#include "stellar/exdata.h"
#include "session_internal.h"
#include "session_manager_stat.h"

void session_init(struct session *sess)
{
    memset(sess, 0, sizeof(struct session));
    sess->empty_seg.data = NULL;
    sess->empty_seg.len = 0;
    sess->empty_seg.user_data = sess;
}

void session_set_id(struct session *sess, uint64_t id)
{
    sess->id = id;
}

uint64_t session_get_id(const struct session *sess)
{
    return sess->id;
}

void session_set_tuple6(struct session *sess, const struct tuple6 *tuple)
{
    memcpy(&sess->tuple, tuple, sizeof(struct tuple6));
}

const struct tuple6 *session_get_tuple6(const struct session *sess)
{
    return &sess->tuple;
}

const char *session_get_readable_addr(const struct session *sess)
{
    return sess->tuple_str;
}

void session_set_direction(struct session *sess, enum session_direction dir)
{
    sess->sess_dir = dir;
}

enum session_direction session_get_direction(const struct session *sess)
{
    return sess->sess_dir;
}

void session_set_flow_type(struct session *sess, enum flow_type type)
{
    sess->flow_type = type;
}

enum flow_type session_get_flow_type(const struct session *sess)
{
    return sess->flow_type;
}

void session_set_current_state(struct session *sess, enum session_state state)
{
    sess->state = state;
}

enum session_state session_get_current_state(const struct session *sess)
{
    return sess->state;
}

void session_set_type(struct session *sess, enum session_type type)
{
    sess->sess_type = type;
}

enum session_type session_get_type(const struct session *sess)
{
    return sess->sess_type;
}

void session_set_duplicate_traffic(struct session *sess)
{
    sess->dup = 1;
}

int session_has_duplicate_traffic(const struct session *sess)
{
    return sess->dup;
}

void session_set_closing_reason(struct session *sess, enum closing_reason reason)
{
    sess->reason = reason;
}

enum closing_reason session_get_closing_reason(const struct session *sess)
{
    return sess->reason;
}

void session_inc_stat(struct session *sess, enum flow_type type, enum session_stat stat, uint64_t val)
{
    sess->stats[type][stat] += val;
}

uint64_t session_get_stat(const struct session *sess, enum flow_type type, enum session_stat stat)
{
    return sess->stats[type][stat];
}

void session_set_timestamp(struct session *sess, enum session_timestamp type, uint64_t value)
{
    sess->timestamps[type] = value;
}

uint64_t session_get_timestamp(const struct session *sess, enum session_timestamp type)
{
    return sess->timestamps[type];
}

void session_clear_sids(struct session *sess, enum flow_type type)
{
    memset(&sess->sids[type], 0, sizeof(struct sids));
}

void session_set_sids(struct session *sess, enum flow_type type, const struct sids *sids)
{
    sess->sids[type] = *sids;
}

const struct sids *session_get_sids(const struct session *sess, enum flow_type type)
{
    return &sess->sids[type];
}

void session_clear_route_ctx(struct session *sess, enum flow_type type)
{
    memset(&sess->route_ctx[type], 0, sizeof(struct route_ctx));
}

void session_set_route_ctx(struct session *sess, enum flow_type type, const struct route_ctx *ctx)
{
    sess->route_ctx[type] = *ctx;
}

const struct route_ctx *session_get_route_ctx(const struct session *sess, enum flow_type type)
{
    return &sess->route_ctx[type];
}

void session_set_first_packet(struct session *sess, enum flow_type type, const struct packet *pkt)
{
    sess->first_pkt[type] = pkt;
}

const struct packet *session_get_first_packet(const struct session *sess, enum flow_type type)
{
    return sess->first_pkt[type];
}

void session_set_current_packet(struct session *sess, const struct packet *pkt)
{
    sess->curr_pkt = pkt;
}

const struct packet *session_get_current_packet(const struct session *sess)
{
    return sess->curr_pkt;
}

int session_is_symmetric(const struct session *sess, unsigned char *flag)
{
    int is_symmetric = 0;
    if (sess->first_pkt[FLOW_TYPE_C2S] && sess->first_pkt[FLOW_TYPE_S2C])
    {
        if (flag)
        {
            *flag = (SESSION_SEEN_C2S_FLOW | SESSION_SEEN_S2C_FLOW);
        }
        is_symmetric = 1;
    }
    else if (sess->first_pkt[FLOW_TYPE_C2S])
    {
        if (flag)
        {
            *flag = SESSION_SEEN_C2S_FLOW;
        }
    }
    else if (sess->first_pkt[FLOW_TYPE_S2C])
    {
        if (flag)
        {
            *flag = SESSION_SEEN_S2C_FLOW;
        }
    }
    return is_symmetric;
}

void session_set_user_data(struct session *sess, void *user_data)
{
    sess->user_data = user_data;
}

void *session_get_user_data(const struct session *sess)
{
    return sess->user_data;
}

struct tcp_segment *session_get_tcp_segment(struct session *sess)
{
    enum flow_type type = session_get_flow_type(sess);
    struct tcp_half *half = &sess->tcp_halfs[type];

    if (half->inorder_seg.data != NULL && half->inorder_seg.len > 0 && !half->inorder_seg_consumed)
    {
        sess->sess_mgr_stat->tcp_segs_consumed++;
        half->inorder_seg_consumed = 1;
        half->inorder_seg.user_data = sess;
        return &half->inorder_seg;
    }
    else
    {
        struct tcp_segment *seg = tcp_reassembly_pop(half->tcp_reass);
        if (seg)
        {
            session_inc_stat(sess, type, STAT_TCP_SEGMENTS_REORDERED, 1);
            session_inc_stat(sess, type, STAT_TCP_PAYLOADS_REORDERED, seg->len);

            // TODO
            sess->sess_mgr_stat->tcp_segs_consumed++;
            sess->sess_mgr_stat->tcp_segs_reordered++;
            seg->user_data = sess;
        }
        return seg;
    }
}

void session_free_tcp_segment(struct session *sess, struct tcp_segment *seg)
{
    if (seg == NULL)
    {
        return;
    }

    // empty segment for end of session
    if (seg == &sess->empty_seg)
    {
        return;
    }

    enum flow_type type = session_get_flow_type(sess);
    struct tcp_half *half = &sess->tcp_halfs[type];

    // in order segment
    if (seg == &half->inorder_seg)
    {
        half->inorder_seg.data = NULL;
        half->inorder_seg.len = 0;
        return;
    }
    // tcp reassembly segment
    else
    {
        session_inc_stat(sess, type, STAT_TCP_SEGMENTS_RELEASED, 1);
        session_inc_stat(sess, type, STAT_TCP_PAYLOADS_RELEASED, seg->len);
        sess->sess_mgr_stat->tcp_segs_freed++;

        tcp_segment_free(seg);
    }
}

const char *closing_reason_to_str(enum closing_reason reason)
{
    switch (reason)
    {
    case CLOSING_BY_TIMEOUT:
        return "closing by timeout";
    case CLOSING_BY_LRU_EVICTED:
        return "closing by lru evicted";
    case CLOSING_BY_PORT_REUSE_EVICTED:
        return "closing by port reuse evicted";
    case CLOSING_BY_CLIENT_FIN:
        return "closing by client FIN";
    case CLOSING_BY_CLIENT_RST:
        return "closing by client RST";
    case CLOSING_BY_SERVER_FIN:
        return "closing by server FIN";
    case CLOSING_BY_SERVER_RST:
        return "closing by server RST";
    default:
        return "unknown";
    }
}

const char *session_state_to_str(enum session_state state)
{
    switch (state)
    {
    case SESSION_STATE_INIT:
        return "init";
    case SESSION_STATE_OPENING:
        return "opening";
    case SESSION_STATE_ACTIVE:
        return "active";
    case SESSION_STATE_CLOSING:
        return "closing";
    case SESSION_STATE_DISCARD:
        return "discard";
    case SESSION_STATE_CLOSED:
        return "closed";
    default:
        return "unknown";
    }
}

const char *session_type_to_str(enum session_type type)
{
    switch (type)
    {
    case SESSION_TYPE_TCP:
        return "TCP";
    case SESSION_TYPE_UDP:
        return "UDP";
    default:
        return "unknown";
    }
}

const char *flow_direction_to_str(enum flow_type type)
{
    switch (type)
    {
    case FLOW_TYPE_C2S:
        return "C2S";
    case FLOW_TYPE_S2C:
        return "S2C";
    default:
        return "unknown";
    }
}

static void tcp_flags_to_str(uint8_t flags, char *buffer, size_t len)
{
    int used = 0;

    if (flags & TH_SYN)
    {
        used += snprintf(buffer + used, len - used, "SYN ");
    }
    if (flags & TH_ACK)
    {
        used += snprintf(buffer + used, len - used, "ACK ");
    }
    if (flags & TH_FIN)
    {
        used += snprintf(buffer + used, len - used, "FIN ");
    }
    if (flags & TH_RST)
    {
        used += snprintf(buffer + used, len - used, "RST ");
    }
}

int session_to_str(const struct session *sess, int bref, char *buff, int size)
{
    memset(buff, 0, size);
    char flags[64] = {0};
    int used = 0;

    if (bref)
    {
        used += snprintf(buff + used, size - used, "session id: %lu, addr: %s, type: %s, state: %s, dir: %s, c2s_rx_pkts: %lu, s2c_rx_pkts: %lu",
                         session_get_id(sess),
                         session_get_readable_addr(sess),
                         session_type_to_str(session_get_type(sess)),
                         session_state_to_str(session_get_current_state(sess)),
                         flow_direction_to_str(session_get_flow_type(sess)),
                         session_get_stat(sess, FLOW_TYPE_C2S, STAT_RAW_PACKETS_RECEIVED),
                         session_get_stat(sess, FLOW_TYPE_S2C, STAT_RAW_PACKETS_RECEIVED));
    }
    else
    {
        used += snprintf(buff + used, size - used, "{");
        used += snprintf(buff + used, size - used, "\"id\":%" PRIu64 ",", session_get_id(sess));
        used += snprintf(buff + used, size - used, "\"start_timestamp_ms\":%" PRIu64 ",", session_get_timestamp(sess, SESSION_TIMESTAMP_START));
        used += snprintf(buff + used, size - used, "\"last_timestamp_ms\":%" PRIu64 ",", session_get_timestamp(sess, SESSION_TIMESTAMP_LAST));
        used += snprintf(buff + used, size - used, "\"tuple\":\"%s\",", session_get_readable_addr(sess));
        used += snprintf(buff + used, size - used, "\"type\":\"%s\",", session_type_to_str(session_get_type(sess)));
        used += snprintf(buff + used, size - used, "\"state\":\"%s\",", session_state_to_str(session_get_current_state(sess)));
        used += snprintf(buff + used, size - used, "\"closing_reason\":\"%s\",", closing_reason_to_str(session_get_closing_reason(sess)));
        used += snprintf(buff + used, size - used, "\"duplicate_traffic\":%d,", session_has_duplicate_traffic(sess));
        used += snprintf(buff + used, size - used, "\"current_packet\":\"%p\",", session_get_current_packet(sess));

        const char *str[] = {"c2s", "s2c"};
        enum flow_type type[] = {FLOW_TYPE_C2S, FLOW_TYPE_S2C};
        for (int i = 0; i < 2; i++)
        {
            // raw packets
            used += snprintf(buff + used, size - used, "\"%s_raw_packets_received\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_RAW_PACKETS_RECEIVED));
            used += snprintf(buff + used, size - used, "\"%s_raw_bytes_received\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_RAW_BYTES_RECEIVED));

            used += snprintf(buff + used, size - used, "\"%s_raw_packets_transmitted\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_RAW_PACKETS_TRANSMITTED));
            used += snprintf(buff + used, size - used, "\"%s_raw_bytes_transmitted\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_RAW_BYTES_TRANSMITTED));

            used += snprintf(buff + used, size - used, "\"%s_raw_packets_dropped\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_RAW_PACKETS_DROPPED));
            used += snprintf(buff + used, size - used, "\"%s_raw_bytes_dropped\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_RAW_BYTES_DROPPED));

            // duplicate packets
            used += snprintf(buff + used, size - used, "\"%s_duplicate_packets_bypass\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_DUPLICATE_PACKETS_BYPASS));
            used += snprintf(buff + used, size - used, "\"%s_duplicate_bytes_bypass\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_DUPLICATE_BYTES_BYPASS));

            // injected packets
            used += snprintf(buff + used, size - used, "\"%s_injected_packets_failed\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_INJECTED_PACKETS_FAILED));
            used += snprintf(buff + used, size - used, "\"%s_injected_packets_success\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_INJECTED_PACKETS_SUCCESS));
            used += snprintf(buff + used, size - used, "\"%s_injected_bytes_success\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_INJECTED_BYTES_SUCCESS));

            // control packets
            used += snprintf(buff + used, size - used, "\"%s_control_packets_received\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_CONTROL_PACKETS_RECEIVED));
            used += snprintf(buff + used, size - used, "\"%s_control_bytes_received\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_CONTROL_BYTES_RECEIVED));

            used += snprintf(buff + used, size - used, "\"%s_control_packets_transmitted\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_CONTROL_PACKETS_TRANSMITTED));
            used += snprintf(buff + used, size - used, "\"%s_control_bytes_transmitted\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_CONTROL_BYTES_TRANSMITTED));

            used += snprintf(buff + used, size - used, "\"%s_control_packets_dropped\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_CONTROL_PACKETS_DROPPED));
            used += snprintf(buff + used, size - used, "\"%s_control_bytes_dropped\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_CONTROL_BYTES_DROPPED));

            if (session_get_type(sess) == SESSION_TYPE_TCP)
            {
                used += snprintf(buff + used, size - used, "\"%s_tcp_last_seq\":%u,", str[i], sess->tcp_halfs[type[i]].seq);
                used += snprintf(buff + used, size - used, "\"%s_tcp_last_ack\":%u,", str[i], sess->tcp_halfs[type[i]].ack);
                memset(flags, 0, sizeof(flags));
                tcp_flags_to_str(sess->tcp_halfs[type[i]].flags, flags, sizeof(flags));
                used += snprintf(buff + used, size - used, "\"%s_tcp_flags\":\"%s\",", str[i], flags);

                used += snprintf(buff + used, size - used, "\"%s_tcp_segments_received\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_SEGMENTS_RECEIVED));
                used += snprintf(buff + used, size - used, "\"%s_tcp_payloads_received\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_PAYLOADS_RECEIVED));

                used += snprintf(buff + used, size - used, "\"%s_tcp_segments_expired\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_SEGMENTS_EXPIRED));
                used += snprintf(buff + used, size - used, "\"%s_tcp_payloads_expired\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_PAYLOADS_EXPIRED));

                used += snprintf(buff + used, size - used, "\"%s_tcp_segments_retransmit\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_SEGMENTS_RETRANSMIT));
                used += snprintf(buff + used, size - used, "\"%s_tcp_payloads_retransmit\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_PAYLOADS_RETRANSMIT));

                used += snprintf(buff + used, size - used, "\"%s_tcp_segments_overlap\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_SEGMENTS_OVERLAP));
                used += snprintf(buff + used, size - used, "\"%s_tcp_payloads_overlap\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_PAYLOADS_OVERLAP));

                used += snprintf(buff + used, size - used, "\"%s_tcp_segments_nospace\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_SEGMENTS_NOSPACE));
                used += snprintf(buff + used, size - used, "\"%s_tcp_payloads_nospace\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_PAYLOADS_NOSPACE));

                used += snprintf(buff + used, size - used, "\"%s_tcp_segments_inorder\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_SEGMENTS_INORDER));
                used += snprintf(buff + used, size - used, "\"%s_tcp_payloads_inorder\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_PAYLOADS_INORDER));

                used += snprintf(buff + used, size - used, "\"%s_tcp_segments_reordered\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_SEGMENTS_REORDERED));
                used += snprintf(buff + used, size - used, "\"%s_tcp_payloads_reordered\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_PAYLOADS_REORDERED));

                used += snprintf(buff + used, size - used, "\"%s_tcp_segments_buffered\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_SEGMENTS_BUFFERED));
                used += snprintf(buff + used, size - used, "\"%s_tcp_payloads_buffered\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_PAYLOADS_BUFFERED));

                used += snprintf(buff + used, size - used, "\"%s_tcp_segments_released\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_SEGMENTS_RELEASED));
                used += snprintf(buff + used, size - used, "\"%s_tcp_payloads_released\":%" PRIu64 ",", str[i], session_get_stat(sess, type[i], STAT_TCP_PAYLOADS_RELEASED));
            }

            used += snprintf(buff + used, size - used, "\"%s_first_packet\":\"%p\"", str[i], session_get_first_packet(sess, type[i]));
            if (i == 0)
            {
                used += snprintf(buff + used, size - used, ",");
            }
        }
        used += snprintf(buff + used, size - used, "}");
    }

    return used;
}

void session_print(const struct session *sess)
{
    char buff[4096];
    session_to_str(sess, 0, buff, sizeof(buff));
    printf("%s\n", buff);
}

void session_set_exdata(struct session *sess, int idx, void *ex_ptr)
{
    struct exdata_runtime *rte = (struct exdata_runtime *)session_get_user_data(sess);
    exdata_set(rte, idx, ex_ptr);
}

void *session_get_exdata(const struct session *sess, int idx)
{
    struct exdata_runtime *rte = (struct exdata_runtime *)session_get_user_data(sess);
    return exdata_get(rte, idx);
}