#include <assert.h>

#include "crc32_hash.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};

/******************************************************************************
 * 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 key
 ******************************************************************************/

uint32_t session_key_hash(const struct session_key *key)
{
    uint32_t hash = crc32_hash(&key->security_zone, sizeof(key->security_zone), key->ip_proto);

    if (key->ip_type == IP_TYPE_V4)
    {
        uint32_t src_addr_hash = crc32_hash(&key->src_addr.v4, sizeof(key->src_addr.v4), hash);
        uint32_t dst_addr_hash = crc32_hash(&key->dst_addr.v4, sizeof(key->dst_addr.v4), hash);
        hash = src_addr_hash + dst_addr_hash;
    }
    else
    {
        uint32_t src_addr_hash = crc32_hash(&key->src_addr.v6, sizeof(key->src_addr.v6), hash);
        uint32_t dst_addr_hash = crc32_hash(&key->dst_addr.v6, sizeof(key->dst_addr.v6), hash);
        hash = src_addr_hash + dst_addr_hash;
    }

    uint32_t src_port_hash = crc32_hash(&key->src_port, sizeof(key->src_port), hash);
    uint32_t dst_port_hash = crc32_hash(&key->dst_port, sizeof(key->dst_port), hash);
    hash = src_port_hash + dst_port_hash;

    return hash;
}

// return  0: equal
// return -1: not equal
int session_key_cmp(const struct session_key *key1, const struct session_key *key2)
{
    if (key1->ip_type != key2->ip_type)
    {
        return -1;
    }

    if (key1->src_port != key2->src_port)
    {
        return -1;
    }

    if (key1->dst_port != key2->dst_port)
    {
        return -1;
    }

    if (key1->ip_proto != key2->ip_proto)
    {
        return -1;
    }

    if (key1->security_zone != key2->security_zone)
    {
        return -1;
    }

    if (key1->ip_type == IP_TYPE_V4)
    {
        if (key1->src_addr.v4.s_addr != key2->src_addr.v4.s_addr)
        {
            return -1;
        }

        if (key1->dst_addr.v4.s_addr != key2->dst_addr.v4.s_addr)
        {
            return -1;
        }
    }
    else
    {
        if (memcmp(&key1->src_addr.v6, &key2->src_addr.v6, sizeof(key1->src_addr.v6)) != 0)
        {
            return -1;
        }

        if (memcmp(&key1->dst_addr.v6, &key2->dst_addr.v6, sizeof(key1->dst_addr.v6)) != 0)
        {
            return -1;
        }
    }

    return 0;
}

void session_key_reverse(const struct session_key *in, struct session_key *out)
{
    out->ip_type = in->ip_type;
    out->src_port = in->dst_port;
    out->dst_port = in->src_port;
    out->ip_proto = in->ip_proto;
    out->security_zone = in->security_zone;

    if (in->ip_type == IP_TYPE_V4)
    {
        out->src_addr.v4.s_addr = in->dst_addr.v4.s_addr;
        out->dst_addr.v4.s_addr = in->src_addr.v4.s_addr;
    }
    else
    {
        memcpy(&out->src_addr.v6, &in->dst_addr.v6, sizeof(in->dst_addr.v6));
        memcpy(&out->dst_addr.v6, &in->src_addr.v6, sizeof(in->src_addr.v6));
    }
}

void session_key_tostring(const struct session_key *key, char *buf, uint32_t buf_len)
{
    char src_addr[INET6_ADDRSTRLEN] = {0};
    char dst_addr[INET6_ADDRSTRLEN] = {0};

    if (key->ip_type == IP_TYPE_V4)
    {
        inet_ntop(AF_INET, &key->src_addr.v4, src_addr, sizeof(src_addr));
        inet_ntop(AF_INET, &key->dst_addr.v4, dst_addr, sizeof(dst_addr));
    }
    else
    {
        inet_ntop(AF_INET6, &key->src_addr.v6, src_addr, sizeof(src_addr));
        inet_ntop(AF_INET6, &key->dst_addr.v6, dst_addr, sizeof(dst_addr));
    }

    snprintf(buf, buf_len, "%s:%u -> %s:%u, proto: %u, zone: %lu",
             src_addr, ntohs(key->src_port),
             dst_addr, ntohs(key->dst_port),
             key->ip_proto,
             key->security_zone);
}

/******************************************************************************
 * 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(struct session *sess)
{
    return sess->id;
}

// session key
void session_set_key(struct session *sess, struct session_key *key)
{
    memcpy(&sess->key, key, sizeof(struct session_key));
}

struct session_key *session_get0_key(struct session *sess)
{
    return &sess->key;
}

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

enum session_state session_get_state(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(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(struct session *sess)
{
    return sess->c2s_bytes;
}

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

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

uint64_t session_get_s2c_packets(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));
}

struct metadata *session_get0_c2s_1st_md(struct session *sess)
{
    return &sess->c2s_1st_md;
}

struct metadata *session_get0_s2c_1st_md(struct session *sess)
{
    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(struct session *sess)
{
    return sess->create_time;
}

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

// 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(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);
    }
}