#include <string.h>
#include <pthread.h>
#include <assert.h>
#include <unistd.h>
#include <MESA/MESA_prof_load.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <net/if_arp.h>
#include <arpa/inet.h>
#include <errno.h>

#include "log.h"
#include "uthash.h"
#include "bfd.h"
#include "health_check.h"


#define     HC_MAC_LEN              6
#define     HC_DEV_NAME_LEN         16
#define     HC_LOCAL_ADDRESS_LEN    64

struct session_table
{
    // rwlock ???;
    // handler;
    struct session_iterm *root_by_id;
    pthread_rwlock_t rwlock;
};

static struct session_table g_handle;

struct session_iterm
{
    int session_id; // key

    struct health_check policy; // value1: deep copy
    int is_active;                     // value2
    uint8_t mac[HC_MAC_LEN];            // value3

    UT_hash_handle hh1; /* handle for first hash table */
};

int sleep_ms = 300;
char path[BFD_PATHLEN];
char hc_dev_name[HC_DEV_NAME_LEN];
char local_address[HC_LOCAL_ADDRESS_LEN];
char gateway_address[HC_LOCAL_ADDRESS_LEN];
uint8_t default_gw_mac[HC_MAC_LEN];

static int get_mac_by_addr(char *addr, uint8_t *buf);
static int health_check_session_foreach();

static struct session_iterm *health_check_get_iterm_by_id(int session_id)
{
    struct session_iterm *tmp = NULL;
    pthread_rwlock_rdlock(&g_handle.rwlock);
    HASH_FIND(hh1, g_handle.root_by_id, &session_id, sizeof(session_id), tmp);
    pthread_rwlock_unlock(&g_handle.rwlock);
    return tmp;
}

void health_check_session_init(const char *profile)
{
    memset(&g_handle, 0, sizeof(g_handle));
    pthread_rwlock_init(&g_handle.rwlock, NULL);
    MESA_load_profile_string_def(profile, "bfdd", "path", path, sizeof(path), "/var/run/frr/bfdd.vty");
    MESA_load_profile_string_def(profile, "bfdd", "device", hc_dev_name, sizeof(hc_dev_name), "eth0");
    MESA_load_profile_string_def(profile, "bfdd", "local_address", local_address, sizeof(local_address), "127.0.0.1");
    MESA_load_profile_string_def(profile, "bfdd", "gateway", gateway_address, sizeof(gateway_address), "127.0.0.1");

    // TODO: 循环获取？
    get_mac_by_addr(gateway_address, default_gw_mac);
    health_check_session_foreach();
}

static void health_check_session_init_bfd_client(struct bfd_vtysh_client *client)
{
    memset(client, 0, sizeof(*client));
    snprintf(client->path, sizeof(client->path), path);
    client->pre_config = bfd_vtysh_pre_config;
}

// return  0 : success
// return -1 : key exist
// struct health_check *policy : need deep copy
int health_check_session_add(int session_id, const struct health_check *policy)
{
    int ret = 0;
    struct bfd_vtysh_client client;
    struct session_iterm *tmp = NULL;

    tmp = health_check_get_iterm_by_id(session_id);
    if (tmp) {
        LOG_DEBUG("health check session table insert: key %d exists", session_id);
        return -1;
    }

    tmp = (struct session_iterm *)calloc(1, sizeof(struct session_iterm));
    assert(tmp);

    health_check_session_init_bfd_client(&client);
    bfd_vtysh_connect(&client);
    ret = bfd_vtysh_add_dev(&client, local_address, policy->address, policy->retires, policy->interval_ms);
    if (ret != 0) {
        LOG_DEBUG("bfd vtysh add dev address [%s] failed!", tmp->policy.address);
        bfd_vtysh_close(&client);
        return -1;
    }
    bfd_vtysh_close(&client);

    memset(tmp, 0, sizeof(*tmp));
    tmp->session_id = session_id;
    memcpy(&tmp->policy, policy, sizeof(struct health_check));
    
    pthread_rwlock_wrlock(&g_handle.rwlock);
    HASH_ADD(hh1, g_handle.root_by_id, session_id, sizeof(tmp->session_id), tmp);
    pthread_rwlock_unlock(&g_handle.rwlock);

    LOG_DEBUG("health check session table insert: key %d success", session_id);
    return 0;
}

// return  0 : success
// return -1 : key not exist
int health_check_session_del(int session_id)
{
    int ret = 0;
    struct bfd_vtysh_client client;
    struct session_iterm *tmp = NULL;

    tmp = health_check_get_iterm_by_id(session_id);
    if (!tmp) {
        LOG_DEBUG("health check session table delete: key %d not exists", session_id);
        return -1;
    }

    health_check_session_init_bfd_client(&client);
    bfd_vtysh_connect(&client);
    ret = bfd_vtysh_del_dev(&client, local_address, tmp->policy.address);
    if (ret != 0) {
        LOG_DEBUG("bfd vtysh delete dev address [%s] failed!", tmp->policy.address);
        bfd_vtysh_close(&client);
        return -1;
    }
    bfd_vtysh_close(&client);

    pthread_rwlock_wrlock(&g_handle.rwlock);
    HASH_DELETE(hh1, g_handle.root_by_id, tmp);
    pthread_rwlock_unlock(&g_handle.rwlock);
    free(tmp);
    tmp = NULL;

    LOG_DEBUG("health check session table delete: key %d success", session_id);
    return 0;
}

// return  1 : active
// return  0 : inactive
// return -1 : key not exist
int health_check_session_get_status(int session_id)
{
    int status = 0;
    struct session_iterm *tmp = NULL;

    pthread_rwlock_rdlock(&g_handle.rwlock);
    HASH_FIND(hh1, g_handle.root_by_id, &session_id, sizeof(session_id), tmp);
    if (!tmp) {
        LOG_DEBUG("health check session table get status: key %d not exists", session_id);
        pthread_rwlock_unlock(&g_handle.rwlock);
        return -1;
    }

    status = tmp->is_active;
    pthread_rwlock_unlock(&g_handle.rwlock);
    LOG_DEBUG("health check session get status: %d", status);
    return status;
}

// return  0 : success
// return -1 : key not exist
int health_check_session_set_status(int session_id, int is_active)
{
    struct session_iterm *tmp = NULL;

    pthread_rwlock_wrlock(&g_handle.rwlock);
    HASH_FIND(hh1, g_handle.root_by_id, &session_id, sizeof(session_id), tmp);
    if (!tmp) {
        LOG_DEBUG("health check session table get status: key %d not exists", session_id);
        pthread_rwlock_unlock(&g_handle.rwlock);
        return -1;
    }

    tmp->is_active = is_active;
    pthread_rwlock_unlock(&g_handle.rwlock);
    return 0;
}

static int get_mac_by_addr(char *addr, uint8_t *buf)
{
    int sfd, saved_errno, ret;
    struct arpreq arp_req;
    struct sockaddr_in *sin;

    sin = (struct sockaddr_in *)&(arp_req.arp_pa);

    memset(&arp_req, 0, sizeof(arp_req));
    sin->sin_family = AF_INET;
    inet_pton(AF_INET, addr, &(sin->sin_addr));
    snprintf(arp_req.arp_dev, IFNAMSIZ, hc_dev_name);

    sfd = socket(AF_INET, SOCK_DGRAM, 0);

    saved_errno = errno;
    ret = ioctl(sfd, SIOCGARP, &arp_req);
    if (ret < 0) {
        LOG_DEBUG("Get ARP entry failed : %s\n", strerror(errno));
        return -1;
    }
    errno = saved_errno;

    if (arp_req.arp_flags & ATF_COM)
        memcpy(buf, arp_req.arp_ha.sa_data, HC_MAC_LEN);        
    else
        memcpy(buf, default_gw_mac, HC_MAC_LEN);

    LOG_DEBUG("MAC: %02x:%02x:%02x:%02x:%02x:%02x\n",
                buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]);
    return 0;
}

static void *_health_check_session_foreach(void *arg)
{
    int is_active = 0;
    struct bfd_vtysh_client client;
    struct session_iterm *tmp = NULL;
    struct session_iterm *node = NULL;

    health_check_session_init_bfd_client(&client);
    bfd_vtysh_connect(&client);

    while(1) {
        // TODO: 改为读锁，更新数据入队列，通过写锁更新
        pthread_rwlock_wrlock(&g_handle.rwlock);
        HASH_ITER(hh1, g_handle.root_by_id, node, tmp) {
            if (node->policy.method != HEALTH_CHECK_METHOD_BFD)
                continue;

            is_active = bfd_vtysh_get_dev_active(&client, node->policy.address);
            if (is_active == -1)
                continue;
            if (node->is_active != is_active) {
                node->is_active = is_active;
                if (node->is_active == 1) {
                    get_mac_by_addr(node->policy.address, node->mac);
                }
                else {
                    memset(node->mac, 0, sizeof(node->mac));
                }
            }
            if (sleep_ms > node->policy.interval_ms)
                sleep_ms = node->policy.interval_ms;
        }
        pthread_rwlock_unlock(&g_handle.rwlock);
        usleep(sleep_ms*1000);
    }
    bfd_vtysh_close(&client);
}

static int health_check_session_foreach()
{    
    pthread_t pid;
    pthread_create(&pid, NULL, _health_check_session_foreach, NULL);
    pthread_detach(pid);
    return pid;
}

// return  0 : success
// return -1 : key not exist
int health_check_session_get_mac(int session_id, char *mac_buff)
{
    uint8_t *p = NULL;
    struct session_iterm *tmp = NULL;

    pthread_rwlock_rdlock(&g_handle.rwlock);
    HASH_FIND(hh1, g_handle.root_by_id, &session_id, sizeof(session_id), tmp);
    if (!tmp) {
        LOG_DEBUG("health check session table get status: key %d not exists", session_id);
        pthread_rwlock_unlock(&g_handle.rwlock);
        return -1;
    }

    p = (uint8_t *)tmp->mac;
    snprintf(mac_buff, 18, "%02x:%02x:%02x:%02x:%02x:%02x", p[0], p[1], p[2], p[3], p[4], p[5]);
    pthread_rwlock_unlock(&g_handle.rwlock);
    LOG_DEBUG("health check session get mac: %s", mac_buff);
    return 0;
}