#include <string>
#include <thread>
#include <iostream>
#include <mutex>
#include <enet/enet.h>
using namespace std;

std::mutex mtx_flush;
void main()
{
    // initialize
    if(enet_initialize()) {
        cout << "fail init" << endl;
        return;
    }

    ENetAddress address;
    address.host = ENET_HOST_ANY;
    address.port = 9000;

    ENetHost* server;
    server = enet_host_create(&address,
                  32,
                  2,
                  0,
                  0);
    if(server == NULL) {
        cout << "fail create host" << endl;
        enet_deinitialize();
        return;
    }

    ENetEvent event;
    while(enet_host_service(server, &event, 5000) >= 0) {
        if(event.type == ENET_EVENT_TYPE_CONNECT) { // client connected
            ENetAddress remote = event.peer->address; // peer address
        } else if(event.type == ENET_EVENT_TYPE_RECEIVE) {    // recv data
            enet_packet_destroy(event.packet); // free
            // ----------- send ------------
            thread t(std::bind([&] (ENetHost* server, ENetPeer* peer)
            {
                cout << "now reply" << endl;
                string data(2 * 1024, 'b'); // not ok
                ENetPacket* packet1 = enet_packet_create(data.c_str(), data.length(), ENET_PACKET_FLAG_RELIABLE);
                if(!packet1) {
                    cout << "create packet fail" << endl;
                    return;
                }

                if(enet_peer_send(peer, 0, packet1) < 0) {
                    cout << "send fail" << endl;
                    return;
                }

                {

                    std::lock_guard<std::mutex> guard(mtx_flush);
                    enet_host_flush (server);
                }
            }, server, event.peer));
            t.detach();
        } else if(event.type == ENET_EVENT_TYPE_DISCONNECT) {     // disconnect
            // cout << "peer disconnected" << endl;
        }
    }

    enet_deinitialize();
}