#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>

#include <sys/socket.h>
#include <sys/types.h>
#include <linux/rtnetlink.h>

#include "ip4.h"
#include "rtnetlink.h"
#include "interface.h"

namespace interface {
  static void newaddr(int fd,
                      uint32_t ifa_index, uint8_t ifa_prefixlen, uint32_t local, uint32_t address)
  {
    int dret = rtnetlink::send_typeaddr(fd, RTM_NEWADDR, ifa_index,
                                        ifa_prefixlen, local, address);
    if (dret < 0) {
      exit(EXIT_FAILURE);
    }
    int eret = rtnetlink::handle_error(fd);
    if (eret < 0) {
      exit(EXIT_FAILURE);
    }
  }

  static void deladdr(int fd,
                      uint32_t ifa_index, uint8_t ifa_prefixlen, uint32_t local, uint32_t address)
  {
    int dret = rtnetlink::send_typeaddr(fd, RTM_DELADDR, ifa_index,
                                        ifa_prefixlen, local, address);
    if (dret < 0) {
      exit(EXIT_FAILURE);
    }
    int eret = rtnetlink::handle_error(fd);
    if (eret < 0) {
      exit(EXIT_FAILURE);
    }
  }

  static void newroute(int fd,
                       uint32_t ifa_index, uint32_t gateway)
  {
    int dret = rtnetlink::send_newroute(fd, ifa_index, gateway);
    if (dret < 0) {
      exit(EXIT_FAILURE);
    }
    int eret = rtnetlink::handle_error(fd);
    if (eret < 0) {
      exit(EXIT_FAILURE);
    }
  }

  static void flush_addresses(int fd,
                              uint32_t ifa_index)
  {
    int grets = rtnetlink::send_getaddr(fd, ifa_index);
    if (grets < 0) {
      exit(EXIT_FAILURE);
    }

    const int out_length = 64;
    rtnetlink::newaddr out[out_length];
    int greth = rtnetlink::handle_getaddr(fd, ifa_index, out, out_length);
    if (greth < 0) {
      exit(EXIT_FAILURE);
    }

    for (int i = 0; i < greth; i++) {
      printf("deladdr[%d]:\n", i);
      printf("  prefixlen %d\n", out[i].ifa_prefixlen);
      printf("  local %s\n", ip4::tostr(out[i].local));
      printf("  address %s\n", ip4::tostr(out[i].address));

      deladdr(fd, ifa_index, out[i].ifa_prefixlen, out[i].local, out[i].address);
    }
  }

  void configure(uint32_t ifa_index,
                 uint8_t ifa_prefixlen,
                 uint32_t address,
                 uint32_t gateway)
  {
    //////////////////////////////////////////////////////////////////////
    // netlink socket
    //////////////////////////////////////////////////////////////////////

    int fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
    if (fd < 0) {
      perror("socket");
      exit(EXIT_FAILURE);
    }

    struct sockaddr_nl bsa = { .nl_family = AF_NETLINK };
    int ret = bind(fd, (struct sockaddr *)&bsa, (sizeof (sockaddr_nl)));
    if (ret < 0) {
      perror("bind");
      exit(EXIT_FAILURE);
    }

    //////////////////////////////////////////////////////////////////////
    //
    //////////////////////////////////////////////////////////////////////

    flush_addresses(fd, ifa_index);

    newaddr(fd,
            ifa_index, ifa_prefixlen, address, address);

    newroute(fd,
             ifa_index, gateway);
  }
}