// ==========================================================================
//  Squidex Headless CMS
// ==========================================================================
//  Copyright (c) Squidex UG (haftungsbeschraenkt)
//  All rights reserved. Licensed under the MIT license.
// ==========================================================================

using System.Diagnostics;

namespace Squidex.Infrastructure
{
    public struct ValueStopwatch
    {
        private const long TicksPerMillisecond = 10000;
        private const long TicksPerSecond = TicksPerMillisecond * 1000;

        private static readonly double TickFrequency;

        private readonly long startTime;

        static ValueStopwatch()
        {
            if (Stopwatch.IsHighResolution)
            {
                TickFrequency = (double)TicksPerSecond / Stopwatch.Frequency;
            }
        }

        public ValueStopwatch(long startTime)
        {
            this.startTime = startTime;
        }

        public static ValueStopwatch StartNew()
        {
            return new ValueStopwatch(Stopwatch.GetTimestamp());
        }

        public long Stop()
        {
            var elapsed = Stopwatch.GetTimestamp() - startTime;

            if (elapsed < 0)
            {
                return elapsed;
            }

            if (Stopwatch.IsHighResolution)
            {
                elapsed = unchecked((long)(elapsed * TickFrequency));
            }

            return elapsed / TicksPerMillisecond;
        }
    }
}