// 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.
 
#nullable disable
 
using System.Collections.Immutable;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.FindSymbols;
using Microsoft.CodeAnalysis.Internal.Log;
using Microsoft.VisualStudio.GraphModel;
using Microsoft.VisualStudio.GraphModel.Schemas;
 
namespace Microsoft.VisualStudio.LanguageServices.Implementation.Progression;
 
internal sealed class ImplementsGraphQuery : IGraphQuery
{
    public async Task<GraphBuilder> GetGraphAsync(Solution solution, IGraphContext context, CancellationToken cancellationToken)
    {
        using (Logger.LogBlock(FunctionId.GraphQuery_Implements, KeyValueLogMessage.Create(LogType.UserAction), cancellationToken))
        {
            var graphBuilder = await GraphBuilder.CreateForInputNodesAsync(solution, context.InputNodes, cancellationToken).ConfigureAwait(false);
 
            foreach (var node in context.InputNodes)
            {
                var symbol = graphBuilder.GetSymbol(node, cancellationToken);
                if (symbol is INamedTypeSymbol namedType)
                {
                    var implementedSymbols = ImmutableArray<ISymbol>.CastUp(namedType.AllInterfaces);
 
                    await AddImplementedSymbolsAsync(graphBuilder, node, implementedSymbols, cancellationToken).ConfigureAwait(false);
                }
                else if (symbol is IMethodSymbol or
                         IPropertySymbol or
                         IEventSymbol)
                {
                    var implements = await SymbolFinder.FindImplementedInterfaceMembersArrayAsync(symbol, solution, cancellationToken: cancellationToken).ConfigureAwait(false);
                    await AddImplementedSymbolsAsync(graphBuilder, node, implements, cancellationToken).ConfigureAwait(false);
                }
            }
 
            return graphBuilder;
        }
    }
 
    private static async Task AddImplementedSymbolsAsync(
        GraphBuilder graphBuilder, GraphNode node, ImmutableArray<ISymbol> implementedSymbols, CancellationToken cancellationToken)
    {
        foreach (var interfaceType in implementedSymbols)
        {
            var interfaceTypeNode = await graphBuilder.AddNodeAsync(
                interfaceType, relatedNode: node, cancellationToken).ConfigureAwait(false);
            graphBuilder.AddLink(node, CodeLinkCategories.Implements, interfaceTypeNode, cancellationToken);
        }
    }
}