#ifndef UDPC_DEFINES_HPP
#define UDPC_DEFINES_HPP

#define UDPC_CONTEXT_IDENTIFIER 0x902F4DB3
#define UDPC_SENT_PKTS_MAX_SIZE 33
#define UDPC_QUEUED_PKTS_MAX_SIZE 32
#define UDPC_RECEIVED_PKTS_MAX_SIZE 50

#define UDPC_ID_CONNECT 0x80000000
#define UDPC_ID_PING 0x40000000
#define UDPC_ID_NO_REC_CHK 0x20000000
#define UDPC_ID_RESENDING 0x10000000

#include <atomic>
#include <bitset>
#include <chrono>
#include <cstdint>
#include <deque>
#include <unordered_map>
#include <unordered_set>
#include <queue>
#include <random>
#include <memory>

#include "TSQueue.hpp"
#include "UDPConnection.h"

namespace UDPC {

static const auto ONE_SECOND = std::chrono::seconds(1);
static const auto TEN_SECONDS = std::chrono::seconds(10);
static const auto THIRTY_SECONDS = std::chrono::seconds(30);

static uint32_t LOCAL_ADDR = 0;
static const auto INIT_PKT_INTERVAL_DT = std::chrono::seconds(5);
static const auto HEARTBEAT_PKT_INTERVAL_DT = std::chrono::milliseconds(150);
static const auto PACKET_TIMEOUT_TIME = ONE_SECOND;
static const auto GOOD_RTT_LIMIT = std::chrono::milliseconds(250);
static const auto CONNECTION_TIMEOUT = TEN_SECONDS;
static const auto GOOD_MODE_SEND_RATE = std::chrono::microseconds(33333);
static const auto BAD_MODE_SEND_RATE = std::chrono::milliseconds(100);

// forward declaration
struct Context;

struct SentPktInfo {
    typedef std::shared_ptr<SentPktInfo> Ptr;

    SentPktInfo();

    uint32_t id;
    std::chrono::steady_clock::time_point sentTime;
};

struct ConnectionIdentifier {
    ConnectionIdentifier();
    ConnectionIdentifier(uint32_t addr, uint16_t port);

    // copy
    ConnectionIdentifier(const ConnectionIdentifier& other) = default;
    ConnectionIdentifier& operator =(const ConnectionIdentifier& other) = default;

    // move
    ConnectionIdentifier(ConnectionIdentifier&& other) = default;
    ConnectionIdentifier& operator =(ConnectionIdentifier&& other) = default;

    uint64_t id;

    /// expects address to be in network byte order (big-endian)
    void setAddr(uint32_t addr);
    /// expects port to be in native order (not network byte order)
    void setPort(uint16_t port);

    /// returns address as a 4 byte unsigned int in network byte order (big-endian)
    uint32_t getAddr() const;
    /// returns port as a 2 byte unsigned int in native order (not network byte order)
    uint16_t getPort() const;

    bool operator ==(const ConnectionIdentifier& other) const;

    struct Hasher {
        std::size_t operator()(const ConnectionIdentifier& key) const;
    };
};

struct ConnectionData {
    ConnectionData();
    ConnectionData(bool isServer, Context *ctx);

    // copy
    ConnectionData(const ConnectionData& other) = delete;
    ConnectionData& operator=(const ConnectionData& other) = delete;

    // move
    ConnectionData(ConnectionData&& other) = default;
    ConnectionData& operator=(ConnectionData&& other) = default;

    void cleanupSentPkts();

    /*
     * 0 - trigger send
     * 1 - is good mode
     * 2 - is good rtt
     * 3 - initiating connection
     * 4 - is id set
     */
    std::bitset<32> flags;
    uint32_t id;
    uint32_t lseq;
    uint32_t rseq;
    uint32_t ack;
    std::chrono::steady_clock::duration timer;
    std::chrono::steady_clock::duration toggleT;
    std::chrono::steady_clock::duration toggleTimer;
    std::chrono::steady_clock::duration toggledTimer;
    uint32_t addr; // in network order
    uint16_t port; // in native order
    std::deque<UDPC_PacketInfo> sentPkts;
    TSQueue<UDPC_PacketInfo> sendPkts;
    TSQueue<UDPC_PacketInfo> priorityPkts;
    TSQueue<UDPC_PacketInfo> receivedPkts;
    // pkt id to pkt shared_ptr
    std::unordered_map<uint32_t, SentPktInfo::Ptr> sentInfoMap;
    std::chrono::steady_clock::time_point received;
    std::chrono::steady_clock::time_point sent;
    std::chrono::steady_clock::duration rtt;
}; // struct ConnectionData

struct Context {
    Context(bool isThreaded);

    uint_fast32_t _contextIdentifier;

    char recvBuf[UDPC_PACKET_MAX_SIZE];
    /*
     * 0 - is threaded
     * 1 - is client
     * 2 - is accepting new connections
     */
    std::bitset<32> flags;
    std::atomic_bool isAcceptNewConnections;
    std::atomic_uint32_t protocolID;
    std::atomic_uint_fast8_t loggingType;
    char atostrBuf[16];

    int socketHandle;
    struct sockaddr_in socketInfo;

    std::chrono::steady_clock::time_point lastUpdated;
    // ipv4 address and port (as ConnectionIdentifier) to ConnectionData
    std::unordered_map<ConnectionIdentifier, ConnectionData, ConnectionIdentifier::Hasher> conMap;
    // ipv4 address to all connected ConnectionIdentifiers
    std::unordered_map<uint32_t, std::unordered_set<ConnectionIdentifier, ConnectionIdentifier::Hasher> > addrConMap;
    // id to ipv4 address and port (as ConnectionIdentifier)
    std::unordered_map<uint32_t, ConnectionIdentifier> idMap;

    std::default_random_engine rng_engine;

}; // struct Context

Context *verifyContext(void *ctx);

bool isBigEndian();

/*
 * flags:
 *   - 0x1 - connect
 *   - 0x2 - ping
 *   - 0x4 - no_rec_chk
 *   - 0x8 - resending
 */
void preparePacket(char *data, uint32_t protocolID, uint32_t conID,
                   uint32_t rseq, uint32_t ack, uint32_t *seqID, int flags);

uint32_t generateConnectionID(Context &ctx);

float durationToFSec(
    const std::chrono::steady_clock::time_point& older,
    const std::chrono::steady_clock::time_point& newer);

} // namespace UDPC

#endif