using System;
using System.Collections.Generic;
using System.Collections.Concurrent;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Google.Protobuf.WellKnownTypes;





namespace ServerCore;

//=============================================================================================
// 병렬 프로그래밍 환경에서 특정 객체의 Read & Write 처리를 ReaderWriterLockSlim 활용하여
// 동기화해주는 클래스 이다.
//
// author : kangms
// 
//=============================================================================================

public class Synchronizer<TObject>
    where TObject : class
{
    private readonly ReaderWriterLockSlim m_rw_lock;

    private readonly TObject m_value;

    public Synchronizer(TObject value)
    {
        ArgumentNullReferenceCheckHelper.throwIfNull(value, () => $"value is null !!!");

        m_value = value;

        var dynamic_obj = (value as dynamic);
        ArgumentNullException.ThrowIfNull(dynamic_obj, "dynamic_obj is null !!!");

        m_rw_lock = dynamic_obj.getRWLock();
    }

    //=============================================================================================
    // 호출자의 읽기를 위한 로직을 동기화 해준다.
    // ReaderWriterLockSlim의 EnterReadLock() 호출하여 동기화 해준다.
    //=============================================================================================
    public TResult callReadFunc<TResult>(Func<TObject, TResult> readFunc)
    {
        ArgumentNullReferenceCheckHelper.throwIfNull(readFunc, () => $"readFunc is null !!!");

        m_rw_lock.EnterReadLock();
        try
        {
            return readFunc(m_value);
        }
        finally
        {
            m_rw_lock.ExitReadLock();
        }
    }

    //=============================================================================================
    // 호출자의 쓰기를 위한 로직을 동기화 해준다.
    // ReaderWriterLockSlim의 EnterWriteLock() 호출하여 동기화 해준다.
    //=============================================================================================
    public TResult callWriteFunc<TResult>(Func<TObject, TResult> writeFunc)
    {
        ArgumentNullReferenceCheckHelper.throwIfNull(writeFunc, () => $"writeFunc is null !!!");

        m_rw_lock.EnterWriteLock();
        try
        {
            return writeFunc(m_value);
        }
        finally
        {
            m_rw_lock.ExitWriteLock();
        }
    }

    public IDisposable tryReadLock()
    {
        m_rw_lock.EnterReadLock();

        return new Unlocker(m_rw_lock, isReadLock: true);
    }

    public IDisposable tryWriteLock()
    {
        m_rw_lock.EnterWriteLock();

        return new Unlocker(m_rw_lock, isReadLock: false);
    }
}

//=============================================================================================
// Synchronizer를 복수개로 처리할 때 사용하는 클래스 이다.
//
// author : kangms
// 
//=============================================================================================

public class MultipleSynchronizer<TObject>
    where TObject : class
{
    private readonly ConcurrentDictionary<string, Synchronizer<TObject>> m_synchronizers = new();

    public MultipleSynchronizer(Dictionary<string, TObject> toSyncObjects)
    {
        foreach (var each in toSyncObjects)
        {
            var synchronizer = new Synchronizer<TObject>(each.Value);
            m_synchronizers[each.Key] = synchronizer;
        }
    }

    //=============================================================================================
    // 등록된 객체중에서 locks 파라메터에 의해 선택적으로 Read & Write Lock을 설정해 준다.
    //=============================================================================================

    public MultiLock tryLockAll(IEnumerable<(string Key, bool IsReadLock)> locks)
    {
        return new MultiLock(m_synchronizers, locks);
    }

    //=============================================================================================
    // 등록된 모든 객체를 Read Lock 설정을 해준다.
    //=============================================================================================
    public MultiReadLock tryReadLockAll()
    {
        return new MultiReadLock(m_synchronizers);
    }

    //=============================================================================================
    // 등록된 모든 객체를 Write Lock 설정을 해준다.
    //=============================================================================================
    public MultiWriteLock tryWriteLockAll()
    {
        return new MultiWriteLock(m_synchronizers);
    }

    public Synchronizer<TObject> this[string index] => m_synchronizers[index];


    public class MultiLock : IDisposable
    {
        private readonly List<IDisposable> m_lock_objects;

        public MultiLock(ConcurrentDictionary<string, Synchronizer<TObject>> syncObjects, IEnumerable<(string Key, bool IsReadLock)> locks)
        {
            m_lock_objects = new List<IDisposable>();

            foreach (var (key, isReadLock) in locks)
            {
                if (true == syncObjects.TryGetValue(key, out var found_object))
                {
                    m_lock_objects.Add(isReadLock ? found_object.tryReadLock() : found_object.tryWriteLock());
                }
            }
        } 

        public void Dispose()
        {
            foreach (var lock_obj in m_lock_objects)
            {
                lock_obj.Dispose();
            }
        }
    }

    public class MultiReadLock : IDisposable
    {
        private readonly List<IDisposable> m_lock_objects;

        public MultiReadLock(IEnumerable<KeyValuePair<string, Synchronizer<TObject>>> syncObjects)
        {
            m_lock_objects = new List<IDisposable>();

            foreach (var each in syncObjects)
            {
                m_lock_objects.Add(each.Value.tryReadLock());
            }
        }

        public void Dispose()
        {
            foreach (var lock_obj in m_lock_objects)
            {
                lock_obj.Dispose();
            }
        }
    }

    public class MultiWriteLock : IDisposable
    {
        private readonly List<IDisposable> m_lock_objects;

        public MultiWriteLock(IEnumerable<KeyValuePair<string, Synchronizer<TObject>>> syncObjects)
        {
            m_lock_objects = new List<IDisposable>();

            foreach (var each in syncObjects)
            {
                m_lock_objects.Add(each.Value.tryWriteLock());
            }
        }

        public void Dispose()
        {
            foreach (var lock_obj in m_lock_objects)
            {
                lock_obj.Dispose();
            }
        }
    }
}

//=============================================================================================
// 병렬 프로그래밍 환경에서 특정 객체의 Read & Write 처리를 ReaderWriterLockSlim 활용하여
// async 기반으로 동기화해주는 클래스 이다.
//
// author : kangms
// 
//=============================================================================================

public class SynchronizerAsync<TObject>
    where TObject : class
{
    private readonly ReaderWriterLockSlim m_rw_lock;

    private readonly TObject m_value;

    public SynchronizerAsync(TObject value)
    {
        m_value = value;
        m_rw_lock = (value as dynamic).getRWLock();
    }

    //=============================================================================================
    // 호출자의 읽기를 위한 로직을 async 기반으로 동기화 해준다.
    // ReaderWriterLockSlim의 tryReadLockAsync() 호출하여 동기화 해준다.
    //=============================================================================================
    public async Task<TResult> callReadFuncAsync<TResult>(Func<TObject, Task<TResult>> readFunc)
    {
        ArgumentNullReferenceCheckHelper.throwIfNull(readFunc, () => $"readFunc is null !!!");

        await m_rw_lock.tryReadLockAsync();
        try
        {
            return await readFunc(m_value);
        }
        finally
        {
            m_rw_lock.ExitReadLock();
        }
    }

    //=============================================================================================
    // 호출자의 쓰기를 위한 로직을 async 기반으로 동기화 해준다.
    // ReaderWriterLockSlim의 tryWriteLockAsync() 호출하여 동기화 해준다.
    //=============================================================================================
    public async Task<TResult> callWriteFuncAsync<TResult>(Func<TObject, Task<TResult>> writeFunc)
    {
        ArgumentNullReferenceCheckHelper.throwIfNull(writeFunc, () => $"writeFunc is null !!!");

        await m_rw_lock.tryWriteLockAsync();
        try
        {
            return await writeFunc(m_value);
        }
        finally
        {
            m_rw_lock.ExitWriteLock();
        }
    }

    public async Task<IDisposable> tryReadLockAsync()
    {
        return await m_rw_lock.tryReadLockAsync();
    }

    public async Task<IDisposable> tryWriteLockAsync()
    {
        return await m_rw_lock.tryWriteLockAsync();
    }
}

//=============================================================================================
// SynchronizerAsync를 복수개로 처리할 때 사용하는 클래스 이다.
//
// author : kangms
// 
//=============================================================================================

public class MultipleSynchronizerAsync<TObject>
    where TObject : class
{
    private readonly ConcurrentDictionary<string, SynchronizerAsync<TObject>> m_synchronizers = new();

    public MultipleSynchronizerAsync(Dictionary<string, TObject> toSyncObjects)
    {
        foreach (var each in toSyncObjects)
        {
            var synchronizer = new SynchronizerAsync<TObject>(each.Value);
            m_synchronizers[each.Key] = synchronizer;
        }
    }

    //=============================================================================================
    // 등록된 객체중에서 locks 파라메터에 의해 선택적으로 Read & Write Lock을 설정해 준다.
    //=============================================================================================

    public MultiLockAsync tryLockAllAsync(IEnumerable<(string Key, bool IsReadLock)> locks)
    {
        return new MultiLockAsync(m_synchronizers, locks);
    }

    //=============================================================================================
    // 등록된 모든 객체를 Read Lock 설정을 해준다.
    //=============================================================================================
    public MultiReadLockAsync tryReadLockAllAsync()
    {
        return new MultiReadLockAsync(m_synchronizers);
    }

    //=============================================================================================
    // 등록된 모든 객체를 Write Lock 설정을 해준다.
    //=============================================================================================
    public MultiWriteLockAsync tryWriteLockAllAsync()
    {
        return new MultiWriteLockAsync(m_synchronizers);
    }

    public SynchronizerAsync<TObject> this[string index] => m_synchronizers[index];


    public class MultiLockAsync : IDisposable
    {
        private readonly List<IDisposable> m_lock_objects;

        public MultiLockAsync(ConcurrentDictionary<string, SynchronizerAsync<TObject>> syncObjects, IEnumerable<(string Key, bool IsReadLock)> locks)
        {
            m_lock_objects = new List<IDisposable>();

            foreach (var (key, isReadLock) in locks)
            {
                if (true == syncObjects.TryGetValue(key, out var found_object))
                {
                    m_lock_objects.Add(isReadLock ? found_object.tryReadLockAsync() : found_object.tryWriteLockAsync());
                }
            }
        } 

        public void Dispose()
        {
            foreach (var lock_obj in m_lock_objects)
            {
                lock_obj.Dispose();
            }
        }
    }

    public class MultiReadLockAsync : IDisposable
    {
        private readonly List<IDisposable> m_lock_objects;

        public MultiReadLockAsync(IEnumerable<KeyValuePair<string, SynchronizerAsync<TObject>>> syncObjects)
        {
            m_lock_objects = new List<IDisposable>();

            foreach (var each in syncObjects)
            {
                m_lock_objects.Add(each.Value.tryReadLockAsync());
            }
        }

        public void Dispose()
        {
            foreach (var lock_obj in m_lock_objects)
            {
                lock_obj.Dispose();
            }
        }
    }

    public class MultiWriteLockAsync : IDisposable
    {
        private readonly List<IDisposable> m_lock_objects;

        public MultiWriteLockAsync(IEnumerable<KeyValuePair<string, SynchronizerAsync<TObject>>> syncObjects)
        {
            m_lock_objects = new List<IDisposable>();

            foreach (var each in syncObjects)
            {
                m_lock_objects.Add(each.Value.tryWriteLockAsync());
            }
        }

        public void Dispose()
        {
            foreach (var lock_obj in m_lock_objects)
            {
                lock_obj.Dispose();
            }
        }
    }
}

//=============================================================================================
// Unlocker가 소멸될 때 ReaderWriterLockSlim가 Exit 될 수 있도록 해주는 클래스 이다.
//=============================================================================================
public class Unlocker : IDisposable
{
    private readonly ReaderWriterLockSlim m_ref_rw_lock;
    private readonly bool m_is_read_lock;

    public Unlocker(ReaderWriterLockSlim readWriteLockObject, bool isReadLock)
    {
        m_ref_rw_lock = readWriteLockObject;
        m_is_read_lock = isReadLock;
    }

    public void Dispose()
    {
        if (m_is_read_lock)
        {
            m_ref_rw_lock.ExitReadLock();
        }
        else
        {
            m_ref_rw_lock.ExitWriteLock();
        }
    }
}