// 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 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);
        }
 
        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
            };
    }
}