#include <stdio.h>
#include <assert.h>
#include <errno.h>
#include <pthread.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/prctl.h>
#include <netinet/ether.h>

#include "logo.h"
#include "marsio.h"
#include "config.h"
#include "packet.h"
#include "timestamp.h"
#include "session_manager.h"

#ifdef STELLAR_GIT_VERSION
static __attribute__((__used__)) const char *__stellar_version = STELLAR_GIT_VERSION;
#else
static __attribute__((__used__)) const char *__stellar_version = "Unknown";
#endif

#define STELLAR_LOG_STATE(format, ...) LOG_STATE("stellar", format, ##__VA_ARGS__)
#define STELLAR_LOG_ERROR(format, ...) LOG_ERROR("stellar", format, ##__VA_ARGS__)
#define STELLAR_LOG_DEBUG(format, ...) LOG_DEBUG("stellar", format, ##__VA_ARGS__)

#define ATOMIC_SET(x, y) __atomic_store_n(x, y, __ATOMIC_RELAXED)
#define ATOMIC_READ(x) __atomic_load_n(x, __ATOMIC_RELAXED)

#define RX_BURST_MAX 128

struct packet_io
{
    struct mr_instance *mr_ins;
    struct mr_vdev *mr_dev;
    struct mr_sendpath *mr_path;
};

struct thread_context
{
    pthread_t tid;
    uint16_t index;
    uint64_t need_exit;
    uint64_t is_runing;
    struct session_manager *sess_mgr;
};

struct stellar_context
{
    uint64_t need_exit;
    struct config config;

    struct packet_io *pkt_io;
    struct thread_context threads_ctx[MAX_THREAD_NUM];
};

struct stellar_context stellar_context;
struct stellar_context *stellar_ctx_ptr = &stellar_context;

static const char *log_config_file = "./conf/log.toml";
static const char *stellar_config_file = "./conf/stellar.toml";

/******************************************************************************
 * example
 ******************************************************************************/

static void __packet_plugin_dispatch_example(const struct packet *pkt)
{
    if (pkt == NULL)
    {
        return;
    }

    printf("\n");
    printf("=> packet dispatch: %p\n", pkt);
    printf("<= packet dispatch\n\n");
}

static void __session_plugin_dispatch_example(struct session *sess)
{
    if (sess == NULL)
    {
        return;
    }

    printf("\n");
    printf("=> session dispatch: %p\n", sess);
    session_dump(sess);
    printf("<= session dispatch\n\n");

    // after session dispatch, we should reset session current packet and direction
    session_set0_cur_pkt(sess, NULL);
    session_set_cur_dir(sess, SESSION_DIR_NONE);
}

/******************************************************************************
 * util
 ******************************************************************************/

static void signal_handler(int signo)
{
    if (signo == SIGINT)
    {
        STELLAR_LOG_DEBUG("recv SIGINT, exit !!!");
        ATOMIC_SET(&stellar_ctx_ptr->need_exit, 1);
    }

    if (signo == SIGQUIT)
    {
        STELLAR_LOG_DEBUG("recv SIGQUIT, exit !!!");
        ATOMIC_SET(&stellar_ctx_ptr->need_exit, 1);
    }

    if (signo == SIGTERM)
    {
        STELLAR_LOG_DEBUG("recv SIGTERM, exit !!!");
        ATOMIC_SET(&stellar_ctx_ptr->need_exit, 1);
    }

    if (signo == SIGHUP)
    {
        STELLAR_LOG_DEBUG("recv SIGHUP, reload log config file !!!");
        log_reload_level(log_config_file);
    }
}

// return 0 : not keepalive packet
// return 1 : is  keepalive packet
static inline int is_keepalive_packet(const char *data, int len)
{
    if (data == NULL || len < (int)(sizeof(struct ethhdr)))
    {
        return 0;
    }

    struct ethhdr *eth_hdr = (struct ethhdr *)data;
    if (eth_hdr->h_proto == 0xAAAA)
    {
        return 1;
    }
    else
    {
        return 0;
    }
}

/******************************************************************************
 * thread
 ******************************************************************************/

static inline void thread_set_name(const char *thd_symbol, uint16_t thd_idx)
{
    char thd_name[16];
    snprintf(thd_name, sizeof(thd_name), "%s:%d", thd_symbol, thd_idx);
    prctl(PR_SET_NAME, (unsigned long long)thd_name, NULL, NULL, NULL);
}

static void *main_loop(void *arg)
{
    int n_pkt_recved;
    uint16_t len = 0;
    const char *data;
    struct packet pkt;
    struct session *sess;
    marsio_buff_t *rx_buff;
    marsio_buff_t *rx_buffs[RX_BURST_MAX];
    struct thread_context *threads_ctx = (struct thread_context *)arg;
    struct session_manager *sess_mgr = threads_ctx->sess_mgr;
    struct packet_io *pkt_io = stellar_ctx_ptr->pkt_io;
    uint16_t thd_idx = threads_ctx->index;

    struct mr_vdev *mr_dev = pkt_io->mr_dev;
    struct mr_sendpath *mr_path = pkt_io->mr_path;
    struct mr_instance *mr_ins = pkt_io->mr_ins;
    struct mr_vdev *vdevs[1] = {
        mr_dev,
    };
    int min_timeout_ms = 10;

    if (marsio_thread_init(mr_ins) != 0)
    {
        STELLAR_LOG_ERROR("unable to init marsio thread");
        return NULL;
    }

    ATOMIC_SET(&threads_ctx->is_runing, 1);
    thread_set_name("stellar", thd_idx);
    STELLAR_LOG_DEBUG("worker thread %d runing\n", thd_idx);

    while (ATOMIC_READ(&threads_ctx->need_exit) == 0)
    {
        n_pkt_recved = marsio_recv_burst(mr_dev, thd_idx, rx_buffs, RX_BURST_MAX);
        if (n_pkt_recved <= 0)
        {
            goto poll_wait;
        }

        for (int i = 0; i < n_pkt_recved; i++)
        {
            rx_buff = rx_buffs[i];
            data = marsio_buff_mtod(rx_buff);
            len = marsio_buff_datalen(rx_buff);

            if (is_keepalive_packet(data, len))
            {
                marsio_send_burst(mr_path, thd_idx, &rx_buff, 1);
                continue;
            }
            else
            {
                packet_parse(&pkt, data, len);
                __packet_plugin_dispatch_example(&pkt);

                sess = session_manager_update_session(sess_mgr, &pkt);
                __session_plugin_dispatch_example(sess);

                sess = session_manager_get_evicted_session(sess_mgr);
                __session_plugin_dispatch_example(sess);

                // TODO
                if (1) // action == forward
                {
                    marsio_send_burst(mr_path, thd_idx, &rx_buff, 1);
                }
                else // action == drop
                {
                    marsio_buff_free(mr_ins, &rx_buff, 1, 0, thd_idx);
                }
            }
        }

    poll_wait:
        sess = session_manager_get_expired_session(sess_mgr);
        __session_plugin_dispatch_example(sess);
        marsio_poll_wait(mr_ins, vdevs, 1, thd_idx, min_timeout_ms);
    }

    ATOMIC_SET(&threads_ctx->is_runing, 0);
    STELLAR_LOG_DEBUG("worker thread %d exit\n", thd_idx);

    return NULL;
}

static int thread_context_init(struct stellar_context *ctx)
{
    struct system_config *sys_cfg = &ctx->config.sys_cfg;
    struct session_manager_config *sess_mgr_cfg = &ctx->config.sess_mgr_cfg;

    for (uint16_t i = 0; i < sys_cfg->nr_threads; i++)
    {
        struct thread_context *threads_ctx = &ctx->threads_ctx[i];
        threads_ctx->index = i;
        threads_ctx->need_exit = 0;
        threads_ctx->is_runing = 0;

        threads_ctx->sess_mgr = session_manager_create(sess_mgr_cfg);
        if (threads_ctx->sess_mgr == NULL)
        {
            STELLAR_LOG_ERROR("unable to create session manager");
            return -1;
        }
    }

    return 0;
}

static void thread_context_free(struct stellar_context *ctx)
{
    struct system_config *sys_cfg = &ctx->config.sys_cfg;

    for (uint16_t i = 0; i < sys_cfg->nr_threads; i++)
    {
        struct thread_context *threads_ctx = &ctx->threads_ctx[i];
        if (ATOMIC_READ(&threads_ctx->is_runing) == 0)
        {
            session_manager_destroy(threads_ctx->sess_mgr);
        }
    }
}

static int thread_create(struct thread_context threads_ctx[], uint16_t nr_threads)
{
    for (uint16_t i = 0; i < nr_threads; i++)
    {
        struct thread_context *ctx = &threads_ctx[i];
        if (pthread_create(&ctx->tid, NULL, main_loop, (void *)ctx) < 0)
        {
            STELLAR_LOG_ERROR("unable to create worker thread, error %d: %s", errno, strerror(errno));
            return -1;
        }
    }

    return 0;
}

static void thread_destroy(struct thread_context threads_ctx[], uint16_t nr_threads)
{
    for (uint16_t i = 0; i < nr_threads; i++)
    {
        struct thread_context *ctx = &threads_ctx[i];
        ATOMIC_SET(&ctx->need_exit, 1);
        while (ATOMIC_READ(&ctx->is_runing) == 1)
        {
            sleep(1);
        }
    }
}

/******************************************************************************
 * packet io
 ******************************************************************************/

void packet_io_destroy(struct packet_io *pkt_io)
{
    if (pkt_io == NULL)
    {
        return;
    }

    if (pkt_io->mr_path != NULL)
    {
        marsio_sendpath_destory(pkt_io->mr_path);
        pkt_io->mr_path = NULL;
    }
    if (pkt_io->mr_dev != NULL)
    {
        marsio_close_device(pkt_io->mr_dev);
        pkt_io->mr_dev = NULL;
    }
    if (pkt_io->mr_ins != NULL)
    {
        marsio_destory(pkt_io->mr_ins);
        pkt_io->mr_ins = NULL;
    }
    free(pkt_io);
    pkt_io = NULL;
}

struct packet_io *packet_io_create(struct system_config *sys_cfg)
{
    struct packet_io *pkt_io = (struct packet_io *)calloc(1, sizeof(struct packet_io));
    if (pkt_io == NULL)
    {
        STELLAR_LOG_ERROR("unable to alloc packet io");
        return NULL;
    }

    int opt = 1;
    cpu_set_t coremask;
    CPU_ZERO(&coremask);
    for (int i = 0; i < sys_cfg->nr_threads; i++)
    {
        CPU_SET(sys_cfg->cpu_mask[i], &coremask);
    }

    pkt_io->mr_ins = marsio_create();
    if (pkt_io->mr_ins == NULL)
    {
        STELLAR_LOG_ERROR("unable to create marsio instance");
        goto error_out;
    }
    marsio_option_set(pkt_io->mr_ins, MARSIO_OPT_THREAD_MASK_IN_CPUSET, &coremask, sizeof(coremask));
    marsio_option_set(pkt_io->mr_ins, MARSIO_OPT_EXIT_WHEN_ERR, &opt, sizeof(opt));
    if (marsio_init(pkt_io->mr_ins, sys_cfg->app_symbol) != 0)
    {
        STELLAR_LOG_ERROR("unable to init marsio instance");
        goto error_out;
    }
    pkt_io->mr_dev = marsio_open_device(pkt_io->mr_ins, sys_cfg->dev_symbol, sys_cfg->nr_threads, sys_cfg->nr_threads);
    if (pkt_io->mr_dev == NULL)
    {
        STELLAR_LOG_ERROR("unable to open marsio device");
        goto error_out;
    }
    pkt_io->mr_path = marsio_sendpath_create_by_vdev(pkt_io->mr_dev);
    if (pkt_io->mr_path == NULL)
    {
        STELLAR_LOG_ERROR("unable to create marsio sendpath");
        goto error_out;
    }

    return pkt_io;

error_out:
    packet_io_destroy(pkt_io);
    return NULL;
}

/******************************************************************************
 * main
 ******************************************************************************/

int main(int argc, char **argv)
{
    memset(stellar_ctx_ptr, 0, sizeof(struct stellar_context));
    timestamp_update();

    if (log_init(log_config_file) != 0)
    {
        return -1;
    }

    STELLAR_LOG_STATE("Start Stellar (version: %s)\n %s", __stellar_version, logo_str);

    if (config_load(&stellar_ctx_ptr->config, stellar_config_file) != 0)
    {
        return -1;
    }

    config_dump(&stellar_ctx_ptr->config);
    struct system_config *sys_cfg = &stellar_ctx_ptr->config.sys_cfg;
    uint16_t nr_threads = sys_cfg->nr_threads;

    // TODO init plugin

    signal(SIGINT, signal_handler);
    signal(SIGQUIT, signal_handler);
    signal(SIGTERM, signal_handler);
    signal(SIGHUP, signal_handler);

    stellar_ctx_ptr->pkt_io = packet_io_create(sys_cfg);
    if (stellar_ctx_ptr->pkt_io == NULL)
    {
        STELLAR_LOG_ERROR("unable to create packet io");
        goto error_out;
    }

    if (thread_context_init(stellar_ctx_ptr) != 0)
    {
        STELLAR_LOG_ERROR("unable to init thread context");
        goto error_out;
    }

    if (thread_create(stellar_ctx_ptr->threads_ctx, nr_threads) != 0)
    {
        STELLAR_LOG_ERROR("unable to create worker thread");
        goto error_out;
    }

    while (!ATOMIC_READ(&stellar_ctx_ptr->need_exit))
    {
        timestamp_update();
        sleep(1);
    }

error_out:
    packet_io_destroy(stellar_ctx_ptr->pkt_io);

    thread_destroy(stellar_ctx_ptr->threads_ctx, nr_threads);

    thread_context_free(stellar_ctx_ptr);

    // TODO free plugin

    log_free();

    return 0;
}