// 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.Threading;
using System.Threading.Tasks;
 
namespace Microsoft.CodeAnalysis.ValueTracking
{
    internal class ValueTrackingProgressCollector : IProgress<ValueTrackedItem>
    {
        private readonly object _lock = new();
        private readonly Stack<ValueTrackedItem> _items = new();
 
        public event EventHandler<ValueTrackedItem>? OnNewItem;
 
        internal ValueTrackedItem? Parent { get; set; }
 
        public void Report(ValueTrackedItem item)
        {
            lock (_lock)
            {
                _items.Push(item);
            }
 
            OnNewItem?.Invoke(null, item);
        }
 
        public ImmutableArray<ValueTrackedItem> GetItems()
        {
            lock (_lock)
            {
                return _items.ToImmutableArray();
            }
        }
 
        internal async Task<bool> TryReportAsync(Solution solution, Location location, ISymbol symbol, CancellationToken cancellationToken = default)
        {
            var item = await ValueTrackedItem.TryCreateAsync(solution, location, symbol, Parent, cancellationToken).ConfigureAwait(false);
            if (item is not null)
            {
                Report(item);
                return true;
            }
 
            return false;
        }
    }
}