#pragma once

/** A peer of a bound (server) instance of UdpVpn */

#include <netinet/in.h>
#include <bitset>
#include "util.hpp"
#include "VpnPacket.hpp"

class UdpVpn;

const int PACKET_LOSS_HISTSIZE = 128, PACKET_LOST_AFTER = 8;

class PacketLossLogger {
    public:
        PacketLossLogger();
        void log_packet(uint32_t seqno);
        double get_loss_rate() const {
            return (double)_packet_loss_hist.count() / PACKET_LOSS_HISTSIZE;
        }

        const std::bitset<PACKET_LOSS_HISTSIZE> get_loss_hist() const {
            return _packet_loss_hist;
        }

        const std::bitset<PACKET_LOST_AFTER> get_received_ahead() const {
            return _received_ahead;
        }

        uint32_t get_cur_seqno() const { return _cur_seqno; }

    private:
        void reboot(); ///< completely reset the internal state

        std::bitset<PACKET_LOSS_HISTSIZE> _packet_loss_hist;
        std::bitset<PACKET_LOST_AFTER> _received_ahead;
        uint32_t _cur_seqno;
};

class VpnPeer {
    public:
        class NetError : public MsgException {
            public:
                NetError(
                        const std::string& msg,
                        int code=0,
                        bool is_perror=false)
                    : MsgException(msg, code, is_perror) {}
        };

        VpnPeer(UdpVpn* vpn, const sockaddr_in6& ext_addr,
                const in6_addr& int_addr);

        const sockaddr_in6& get_ext_addr() const { return _ext_addr; }
        const in6_addr& get_int_addr() const { return _int_addr; }

        void set_int_addr(const in6_addr& int_addr);

        const PacketLossLogger& get_loss_logger() { return _packet_loss; }

        size_t write(const char* data, size_t len);
        size_t write(const VpnPacket& packet);

        uint32_t peek_next_seqno() const { return _next_send_seqno; }
        uint32_t next_seqno() { return _next_send_seqno++; }

        void got_inbound_packet(const VpnPacket& packet);

    private:
        UdpVpn* _vpn;
        sockaddr_in6 _ext_addr;
        in6_addr _int_addr;
        uint32_t _next_send_seqno;

        PacketLossLogger _packet_loss;
};