#ifndef _SESSION_MANAGER_H
#define _SESSION_MANAGER_H

#ifdef __cpluscplus
extern "C"
{
#endif

#include "session.h"
#include "log.h"

#define SESSION_LOG_ERROR(format, ...) LOG_ERROR("session", format, ##__VA_ARGS__)
#define SESSION_LOG_DEBUG(format, ...) LOG_DEBUG("session", format, ##__VA_ARGS__)

struct session_manager_options
{
    // max session number
    uint64_t max_tcp_session_num;
    uint64_t max_udp_session_num;

    // session overload
    uint8_t tcp_overload_evict_old_sess; // 1: evict old session, 0: bypass new session
    uint8_t udp_overload_evict_old_sess; // 1: evict old session, 0: bypass new session

    // TCP timeout
    uint64_t tcp_init_timeout;           // range: [1, 60000] (ms)
    uint64_t tcp_handshake_timeout;      // range: [1, 60000] (ms)
    uint64_t tcp_data_timeout;           // range: [1, 15999999000] (ms)
    uint64_t tcp_half_closed_timeout;    // range: [1, 604800000] (ms)
    uint64_t tcp_time_wait_timeout;      // range: [1, 600000] (ms)
    uint64_t tcp_discard_timeout;        // range: [1, 15999999000] (ms)
    uint64_t tcp_unverified_rst_timeout; // range: [1, 600000] (ms)
    // UDP timeout
    uint64_t udp_data_timeout; // range: [1, 15999999000] (ms)

    // duplicate packet filter
    uint8_t duplicated_packet_filter_enable;
    uint32_t duplicated_packet_filter_capacity; // range: [1, 4294967295]
    uint32_t duplicated_packet_filter_timeout;  // range: [1, 60000] (ms)
    double duplicated_packet_filter_error_rate; // range: [0.0, 1.0]

    // evicted session filter
    uint8_t evicted_session_filter_enable;
    uint32_t evicted_session_filter_capacity; // range: [1, 4294967295]
    uint32_t evicted_session_filter_timeout;  // range: [1, 60000] (ms)
    double evicted_session_filter_error_rate; // range: [0.0, 1.0]

    // TCP reassembly
    uint8_t tcp_reassembly_enable;        // TODO not support
    uint32_t tcp_reassembly_max_timeout;  // range: [1, 60000] (ms)
    uint32_t tcp_reassembly_max_segments; // range: [2, 32]
};

struct session_stat
{
    uint64_t nr_sess_used;
    uint64_t nr_sess_init;
    uint64_t nr_sess_opening;
    uint64_t nr_sess_active;
    uint64_t nr_sess_closing;
    uint64_t nr_sess_discard;
    uint64_t nr_sess_closed;

    uint64_t nr_new_sess_evicted;
    uint64_t nr_old_sess_evicted;
};

struct packet_stat
{
    uint64_t nr_pkts;
    uint64_t nr_bytes;
};

struct session_manager_stat
{
    struct packet_stat dup_pkt;
    struct packet_stat evc_pkt;

    struct session_stat tcp_sess;
    struct session_stat udp_sess;
};

struct session_manager;
struct session_manager *session_manager_new(struct session_manager_options *opts, uint64_t now);
void session_manager_free(struct session_manager *mgr);

struct session *session_manager_new_session(struct session_manager *mgr, const struct packet *pkt, uint64_t now);
void session_manager_free_session(struct session_manager *mgr, struct session *sess);

struct session *session_manager_lookup_session(struct session_manager *mgr, const struct packet *pkt);
int session_manager_update_session(struct session_manager *mgr, struct session *sess, const struct packet *pkt, uint64_t now);

// return session need free by session_manager_free_session()
struct session *session_manager_get_expired_session(struct session_manager *mgr, uint64_t now);
struct session *session_manager_get_evicted_session(struct session_manager *mgr);

// return  0: have already timeout session
// return >0: next expire interval
uint64_t session_manager_get_expire_interval(struct session_manager *mgr);

void session_manager_print_stat(struct session_manager *mgr);
struct session_manager_stat *session_manager_get_stat(struct session_manager *mgr);

#ifdef __cpluscplus
}
#endif

#endif