// 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.Collections.Immutable;
using System.Composition;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Editor;
using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
using Microsoft.CodeAnalysis.ExternalAccess.FSharp.Editor;
using Microsoft.CodeAnalysis.ExternalAccess.FSharp.Navigation;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.Notification;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Editor;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.ExternalAccess.FSharp.Internal.Editor;
 
[Shared]
[ExportLanguageService(typeof(INavigationBarItemService), LanguageNames.FSharp)]
internal class FSharpNavigationBarItemService : INavigationBarItemService
{
    private readonly IThreadingContext _threadingContext;
    private readonly IFSharpNavigationBarItemService _service;
 
    [ImportingConstructor]
    [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
    public FSharpNavigationBarItemService(
        IThreadingContext threadingContext,
        IFSharpNavigationBarItemService service)
    {
        _threadingContext = threadingContext;
        _service = service;
    }
 
    public Task<ImmutableArray<NavigationBarItem>> GetItemsAsync(Document document, ITextVersion textVersion, CancellationToken cancellationToken)
    {
        return ((INavigationBarItemService)this).GetItemsAsync(
            document, workspaceSupportsDocumentChanges: true, frozenPartialSemantics: false, textVersion, cancellationToken);
    }
 
    async Task<ImmutableArray<NavigationBarItem>> INavigationBarItemService.GetItemsAsync(
        Document document,
        bool workspaceSupportsDocumentChanges,
        bool forceFrozenPartialSemanticsForCrossProcessOperations,
        ITextVersion textVersion,
        CancellationToken cancellationToken)
    {
        var items = await _service.GetItemsAsync(document, cancellationToken).ConfigureAwait(false);
        return items == null
            ? []
            : ConvertItems(items, textVersion);
    }
 
    private static ImmutableArray<NavigationBarItem> ConvertItems(IList<FSharpNavigationBarItem> items, ITextVersion textVersion)
        => (items ?? SpecializedCollections.EmptyList<FSharpNavigationBarItem>()).Where(x => x.Spans.Any()).SelectAsArray(x => ConvertToNavigationBarItem(x, textVersion));
 
    public async Task<bool> TryNavigateToItemAsync(
        Document document, NavigationBarItem item, ITextView view, ITextVersion textVersion, CancellationToken cancellationToken)
    {
        // The logic here was ported from FSharp's implementation. The main reason was to avoid shimming INotificationService.
        // Spans.First() is safe here as we filtered down to only items that have spans in ConvertItems.
        var span = item.GetCurrentItemSpan(textVersion, item.Spans.First());
        var workspace = document.Project.Solution.Workspace;
        var navigationService = workspace.Services.GetRequiredService<IFSharpDocumentNavigationService>();
 
        await _threadingContext.JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
 
        if (navigationService.CanNavigateToPosition(workspace, document.Id, span.Start, virtualSpace: 0, cancellationToken))
        {
            navigationService.TryNavigateToPosition(workspace, document.Id, span.Start, virtualSpace: 0, cancellationToken);
        }
        else
        {
            var notificationService = workspace.Services.GetRequiredService<INotificationService>();
            notificationService.SendNotification(EditorFeaturesResources.The_definition_of_the_object_is_hidden, severity: NotificationSeverity.Error);
        }
 
        return true;
    }
 
    public bool ShowItemGrayedIfNear(NavigationBarItem item)
    {
        return false;
    }
 
    private static NavigationBarItem ConvertToNavigationBarItem(FSharpNavigationBarItem item, ITextVersion textVersion)
    {
        var spans = item.Spans.ToImmutableArrayOrEmpty();
        return new SimpleNavigationBarItem(
            textVersion,
            item.Text,
            FSharpGlyphHelpers.ConvertTo(item.Glyph),
            spans,
            ConvertItems(item.ChildItems, textVersion),
            item.Indent,
            item.Bolded,
            item.Grayed);
    }
}