#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "setup_interfaces.h"
#include "sysfs_reader.h"

struct net_iface* get_all_interfaces()
{
    struct ifreq *ifr;
    struct ifconf ifc;
    int s;
    int numif;

    memset(&ifc, 0, sizeof(ifc));
    ifc.ifc_ifcu.ifcu_req = NULL;
    ifc.ifc_len = 0;

    if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("socket");
        return NULL;
    }

    if (ioctl(s, SIOCGIFCONF, &ifc) < 0) {
            perror("ioctl");
        return NULL;
    }

    if ((ifr = malloc(ifc.ifc_len)) == NULL) {
            perror("malloc");
            return NULL;
    }

    ifc.ifc_ifcu.ifcu_req = ifr;

    if (ioctl(s, SIOCGIFCONF, &ifc) < 0) {
        perror("ioctl");
        return NULL;
    }

    close(s);

    numif = ifc.ifc_len / sizeof(struct ifreq);

    if (!numif) {
        free(ifr);
        return NULL;
    }

    struct net_iface* iflist;

    if ((iflist = malloc(sizeof(struct net_iface) * numif)) == NULL) {
        perror("malloc");
        return NULL;
    }

    int sysfs_avail = is_sysfs_available();

    int i;

    for (i = 0; i < numif; i++) {
        struct ifreq *r = &ifr[i];
        struct sockaddr_in *sin = (struct sockaddr_in *)&r->ifr_addr;

        iflist[i].if_idx = r->ifr_ifindex;
        strncpy(iflist[i].if_name, r->ifr_name, IFNAMSIZ);

        if (sysfs_avail) {
            iflist[i].get_stat = get_stat_sysfs;
        }

        inet_ntop(AF_INET, &sin->sin_addr, iflist[i].str_ip4_addr, INET_ADDRSTRLEN);

        if (i) {
            iflist[i-1].next = &iflist[i];
        }
    }

    free(ifr);

    return iflist;
}