using System;
using ProtoBuf.Compiler;
using ProtoBuf.Meta;

namespace ProtoBuf.Serializers;

internal sealed class TimeSpanSerializer : IProtoSerializer
{
	private static readonly Type expectedType = typeof(TimeSpan);

	private readonly bool wellKnown;

	public Type ExpectedType => expectedType;

	bool IProtoSerializer.RequiresOldValue => false;

	bool IProtoSerializer.ReturnsValue => true;

	public TimeSpanSerializer(DataFormat dataFormat, TypeModel model)
	{
		wellKnown = dataFormat == DataFormat.WellKnown;
	}

	public object Read(object value, ProtoReader source)
	{
		if (wellKnown)
		{
			return BclHelpers.ReadDuration(source);
		}
		return BclHelpers.ReadTimeSpan(source);
	}

	public void Write(object value, ProtoWriter dest)
	{
		if (wellKnown)
		{
			BclHelpers.WriteDuration((TimeSpan)value, dest);
		}
		else
		{
			BclHelpers.WriteTimeSpan((TimeSpan)value, dest);
		}
	}

	void IProtoSerializer.EmitWrite(CompilerContext ctx, Local valueFrom)
	{
		ctx.EmitWrite(ctx.MapType(typeof(BclHelpers)), wellKnown ? "WriteDuration" : "WriteTimeSpan", valueFrom);
	}

	void IProtoSerializer.EmitRead(CompilerContext ctx, Local valueFrom)
	{
		if (wellKnown)
		{
			ctx.LoadValue(valueFrom);
		}
		ctx.EmitBasicRead(ctx.MapType(typeof(BclHelpers)), wellKnown ? "ReadDuration" : "ReadTimeSpan", ExpectedType);
	}
}