#include <assert.h>

#include "session_private.h"

#define EX_KEY_MAX_LEN 64

struct ex_schema
{
    char key[EX_KEY_MAX_LEN];
    session_ex_free_cb *free_cb;
    void *args;
};

struct ex_manager
{
    struct ex_schema schemas[EX_DATA_MAX_COUNT];
    uint8_t count;
};

static struct ex_manager g_ex_manager = {0};
uint8_t tcp_builtin_ex = 0; // built-in ex_data index
uint8_t udp_builtin_ex = 0; // built-in ex_data index

/******************************************************************************
 * ev queue
 ******************************************************************************/

static void event_queue_init(struct event_queue *queue)
{
    queue->head_idx = 0;
    queue->tail_idx = 0;
}

static bool event_queue_is_empty(struct event_queue *queue)
{
    return queue->head_idx == queue->tail_idx;
}

static bool event_queue_is_full(struct event_queue *queue)
{
    return (queue->tail_idx + 1) % SESSION_EVENT_QUEUE_SIZE == queue->head_idx;
}

static bool event_queue_push(struct event_queue *queue, uint32_t event)
{
    if (event_queue_is_full(queue))
    {
        return false;
    }

    queue->events[queue->tail_idx] = event;
    queue->tail_idx = (queue->tail_idx + 1) % SESSION_EVENT_QUEUE_SIZE;

    return true;
}

static bool event_queue_pop(struct event_queue *queue, uint32_t *event)
{
    if (event_queue_is_empty(queue))
    {
        return false;
    }

    *event = queue->events[queue->head_idx];
    queue->head_idx = (queue->head_idx + 1) % SESSION_EVENT_QUEUE_SIZE;

    return true;
}

/******************************************************************************
 * session
 ******************************************************************************/

void session_init(struct session *sess)
{
    memset(sess, 0, sizeof(struct session));
    event_queue_init(&sess->events);
}

// session id
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;
}

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

const struct tuple6 *session_get0_tuple6(const struct session *sess)
{
    return &sess->tuple;
}

void session_set_tuple6_dir(struct session *sess, enum session_dir dir)
{
    sess->tuple_dir = dir;
}

enum session_dir session_get_tuple6_dir(const struct session *sess)
{
    return sess->tuple_dir;
}

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

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

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

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

// session metrics
void session_inc_c2s_metrics(struct session *sess, uint64_t packets, uint64_t bytes)
{
    sess->c2s_bytes += bytes;
    sess->c2s_packets += packets;
}

void session_inc_s2c_metrics(struct session *sess, uint64_t packets, uint64_t bytes)
{
    sess->s2c_bytes += bytes;
    sess->s2c_packets += packets;
}

uint64_t session_get_c2s_bytes(const struct session *sess)
{
    return sess->c2s_bytes;
}

uint64_t session_get_s2c_bytes(const struct session *sess)
{
    return sess->s2c_bytes;
}

uint64_t session_get_c2s_packets(const struct session *sess)
{
    return sess->c2s_packets;
}

uint64_t session_get_s2c_packets(const struct session *sess)
{
    return sess->s2c_packets;
}

// session metadata
void session_set_c2s_1st_md(struct session *sess, struct metadata *md)
{
    memcpy(&sess->c2s_1st_md, md, sizeof(struct metadata));
}

void session_set_s2c_1st_md(struct session *sess, struct metadata *md)
{
    memcpy(&sess->s2c_1st_md, md, sizeof(struct metadata));
}

const struct metadata *session_get0_c2s_1st_md(const struct session *sess)
{
    if (sess->c2s_1st_md.len == 0)
    {
        return NULL;
    }
    return &sess->c2s_1st_md;
}

const struct metadata *session_get0_s2c_1st_md(const struct session *sess)
{
    if (sess->s2c_1st_md.len == 0)
    {
        return NULL;
    }
    return &sess->s2c_1st_md;
}

// session timestamp
void session_set_create_time(struct session *sess, uint64_t timestamp)
{
    sess->create_time = timestamp;
}

void session_set_last_time(struct session *sess, uint64_t timestamp)
{
    sess->last_time = timestamp;
}

uint64_t session_get_create_time(const struct session *sess)
{
    return sess->create_time;
}

uint64_t session_get_last_time(const struct session *sess)
{
    return sess->last_time;
}

/******************************************************************************
 * session current packet
 ******************************************************************************/

// session current packet
void session_set0_cur_pkt(struct session *sess, const struct packet *pkt)
{
    sess->cur_pkt = pkt;
}

const struct packet *session_get0_cur_pkt(const struct session *sess)
{
    return sess->cur_pkt;
}

// session current dir
void session_set_cur_dir(struct session *sess, enum session_dir dir)
{
    sess->cur_dir = dir;
}

enum session_dir session_get_cur_dir(const struct session *sess)
{
    return sess->cur_dir;
}

/******************************************************************************
 * session event
 ******************************************************************************/

// session event
bool session_push_event(struct session *sess, uint32_t event)
{
    return event_queue_push(&sess->events, event);
}

bool session_pop_event(struct session *sess, uint32_t *event)
{
    return event_queue_pop(&sess->events, event);
}

/******************************************************************************
 * session ex data
 ******************************************************************************/

/*
 * the exdata prodoced by user, and comsumed by same user.
 * so, the exdata is not shared by different user.
 * otherwise, the exdata need dup by refer count, and free by refer count.
 *
 * if key exist, not allow update, return original index.
 */
uint8_t session_get_ex_new_index(const char *key, session_ex_free_cb *free_cb, void *args)
{
    if (g_ex_manager.count >= EX_DATA_MAX_COUNT)
    {
        abort();
        return EX_DATA_MAX_COUNT;
    }

    for (uint8_t i = 0; i < g_ex_manager.count; i++)
    {
        if (strcmp(g_ex_manager.schemas[i].key, key) == 0)
        {
            return i;
        }
    }

    uint8_t idx = g_ex_manager.count;
    g_ex_manager.count++;

    struct ex_schema *schema = &g_ex_manager.schemas[idx];
    strncpy(schema->key, key, EX_KEY_MAX_LEN);
    schema->free_cb = free_cb;
    schema->args = args;

    return idx;
}

/*
 * Support update ex_data.
 *
 * if key exist: run free_cb free old value, then set new value.
 *     if not run free_cb, old value will be memory leak.
 *     if not allow update, new value will be memory leak.
 * if key not exist: set new value.
 */
void session_set_ex_data(struct session *sess, uint8_t idx, void *val)
{
    if (idx >= g_ex_manager.count)
    {
        assert(0);
        return;
    }

    session_free_ex_data(sess, idx);
    sess->ex_data[idx] = val;
}

void *session_get0_ex_data(const struct session *sess, uint8_t idx)
{
    if (idx >= g_ex_manager.count)
    {
        assert(0);
        return NULL;
    }

    return sess->ex_data[idx];
}

/*
 * after set ex_data, the owner of ex_data is session, so user should not free it directly.
 * if user want to free ex_data, should use session_free_ex_data.
 */
void session_free_ex_data(struct session *sess, uint8_t idx)
{
    if (idx >= g_ex_manager.count)
    {
        assert(0);
        return;
    }

    struct ex_schema *schema = &g_ex_manager.schemas[idx];
    if (schema->free_cb != NULL && sess->ex_data[idx] != NULL)
    {
        schema->free_cb(sess, idx, sess->ex_data[idx], schema->args);
    }

    sess->ex_data[idx] = NULL;
}

/******************************************************************************
 * session expire
 ******************************************************************************/

// session expire
void session_set_expirecb(struct session *sess, session_expire_cb expire_cb, void *expire_arg, uint64_t expire_abs_ts)
{
    struct timeout *timeout = &sess->timeout;

    timeout_init(timeout, TIMEOUT_ABS);
    timeout_setcb(timeout, NULL, sess);
    sess->expire_cb = expire_cb;
    sess->expire_arg = expire_arg;
    sess->expire_abs_ts = expire_abs_ts;
}

void session_del_expirecb(struct session *sess)
{
    struct timeout *timeout = &sess->timeout;

    timeout_init(timeout, 0);
    sess->expire_cb = NULL;
    sess->expire_arg = NULL;
    sess->expire_abs_ts = 0;
}

void session_run_expirecb(struct session *sess)
{
    if (sess->expire_cb)
    {
        sess->expire_cb(sess, sess->expire_arg);
    }
}

/******************************************************************************
 * session dump
 ******************************************************************************/

static void tcp_ex_data_tostring(uint64_t ex_data, char *buffer, size_t buffer_len)
{
    if (ex_data == 0)
    {
        return;
    }

    int nused = 0;
    if (ex_data & TCP_SYN_RECVED)
    {
        snprintf(buffer + nused, buffer_len - nused, "TCP_SYN_RECVED ");
    }

    if (ex_data & TCP_SYNACK_RECVED)
    {
        snprintf(buffer + nused, buffer_len - nused, "TCP_SYNACK_RECVED ");
    }

    if (ex_data & TCP_ACK_RECVED)
    {
        snprintf(buffer + nused, buffer_len - nused, "TCP_ACK_RECVED ");
    }

    if (ex_data & TCP_C2S_PAYLOAD_RECVED)
    {
        snprintf(buffer + nused, buffer_len - nused, "TCP_C2S_PAYLOAD_RECVED ");
    }

    if (ex_data & TCP_S2C_PAYLOAD_RECVED)
    {
        snprintf(buffer + nused, buffer_len - nused, "TCP_S2C_PAYLOAD_RECVED ");
    }

    if (ex_data & TCP_C2S_FIN_RECVED)
    {
        snprintf(buffer + nused, buffer_len - nused, "TCP_C2S_FIN_RECVED ");
    }

    if (ex_data & TCP_S2C_FIN_RECVED)
    {
        snprintf(buffer + nused, buffer_len - nused, "TCP_S2C_FIN_RECVED ");
    }

    if (ex_data & TCP_C2S_RST_RECVED)
    {
        snprintf(buffer + nused, buffer_len - nused, "TCP_C2S_RST_RECVED ");
    }

    if (ex_data & TCP_S2C_RST_RECVED)
    {
        snprintf(buffer + nused, buffer_len - nused, "TCP_S2C_RST_RECVED ");
    }
}

static void udp_ex_data_tostring(uint64_t ex_data, char *buffer, size_t buffer_len)
{
    if (ex_data == 0)
    {
        return;
    }

    int nused = 0;
    if (ex_data & UDP_C2S_RECVED)
    {
        snprintf(buffer + nused, buffer_len - nused, "UDP_C2S_RECVED ");
    }

    if (ex_data & UDP_S2C_RECVED)
    {
        snprintf(buffer + nused, buffer_len - nused, "UDP_S2C_RECVED ");
    }
}

const char *session_event_tostring(enum session_event event)
{
    switch (event)
    {
    case SESSION_EVENT_NONE:
        return "none";
    case SESSION_EVENT_OPENING:
        return "opening";
    case SESSION_EVENT_ACTIVE:
        return "active";
    case SESSION_EVENT_CLOSING:
        return "closing";
    default:
        return "unknown";
    }
}

const char *session_state_tostring(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_DISCARD:
        return "discard";
    case SESSION_STATE_CLOSING:
        return "closing";
    case SESSION_STATE_CLOSED:
        return "closed";
    default:
        return "unknown";
    }
}

const char *session_type_tostring(enum session_type type)
{
    switch (type)
    {
    case SESSION_TYPE_NONE:
        return "none";
    case SESSION_TYPE_TCP:
        return "tcp";
    case SESSION_TYPE_TCP_STREAM:
        return "tcp_stream";
    case SESSION_TYPE_UDP:
        return "udp";
    default:
        return "unknown";
    }
}

const char *session_dir_tostring(enum session_dir dir)
{
    switch (dir)
    {
    case SESSION_DIR_NONE:
        return "none";
    case SESSION_DIR_C2S:
        return "c2s";
    case SESSION_DIR_S2C:
        return "s2c";
    default:
        return "unknown";
    }
}

void session_dump(struct session *sess)
{
    char buffer[128] = {0};
    tuple6_tostring(session_get0_tuple6(sess), buffer, sizeof(buffer));

    printf("session id               : %" PRIu64 "\n", session_get_id(sess));
    printf("session tuple6           : %s\n", buffer);
    printf("session tuple6 dir       : %s\n", session_dir_tostring(session_get_tuple6_dir(sess)));
    printf("session state            : %s\n", session_state_tostring(session_get_state(sess)));
    printf("session type             : %s\n", session_type_tostring(session_get_type(sess)));
    printf("session c2s packets      : %" PRIu64 "\n", session_get_c2s_packets(sess));
    printf("session c2s bytes        : %" PRIu64 "\n", session_get_c2s_bytes(sess));
    printf("session s2c packets      : %" PRIu64 "\n", session_get_s2c_packets(sess));
    printf("session s2c bytes        : %" PRIu64 "\n", session_get_s2c_bytes(sess));
    printf("session c2s 1st metadata : %p\n", (void *)session_get0_c2s_1st_md(sess));
    printf("session s2c 1st metadata : %p\n", (void *)session_get0_s2c_1st_md(sess));
    printf("session create time      : %" PRIu64 "\n", session_get_create_time(sess));
    printf("session last time        : %" PRIu64 "\n", session_get_last_time(sess));
    printf("session current packet   : %p\n", (void *)session_get0_cur_pkt(sess));
    printf("session current dir      : %s\n", session_dir_tostring(session_get_cur_dir(sess)));
    printf("session ex data: \n");
    for (uint8_t i = 0; i < g_ex_manager.count; i++)
    {
        if (i == tcp_builtin_ex)
        {
            memset(buffer, 0, sizeof(buffer));
            tcp_ex_data_tostring((uint64_t)sess->ex_data[i], buffer, sizeof(buffer));
            printf("    ex_idx: %d, ex_key: %s, ex_val: %s\n", i, g_ex_manager.schemas[i].key, buffer);
        }
        else if (i == udp_builtin_ex)
        {
            memset(buffer, 0, sizeof(buffer));
            udp_ex_data_tostring((uint64_t)sess->ex_data[i], buffer, sizeof(buffer));
            printf("    ex_idx: %d, ex_key: %s, ex_val: %s\n", i, g_ex_manager.schemas[i].key, buffer);
        }
        else
        {
            printf("    ex_idx: %d, ex_key: %s, ex_val: %p\n", i, g_ex_manager.schemas[i].key, sess->ex_data[i]);
        }
    }
}