// Copyright (c) .NET Foundation and contributors. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

using System;
using System.Diagnostics;
using ILLink.Shared.DataFlow;
using Microsoft.CodeAnalysis;

namespace ILLink.RoslynAnalyzer.DataFlow
{
    public readonly struct CapturedReferenceValue : IEquatable<CapturedReferenceValue>
    {
        public readonly IOperation Reference;

        public CapturedReferenceValue(IOperation operation)
        {
            switch (operation.Kind)
            {
                case OperationKind.PropertyReference:
                case OperationKind.EventReference:
                case OperationKind.LocalReference:
                case OperationKind.FieldReference:
                case OperationKind.ParameterReference:
                case OperationKind.ArrayElementReference:
                case OperationKind.InlineArrayAccess:
                case OperationKind.ImplicitIndexerReference:
                    break;
                case OperationKind.InstanceReference:
                case OperationKind.Invocation:
                    // These will just be ignored when referenced later.
                    break;
                default:
                    UnexpectedOperationHandler.Handle(operation);
                    break;
            }
            Reference = operation;
        }

        public bool Equals(CapturedReferenceValue other) => Reference == other.Reference;

        public override bool Equals(object obj)
            => obj is CapturedReferenceValue inst && Equals(inst);

        public override int GetHashCode()
            => Reference?.GetHashCode() ?? 0;
    }
}