﻿// 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;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Editor.Host;
using Microsoft.CodeAnalysis.Editor.UnitTests.Utilities;
using Microsoft.CodeAnalysis.Editor.UnitTests.Workspaces;
using Microsoft.CodeAnalysis.FindReferences;
using Microsoft.CodeAnalysis.FindUsages;
using Microsoft.CodeAnalysis.Shared.TestHooks;
using Microsoft.CodeAnalysis.Test.Utilities;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Editor.Commanding.Commands;
using Roslyn.Test.Utilities;
using Roslyn.Utilities;
using Xunit;

namespace Microsoft.CodeAnalysis.Editor.UnitTests.FindReferences
{
    [UseExportProvider]
    public class FindReferencesCommandHandlerTests
    {
        private class MockFindUsagesContext : FindUsagesContext
        {
            public readonly List<DefinitionItem> Result = new();

            public MockFindUsagesContext()
            {
            }

            public override ValueTask<FindUsagesOptions> GetOptionsAsync(string language, CancellationToken cancellationToken)
                => ValueTaskFactory.FromResult(FindUsagesOptions.Default);

            public override ValueTask OnDefinitionFoundAsync(DefinitionItem definition, CancellationToken cancellationToken)
            {
                lock (Result)
                {
                    Result.Add(definition);
                }

                return default;
            }
        }

        private class MockStreamingFindUsagesPresenter : IStreamingFindUsagesPresenter
        {
            private readonly FindUsagesContext _context;

            public MockStreamingFindUsagesPresenter(FindUsagesContext context)
                => _context = context;

            public (FindUsagesContext, CancellationToken) StartSearch(string title, bool supportsReferences)
                => (_context, CancellationToken.None);

            public void ClearAll()
            {
            }

            public (FindUsagesContext, CancellationToken) StartSearchWithCustomColumns(string title, bool supportsReferences, bool includeContainingTypeAndMemberColumns, bool includeKindColumn)
                => (_context, CancellationToken.None);
        }

        [WpfFact, Trait(Traits.Feature, Traits.Features.FindReferences)]
        public async Task TestFindReferencesAsynchronousCall()
        {
            using var workspace = TestWorkspace.CreateCSharp("class C { C() { new C(); } }");
            var context = new MockFindUsagesContext();
            var presenter = new MockStreamingFindUsagesPresenter(context);

            var listenerProvider = workspace.ExportProvider.GetExportedValue<IAsynchronousOperationListenerProvider>();

            var handler = new FindReferencesCommandHandler(
                presenter,
                workspace.GlobalOptions,
                listenerProvider);

            var textView = workspace.Documents[0].GetTextView();
            textView.Caret.MoveTo(new SnapshotPoint(textView.TextSnapshot, 7));
            handler.ExecuteCommand(new FindReferencesCommandArgs(
                textView,
                textView.TextBuffer), TestCommandExecutionContext.Create());

            var waiter = listenerProvider.GetWaiter(FeatureAttribute.FindReferences);
            await waiter.ExpeditedWaitAsync();
            AssertResult(context.Result, "C.C()", "class C");
        }

        private static void AssertResult(
            List<DefinitionItem> result,
            params string[] definitions)
        {
            Assert.Equal(result.Select(kvp => kvp.DisplayParts.JoinText()).OrderBy(a => a),
                         definitions.OrderBy(a => a));
        }
    }
}
