// 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.Linq;
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 IsUsedByGraphQuery : IGraphQuery
{
    public async Task<GraphBuilder> GetGraphAsync(Solution solution, IGraphContext context, CancellationToken cancellationToken)
    {
        using (Logger.LogBlock(FunctionId.GraphQuery_IsUsedBy, 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);
                var references = await SymbolFinder.FindReferencesAsync(symbol, solution, cancellationToken).ConfigureAwait(false);
 
                foreach (var reference in references)
                {
                    var referencedSymbol = reference.Definition;
                    var projectId = graphBuilder.GetContextProject(node, cancellationToken).Id;
 
                    var allLocations = referencedSymbol.Locations.Concat(reference.Locations.Select(r => r.Location))
                                                                 .Where(l => l != null && l.IsInSource);
 
                    foreach (var location in allLocations)
                    {
                        var locationNode = GetLocationNode(location, context, projectId, cancellationToken);
                        if (locationNode != null)
                            graphBuilder.AddLink(node, CodeLinkCategories.SourceReferences, locationNode, cancellationToken);
                    }
                }
            }
 
            return graphBuilder;
        }
    }
 
    private static GraphNode? GetLocationNode(Location location, IGraphContext context, ProjectId projectId, CancellationToken cancellationToken)
    {
        var span = location.GetLineSpan();
        if (location.SourceTree == null)
            return null;
 
        var lineText = location.SourceTree.GetText(cancellationToken).Lines[span.StartLinePosition.Line].ToString();
        var filePath = location.SourceTree.FilePath;
        var sourceLocation = GraphBuilder.TryCreateSourceLocation(filePath, span.Span);
        if (sourceLocation == null)
            return null;
 
        var label = string.Format("{0} ({1}, {2}): {3}",
                                    System.IO.Path.GetFileName(filePath),
                                    span.StartLinePosition.Line + 1,
                                    span.StartLinePosition.Character + 1,
                                    lineText.TrimStart());
        var locationNode = context.Graph.Nodes.GetOrCreate(sourceLocation.Value.CreateGraphNodeId(), label, CodeNodeCategories.SourceLocation);
        locationNode[CodeNodeProperties.SourceLocation] = sourceLocation.Value;
        locationNode[RoslynGraphProperties.ContextProjectId] = projectId;
        locationNode[DgmlNodeProperties.Icon] = IconHelper.GetIconName("Reference", Accessibility.NotApplicable);
 
        return locationNode;
    }
}