributeString("name", kvp.Name);
                        xtw.WriteRequiredAttributeString("value", kvp.Value);
                        xtw.WriteEndElement();
                    }
                }

                if (datItem.Machine.DipSwitches != null && datItem.Machine.DipSwitches.Count > 0)
                {
                    foreach (ListXmlDipSwitch dip in datItem.Machine.DipSwitches)
                    {
                        xtw.WriteStartElement("dipswitch");
                        xtw.WriteRequiredAttributeString("name", dip.Name);
                        xtw.WriteRequiredAttributeString("tag", dip.Tag);
                        xtw.WriteRequiredAttributeString("mask", dip.Mask);

                        foreach (ListXmlDipValue dipval in dip.Values)
                        {
                            xtw.WriteStartElement("dipvalue");
                            xtw.WriteRequiredAttributeString("name", dipval.Name);
                            xtw.WriteRequiredAttributeString("value", dipval.Value);
                            xtw.WriteRequiredAttributeString("default", dipval.Default == true ? "yes" : "no");
                            xtw.WriteEndElement();
                        }

                        // End dipswitch
                        xtw.WriteEndElement();
                    }
                }

                xtw.Flush();
            }
            catch (Exception ex)
            {
                Globals.Logger.Error(ex.ToString());
                return false;
            }

            return true;
        }

        /// <summary>
        /// Write out Game start using the supplied StreamWriter
        /// </summary>
        /// <param name="xtw">XmlTextWriter to output to</param>
        /// <returns>True if the data was written, false on error</returns>
        private bool WriteEndGame(XmlTextWriter xtw)
        {
            try
            {
                // End software
                xtw.WriteEndElement();

                xtw.Flush();
            }
            catch (Exception ex)
            {
                Globals.Logger.Error(ex.ToString());
                return false;
            }

            return true;
        }

        /// <summary>
        /// Write out DatItem using the supplied StreamWriter
        /// </summary>
        /// <param name="xtw">XmlTextWriter to output to</param>
        /// <param name="datItem">DatItem object to be output</param>
        /// <param name="ignoreblanks">True if blank roms should be skipped on output, false otherwise (default)</param>
        /// <returns>True if the data was written, false on error</returns>
        private bool WriteDatItem(XmlTextWriter xtw, DatItem datItem, bool ignoreblanks = false)
        {
            // If we are in ignore blanks mode AND we have a blank (0-size) rom, skip
            if (ignoreblanks && (datItem.ItemType == ItemType.Rom && ((datItem as Rom).Size == 0 || (datItem as Rom).Size == -1)))
                return true;

            try
            {
                // Pre-process the item name
                ProcessItemName(datItem, true);

                // Build the state
                xtw.WriteStartElement("part");
                xtw.WriteRequiredAttributeString("name", datItem.PartName);
                xtw.WriteRequiredAttributeString("interface", datItem.PartInterface);

                if (datItem.Features != null && datItem.Features.Count > 0)
                {
                    foreach (SoftwareListFeature kvp in datItem.Features)
                    {
                        xtw.WriteStartElement("feature");
                        xtw.WriteRequiredAttributeString("name", kvp.Name);
                        xtw.WriteRequiredAttributeString("value", kvp.Value);
                        xtw.WriteEndElement();
                    }
                }

                string areaName = datItem.AreaName;
                switch (datItem.ItemType)
                {
                    case ItemType.Disk:
                        var disk = datItem as Disk;
                        if (string.IsNullOrWhiteSpace(areaName))
                            areaName = "cdrom";

                        xtw.WriteStartElement("diskarea");
                        xtw.WriteRequiredAttributeString("name", areaName);
                        xtw.WriteOptionalAttributeString("size", disk.AreaSize.ToString());

                        xtw.WriteStartElement("disk");
                        xtw.WriteRequiredAttributeString("name", disk.Name);
                        xtw.WriteOptionalAttributeString("md5", disk.MD5?.ToLowerInvariant());
#if NET_FRAMEWORK
                        xtw.WriteOptionalAttributeString("ripemd160", disk.RIPEMD160?.ToLowerInvariant());
#endif
                        xtw.WriteOptionalAttributeString("sha1", disk.SHA1?.ToLowerInvariant());
                        xtw.WriteOptionalAttributeString("sha256", disk.SHA256?.ToLowerInvariant());
                        xtw.WriteOptionalAttributeString("sha384", disk.SHA384?.ToLowerInvariant());
                        xtw.WriteOptionalAttributeString("sha512", disk.SHA512?.ToLowerInvariant());
                        xtw.WriteOptionalAttributeString("status", disk.ItemStatus.FromItemStatus(false));
                        xtw.WriteOptionalAttributeString("writable", disk.Writable.FromYesNo());
                        xtw.WriteEndElement();

                        // End diskarea
                        xtw.WriteEndElement();
                        break;

                    case ItemType.Rom:
                        var rom = datItem as Rom;
                        if (string.IsNullOrWhiteSpace(areaName))
                            areaName = "rom";

                        xtw.WriteStartElement("dataarea");
                        xtw.WriteRequiredAttributeString("name", areaName);
                        xtw.WriteOptionalAttributeString("size", rom.AreaSize.ToString());
                        xtw.WriteOptionalAttributeString("width", rom.AreaWidth);
                        xtw.WriteOptionalAttributeString("endianness", rom.AreaEndianness);

                        xtw.WriteStartElement("rom");
                        xtw.WriteRequiredAttributeString("name", rom.Name);
                        if (rom.Size != -1) xtw.WriteAttributeString("size", rom.Size.ToString());
                        xtw.WriteOptionalAttributeString("crc", rom.CRC?.ToLowerInvariant());
                        xtw.WriteOptionalAttributeString("md5", rom.MD5?.ToLowerInvariant());
#if NET_FRAMEWORK
                        xtw.WriteOptionalAttributeString("ripemd160", rom.RIPEMD160?.ToLowerInvariant());
#endif
                        xtw.WriteOptionalAttributeString("sha1", rom.SHA1?.ToLowerInvariant());
                        xtw.WriteOptionalAttributeString("sha256", rom.SHA256?.ToLowerInvariant());
                        xtw.WriteOptionalAttributeString("sha384", rom.SHA384?.ToLowerInvariant());
                        xtw.WriteOptionalAttributeString("sha512", rom.SHA512?.ToLowerInvariant());
                        xtw.WriteOptionalAttributeString("offset", rom.Offset);
                        xtw.WriteOptionalAttributeString("value", rom.Value);
                        xtw.WriteOptionalAttributeString("status", rom.ItemStatus.FromItemStatus(false));
                        xtw.WriteOptionalAttributeString("loadflag", rom.LoadFlag);
                        xtw.WriteEndElement();

                        // End dataarea
                        xtw.WriteEndElement();
                        break;
                }

                // End part
                xtw.WriteEndElement();

                xtw.Flush();
            }
            catch (Exception ex)
            {
                Globals.Logger.Error(ex.ToString());
                return false;
            }

            return true;
        }

        /// <summary>
        /// Write out DAT footer using the supplied StreamWriter
        /// </summary>
        /// <param name="xtw">XmlTextWriter to output to</param>
        /// <returns>True if the data was written, false on error</returns>
        private bool WriteFooter(XmlTextWriter xtw)
        {
            try
            {
                // End software
                xtw.WriteEndElement();

                // End softwarelist
                xtw.WriteEndElement();

                xtw.Flush();
            }
            catch (Exception ex)
            {
                Globals.Logger.Error(ex.ToString());
                return false;
            }

            return true;
        }
    }
}