using System.Collections.Immutable;
using Microsoft.CodeAnalysis.CSharp.Symbols;
using Microsoft.CodeAnalysis.CodeGen;
using Microsoft.CodeAnalysis.PooledObjects;
using Roslyn.Utilities;

namespace Microsoft.CodeAnalysis.CSharp;

internal sealed class IteratorStateMachine : StateMachineTypeSymbol
{
	private readonly MethodSymbol _constructor;

	private readonly ImmutableArray<NamedTypeSymbol> _interfaces;

	internal readonly TypeWithAnnotations ElementType;

	public override TypeKind TypeKind => (TypeKind)2;

	internal override MethodSymbol Constructor => _constructor;

	internal override NamedTypeSymbol BaseTypeNoUseSiteDiagnostics => ContainingAssembly.GetSpecialType((SpecialType)1);

	internal override bool IsRecord => false;

	internal override bool IsRecordStruct => false;

	public IteratorStateMachine(VariableSlotAllocator slotAllocatorOpt, TypeCompilationState compilationState, MethodSymbol iteratorMethod, int iteratorMethodOrdinal, bool isEnumerable, TypeWithAnnotations elementType)
		: base(slotAllocatorOpt, compilationState, iteratorMethod, iteratorMethodOrdinal)
	{
		ElementType = base.TypeMap.SubstituteType(elementType);
		ArrayBuilder<NamedTypeSymbol> instance = ArrayBuilder<NamedTypeSymbol>.GetInstance();
		if (isEnumerable)
		{
			instance.Add(ContainingAssembly.GetSpecialType((SpecialType)25).Construct(ElementType.Type));
			instance.Add(ContainingAssembly.GetSpecialType((SpecialType)24));
		}
		instance.Add(ContainingAssembly.GetSpecialType((SpecialType)29).Construct(ElementType.Type));
		instance.Add(ContainingAssembly.GetSpecialType((SpecialType)35));
		instance.Add(ContainingAssembly.GetSpecialType((SpecialType)28));
		_interfaces = instance.ToImmutableAndFree();
		_constructor = new IteratorConstructor(this);
	}

	internal override ImmutableArray<NamedTypeSymbol> InterfacesNoUseSiteDiagnostics(ConsList<TypeSymbol> basesBeingResolved)
	{
		return _interfaces;
	}

	internal override bool HasPossibleWellKnownCloneMethod()
	{
		return false;
	}
}