// 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.ComponentModel.Composition;
using System.Linq;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.Editor;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.VisualStudio.Commanding;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Editor.Commanding.Commands;
using Microsoft.VisualStudio.Utilities;
 
namespace Microsoft.CodeAnalysis.Interactive
{
    /// <summary>
    /// Implements a execute in interactive command handler.
    /// This class is separated from the <see cref="IExecuteInInteractiveCommandHandler"/>
    /// in order to ensure that the interactive command can be exposed without the necessity
    /// to load any of the interactive dll files just to get the command's status.
    /// </summary>
    [Export(typeof(ICommandHandler))]
    [ContentType(ContentTypeNames.RoslynContentType)]
    [Name("Interactive Command Handler")]
    internal class ExecuteInInteractiveCommandHandler
        : ICommandHandler<ExecuteInInteractiveCommandArgs>
    {
        private readonly IEnumerable<Lazy<IExecuteInInteractiveCommandHandler, ContentTypeMetadata>> _executeInInteractiveHandlers;
 
        public string DisplayName => EditorFeaturesResources.Execute_In_Interactive;
 
        [ImportingConstructor]
        [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
        public ExecuteInInteractiveCommandHandler(
            [ImportMany] IEnumerable<Lazy<IExecuteInInteractiveCommandHandler, ContentTypeMetadata>> executeInInteractiveHandlers)
        {
            _executeInInteractiveHandlers = executeInInteractiveHandlers;
        }
 
        private Lazy<IExecuteInInteractiveCommandHandler> GetCommandHandler(ITextBuffer textBuffer)
        {
            return _executeInInteractiveHandlers
                .Where(handler => handler.Metadata.ContentTypes.Any(textBuffer.ContentType.IsOfType))
                .SingleOrDefault();
        }
 
        bool ICommandHandler<ExecuteInInteractiveCommandArgs>.ExecuteCommand(ExecuteInInteractiveCommandArgs args, CommandExecutionContext context)
            => GetCommandHandler(args.SubjectBuffer)?.Value.ExecuteCommand(args, context) ?? false;
 
        CommandState ICommandHandler<ExecuteInInteractiveCommandArgs>.GetCommandState(ExecuteInInteractiveCommandArgs args)
        {
            return GetCommandHandler(args.SubjectBuffer) == null
                ? CommandState.Unavailable
                : CommandState.Available;
        }
    }
}