#include <pcap/pcap.h>
#include <pthread.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/types.h>

#include "macro.h"
#include "dumpfile_io.h"
#include "packet_priv.h"
#include "lock_free_queue.h"

#define MAX_PACKET_QUEUE_SIZE (4096 * 1000)

struct dumpfile_io
{
    uint16_t nr_threads;
    char directory[256];

    pcap_t *pcap;
    struct lock_free_queue *queue[MAX_THREAD_NUM];
    struct io_stat stat[MAX_THREAD_NUM];
    uint64_t io_thread_need_exit;
    uint64_t io_thread_is_runing;
};

struct pcap_pkt
{
    char *data;
    int len;
};

/******************************************************************************
 * Private API
 ******************************************************************************/

typedef int file_handle(const char *file, void *arg);

static int scan_directory(const char *dir, file_handle *handler, void *arg)
{
    struct stat statbuf;
    struct dirent *entry;

    DIR *dp = opendir(dir);
    if (NULL == dp)
    {
        PACKET_IO_LOG_ERROR("opendir %s failed, %s", dir, strerror(errno));
        return -1;
    }

    if (chdir(dir) == -1)
    {
        PACKET_IO_LOG_ERROR("chdir %s failed, %s", dir, strerror(errno));
        goto error_out;
    }

    while ((entry = readdir(dp)))
    {
        if (lstat(entry->d_name, &statbuf) == -1)
        {
            PACKET_IO_LOG_ERROR("lstat %s failed, %s", entry->d_name, strerror(errno));
            goto error_out;
        }

        if (S_IFDIR & statbuf.st_mode)
        {
            if (!strcmp(".", entry->d_name) || !strcmp("..", entry->d_name))
            {
                continue;
            }

            if (scan_directory(entry->d_name, handler, arg) == -1)
            {
                goto error_out;
            }
        }
        else
        {
            if (handler(entry->d_name, arg) == -1)
            {
                goto error_out;
            }
        }
    }

    if (chdir("..") == -1)
    {
        PACKET_IO_LOG_ERROR("chdir .. failed, %s", strerror(errno));
        goto error_out;
    }

    closedir(dp);
    return 0;

error_out:
    closedir(dp);
    return -1;
}

static void pcap_packet_handler(u_char *user, const struct pcap_pkthdr *h, const u_char *bytes)
{
    struct dumpfile_io *handle = (struct dumpfile_io *)user;

    // copy packet data to new memory
    struct pcap_pkt *pcap_pkt = (struct pcap_pkt *)calloc(1, sizeof(struct pcap_pkt) + h->caplen);
    if (pcap_pkt == NULL)
    {
        PACKET_IO_LOG_ERROR("unable to alloc packet");
        return;
    }
    pcap_pkt->data = (char *)pcap_pkt + sizeof(struct pcap_pkt);
    pcap_pkt->len = h->caplen;
    memcpy((char *)pcap_pkt->data, bytes, h->caplen);

    // calculate packet hash
    struct packet pkt;
    packet_parse(&pkt, pcap_pkt->data, pcap_pkt->len);
    uint64_t hash = packet_get_hash(&pkt, LDBC_METHOD_HASH_INT_IP_AND_EXT_IP, 0);

    // push packet to queue
    struct lock_free_queue *queue = handle->queue[hash % handle->nr_threads];
    while (lock_free_queue_push(queue, pcap_pkt) == -1)
    {
        if (ATOMIC_READ(&handle->io_thread_need_exit))
        {
            free(pcap_pkt);
            PACKET_IO_LOG_STATE("dumpfile io thread need exit");
            pcap_breakloop(handle->pcap);
            break;
        }
        usleep(1000);
    }

    if (ATOMIC_READ(&handle->io_thread_need_exit))
    {
        PACKET_IO_LOG_STATE("dumpfile io thread need exit");
        pcap_breakloop(handle->pcap);
    }
}

static int dumpfile_handler(const char *file, void *arg)
{
    char resolved_path[256];
    char pcap_errbuf[PCAP_ERRBUF_SIZE];
    struct dumpfile_io *handle = (struct dumpfile_io *)arg;

    realpath(file, resolved_path);
    PACKET_IO_LOG_STATE("dumpfile %s in-processing", resolved_path)

    handle->pcap = pcap_open_offline(file, pcap_errbuf);
    if (handle->pcap == NULL)
    {
        PACKET_IO_LOG_ERROR("unable to open pcap file: %s, %s", resolved_path, pcap_errbuf);
        return -1;
    }
    pcap_loop(handle->pcap, -1, pcap_packet_handler, (u_char *)handle);
    pcap_close(handle->pcap);

    PACKET_IO_LOG_STATE("dumpfile %s processed", resolved_path)

    return 0;
}

static void *dumpfile_thread(void *arg)
{
    struct dumpfile_io *handle = (struct dumpfile_io *)arg;

    ATOMIC_SET(&handle->io_thread_is_runing, 1);
    PACKET_IO_LOG_STATE("dumpfile io thread is running");

    scan_directory(handle->directory, dumpfile_handler, arg);

    while (ATOMIC_READ(&handle->io_thread_need_exit) == 0)
    {
        PACKET_IO_LOG_STATE("dumpfile io thread waiting");
        sleep(1);
    }

    PACKET_IO_LOG_STATE("dumpfile io thread exit !!!");
    ATOMIC_SET(&handle->io_thread_is_runing, 0);

    return NULL;
}

/******************************************************************************
 * Public API
 ******************************************************************************/

struct dumpfile_io *dumpfile_io_new(const char *directory, uint16_t nr_threads)
{
    pthread_t tid;
    struct dumpfile_io *handle = (struct dumpfile_io *)calloc(1, sizeof(struct dumpfile_io));
    if (handle == NULL)
    {
        PACKET_IO_LOG_ERROR("unable to allocate memory for dumpfile_io");
        return NULL;
    }

    handle->nr_threads = nr_threads;
    strncpy(handle->directory, directory, MIN(strlen(directory), sizeof(handle->directory)));

    for (uint16_t i = 0; i < handle->nr_threads; i++)
    {
        handle->queue[i] = lock_free_queue_new(MAX_PACKET_QUEUE_SIZE);
        if (handle->queue[i] == NULL)
        {
            PACKET_IO_LOG_ERROR("unable to create packet queue");
            goto error_out;
        }
    }
    if (pthread_create(&tid, NULL, dumpfile_thread, (void *)handle) != 0)
    {
        PACKET_IO_LOG_ERROR("unable to create packet io thread");
        goto error_out;
    }

    return handle;

error_out:
    dumpfile_io_free(handle);
    return NULL;
}

void dumpfile_io_free(struct dumpfile_io *handle)
{
    if (handle)
    {
        ATOMIC_SET(&handle->io_thread_need_exit, 1);

        while (ATOMIC_READ(&handle->io_thread_is_runing))
        {
            usleep(1000);
        }

        struct pcap_pkt *pcap_pkt = NULL;
        for (uint16_t i = 0; i < handle->nr_threads; i++)
        {
            while (1)
            {
                lock_free_queue_pop(handle->queue[i], (void **)&pcap_pkt);
                if (pcap_pkt)
                {
                    free(pcap_pkt);
                }
                else
                {
                    break;
                }
            }

            lock_free_queue_free(handle->queue[i]);
        }
        free(handle);
        handle = NULL;
    }
}

int dumpfile_io_init(struct dumpfile_io *handle, uint16_t thr_idx)
{
    return 0;
}

int dumpfile_io_ingress(struct dumpfile_io *handle, uint16_t thr_idx, struct packet *pkts, int nr_pkts)
{
    struct lock_free_queue *queue = handle->queue[thr_idx];
    struct io_stat *stat = &handle->stat[thr_idx];
    struct pcap_pkt *pcap_pkt = NULL;
    struct packet *pkt;
    int nr_parsed = 0;

    for (int i = 0; i < nr_pkts; i++)
    {
        lock_free_queue_pop(queue, (void **)&pcap_pkt);
        if (pcap_pkt == NULL)
        {
            break;
        }
        else
        {
            stat->dev_rx_pkts++;
            stat->dev_rx_bytes += pcap_pkt->len;

            stat->raw_rx_pkts++;
            stat->raw_rx_bytes += pcap_pkt->len;

            pkt = &pkts[nr_parsed];
            memset(pkt, 0, sizeof(struct packet));
            packet_parse(pkt, pcap_pkt->data, pcap_pkt->len);
            packet_set_origin_ctx(pkt, pcap_pkt);
            packet_set_origin(pkt, PACKET_ORIGIN_DUMPFILE);
            packet_set_action(pkt, PACKET_ACTION_FORWARD);
            nr_parsed++;
        }
    }

    return nr_parsed;
}

void dumpfile_io_egress(struct dumpfile_io *handle, uint16_t thr_idx, struct packet *pkts, int nr_pkts)
{
    int len;
    struct packet *pkt = NULL;
    struct io_stat *stat = &handle->stat[thr_idx];

    for (int i = 0; i < nr_pkts; i++)
    {
        pkt = &pkts[i];
        len = packet_get_len(pkt);

        stat->dev_tx_pkts++;
        stat->dev_tx_bytes += len;

        stat->raw_tx_pkts++;
        stat->raw_tx_bytes += len;

        struct pcap_pkt *pcap_pkt = (struct pcap_pkt *)packet_get_origin_ctx(pkt);
        if (pcap_pkt)
        {
            free(pcap_pkt);
        }
        packet_free(pkt);
    }
}

void dumpfile_io_drop(struct dumpfile_io *handle, uint16_t thr_idx, struct packet *pkts, int nr_pkts)
{
    struct packet *pkt = NULL;
    struct io_stat *stat = &handle->stat[thr_idx];

    for (int i = 0; i < nr_pkts; i++)
    {
        pkt = &pkts[i];
        struct pcap_pkt *pcap_pkt = (struct pcap_pkt *)packet_get_origin_ctx(pkt);
        if (pcap_pkt)
        {
            stat->drop_pkts++;
            stat->drop_bytes += packet_get_len(pkt);
            free(pcap_pkt);
        }
        packet_free(pkt);
    }
}

int dumpfile_io_inject(struct dumpfile_io *handle, uint16_t thr_idx, struct packet *pkts, int nr_pkts)
{
    int len;
    struct packet *pkt = NULL;
    struct io_stat *stat = &handle->stat[thr_idx];

    for (int i = 0; i < nr_pkts; i++)
    {
        pkt = &pkts[i];
        len = packet_get_len(pkt);

        stat->inject_pkts++;
        stat->inject_bytes += len;

        stat->raw_tx_pkts++;
        stat->raw_tx_bytes += len;

        stat->dev_tx_pkts++;
        stat->dev_tx_bytes += len;

        packet_free(pkt);
    }

    return nr_pkts;
}

void dumpfile_io_yield(struct dumpfile_io *handle, uint16_t thr_idx, uint64_t timeout_ms)
{
    return;
}

struct io_stat *dumpfile_io_stat(struct dumpfile_io *handle, uint16_t thr_idx)
{
    return &handle->stat[thr_idx];
}