#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_timeout_init;        // seconds, Range: 1-60
    uint64_t tcp_timeout_handshake;   // seconds, Range: 1-60
    uint64_t tcp_timeout_data;        // seconds, Range: 1-15,999,999
    uint64_t tcp_timeout_half_closed; // seconds, Range: 1-604,800
    uint64_t tcp_timeout_time_wait;   // seconds, Range: 1-600
    uint64_t tcp_timeout_discard;     // seconds, Range: 1-15,999,999

    // UDP timeout
    uint64_t udp_timeout_data; // seconds, Range: 1-15,999,999

    // duplicate packet filter
    uint8_t duplicated_packet_filter_enable;
    uint32_t duplicated_packet_filter_capacity;
    uint32_t duplicated_packet_filter_timeout; // seconds, Range: 1-60
    double duplicated_packet_filter_error_rate;

    // evicted session filter
    uint8_t evicted_session_filter_enable;
    uint32_t evicted_session_filter_capacity;
    uint32_t evicted_session_filter_timeout; // seconds, Range: 1-60
    double evicted_session_filter_error_rate;
};

struct session_manager;
struct session_manager *session_manager_new(struct session_manager_options *opts);
void session_manager_free(struct session_manager *mgr);
struct session *session_manager_lookup_session(struct session_manager *mgr, const struct packet *pkt);

/*
 * return NULL following case:
 *      1.Not TCP or UDP
 *      2.UDP eviction packet
 *      3.UDP overloading and config to bypass new session
 *      4.TCP no SYN flag
 *      5.UDP overloading and config to bypass new session
 */
struct session *session_manager_new_session(struct session_manager *mgr, const struct packet *pkt);
void session_manager_free_session(struct session_manager *mgr, struct session *sess);
/*
 * return NULL following case:
 *      1.Not TCP or UDP
 *      2.TCP duplicate packet
 */
int session_manager_update_session(struct session_manager *mgr, struct session *sess, const struct packet *pkt);
// return session need free by session_manager_free_session()
struct session *session_manager_get_expired_session(struct session_manager *mgr);
// return session need free by session_manager_free_session()
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);

struct session_manager_stat
{
    uint64_t tcp_sess_num;
    uint64_t tcp_opening_sess_num;
    uint64_t tcp_active_sess_num;
    uint64_t tcp_closing_sess_num;

    uint64_t udp_sess_num;
    uint64_t udp_opening_sess_num;
    uint64_t udp_active_sess_num;
    uint64_t udp_closing_sess_num;

    uint64_t tcp_overload_evict_old_sess_num;
    uint64_t tcp_overload_evict_new_sess_num;
    uint64_t udp_overload_evict_old_sess_num;
    uint64_t udp_overload_evict_new_sess_num;
};

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

#ifdef __cpluscplus
}
#endif

#endif