// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System.Collections.Immutable;
using System.Threading;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.PooledObjects;

namespace Microsoft.CodeAnalysis.FindSymbols.Finders;

internal abstract class AbstractMethodOrPropertyOrEventSymbolReferenceFinder<TSymbol> : AbstractReferenceFinder<TSymbol>
    where TSymbol : ISymbol
{
    protected static ImmutableArray<IMethodSymbol> GetReferencedAccessorSymbols(
        FindReferencesDocumentState state, IPropertySymbol property, SyntaxNode node, CancellationToken cancellationToken)
    {
        var semanticFacts = state.SemanticFacts;
        var semanticModel = state.SemanticModel;

        if (state.SyntaxFacts.IsForEachStatement(node))
        {
            var symbols = semanticFacts.GetForEachSymbols(semanticModel, node);

            // the only accessor method referenced in a foreach-statement is the .Current's
            // get-accessor
            return symbols.CurrentProperty?.GetMethod == null
                ? []
                : [symbols.CurrentProperty.GetMethod];
        }

        if (semanticFacts.IsWrittenTo(semanticModel, node, cancellationToken))
        {
            // if it was only written to, then only the setter was referenced.
            // if it was written *and* read, then both accessors were referenced.
            using var _ = ArrayBuilder<IMethodSymbol>.GetInstance(out var result);
            result.AddIfNotNull(property.SetMethod);

            if (!semanticFacts.IsOnlyWrittenTo(semanticModel, node, cancellationToken))
                result.AddIfNotNull(property.GetMethod);

            return result.ToImmutableAndClear();
        }
        else
        {
            // Wasn't written. This could be a normal read, or it could be neither a read nor
            // write. Example of this include:
            //
            // 1) referencing through something like nameof().
            // 2) referencing in a cref in a doc-comment.
            //
            // This list is thought to be complete.  However, if new examples are found, they
            // can be added here.
            var inNameOf = semanticFacts.IsInsideNameOfExpression(semanticModel, node, cancellationToken);
            var inStructuredTrivia = node.IsPartOfStructuredTrivia();

            return inNameOf || inStructuredTrivia || property.GetMethod == null
                ? []
                : [property.GetMethod];
        }
    }
}