// 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.Collections.Immutable;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Microsoft.CodeAnalysis.Text;
 
namespace Microsoft.CodeAnalysis.Copilot;
 
internal static class Extensions
{
    public static async Task<ImmutableArray<DiagnosticData>> GetCachedCopilotDiagnosticsAsync(this TextDocument document, TextSpan? span, CancellationToken cancellationToken)
    {
        if (document is not Document sourceDocument)
            return [];
 
        if (sourceDocument.GetLanguageService<ICopilotOptionsService>() is not { } optionsService ||
            await optionsService.IsCodeAnalysisOptionEnabledAsync().ConfigureAwait(false) is false)
        {
            return [];
        }
 
        var copilotCodeAnalysisService = sourceDocument.GetLanguageService<ICopilotCodeAnalysisService>();
        if (copilotCodeAnalysisService is null)
            return [];
 
        var promptTitles = await copilotCodeAnalysisService.GetAvailablePromptTitlesAsync(sourceDocument, cancellationToken).ConfigureAwait(false);
        var copilotDiagnostics = await copilotCodeAnalysisService.GetCachedDocumentDiagnosticsAsync(sourceDocument, span, promptTitles, cancellationToken).ConfigureAwait(false);
        return copilotDiagnostics.SelectAsArray(d => DiagnosticData.Create(d, sourceDocument));
    }
}