// 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.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Microsoft.CodeAnalysis.Structure;
using Microsoft.CodeAnalysis.Test.Utilities;
using Xunit;
 
namespace Microsoft.CodeAnalysis.Editor.UnitTests.Structure;
 
[UseExportProvider]
[Trait(Traits.Feature, Traits.Features.Outlining)]
public class BlockStructureServiceTests
{
    [Fact]
    public async Task TestSimpleLambda()
    {
        var code =
@"using System.Linq;
class C
{
    static void Goo()
    {
        var q = Enumerable.Range(1, 100).Where(x =>
        {
            return x % 2 == 0;
        });
    }
}
";
 
        using var workspace = TestWorkspace.CreateCSharp(code);
        var spans = await GetSpansFromWorkspaceAsync(workspace);
 
        // ensure all 4 outlining region tags were found (usings, class, method, lambda)
        Assert.Equal(4, spans.Length);
    }
 
    [Fact]
    public async Task TestParenthesizedLambda()
    {
        var code =
@"using System.Linq;
class C
{
    static void Goo()
    {
        var q = Enumerable.Range(1, 100).Where((x) =>
        {
            return x % 2 == 0;
        });
    }
}
";
 
        using var workspace = TestWorkspace.CreateCSharp(code);
        var spans = await GetSpansFromWorkspaceAsync(workspace);
 
        // ensure all 4 outlining region tags were found (usings, class, method, lambda)
        Assert.Equal(4, spans.Length);
    }
 
    [Fact]
    public async Task TestAnonymousDelegate()
    {
        var code =
@"using System.Linq;
class C
{
    static void Goo()
    {
        var q = Enumerable.Range(1, 100).Where(delegate (int x)
        {
            return x % 2 == 0;
        });
    }
}
";
 
        using var workspace = TestWorkspace.CreateCSharp(code);
        var spans = await GetSpansFromWorkspaceAsync(workspace);
 
        // ensure all 4 outlining region tags were found (usings, class, method, anonymous delegate)
        Assert.Equal(4, spans.Length);
    }
 
    [Fact]
    public async Task TestTwoInvocationExpressionsThreeLines()
    {
        // The inner argument list should be collapsible, but the outer one shouldn't.
        var code = """
            var x = MyMethod1(MyMethod2(
                "",
                "");
            """;
 
        using var workspace = TestWorkspace.CreateCSharp(code);
        var spans = await GetSpansFromWorkspaceAsync(workspace);
 
        Assert.Equal(1, spans.Length);
 
        Assert.Equal(27, spans[0].TextSpan.Start);
    }
 
    private static async Task<ImmutableArray<BlockSpan>> GetSpansFromWorkspaceAsync(
        TestWorkspace workspace)
    {
        var hostDocument = workspace.Documents.First();
        var document = workspace.CurrentSolution.GetDocument(hostDocument.Id);
        var outliningService = document.GetLanguageService<BlockStructureService>();
        var options = BlockStructureOptions.Default;
 
        var structure = await outliningService.GetBlockStructureAsync(document, options, CancellationToken.None);
        return structure.Spans;
    }
}