// 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 Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.FlowAnalysis;

namespace ILLink.RoslynAnalyzer.DataFlow
{
    // Wrapper type which holds a method (or local function or lambda method),
    // along with its control flow graph. It implements IEquatable for the method.
    public readonly struct MethodBodyValue : IEquatable<MethodBodyValue>
    {
        // Usually an IMethodSymbol, but may also be an IFieldSymbol or IPropertySymbol
        // for field initializers.
        public ISymbol OwningSymbol { get; }

        public ControlFlowGraph ControlFlowGraph { get; }

        public MethodBodyValue(ISymbol owningSymbol, ControlFlowGraph cfg)
        {
            Debug.Assert(owningSymbol is (IMethodSymbol or IFieldSymbol or IPropertySymbol));
            OwningSymbol = owningSymbol;
            ControlFlowGraph = cfg;
        }

        public bool Equals(MethodBodyValue other)
        {
            if (!ReferenceEquals(OwningSymbol, other.OwningSymbol))
                return false;

            Debug.Assert(ControlFlowGraph == other.ControlFlowGraph);
            return true;
        }

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

        public override int GetHashCode() => SymbolEqualityComparer.Default.GetHashCode(OwningSymbol);
    }
}