#pragma once
#include "Utils/ThreadPool.hpp"
#include "Socket/WSAManager.hpp"
#include "Socket/TCPSocket.hpp"
#include "Socket/Log.hpp"
#include <functional>
#include <vector>

#include "precomp.hpp"

#ifndef _WIN32

typedef struct _OVERLAPPED {
    char dummy;
} OVERLAPPED;

typedef struct __WSABUF {
    std::uint32_t len;
    char *buf;
} WSABUF;

#endif

namespace Chattr {

class IOCP;

struct IOCPPASSINDATA {
    OVERLAPPED overlapped;
    std::shared_ptr<TCPSocket> socket;
    char buf[1501];
    std::uint32_t recvbytes;
    std::uint32_t sendbytes;
    std::uint32_t transfrredbytes;
    WSABUF wsabuf;
    IOCP* IOCPInstance;
};

class IOCP {
public:
#ifdef _WIN32
    static void iocpWather(ThreadPool* threadPool, HANDLE completionPort_, std::function<void(ThreadPool*, IOCPPASSINDATA*)> callback) {
        DWORD tid = GetCurrentThreadId();
        spdlog::trace("Waiting IO to complete on TID: {}.", tid);
        IOCPPASSINDATA* data;
        SOCKET sock;
        DWORD cbTransfrred;
        int retVal = GetQueuedCompletionStatus(completionPort_, &cbTransfrred, (PULONG_PTR)&sock, (LPOVERLAPPED*)&data, INFINITE);
        if (retVal == 0 || cbTransfrred == 0) {
            spdlog::debug("Client disconnected. [{}]", (std::string)(data->socket->remoteAddr));
            delete data;
            threadPool->enqueueJob(iocpWather, completionPort_, callback);
            return;
        }
        data->transfrredbytes = cbTransfrred;
        threadPool->enqueueJob(callback, data);
        threadPool->enqueueJob(iocpWather, completionPort_, callback);
    };
#elif __linux__
    static void socketReader(ThreadPool* threadPool, epoll_event event, int epollfd, std::function<void(ThreadPool*, IOCPPASSINDATA*)> callback) {
        IOCPPASSINDATA* iocpData = (IOCPPASSINDATA*)event.data.ptr;
        
        pthread_t tid = pthread_self();

        if (iocpData == nullptr) {
            spdlog::error("invalid call on {}", tid);
            return;
        }

        spdlog::trace("reading on tid: {} [{}]", tid, (std::string)iocpData->socket.remoteAddr);

        int redSize = 0;
        int packetSize = iocpData->wsabuf.len;
        int totalRedSize = 0;

        while (totalRedSize < packetSize) {
            redSize = iocpData->socket.recv(iocpData->buf, packetSize - totalRedSize, 0);
            
            if (redSize <= 0) {
                spdlog::debug("Client disconnected. [{}]", (std::string)iocpData->socket.remoteAddr);
                ::epoll_ctl(epollfd, EPOLL_CTL_DEL, iocpData->socket.sock, NULL);
                delete iocpData;
                return;
            }
            totalRedSize += redSize;
        }
        iocpData->sendbytes = packetSize - totalRedSize;
        iocpData->recvbytes = totalRedSize;
        threadPool->enqueueJob(callback, iocpData);
    };
    static void socketWriter(ThreadPool* threadPool, epoll_event event, int epollfd, std::function<void(ThreadPool*, IOCPPASSINDATA*)> callback) {
        IOCPPASSINDATA* iocpData = (IOCPPASSINDATA*)event.data.ptr;

        int packetSize = iocpData->wsabuf.len;
        int totalSentSize = 0;
        int sentSize = 0;

        spdlog::trace("Sending to: [{}]", (std::string)iocpData->socket.remoteAddr);

        while (totalSentSize < packetSize) {
            sentSize = iocpData->socket.send(iocpData->buf, packetSize - totalSentSize, 0);

            if (sentSize <= 0) {
                spdlog::debug("Client disconnected. [{}]", (std::string)iocpData->socket.remoteAddr);
                ::epoll_ctl(epollfd, EPOLL_CTL_DEL, iocpData->socket.sock, NULL);
                delete iocpData;
                return;
            }
            totalSentSize += sentSize;
        }
        iocpData->recvbytes = packetSize - totalSentSize;
        iocpData->sendbytes = totalSentSize;
        threadPool->enqueueJob(callback, iocpData);
    };
    static void iocpWatcher(ThreadPool* threadPool, int epollfd, std::function<void(ThreadPool*, IOCPPASSINDATA*)> callback) {
        struct epoll_event events[FD_SETSIZE];
        pthread_t tid = pthread_self();

        spdlog::trace("epoll waiting on {}", tid);
        int nready = ::epoll_wait(epollfd, events, FD_SETSIZE, -1);

        for (int i=0; i<nready; i++) {
            struct epoll_event current_event = events[i];

            if (current_event.events & EPOLLIN) {
                std::function<void(ThreadPool*, IOCPPASSINDATA*)> task(callback);
                threadPool->enqueueJob(socketReader, current_event, epollfd, task);
            }
            else if (current_event.events & EPOLLOUT) {
                std::function<void(ThreadPool*, IOCPPASSINDATA*)> task(callback);
                threadPool->enqueueJob(socketWriter, current_event, epollfd, task);
            }
        }
        threadPool->enqueueJob(iocpWatcher, epollfd, callback);
    };
#endif

    template<typename _Callable>
    void init(ThreadPool* __IOCPThread, _Callable&& callback) {
        IOCPThread_ = __IOCPThread;
#ifdef _WIN32
        completionPort_ = ::CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0);
        if (completionPort_ == NULL)
            log::critical("CreateIoCompletionPort()");
#elif __linux__
        epollfd_ = ::epoll_create(1);
#endif
        auto boundFunc = [callback = std::move(callback)](ThreadPool* __IOCPThread, IOCPPASSINDATA* data) mutable {
            callback(__IOCPThread, data);
        };

#ifdef _WIN32
        int tCount = __IOCPThread->threadCount;

        spdlog::info("Resizing threadpool size to: {}", tCount * 2);

        __IOCPThread->respawnWorker(tCount * 2);

        for (int i = 0; i < tCount; i++) {
            std::function<void(ThreadPool*, IOCPPASSINDATA*)> task(boundFunc);
            __IOCPThread->enqueueJob(iocpWather, completionPort_, task);
        }
#elif __linux__
        spdlog::info("Spawning 1 Epoll Waiter...");
        __IOCPThread->enqueueJob(iocpWatcher, epollfd_, boundFunc);
#endif
    }

    void registerSocket(Chattr::IOCPPASSINDATA* data);

    int recv(Chattr::IOCPPASSINDATA* data, int bufferCount);
    int send(Chattr::IOCPPASSINDATA* data, int bufferCount, int __flags);

private:
    struct Chattr::WSAManager wsaManager;
    ThreadPool* IOCPThread_;

#ifdef _WIN32
    HANDLE completionPort_ = INVALID_HANDLE_VALUE;
#elif __linux__
    int epollfd_ = -1;
#endif
};

}