// 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.Threading;
 
namespace Microsoft.CodeAnalysis.Shared.Utilities
{
    /// <summary>
    /// Utility class that can be used to track the progress of an operation in a threadsafe manner.
    /// </summary>
    internal class ProgressTracker : IProgressTracker
    {
        private string _description;
        private int _completedItems;
        private int _totalItems;
 
        private readonly Action<string, int, int> _updateActionOpt;
 
        public ProgressTracker()
            : this(null)
        {
        }
 
        public ProgressTracker(Action<string, int, int> updateActionOpt)
            => _updateActionOpt = updateActionOpt;
 
        public string Description
        {
            get => _description;
            set
            {
                _description = value;
                Update();
            }
        }
 
        public int CompletedItems => _completedItems;
 
        public int TotalItems => _totalItems;
 
        public void AddItems(int count)
        {
            Interlocked.Add(ref _totalItems, count);
            Update();
        }
 
        public void ItemCompleted()
        {
            Interlocked.Increment(ref _completedItems);
            Update();
        }
 
        public void Clear()
        {
            _totalItems = 0;
            _completedItems = 0;
            _description = null;
            Update();
        }
 
        private void Update()
            => _updateActionOpt?.Invoke(_description, _completedItems, _totalItems);
    }
}