// 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;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Options;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.Diagnostics.EngineV2
{
    internal partial class DiagnosticIncrementalAnalyzer
    {
        /// <summary>
        /// this contains all states regarding a <see cref="DiagnosticAnalyzer"/>
        /// </summary>
        private sealed class StateSet
        {
            public readonly string Language;
            public readonly DiagnosticAnalyzer Analyzer;
            public readonly bool IsHostAnalyzer;
 
            private readonly ConcurrentSet<DocumentId> _activeDocuments;
            private readonly ConcurrentDictionary<ProjectId, ProjectState> _projectStates;
 
            public StateSet(string language, DiagnosticAnalyzer analyzer, bool isHostAnalyzer)
            {
                Language = language;
                Analyzer = analyzer;
                IsHostAnalyzer = isHostAnalyzer;
 
                _activeDocuments = [];
                _projectStates = new ConcurrentDictionary<ProjectId, ProjectState>(concurrencyLevel: 2, capacity: 1);
            }
 
            public bool IsActiveFile(DocumentId documentId)
                => _activeDocuments.Contains(documentId);
 
            public bool TryGetProjectState(ProjectId projectId, [NotNullWhen(true)] out ProjectState? state)
                => _projectStates.TryGetValue(projectId, out state);
 
            public void AddActiveDocument(DocumentId documentId)
                => _activeDocuments.Add(documentId);
 
            public ProjectState GetOrCreateProjectState(ProjectId projectId)
                => _projectStates.GetOrAdd(projectId, static (id, self) => new ProjectState(self, id), this);
 
            public void OnRemoved()
            {
                // ths stateset is being removed.
                // TODO: we do this since InMemoryCache is static type. we might consider making it instance object
                //       of something.
                InMemoryStorage.DropCache(Analyzer);
            }
        }
    }
}