// 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.Internal.Log;

internal sealed class StatisticLogAggregator<TKey> : AbstractLogAggregator<TKey, StatisticLogAggregator<TKey>.StatisticCounter> where TKey : notnull
{
    protected override StatisticCounter CreateCounter()
        => new();

    public void AddDataPoint(TKey key, int value)
    {
        var counter = GetCounter(key);
        counter.AddDataPoint(value);
    }

    public void AddDataPoint(TKey key, TimeSpan timeSpan)
    {
        AddDataPoint(key, (int)timeSpan.TotalMilliseconds);
    }

    public StatisticResult GetStatisticResult(TKey key)
    {
        if (TryGetCounter(key, out var counter))
        {
            return counter.GetStatisticResult();
        }

        return default;
    }

    internal sealed class StatisticCounter
    {
        private readonly object _lock = new();
        private int _count;
        private int _maximum;
        private int _mininum;

        private int _total;

        public void AddDataPoint(int value)
        {
            lock (_lock)
            {
                if (_count == 0 || value > _maximum)
                {
                    _maximum = value;
                }

                if (_count == 0 || value < _mininum)
                {
                    _mininum = value;
                }

                _count++;
                _total += value;
            }
        }

        public StatisticResult GetStatisticResult()
        {
            if (_count == 0)
            {
                return default;
            }
            else
            {
                return new StatisticResult(_maximum, _mininum, mean: (double)_total / _count, range: _maximum - _mininum, mode: null, count: _count);
            }
        }
    }
}