using System;
using System.Runtime.InteropServices;
using System.Threading;

namespace VictusLauncher
{
    public static class Timing
    {
        private const String Winmm = "winmm.dll";
        private const String Kernel32 = "kernel32.dll";

        [DllImport(Winmm)]
        private static extern UInt32 timeBeginPeriod(uint period);
        [DllImport(Kernel32)]
        private static extern Boolean QueryPerformanceCounter(out long performanceCount);
        [DllImport(Kernel32)]
        private static extern Boolean QueryPerformanceFrequency(out long frequency);

        private static readonly Int64 Freq;

        static Timing()
        {
            timeBeginPeriod(1);
            QueryPerformanceFrequency(out Freq);
        }

        public static Int64 GetTimestamp()
        {
            Int64 result;
            QueryPerformanceCounter(out result);
            return result;
        }

        public static Int64 DeltaMicroseconds(Int64 earlyTimestamp, Int64 lateTimestamp)
        {
            return Freq != 0 ? ((lateTimestamp - earlyTimestamp) * 1000000) / Freq : 0;
        }

        public static Int64 DeltaMilliseconds(Int64 earlyTimestamp, Int64 lateTimestamp)
        {
            return Freq != 0 ? ((lateTimestamp - earlyTimestamp) * 1000) / Freq : 0;
        }

        public static Int64 DeltaSeconds(Int64 earlyTimestamp, Int64 lateTimestamp)
        {
            return Freq != 0 ? (lateTimestamp - earlyTimestamp) / Freq : 0;
        }

        public static void Sleep(Int32 delay)
        {
            Int64 elapsed = 0;
            Int64 before = GetTimestamp();

            while (delay > elapsed)
            {
                Thread.Sleep(delay);
                elapsed = DeltaMicroseconds(before, GetTimestamp());
            }
        }
    }
}