// 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;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using Microsoft.CodeAnalysis.Host;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.MSBuild;
 
internal sealed class ProjectFileExtensionRegistry
{
    private readonly SolutionServices _solutionServices;
    private readonly DiagnosticReporter _diagnosticReporter;
    private readonly Dictionary<string, string> _extensionToLanguageMap;
    private readonly NonReentrantLock _dataGuard;
 
    public ProjectFileExtensionRegistry(SolutionServices solutionServices, DiagnosticReporter diagnosticReporter)
    {
        _solutionServices = solutionServices;
        _diagnosticReporter = diagnosticReporter;
        _extensionToLanguageMap = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
        {
            { "csproj", LanguageNames.CSharp },
            { "vbproj", LanguageNames.VisualBasic }
        };
 
        _dataGuard = new NonReentrantLock();
    }
 
    /// <summary>
    /// Associates a project file extension with a language name.
    /// </summary>
    public void AssociateFileExtensionWithLanguage(string fileExtension, string language)
    {
        using (_dataGuard.DisposableWait())
        {
            _extensionToLanguageMap[fileExtension] = language;
        }
    }
 
    public bool TryGetLanguageNameFromProjectPath(string? projectFilePath, DiagnosticReportingMode mode, [NotNullWhen(true)] out string? languageName)
    {
        using (_dataGuard.DisposableWait())
        {
            var extension = Path.GetExtension(projectFilePath);
            if (extension is null)
            {
                languageName = null;
                _diagnosticReporter.Report(mode, $"Project file path was 'null'");
                return false;
            }
 
            if (extension is ['.', .. var rest])
                extension = rest;
 
            if (_extensionToLanguageMap.TryGetValue(extension, out var language))
            {
                if (_solutionServices.SupportedLanguages.Contains(language) &&
                    _solutionServices.GetLanguageServices(language).GetService<ICommandLineParserService>() is not null)
                {
                    languageName = language;
                    return true;
                }
                else
                {
                    _diagnosticReporter.Report(mode, string.Format(WorkspacesResources.Cannot_open_project_0_because_the_language_1_is_not_supported, projectFilePath, language));
                    languageName = null;
                    return false;
                }
            }
            else
            {
                _diagnosticReporter.Report(mode, string.Format(WorkspacesResources.Cannot_open_project_0_because_the_file_extension_1_is_not_associated_with_a_language, projectFilePath, Path.GetExtension(projectFilePath)));
                languageName = null;
                return false;
            }
        }
    }
}