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 string Value;
    }

    public class FugSerializer : BinaryObjectSerializer<FugObject>
    {
        public override void Deserialize(ref FugObject obj)
        {
            obj.Value = reader.ReadString();
        }

        public override void Serialize(ref FugObject obj)
        {
            writer.Write(obj.Value);
        }
    }

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

        public void ConcurrentReader(ref FugObject key, ref string input, ref FugObject value, ref string 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 string input, ref FugObject oldValue, ref FugObject newValue)
        {
        }

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

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

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

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

        public void RMWCompletionCallback(ref FugObject key, ref string 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)
        {
            if (k1.Value == null && k2.Value == null)
                return true;

            if (k1.Value == null || k2.Value == null)
                return false;

            return StringComparer.Ordinal.Compare(k1.Value, k2.Value) == 0;
        }

        public long GetHashCode64(ref FugObject k)
        {
            var hashCode = StringComparer.Ordinal.GetHashCode(k.Value);
            return Utility.GetHashCode(hashCode);
        }
    }

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

            var mainLog = Devices.CreateLogDevice(mainLogPath);
            var objectLog = Devices.CreateLogDevice(objectLogPath);
            var faster = new FasterKV<FugObject, FugObject, string, string, Empty, FugFunctions>(
                1 << 21,
                new FugFunctions(),
                new LogSettings() { LogDevice = mainLog, ObjectLogDevice = objectLog },
                new CheckpointSettings() { CheckpointDir = checkpointPath, CheckPointType = CheckpointType.Snapshot },
                new SerializerSettings<FugObject, FugObject>() { keySerializer = () => new FugSerializer(), valueSerializer = () => new FugSerializer() },
                new FugEqualityComparer(),
                null);

            faster.StartSession();

            var valueString = "3.14159265359";
            var sequence = 0L;
            for (var i = 0; i < 4000000; i++)
            {
                var key = new FugObject() { Value = i.ToString() };
                var value = new FugObject() { Value = valueString };

                faster.Upsert(ref key, ref value, Empty.Default, sequence);
                sequence++;
            }

            faster.TakeFullCheckpoint(out var _);
            faster.CompleteCheckpoint(true); // <- exception here

            faster.StopSession();
            faster.Dispose();

            objectLog.Close();
            mainLog.Close();
        }
    }
}