// 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;

namespace Microsoft.CodeAnalysis.ExternalAccess.UnitTesting.SolutionCrawler;

/// <summary>
/// Provide a way to see whether solution crawler is started or not
/// </summary>
internal interface IUnitTestingSolutionCrawlerProgressReporter
{
    /// <summary>
    /// Return true if solution crawler is in progress.
    /// </summary>
    bool InProgress { get; }

    /// <summary>
    /// Raised when solution crawler progress changed
    /// 
    /// Notifications for this event are serialized to preserve order. 
    /// However, individual event notifications may occur on any thread.
    /// </summary>
    event EventHandler<UnitTestingProgressData> ProgressChanged;
}

internal readonly struct UnitTestingProgressData(UnitTestingProgressStatus type, int? pendingItemCount)
{
    public UnitTestingProgressStatus Status { get; } = type;

    /// <summary>
    /// number of pending work item in the queue. 
    /// null means N/A for the associated <see cref="Status"/>
    /// </summary>
    public int? PendingItemCount { get; } = pendingItemCount;
}

internal enum UnitTestingProgressStatus
{
    Started,
    Paused,
    PendingItemCountUpdated,
    Evaluating,
    Stopped
}