using System.IO;
using System.Xml;
using System.Xml.Schema;
using System.Xml.Serialization;

namespace SabreTools.Serialization.Readers
{
    /// <summary>
    /// Base class for other XML deserializers
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public abstract class XmlFile<T> : BaseBinaryReader<T>
    {
        /// <inheritdoc/>
        public override T? Deserialize(Stream? data)
        {
            // If the stream is invalid
            if (data is null || !data.CanRead)
                return default;

            try
            {
                // Setup the serializer and the reader
                var serializer = new XmlSerializer(typeof(T));
                var settings = new XmlReaderSettings
                {
                    CheckCharacters = false,
#if NET40_OR_GREATER || NETCOREAPP || NETSTANDARD2_0_OR_GREATER
                    DtdProcessing = DtdProcessing.Ignore,
#endif
                    ValidationFlags = XmlSchemaValidationFlags.None,
                    ValidationType = ValidationType.None,
                };
                var streamReader = new StreamReader(data);
                var xmlReader = XmlReader.Create(streamReader, settings);

                // Perform the deserialization and return
                return (T?)serializer.Deserialize(xmlReader);
            }
            catch
            {
                // Ignore the actual error
                return default;
            }
        }
    }
}