// 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.Linq;
using Microsoft.CodeAnalysis.Test.Utilities;
using Microsoft.CodeAnalysis.Text;
using Microsoft.VisualStudio.Text;
using Roslyn.Test.Utilities;
using Xunit;

namespace Microsoft.CodeAnalysis.Editor.UnitTests.TextEditor;

[UseExportProvider]
public sealed class TryGetDocumentTests
{
    [Fact, WorkItem("http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/624315")]
    public void MultipleTextChangesTest()
    {
        var code = """
            class C

            """;
        using var workspace = EditorTestWorkspace.CreateCSharp(code);
        var hostDocument = workspace.Documents.First();
        var document = workspace.CurrentSolution.GetDocument(workspace.GetDocumentId(hostDocument));

        var buffer = hostDocument.GetTextBuffer();
        var container = buffer.AsTextContainer();
        var startPosition = buffer.CurrentSnapshot.GetLineFromLineNumber(1).Start.Position;

        buffer.Insert(startPosition, "{");
        buffer.Insert(startPosition + 1, " ");
        buffer.Insert(startPosition + 2, "}");

        var newDocument = buffer.CurrentSnapshot.GetRelatedDocumentsWithChanges().FirstOrDefault();
        Assert.NotNull(newDocument);
        var newSourceText = newDocument.GetTextAsync().Result;
        Assert.Equal("""
            class C
            { }
            """, newSourceText.ToString());

        Assert.True(container == newSourceText.Container);
    }

    [Fact]
    public void EmptyTextChanges()
    {
        var code = @"class C";
        using var workspace = EditorTestWorkspace.CreateCSharp(code);
        var hostDocument = workspace.Documents.First();
        var document = workspace.CurrentSolution.GetDocument(workspace.GetDocumentId(hostDocument));

        var buffer = hostDocument.GetTextBuffer();
        var startingSnapshotVersion = buffer.CurrentSnapshot.Version;
        var text = buffer.CurrentSnapshot.AsText();
        var container = buffer.AsTextContainer();
        Assert.Same(text.Container, container);

        using (var edit = buffer.CreateEdit(EditOptions.DefaultMinimalChange, null, null))
        {
            edit.Delete(0, 3);
            edit.Insert(0, "cla");
            edit.Apply();
        }

        Assert.Equal(startingSnapshotVersion.VersionNumber + 1, buffer.CurrentSnapshot.Version.VersionNumber);
        Assert.Equal(startingSnapshotVersion.VersionNumber, buffer.CurrentSnapshot.Version.ReiteratedVersionNumber);

        var newText = buffer.CurrentSnapshot.AsText();

        // different buffer snapshot should never return same roslyn text snapshot
        Assert.NotSame(text, newText);

        var newDocument = newText.GetRelatedDocumentsWithChanges().First();

        // different text snapshot never gives back same roslyn snapshot
        Assert.NotSame(document, newDocument);
    }
}
