/* ISC license. */

#include <string.h>
#include <unistd.h>
#include <net/if.h>

#include <skalibs/uint64.h>
#include <skalibs/types.h>
#include <skalibs/strerr.h>
#include <skalibs/prog.h>
#include <skalibs/gol.h>
#include <skalibs/tai.h>
#include <skalibs/iopause.h>

#include <bcnm/if.h>

#define USAGE "bcnm-waitif [ -u | -d ] [ -t timeout ] [ -k kbufsize ] mask interface..."
#define dieusage() strerr_dieusage(100, USAGE)

enum golb_e
{
  GOLB_DOWN = 0x01,
} ;

enum gola_e
{
  GOLA_TIMEOUT,
  GOLA_KBUFSIZE,
  GOLA_N
} ;

static inline int check (bcnm_if_link_state_t *tab, unsigned int n, unsigned int mask, int up)
{
  for (unsigned int i = 0 ; i < n ; i++)
    if ((tab[i].state & mask) != (up ? mask : 0)) return 0 ;
  return 1 ;
}

int main (int argc, char const *const *argv)
{
  static gol_bool const rgolb[] =
  {
    { .so = 'u', .lo = "up", .clear = GOLB_DOWN, .set = 0 },
    { .so = 'd', .lo = "down", .clear = 0, .set = GOLB_DOWN },
  } ;
  static gol_arg const rgola[] =
  {
    { .so = 't', .lo = "timeout", .i = GOLA_TIMEOUT },
    { .so = 'k', .lo = "kbufsize", .i = GOLA_KBUFSIZE },
  } ;
  uint64_t wgolb = 0 ;
  char const *wgola[GOLA_N] = { 0 } ;
  iopause_fd x = { .events = IOPAUSE_READ } ;
  tain deadline = TAIN_INFINITE_RELATIVE ;
  unsigned int mask = 1 ;
  unsigned int kbufsize = 131072 ;
  unsigned int golc ;
  PROG = "bcnm-waitif" ;

  golc = GOL_main(argc, argv, rgolb, rgola, &wgolb, wgola) ;
  argc -= golc ; argv += golc ;
  if (argc-- < 2) dieusage() ;

  if (wgola[GOLA_TIMEOUT])
  {
    unsigned int t ;
    if (!uint0_scan(wgola[GOLA_TIMEOUT], &t))
      strerr_dief(100, "timeout", " must be an unsigned integer") ;
    if (t) tain_from_millisecs(&deadline, t) ;
  }
  if (wgola[GOLA_KBUFSIZE])
    if (!uint0_scan(wgola[GOLA_KBUFSIZE], &kbufsize))
      strerr_dief(100, "kbufsize", " must be an unsigned integer") ;

  if (!uint0_scan(*argv++, &mask))
    strerr_dief(100, "invalid mask: ", argv[-1]) ;

  x.fd = bcnm_if_link_init(kbufsize) ;
  if (x.fd == -1) strerr_diefusys(111, "bcnm_if_link_init") ;

  tain_now_set_stopwatch_g() ;
  tain_add_g(&deadline, &deadline) ;

  bcnm_if_link_state_t tab[argc] ;
  for (unsigned int i = 0 ; i < argc ; i++)
  {
    int r ;
    size_t len = strlen(argv[i]) ;
    if (len >= IF_NAMESIZE) strerr_dief(100, "interface name too long: ", argv[i]) ;
    memcpy(tab[i].ifname, argv[i], len+1) ;
    tab[i].changed = 0 ;
    r = bcnm_if_getstate(argv[i]) ;
    if (r == -1) strerr_diefusys(111, "get state for interface ", argv[i]) ;
    tab[i].state = r ;
  }

  for (;;)
  {
    int r ;
    if (check(tab, argc, mask, !(wgolb & GOLB_DOWN))) return 0 ;
    r = iopause_g(&x, 1, &deadline) ;
    if (r == -1) strerr_diefusys(111, "iopause") ;
    if (!r) strerr_dief(99, "timed out") ;
    if (bcnm_if_link_event(x.fd, tab, argc) == -1)
      strerr_diefusys(111, "read rtnetlink event") ;
  }
  _exit(0) ;
}