// 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 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;
                }
            }
        }
    }
}