using System;
using System.IO;
using System.Runtime.Serialization;
using System.Xml;

namespace Asb.Base.V2.Serialization;

public sealed class BaseV2Serializer : XmlObjectSerializer
{
	private const string BaseV2Prefix = "ASBBaseV2";

	private readonly Type elementType;

	private readonly bool useCustomSerialization;

	private readonly XmlObjectSerializer fallbackSerializer;

	public BaseV2Serializer(Type type, XmlObjectSerializer fallbackSerializer)
	{
		this.fallbackSerializer = fallbackSerializer;
		elementType = type;
		if (!(type == null))
		{
			Type c = (type.IsArray ? type.GetElementType() : type);
			useCustomSerialization = typeof(IBaseV2CustomSerializable).IsAssignableFrom(c);
		}
	}

	public override bool IsStartObject(XmlDictionaryReader reader)
	{
		if (useCustomSerialization)
		{
			return string.Compare(reader.LocalName, "ASBBaseV2", StringComparison.CurrentCultureIgnoreCase) == 0;
		}
		return fallbackSerializer.IsStartObject(reader);
	}

	public override object ReadObject(XmlDictionaryReader reader, bool verifyObjectName)
	{
		if (useCustomSerialization)
		{
			using MemoryStream input = new MemoryStream(reader.ReadElementContentAsBase64());
			using BinaryReader binaryReader = new BinaryReader(input);
			if (binaryReader.ReadBoolean())
			{
				return null;
			}
			if (Activator.CreateInstance(elementType.IsArray ? elementType.GetElementType() : elementType) is IBaseV2CustomSerializable baseV2CustomSerializable)
			{
				if (elementType.IsArray)
				{
					int arrayLength = binaryReader.ReadInt32();
					return baseV2CustomSerializable.InitializeArrayFromStream(binaryReader, arrayLength);
				}
				baseV2CustomSerializable.InitializeFromStream(binaryReader);
				return baseV2CustomSerializable;
			}
		}
		return fallbackSerializer.ReadObject(reader, verifyObjectName);
	}

	public override void WriteEndObject(XmlDictionaryWriter writer)
	{
		if (useCustomSerialization)
		{
			writer.WriteEndElement();
		}
		else
		{
			fallbackSerializer.WriteEndObject(writer);
		}
	}

	public override void WriteObjectContent(XmlDictionaryWriter writer, object graph)
	{
		bool flag = false;
		if (useCustomSerialization)
		{
			using MemoryStream memoryStream = new MemoryStream();
			using BinaryWriter binaryWriter = new BinaryWriter(memoryStream);
			binaryWriter.Write(graph == null);
			if (graph == null)
			{
				flag = true;
			}
			else if (elementType.IsArray)
			{
				if (Activator.CreateInstance(elementType.GetElementType()) is IBaseV2CustomSerializable baseV2CustomSerializable)
				{
					baseV2CustomSerializable.WriteArrayToStream(graph, binaryWriter);
					flag = true;
				}
			}
			else if (graph is IBaseV2CustomSerializable baseV2CustomSerializable2)
			{
				baseV2CustomSerializable2.WriteToStream(binaryWriter);
				flag = true;
			}
			if (flag)
			{
				byte[] array = memoryStream.ToArray();
				writer.WriteBase64(array, 0, array.Length);
			}
		}
		if (!flag)
		{
			fallbackSerializer.WriteObjectContent(writer, graph);
		}
	}

	public override void WriteStartObject(XmlDictionaryWriter writer, object graph)
	{
		if (useCustomSerialization)
		{
			writer.WriteStartElement("ASBBaseV2");
		}
		else
		{
			fallbackSerializer.WriteStartObject(writer, graph);
		}
	}
}