#if LEGACY

using System.Collections.Generic;
using System.Threading.Tasks;
using System.Management.Automation.Language;

namespace System.Management.Automation.Subsystem.Prediction
{
    /// <summary>
    /// Kinds of prediction clients.
    /// </summary>
    public enum PredictionClientKind
    {
        /// <summary>
        /// A terminal client, representing the command-line experience.
        /// </summary>
        Terminal,

        /// <summary>
        /// An editor client, representing the editor experience.
        /// </summary>
        Editor,
    }

    /// <summary>
    /// The class represents a client that interacts with predictors.
    /// </summary>
    public sealed class PredictionClient
    {
        /// <summary>
        /// Gets the client name.
        /// </summary>
        [HiddenAttribute]
        public string Name { get; }

        /// <summary>
        /// Gets the client kind.
        /// </summary>
        [HiddenAttribute]
        public PredictionClientKind Kind { get; }

        /// <summary>
        /// Initializes a new instance of the <see cref="PredictionClient"/> class.
        /// </summary>
        /// <param name="name">Name of the interactive client.</param>
        /// <param name="kind">Kind of the interactive client.</param>
        [HiddenAttribute]
        public PredictionClient(string name, PredictionClientKind kind)
        {
            Name = name;
            Kind = kind;
        }
    }

    /// <summary>
    /// The class represents the prediction result from a predictor.
    /// </summary>
    public sealed class PredictionResult
    {
        /// <summary>
        /// Gets the Id of the predictor.
        /// </summary>
        [HiddenAttribute]
        public Guid Id { get; }

        /// <summary>
        /// Gets the name of the predictor.
        /// </summary>
        [HiddenAttribute]
        public string Name { get; }

        /// <summary>
        /// Gets the mini-session id that represents a specific invocation that returns this result.
        /// When it's not specified, it's considered by a client that the predictor doesn't expect feedback.
        /// </summary>
        [HiddenAttribute]
        public uint? Session { get; }

        /// <summary>
        /// Gets the suggestions.
        /// </summary>
        [HiddenAttribute]
        public IReadOnlyList<PredictiveSuggestion> Suggestions { get; }

        internal PredictionResult(Guid id, string name, uint? session, List<PredictiveSuggestion> suggestions)
        {
            Id = id;
            Name = name;
            Session = session;
            Suggestions = suggestions;
        }
    }

    /// <summary>
    /// The class represents a predictive suggestion generated by a predictor.
    /// </summary>
    public sealed class PredictiveSuggestion
    {
        /// <summary>
        /// Gets the suggestion.
        /// </summary>
        [HiddenAttribute]
        public string SuggestionText { get; }

        /// <summary>
        /// Gets the tooltip of the suggestion.
        /// </summary>
        [HiddenAttribute]
        public string ToolTip { get; }

        /// <summary>
        /// Initializes a new instance of the <see cref="PredictiveSuggestion"/> class.
        /// </summary>
        /// <param name="suggestion">The predictive suggestion text.</param>
        [HiddenAttribute]
        public PredictiveSuggestion(string suggestion)
            : this(suggestion, toolTip: null)
        {
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="PredictiveSuggestion"/> class.
        /// </summary>
        /// <param name="suggestion">The predictive suggestion text.</param>
        /// <param name="toolTip">The tooltip of the suggestion.</param>
        [HiddenAttribute]
        public PredictiveSuggestion(string suggestion, string toolTip)
        {
            if (string.IsNullOrEmpty(suggestion))
            {
                throw new ArgumentNullException(nameof(suggestion));
            }

            SuggestionText = suggestion;
            ToolTip = toolTip;
        }
    }

    /// <summary>
    /// Provides a set of possible predictions for given input.
    /// </summary>
    public static class CommandPrediction
    {
        /// <summary>
        /// Collect the predictive suggestions from registered predictors using the default timeout.
        /// </summary>
        /// <param name="client">Represents the client that initiates the call.</param>
        /// <param name="ast">The <see cref="Ast"/> object from parsing the current command line input.</param>
        /// <param name="astTokens">The <see cref="Token"/> objects from parsing the current command line input.</param>
        /// <returns>A list of <see cref="PredictionResult"/> objects.</returns>
        [HiddenAttribute]
        public static Task<List<PredictionResult>> PredictInputAsync(PredictionClient client, Ast ast, Token[] astTokens)
        {
            return null;
        }

        /// <summary>
        /// Collect the predictive suggestions from registered predictors using the specified timeout.
        /// </summary>
        /// <param name="client">Represents the client that initiates the call.</param>
        /// <param name="ast">The <see cref="Ast"/> object from parsing the current command line input.</param>
        /// <param name="astTokens">The <see cref="Token"/> objects from parsing the current command line input.</param>
        /// <param name="millisecondsTimeout">The milliseconds to timeout.</param>
        /// <returns>A list of <see cref="PredictionResult"/> objects.</returns>
        [HiddenAttribute]
        public static Task<List<PredictionResult>> PredictInputAsync(PredictionClient client, Ast ast, Token[] astTokens, int millisecondsTimeout)
        {
            return null;
        }

        /// <summary>
        /// Allow registered predictors to do early processing when a command line is accepted.
        /// </summary>
        /// <param name="client">Represents the client that initiates the call.</param>
        /// <param name="history">History command lines provided as references for prediction.</param>
        [HiddenAttribute]
        public static void OnCommandLineAccepted(PredictionClient client, IReadOnlyList<string> history)
        {
        }

        /// <summary>
        /// Allow registered predictors to know the execution result (success/failure) of the last accepted command line.
        /// </summary>
        /// <param name="client">Represents the client that initiates the call.</param>
        /// <param name="commandLine">The last accepted command line.</param>
        /// <param name="success">Whether the execution of the last command line was successful.</param>
        [HiddenAttribute]
        public static void OnCommandLineExecuted(PredictionClient client, string commandLine, bool success)
        {
        }

        /// <summary>
        /// Send feedback to a predictor when one or more suggestions from it were displayed to the user.
        /// </summary>
        /// <param name="client">Represents the client that initiates the call.</param>
        /// <param name="predictorId">The identifier of the predictor whose prediction result was accepted.</param>
        /// <param name="session">The mini-session where the displayed suggestions came from.</param>
        /// <param name="countOrIndex">
        /// When the value is <code>> 0</code>, it's the number of displayed suggestions from the list returned in <see cref="session"/>, starting from the index 0.
        /// When the value is <code><= 0</code>, it means a single suggestion from the list got displayed, and the index is the absolute value.
        /// </param>
        [HiddenAttribute]
        public static void OnSuggestionDisplayed(PredictionClient client, Guid predictorId, uint session, int countOrIndex)
        {
        }

        /// <summary>
        /// Send feedback to predictors about their last suggestions.
        /// </summary>
        /// <param name="client">Represents the client that initiates the call.</param>
        /// <param name="predictorId">The identifier of the predictor whose prediction result was accepted.</param>
        /// <param name="session">The mini-session where the accepted suggestion came from.</param>
        /// <param name="suggestionText">The accepted suggestion text.</param>
        [HiddenAttribute]
        public static void OnSuggestionAccepted(PredictionClient client, Guid predictorId, uint session, string suggestionText)
        {
        }
    }
}

#else

using System.Management.Automation.Subsystem.Prediction;
using System.Runtime.CompilerServices;

[assembly: TypeForwardedTo(typeof(PredictionClientKind))]
[assembly: TypeForwardedTo(typeof(PredictionClient))]
[assembly: TypeForwardedTo(typeof(PredictiveSuggestion))]
[assembly: TypeForwardedTo(typeof(PredictionResult))]
[assembly: TypeForwardedTo(typeof(CommandPrediction))]

#endif