// 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 Roslyn.Test.Utilities;
using Xunit;
using Xunit.Abstractions;
using LSP = Roslyn.LanguageServer.Protocol;
 
namespace Microsoft.CodeAnalysis.LanguageServer.UnitTests.SignatureHelp;
 
public sealed class SignatureHelpTests : AbstractLanguageServerProtocolTests
{
    public SignatureHelpTests(ITestOutputHelper testOutputHelper) : base(testOutputHelper)
    {
    }
 
    [Theory, CombinatorialData]
    public async Task TestGetSignatureHelpAsync(bool mutatingLspWorkspace)
    {
        var markup =
            """
            class A
            {
                void M()
                {
                    M2({|caret:|}'a');
                }
                /// <summary>
                /// M2 is a method.
                /// </summary>
                int M2(string a)
                {
                    return 1;
                }
 
            }
            """;
        await using var testLspServer = await CreateTestLspServerAsync(markup, mutatingLspWorkspace);
        var expected = new LSP.SignatureHelp()
        {
            ActiveParameter = 0,
            ActiveSignature = 0,
            Signatures = [CreateSignatureInformation("int A.M2(string a)", "M2 is a method.", "a", "")]
        };
 
        var results = await RunGetSignatureHelpAsync(testLspServer, testLspServer.GetLocations("caret").Single());
        AssertJsonEquals(expected, results);
    }
 
    [Theory, CombinatorialData]
    public async Task TestGetNestedSignatureHelpAsync(bool mutatingLspWorkspace)
    {
        var markup =
            """
            class Foo {
              public Foo(int showMe) {}
 
              public static void Do(Foo foo) {
                Do(new Foo({|caret:|}
              }
            }
            """;
        await using var testLspServer = await CreateTestLspServerAsync(markup, mutatingLspWorkspace);
        var expected = new LSP.SignatureHelp()
        {
            ActiveParameter = 0,
            ActiveSignature = 0,
            Signatures = [CreateSignatureInformation("Foo(int showMe)", "", "showMe", "")]
        };
 
        var results = await RunGetSignatureHelpAsync(testLspServer, testLspServer.GetLocations("caret").Single());
        AssertJsonEquals(expected, results);
    }
 
    [Theory, CombinatorialData, WorkItem("https://github.com/dotnet/vscode-csharp/issues/8154")]
    public async Task TestGetSignatureHelpInGenericAsync(bool mutatingLspWorkspace)
    {
        var markup =
            """
            using System.Collections.Generic;
            class A
            {
                Dictionary<{|caret:|}
            }
            """;
        await using var testLspServer = await CreateTestLspServerAsync(markup, mutatingLspWorkspace);
 
        var results = await RunGetSignatureHelpAsync(testLspServer, testLspServer.GetLocations("caret").Single());
        Assert.Equal(1, results?.Signatures.Length);
        Assert.Equal("Dictionary<TKey, TValue>", results?.Signatures[0].Label);
    }
 
    [Theory, CombinatorialData, WorkItem("https://github.com/dotnet/vscode-csharp/issues/8154")]
    public async Task TestGetSignatureHelpServerCapabilitiesAsync(bool mutatingLspWorkspace)
    {
        await using var testLspServer = await CreateTestLspServerAsync(string.Empty, mutatingLspWorkspace);
        Assert.Contains("(", testLspServer.GetServerCapabilities().SignatureHelpProvider!.TriggerCharacters!);
        Assert.Contains("<", testLspServer.GetServerCapabilities().SignatureHelpProvider!.TriggerCharacters!);
        Assert.Contains("{", testLspServer.GetServerCapabilities().SignatureHelpProvider!.TriggerCharacters!);
    }
 
    private static async Task<LSP.SignatureHelp?> RunGetSignatureHelpAsync(TestLspServer testLspServer, LSP.Location caret)
    {
        return await testLspServer.ExecuteRequestAsync<LSP.TextDocumentPositionParams, LSP.SignatureHelp?>(
            LSP.Methods.TextDocumentSignatureHelpName,
            CreateTextDocumentPositionParams(caret), CancellationToken.None);
    }
 
    private static LSP.SignatureInformation CreateSignatureInformation(string methodLabal, string methodDocumentation, string parameterLabel, string parameterDocumentation)
        => new LSP.SignatureInformation()
        {
            Documentation = CreateMarkupContent(LSP.MarkupKind.PlainText, methodDocumentation),
            Label = methodLabal,
            Parameters =
            [
                CreateParameterInformation(parameterLabel, parameterDocumentation)
            ]
        };
 
    private static LSP.ParameterInformation CreateParameterInformation(string parameter, string documentation)
        => new LSP.ParameterInformation()
        {
            Documentation = CreateMarkupContent(LSP.MarkupKind.PlainText, documentation),
            Label = parameter
        };
}