#ifndef EV_KQUEUE_HPP
#define EV_KQUEUE_HPP

#include <ev/ev.hpp>
#include <net/net.h>
#include <net/net.hpp>
#include <util/buffer.h>
#include <util/logger.hpp>

#include <sys/un.h>

#if __FreeBSD__ || __OpenBSD__ || __NetBSD__ || (__APPLE__ && __MACH__)
// kqueue / kevent
#include <sys/event.h>
#include <fcntl.h>
#endif

// original upstream
#include <unistd.h>
#include <cstdio>

namespace llarp
{
  inline int
  tcp_conn::read(byte_t* buf, size_t sz)
  {
    if(sz == 0)
    {
      if(tcp.read)
        tcp.read(&tcp, llarp::InitBuffer(nullptr, 0));
      return 0;
    }
    if(_shouldClose)
      return -1;

    ssize_t amount = ::read(fd, buf, sz);

    if(amount >= 0)
    {
      if(tcp.read)
        tcp.read(&tcp, llarp::InitBuffer(buf, amount));
    }
    else
    {
      if(errno == EAGAIN || errno == EWOULDBLOCK)
      {
        errno = 0;
        return 0;
      }
      _shouldClose = true;
      return -1;
    }
    return 0;
  }

  inline void
  tcp_conn::flush_write()
  {
    connected();
    ev_io::flush_write();
  }

  inline ssize_t
  tcp_conn::do_write(void* buf, size_t sz)
  {
    if(_shouldClose)
      return -1;

#if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__)
    // macintosh uses a weird sockopt
    return ::send(fd, buf, sz, MSG_NOSIGNAL);  // ignore sigpipe
#else
    return ::send(fd, buf, sz, 0);
#endif
  }

  inline void
  tcp_conn::connect()
  {
    socklen_t slen = sizeof(sockaddr_in);
    if(_addr.ss_family == AF_UNIX)
      slen = sizeof(sockaddr_un);
    else if(_addr.ss_family == AF_INET6)
      slen = sizeof(sockaddr_in6);
    int result = ::connect(fd, (const sockaddr*)&_addr, slen);
    if(result == 0)
    {
      llarp::LogDebug("Connected");
      connected();
    }
    else if(errno == EINPROGRESS)
    {
      llarp::LogDebug("connect in progress");
      errno = 0;
      return;
    }
    else if(_conn)
    {
      _conn->error(_conn);
    }
  }

  inline int
  tcp_serv::read(byte_t*, size_t)
  {
    int new_fd = ::accept(fd, nullptr, nullptr);
    if(new_fd == -1)
    {
      llarp::LogError("failed to accept on ", fd, ": ", strerror(errno));
      return -1;
    }
    // get flags
    int flags = fcntl(new_fd, F_GETFL, 0);
    if(flags == -1)
    {
      ::close(new_fd);
      return -1;
    }
    // set flags
    if(fcntl(new_fd, F_SETFL, flags | O_NONBLOCK) == -1)
    {
      llarp::LogError("Failed to set non block on ", fd, ": ", strerror(errno));
      ::close(new_fd);
      return -1;
    }
    // build handler
    llarp::tcp_conn* connimpl = new llarp::tcp_conn(loop, new_fd);
    if(loop->add_ev(connimpl, true))
    {
      // call callback
      if(tcp->accepted)
        tcp->accepted(tcp, &connimpl->tcp);
      return 0;
    }
    // cleanup error
    delete connimpl;
    return -1;
  }

  struct udp_listener : public ev_io
  {
    llarp_udp_io* udp;

    udp_listener(int fd, llarp_udp_io* u) : ev_io(fd), udp(u){};

    ~udp_listener()
    {
    }

    bool
    tick()
    {
      if(udp->tick)
        udp->tick(udp);
      return true;
    }

    virtual int
    read(byte_t* buf, size_t sz)
    {
      sockaddr_in6 src;
      socklen_t slen = sizeof(sockaddr_in6);
      sockaddr* addr = (sockaddr*)&src;
      ssize_t ret    = ::recvfrom(fd, buf, sz, 0, addr, &slen);
      if(ret < 0)
      {
        llarp::LogWarn("recvfrom failed");
        return -1;
      }
      if(static_cast< size_t >(ret) > sz)
      {
        llarp::LogWarn("ret > sz");
        return -1;
      }
      if(!addr)
      {
        llarp::LogWarn("no source addr");
      }
      // Addr is the source
      udp->recvfrom(udp, addr, llarp::InitBuffer(buf, ret));
      return 0;
    }

    virtual int
    sendto(const sockaddr* to, const void* data, size_t sz)
    {
      socklen_t slen;
      switch(to->sa_family)
      {
        case AF_INET:
          slen = sizeof(struct sockaddr_in);
          break;
        case AF_INET6:
          slen = sizeof(struct sockaddr_in6);
          break;
        default:
          return -1;
      }
      if(!fd)
      {
        printf("kqueue sendto fd empty\n");
        return -1;
      }
      ssize_t sent = ::sendto(fd, data, sz, 0, to, slen);
      if(sent == -1 || errno)
      {
        llarp::LogError("failed to send udp: ", strerror(errno));
        errno = 0;
      }
      return sent;
    }
  };

  struct tun : public ev_io
  {
    llarp_tun_io* t;
    device* tunif;
    tun(llarp_tun_io* tio, llarp_ev_loop* l)
        : ev_io(-1, new LossyWriteQueue_t("kqueue_tun_write", l, l))
        , t(tio)
        , tunif(tuntap_init()){};

    int
    sendto(__attribute__((unused)) const sockaddr* to,
           __attribute__((unused)) const void* data,
           __attribute__((unused)) size_t sz) override
    {
      return -1;
    }

#ifdef __APPLE__
    ssize_t
    do_write(void* buf, size_t sz) override
    {
      iovec vecs[2];
      // TODO: IPV6
      uint32_t t       = htonl(AF_INET);
      vecs[0].iov_base = &t;
      vecs[0].iov_len  = sizeof(t);
      vecs[1].iov_base = buf;
      vecs[1].iov_len  = sz;
      return writev(fd, vecs, 2);
    }
#endif

    void
    before_flush_write() override
    {
      if(t->before_write)
      {
        t->before_write(t);
      }
    }

    bool
    tick() override
    {
      if(t->tick)
        t->tick(t);
      flush_write();
      return true;
    }

    int
    read(byte_t* buf, size_t) override
    {
// all BSDs have packet info except freebsd
#ifdef __FreeBSD__
      const ssize_t offset = 0;
#else
      const ssize_t offset = 4;
#endif

      ssize_t ret = ::read(fd, buf, 1500);
      if(ret > offset && t->recvpkt)
      {
        buf += offset;
        ret -= offset;
        auto pkt = llarp::InitBuffer(buf, ret);
        t->recvpkt(t, pkt);
      }
      return ret;
    }

    bool
    setup()
    {
      llarp::LogDebug("set up tunif");

      if(tuntap_start(tunif, TUNTAP_MODE_TUNNEL, 0) == -1)
      {
        llarp::LogWarn("Can't set tuntap to tunnel mode");
        return false;
      }

      if(tuntap_up(tunif) == -1)
      {
        llarp::LogWarn("Can't bring up tuntap");
        return false;
      }

      if(tuntap_set_ifname(tunif, t->ifname) == -1)
      {
        llarp::LogInfo("Can't set tun interface name to ", tunif->if_name);
        return false;
      }

      // currently trying to set
      llarp::LogInfo("setting ", tunif->if_name, " to use address ", t->ifaddr);
      if(tuntap_set_ip(tunif, t->ifaddr, t->ifaddr, t->netmask) == -1)
      {
        llarp::LogWarn("Can't set tuntap ip on ", tunif->if_name, " to ",
                       t->ifaddr, " netmask ", t->netmask);
        return false;
      }
      fd = tunif->tun_fd;
      return fd != -1;
    }

    ~tun()
    {
      if(tunif)
        tuntap_destroy(tunif);
    }
  };

};  // namespace llarp

struct llarp_kqueue_loop : public llarp_ev_loop
{
  int kqueuefd;

  llarp_kqueue_loop() : kqueuefd(-1)
  {
  }

  llarp::ev_io*
  bind_tcp(llarp_tcp_acceptor* tcp, const sockaddr* bindaddr)
  {
    int fd = ::socket(bindaddr->sa_family, SOCK_STREAM, 0);
    if(fd == -1)
      return nullptr;
    socklen_t sz = sizeof(sockaddr_in);
    if(bindaddr->sa_family == AF_INET6)
    {
      sz = sizeof(sockaddr_in6);
    }
    else if(bindaddr->sa_family == AF_UNIX)
    {
      sz = sizeof(sockaddr_un);
    }
    if(::bind(fd, bindaddr, sz) == -1)
    {
      ::close(fd);
      return nullptr;
    }
    if(::listen(fd, 5) == -1)
    {
      ::close(fd);
      return nullptr;
    }
    // set non blocking
    int flags = fcntl(fd, F_GETFL, 0);
    if(flags == -1)
    {
      ::close(fd);
      return nullptr;
    }
    if(fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
    {
      ::close(fd);
      return nullptr;
    }
    llarp::ev_io* serv = new llarp::tcp_serv(this, fd, tcp);
    tcp->impl          = serv;
    return serv;
  }

  ~llarp_kqueue_loop()
  {
  }

  llarp::ev_io*
  create_tun(llarp_tun_io* tun)
  {
    llarp::tun* t = new llarp::tun(tun, this);
    if(t->setup())
      return t;
    llarp::LogWarn("Could not set up tun");
    delete t;
    return nullptr;
  }

  bool
  init()
  {
    if(kqueuefd == -1)
    {
      kqueuefd = kqueue();
    }
    return kqueuefd != -1;
  }

  bool
  running() const
  {
    return kqueuefd != -1;
  }

  bool
  tcp_connect(llarp_tcp_connecter* tcp, const sockaddr* addr)
  {
    int fd = ::socket(addr->sa_family, SOCK_STREAM, 0);
    if(fd == -1)
      return false;
    int flags = fcntl(fd, F_GETFL, 0);
    if(flags == -1)
    {
      ::close(fd);
      return false;
    }
    if(fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
    {
      ::close(fd);
      return false;
    }

    llarp::tcp_conn* conn = new llarp::tcp_conn(this, fd, addr, tcp);
    add_ev(conn, true);
    conn->connect();
    return true;
  }

  int
  tick(int ms)
  {
    std::array< struct kevent, 1024 > events;
    int result;
    timespec t;
    t.tv_sec  = 0;
    t.tv_nsec = ms * 1000000UL;
    result    = kevent(kqueuefd, nullptr, 0, events.data(), events.size(), &t);
    // result: 0 is a timeout
    if(result > 0)
    {
      int idx = 0;
      while(idx < result)
      {
        llarp::ev_io* ev = static_cast< llarp::ev_io* >(events[idx].udata);
        if(ev)
        {
          if(events[idx].filter & EVFILT_WRITE)
            ev->flush_write_buffers(events[idx].data);
          if(events[idx].filter & EVFILT_READ)
            ev->read(readbuf,
                     std::min(sizeof(readbuf), size_t(events[idx].data)));
        }
        ++idx;
      }
    }
    if(result != -1)
      tick_listeners();
    return result;
  }

  int
  run()
  {
    timespec t;
    t.tv_sec  = 0;
    t.tv_nsec = 1000000UL * EV_TICK_INTERVAL;
    struct kevent events[1024];
    int result;
    do
    {
      result = kevent(kqueuefd, nullptr, 0, events, 1024, &t);
      // result: 0 is a timeout
      if(result > 0)
      {
        int idx = 0;
        while(idx < result)
        {
          llarp::ev_io* ev = static_cast< llarp::ev_io* >(events[idx].udata);
          if(ev)
          {
            if(events[idx].filter & EVFILT_READ)
              ev->read(readbuf,
                       std::min(sizeof(readbuf), size_t(events[idx].data)));
            if(events[idx].filter & EVFILT_WRITE)
              ev->flush_write_buffers(events[idx].data);
          }
          else
          {
            llarp::LogWarn("kqueue event ", idx, " udata wasnt an ev_io");
          }
          ++idx;
        }
      }
      if(result != -1)
        tick_listeners();
    } while(result != -1);
    return result;
  }

  int
  udp_bind(const sockaddr* addr)
  {
    socklen_t slen;
    llarp::LogDebug("kqueue bind affam", addr->sa_family);
    switch(addr->sa_family)
    {
      case AF_INET:
        slen = sizeof(struct sockaddr_in);
        break;
      case AF_INET6:
        slen = sizeof(struct sockaddr_in6);
        break;
#ifdef AF_LINK
#endif
#ifdef AF_PACKET
      case AF_PACKET:
        slen = sizeof(struct sockaddr_ll);
        break;
#endif
      default:
        llarp::LogError("unsupported address family");
        return -1;
    }
    int fd = socket(addr->sa_family, SOCK_DGRAM, 0);
    if(fd == -1)
    {
      perror("socket()");
      return -1;
    }

    if(addr->sa_family == AF_INET6)
    {
      // enable dual stack explicitly
      int dual = 1;
      if(setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &dual, sizeof(dual)) == -1)
      {
        // failed
        perror("setsockopt()");
        close(fd);
        return -1;
      }
    }
    llarp::Addr a(*addr);
    llarp::LogDebug("bind to ", a);
    // FreeBSD handbook said to do this
    if(addr->sa_family == AF_INET && INADDR_ANY)
      a._addr4.sin_addr.s_addr = htonl(INADDR_ANY);

    if(bind(fd, addr, slen) == -1)
    {
      perror("bind()");
      close(fd);
      return -1;
    }
    return fd;
  }

  virtual bool
  udp_listen(llarp_udp_io* l, const sockaddr* src)
  {
    auto ev = create_udp(l, src);
    if(ev)
      l->fd = ev->fd;
    return ev && add_ev(ev, false);
  }

  bool
  close_ev(llarp::ev_io* ev)
  {
    EV_SET(&ev->change, ev->fd, ev->flags, EV_DELETE, 0, 0, nullptr);
    return kevent(kqueuefd, &ev->change, 1, nullptr, 0, nullptr) != -1;
  }

  llarp::ev_io*
  create_udp(llarp_udp_io* l, const sockaddr* src)
  {
    int fd = udp_bind(src);
    if(fd == -1)
      return nullptr;
    llarp::udp_listener* listener = new llarp::udp_listener(fd, l);
    l->impl                       = listener;
    return listener;
  }

  bool
  add_ev(llarp::ev_io* ev, bool w)
  {
    ev->flags = EVFILT_READ;
    EV_SET(&ev->change, ev->fd, EVFILT_READ, EV_ADD, 0, 0, ev);
    if(kevent(kqueuefd, &ev->change, 1, nullptr, 0, nullptr) == -1)
    {
      llarp::LogError("Failed to add event: ", strerror(errno));
      delete ev;
      return false;
    }
    if(w)
    {
      ev->flags |= EVFILT_WRITE;
      EV_SET(&ev->change, ev->fd, EVFILT_WRITE, EV_ADD, 0, 0, ev);
      if(kevent(kqueuefd, &ev->change, 1, nullptr, 0, nullptr) == -1)
      {
        llarp::LogError("Failed to add event: ", strerror(errno));
        delete ev;
        return false;
      }
    }
    handlers.emplace_back(ev);
    return true;
  }

  bool
  udp_close(llarp_udp_io* l)
  {
    bool ret      = false;
    auto listener = static_cast< llarp::udp_listener* >(l->impl);
    if(listener)
    {
      // printf("Calling close_ev for [%x] fd[%d]\n", listener, listener->fd);
      ret = close_ev(listener);
      // remove handler
      auto itr = handlers.begin();
      while(itr != handlers.end())
      {
        if(itr->get() == listener)
        {
          itr = handlers.erase(itr);
          ret = true;
        }
        else
          ++itr;
      }
      l->impl = nullptr;
    }
    return ret;
  }

  void
  stop()
  {
    auto itr = handlers.begin();
    while(itr != handlers.end())
    {
      close_ev(itr->get());
      itr = handlers.erase(itr);
    }

    if(kqueuefd != -1)
      ::close(kqueuefd);

    kqueuefd = -1;
  }
};

#endif