using System;
using System.Reflection;
using ProtoBuf.Compiler;

namespace ProtoBuf.Serializers;

internal sealed class MemberSpecifiedDecorator : ProtoDecoratorBase
{
	private readonly MethodInfo getSpecified;

	private readonly MethodInfo setSpecified;

	public override Type ExpectedType => Tail.ExpectedType;

	public override bool RequiresOldValue => Tail.RequiresOldValue;

	public override bool ReturnsValue => Tail.ReturnsValue;

	public MemberSpecifiedDecorator(MethodInfo getSpecified, MethodInfo setSpecified, IProtoSerializer tail)
		: base(tail)
	{
		if ((object)getSpecified == null && (object)setSpecified == null)
		{
			throw new InvalidOperationException();
		}
		this.getSpecified = getSpecified;
		this.setSpecified = setSpecified;
	}

	public override void Write(object value, ProtoWriter dest)
	{
		if ((object)getSpecified == null || (bool)getSpecified.Invoke(value, null))
		{
			Tail.Write(value, dest);
		}
	}

	public override object Read(object value, ProtoReader source)
	{
		object result = Tail.Read(value, source);
		if ((object)setSpecified != null)
		{
			setSpecified.Invoke(value, new object[1] { true });
		}
		return result;
	}

	protected override void EmitWrite(CompilerContext ctx, Local valueFrom)
	{
		if ((object)getSpecified == null)
		{
			Tail.EmitWrite(ctx, valueFrom);
			return;
		}
		using Local local = ctx.GetLocalWithValue(ExpectedType, valueFrom);
		ctx.LoadAddress(local, ExpectedType);
		ctx.EmitCall(getSpecified);
		CodeLabel label = ctx.DefineLabel();
		ctx.BranchIfFalse(label, @short: false);
		Tail.EmitWrite(ctx, local);
		ctx.MarkLabel(label);
	}

	protected override void EmitRead(CompilerContext ctx, Local valueFrom)
	{
		if ((object)setSpecified == null)
		{
			Tail.EmitRead(ctx, valueFrom);
			return;
		}
		using Local local = ctx.GetLocalWithValue(ExpectedType, valueFrom);
		Tail.EmitRead(ctx, local);
		ctx.LoadAddress(local, ExpectedType);
		ctx.LoadValue(1);
		ctx.EmitCall(setSpecified);
	}
}