using System;
using System.Runtime.Serialization;

namespace ProtoBuf;

public sealed class SerializationContext
{
	private bool frozen;

	private object context;

	private static readonly SerializationContext @default;

	private StreamingContextStates state = StreamingContextStates.Persistence;

	public object Context
	{
		get
		{
			return context;
		}
		set
		{
			if (context != value)
			{
				ThrowIfFrozen();
				context = value;
			}
		}
	}

	internal static SerializationContext Default => @default;

	public StreamingContextStates State
	{
		get
		{
			return state;
		}
		set
		{
			if (state != value)
			{
				ThrowIfFrozen();
				state = value;
			}
		}
	}

	internal void Freeze()
	{
		frozen = true;
	}

	private void ThrowIfFrozen()
	{
		if (frozen)
		{
			throw new InvalidOperationException("The serialization-context cannot be changed once it is in use");
		}
	}

	static SerializationContext()
	{
		@default = new SerializationContext();
		@default.Freeze();
	}

	public static implicit operator StreamingContext(SerializationContext ctx)
	{
		if (ctx == null)
		{
			return new StreamingContext(StreamingContextStates.Persistence);
		}
		return new StreamingContext(ctx.state, ctx.context);
	}

	public static implicit operator SerializationContext(StreamingContext ctx)
	{
		SerializationContext serializationContext = new SerializationContext();
		serializationContext.Context = ctx.Context;
		serializationContext.State = ctx.State;
		return serializationContext;
	}
}