using System.Collections.Immutable;
using Roslyn.Utilities;

namespace Microsoft.CodeAnalysis.CSharp.Symbols;

internal sealed class OverriddenOrHiddenMembersResult
{
	public static readonly OverriddenOrHiddenMembersResult Empty = new OverriddenOrHiddenMembersResult(ImmutableArray<Symbol>.Empty, ImmutableArray<Symbol>.Empty);

	private readonly ImmutableArray<Symbol> _overriddenMembers;

	private readonly ImmutableArray<Symbol> _hiddenMembers;

	public ImmutableArray<Symbol> OverriddenMembers => _overriddenMembers;

	public ImmutableArray<Symbol> HiddenMembers => _hiddenMembers;

	private OverriddenOrHiddenMembersResult(ImmutableArray<Symbol> overriddenMembers, ImmutableArray<Symbol> hiddenMembers)
	{
		_overriddenMembers = overriddenMembers;
		_hiddenMembers = hiddenMembers;
	}

	public static OverriddenOrHiddenMembersResult Create(ImmutableArray<Symbol> overriddenMembers, ImmutableArray<Symbol> hiddenMembers)
	{
		if (overriddenMembers.IsEmpty && hiddenMembers.IsEmpty)
		{
			return Empty;
		}
		return new OverriddenOrHiddenMembersResult(overriddenMembers, hiddenMembers);
	}

	internal static Symbol GetOverriddenMember(Symbol substitutedOverridingMember, Symbol overriddenByDefinitionMember)
	{
		if ((object)overriddenByDefinitionMember != null)
		{
			NamedTypeSymbol containingType = overriddenByDefinitionMember.ContainingType;
			NamedTypeSymbol originalDefinition = containingType.OriginalDefinition;
			NamedTypeSymbol baseTypeNoUseSiteDiagnostics = substitutedOverridingMember.ContainingType.BaseTypeNoUseSiteDiagnostics;
			while ((object)baseTypeNoUseSiteDiagnostics != null)
			{
				if (TypeSymbol.Equals(baseTypeNoUseSiteDiagnostics.OriginalDefinition, originalDefinition, (TypeCompareKind)0))
				{
					if (TypeSymbol.Equals(baseTypeNoUseSiteDiagnostics, containingType, (TypeCompareKind)0))
					{
						return overriddenByDefinitionMember;
					}
					return overriddenByDefinitionMember.OriginalDefinition.SymbolAsMember(baseTypeNoUseSiteDiagnostics);
				}
				baseTypeNoUseSiteDiagnostics = baseTypeNoUseSiteDiagnostics.BaseTypeNoUseSiteDiagnostics;
			}
			throw ExceptionUtilities.Unreachable("/_/src/Compilers/CSharp/Portable/Symbols/OverriddenOrHiddenMembersResult.cs", 77);
		}
		return null;
	}

	internal Symbol GetOverriddenMember()
	{
		ImmutableArray<Symbol>.Enumerator enumerator = _overriddenMembers.GetEnumerator();
		while (enumerator.MoveNext())
		{
			Symbol current = enumerator.Current;
			if (current.IsAbstract || current.IsVirtual || current.IsOverride)
			{
				return current;
			}
		}
		return null;
	}
}