// 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.
 
#nullable disable
 
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Packaging;
using Microsoft.CodeAnalysis.SymbolSearch;
using Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem;
using Microsoft.VisualStudio.LanguageServices.Implementation.Utilities;
using Microsoft.VisualStudio.LanguageServices.Packaging;
using Microsoft.VisualStudio.LanguageServices.SymbolSearch;
using Microsoft.VisualStudio.Shell;
using Microsoft.VisualStudio.Shell.Interop;
using Microsoft.VisualStudio.Threading;
using Task = System.Threading.Tasks.Task;
 
namespace Microsoft.VisualStudio.LanguageServices.Implementation.LanguageService;
 
internal abstract partial class AbstractPackage<TPackage, TLanguageService> : AbstractPackage
    where TPackage : AbstractPackage<TPackage, TLanguageService>
    where TLanguageService : AbstractLanguageService<TPackage, TLanguageService>
{
    private TLanguageService _languageService;
 
    private PackageInstallerService _packageInstallerService;
    private VisualStudioSymbolSearchService _symbolSearchService;
 
    protected AbstractPackage()
    {
    }
 
    protected override async Task InitializeAsync(CancellationToken cancellationToken, IProgress<ServiceProgressData> progress)
    {
        await base.InitializeAsync(cancellationToken, progress).ConfigureAwait(true);
 
        await JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
 
        var shell = (IVsShell7)await GetServiceAsync(typeof(SVsShell)).ConfigureAwait(true);
        var solution = (IVsSolution)await GetServiceAsync(typeof(SVsSolution)).ConfigureAwait(true);
        cancellationToken.ThrowIfCancellationRequested();
        Assumes.Present(shell);
        Assumes.Present(solution);
 
        foreach (var editorFactory in CreateEditorFactories())
        {
            RegisterEditorFactory(editorFactory);
        }
 
        RegisterLanguageService(typeof(TLanguageService), async cancellationToken =>
        {
            // Ensure we're on the BG when creating the language service.
            await TaskScheduler.Default;
 
            // Create the language service, tell it to set itself up, then store it in a field
            // so we can notify it that it's time to clean up.
            _languageService = CreateLanguageService();
            await _languageService.SetupAsync(cancellationToken).ConfigureAwait(false);
 
            return _languageService.ComAggregate;
        });
 
        await shell.LoadPackageAsync(Guids.RoslynPackageId);
 
        var miscellaneousFilesWorkspace = this.ComponentModel.GetService<MiscellaneousFilesWorkspace>();
        RegisterMiscellaneousFilesWorkspaceInformation(miscellaneousFilesWorkspace);
 
        if (!IVsShellExtensions.IsInCommandLineMode(JoinableTaskFactory))
        {
            // not every derived package support object browser and for those languages
            // this is a no op
            await RegisterObjectBrowserLibraryManagerAsync(cancellationToken).ConfigureAwait(true);
        }
 
        LoadComponentsInUIContextOnceSolutionFullyLoadedAsync(cancellationToken).Forget();
    }
 
    protected override async Task LoadComponentsAsync(CancellationToken cancellationToken)
    {
        // Do the MEF loads and initialization in the BG explicitly.
        await TaskScheduler.Default;
 
        // Ensure the nuget package services are initialized. This initialization pass will only run
        // once our package is loaded indirectly through a legacy COM service we proffer (like the legacy project systems
        // loading us) or through something like the IVsEditorFactory or a debugger service. Right now it's fine
        // we only load this there, because we only use these to provide code fixes. But we only show code fixes in
        // open files, and so you would have had to open a file, which loads the editor factory, which loads our package,
        // which will run this.
        //
        // This code will have to be moved elsewhere once any of that load path is changed such that the package
        // no longer loads if a file is opened.
        var workspace = ComponentModel.GetService<VisualStudioWorkspace>();
        _packageInstallerService = workspace.Services.GetService<IPackageInstallerService>() as PackageInstallerService;
        _symbolSearchService = workspace.Services.GetService<ISymbolSearchService>() as VisualStudioSymbolSearchService;
 
        _packageInstallerService?.RegisterLanguage(this.RoslynLanguageName);
        _symbolSearchService?.RegisterLanguage(this.RoslynLanguageName);
    }
 
    protected abstract void RegisterMiscellaneousFilesWorkspaceInformation(MiscellaneousFilesWorkspace miscellaneousFilesWorkspace);
 
    protected abstract IEnumerable<IVsEditorFactory> CreateEditorFactories();
    protected abstract TLanguageService CreateLanguageService();
 
    protected void RegisterService<T>(Func<CancellationToken, Task<T>> serviceCreator)
        => AddService(typeof(T), async (container, cancellationToken, type) => await serviceCreator(cancellationToken).ConfigureAwait(true), promote: true);
 
    // When registering a language service, we need to take its ComAggregate wrapper.
    protected void RegisterLanguageService(Type t, Func<CancellationToken, Task<object>> serviceCreator)
        => AddService(t, async (container, cancellationToken, type) => await serviceCreator(cancellationToken).ConfigureAwait(true), promote: true);
 
    protected override void Dispose(bool disposing)
    {
        if (disposing)
        {
            if (!IVsShellExtensions.IsInCommandLineMode(JoinableTaskFactory))
            {
                JoinableTaskFactory.Run(async () => await UnregisterObjectBrowserLibraryManagerAsync(CancellationToken.None).ConfigureAwait(true));
            }
 
            // If we've created the language service then tell it it's time to clean itself up now.
            if (_languageService != null)
            {
                _languageService.TearDown();
                _languageService = null;
            }
        }
 
        base.Dispose(disposing);
    }
 
    protected abstract string RoslynLanguageName { get; }
 
    protected virtual Task RegisterObjectBrowserLibraryManagerAsync(CancellationToken cancellationToken)
    {
        // it is virtual rather than abstract to not break other languages which derived from our
        // base package implementations
        return Task.CompletedTask;
    }
 
    protected virtual Task UnregisterObjectBrowserLibraryManagerAsync(CancellationToken cancellationToken)
    {
        // it is virtual rather than abstract to not break other languages which derived from our
        // base package implementations
        return Task.CompletedTask;
    }
}