using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using FASTER.core;

namespace Marius.Fug
{
    public struct FugObject
    {
        public long Value;
    }


    public class FugFunctions : IFunctions<FugObject, FugObject, long, long, Empty>
    {
        public void SingleReader(ref FugObject key, ref long input, ref FugObject value, ref long dst)
        {
            dst = value.Value;
        }

        public void ConcurrentReader(ref FugObject key, ref long input, ref FugObject value, ref long dst)
        {
            dst = value.Value;
        }

        public void SingleWriter(ref FugObject key, ref FugObject src, ref FugObject dst)
        {
            dst.Value = src.Value;
        }

        public void ConcurrentWriter(ref FugObject key, ref FugObject src, ref FugObject dst)
        {
            dst.Value = src.Value;
        }

        public void CheckpointCompletionCallback(Guid sessionId, long serialNum)
        {
        }

        public void CopyUpdater(ref FugObject key, ref long input, ref FugObject oldValue, ref FugObject newValue)
        {
        }

        public void DeleteCompletionCallback(ref FugObject key, Empty ctx)
        {
        }

        public void InitialUpdater(ref FugObject key, ref long input, ref FugObject value)
        {
        }

        public void InPlaceUpdater(ref FugObject key, ref long input, ref FugObject value)
        {
        }

        public void ReadCompletionCallback(ref FugObject key, ref long input, ref long output, Empty ctx, Status status)
        {
        }

        public void RMWCompletionCallback(ref FugObject key, ref long input, Empty ctx, Status status)
        {
        }

        public void UpsertCompletionCallback(ref FugObject key, ref FugObject value, Empty ctx)
        {
        }
    }

    public class FugEqualityComparer : IFasterEqualityComparer<FugObject>
    {
        public bool Equals(ref FugObject k1, ref FugObject k2)
        {
            return k1.Value == k2.Value;
        }

        public long GetHashCode64(ref FugObject k)
        {
            return Utility.GetHashCode(k.Value);
        }
    }

    public class Program
    {
        public static void Main(string[] args)
        {
            var mainLogPath = Path.Combine(Directory.GetCurrentDirectory(), @"logs\main.hlog");
            var checkpointPath = Path.Combine(Directory.GetCurrentDirectory(), @"logs");

            var isSecond = Directory.Exists(checkpointPath);

            var mainLog = Devices.CreateLogDevice(mainLogPath);
            var faster = new FasterKV<FugObject, FugObject, long, long, Empty, FugFunctions>(
                1 << 21,
                new FugFunctions(),
                new LogSettings() { LogDevice = mainLog },
                new CheckpointSettings() { CheckpointDir = checkpointPath, CheckPointType = CheckpointType.FoldOver },
                null,
                new FugEqualityComparer(),
                null);

            if (isSecond)
                faster.Recover();

            faster.StartSession();

            var key = new FugObject() { Value = 10000L };
            var value = new FugObject() { Value = 20000L };
            if (!isSecond)
            {
                faster.Upsert(ref key, ref value, Empty.Default, 0);
            }
            else
            {
                var input = default(long);
                var output = default(long);

                faster.Read(ref key, ref input, ref output, Empty.Default, 0);
            }

            faster.TakeFullCheckpoint(out var _);
            faster.CompleteCheckpoint(true);

            faster.StopSession();

            faster.Dispose();

            mainLog.Close();
        }
    }
}