/* ISC license. */

#include <string.h>
#include <stdint.h>
#include <errno.h>

#include <skalibs/types.h>
#include <skalibs/sgetopt.h>
#include <skalibs/fmtscan.h>
#include <skalibs/strerr.h>
#include <skalibs/stralloc.h>
#include <skalibs/genalloc.h>
#include <skalibs/tai.h>
#include <skalibs/djbunix.h>
#include <skalibs/skamisc.h>
#include <skalibs/socket.h>
#include <skalibs/ip46.h>
#include <skalibs/exec.h>

#include <s6-dns/s6dns.h>

#include <s6-networking/ident.h>

 /* XXX: this file is super ugly and full of tech debt */

#ifdef SKALIBS_IPV6_ENABLED
# define USAGE "s6-tcpclient [ -q | -Q | -v ] [ -4 | -6 ] [ -d | -D ] [ -r | -R ] [ -h ] [ -H ] [ -n | -N ] [ -t timeoutinfo ] [ -l localname ] [ -T timeoutconn ] [ -i localip ] [ -p localport ] host port prog..."
# define OPTSTRING "qQv46dDrRhHnNt:l:T:i:p:"
# define FLAGIP6_DEFAULT 1
#else
# define USAGE "s6-tcpclient [ -q | -Q | -v ] [ -4 ] [ -d | -D ] [ -r | -R ] [ -h ] [ -H ] [ -n | -N ] [ -t timeoutinfo ] [ -l localname ] [ -T timeoutconn ] [ -i localip ] [ -p localport ] host port prog..."
# define OPTSTRING "qQvdDrRhHnNt:l:T:i:p:"
# define FLAGIP6_DEFAULT 0
#endif

#define usage() strerr_dieusage(100, USAGE)
#define dienomem() strerr_diefu1sys(111, "allocate")

#define MAXIP 16

typedef struct tflags_s tflags, *tflags_ref ;
struct tflags_s
{
  char const *localname ;
  unsigned int timeout ;
  unsigned int timeoutconn[2] ;
  ip46 localip ;
  uint16_t localport ;
  unsigned int verbosity : 2 ;
  unsigned int ip4 : 1 ;
  unsigned int ip6 : 1 ;
  unsigned int delay : 1 ;
  unsigned int remoteinfo : 1 ;
  unsigned int remotehost : 1 ;
  unsigned int hosts : 1 ;
  unsigned int qualif : 1 ;
} ;
#define TFLAGS_DEFAULT \
{ \
  .localname = 0,\
  .timeout = 0,\
  .timeoutconn = { 2, 58 }, \
  .localip = IP46_ZERO, \
  .localport = 0, \
  .verbosity = 1, \
  .ip4 = 1, \
  .ip6 = FLAGIP6_DEFAULT, \
  .delay = 1, \
  .remoteinfo = 0, \
  .remotehost = 1, \
  .hosts = 0, \
  .qualif = 1 \
}

static tain deadline ;

int main (int argc, char const *const *argv)
{
  int s ;
  int haslocalip = 0 ;
  tflags flags = TFLAGS_DEFAULT ;
  uint16_t remoteport ;
  PROG = "s6-tcpclient" ;
  {
    subgetopt l = SUBGETOPT_ZERO ;
    for (;;)
    {
      int opt = subgetopt_r(argc, argv, OPTSTRING, &l) ;
      if (opt == -1) break ;
      switch (opt)
      {
        case 'q' : if (flags.verbosity) flags.verbosity-- ; break ;
        case 'Q' : flags.verbosity = 1 ; break ;
        case 'v' : flags.verbosity++ ; break ;
        case '4' : flags.ip4 = 1 ; flags.ip6 = 0 ; break ;
#ifdef SKALIBS_IPV6_ENABLED
        case '6' : flags.ip6 = 1 ; flags.ip4 = 0 ; break ;
#endif
        case 'd' : flags.delay = 1 ; break ;
        case 'D' : flags.delay = 0 ; break ;
        case 'r' : flags.remoteinfo = 1 ; break ;
        case 'R' : flags.remoteinfo = 0 ; break ;
        case 'h' : flags.hosts = 1 ; break ;
        case 'H' : flags.remotehost = 0 ; break ;
        case 'n' : flags.qualif = 1 ; break ;
        case 'N' : flags.qualif = 0 ; break ;
        case 't' : if (!uint0_scan(l.arg, &flags.timeout)) usage() ; break ;
        case 'l' : flags.localname = l.arg ; break ;
        case 'T' :
        {
          size_t n = uint_scan(l.arg, &flags.timeoutconn[0]) ;
          if (!n) usage() ;
          if (!l.arg[n])
          {
            flags.timeoutconn[1] = 0 ;
            break ;
          }
          if (l.arg[n] != '+') usage() ;
          if (!uint0_scan(l.arg + n + 1, &flags.timeoutconn[1])) usage() ;
          break ;
        }
        case 'i' : if (!ip46_scan(l.arg, &flags.localip)) usage() ; haslocalip = 1 ; break ;
        case 'p' : if (!uint160_scan(l.arg, &flags.localport)) usage() ; break ;
        default : usage() ;
      }
    }
    argc -= l.ind ; argv += l.ind ;
  }
  if (argc < 3) usage() ;
  if (!uint160_scan(argv[1], &remoteport))
    strerr_dief2x(100, "invalid port number: ", argv[1]) ;
  tain_now_set_stopwatch_g() ;
  if (flags.timeout) tain_addsec_g(&deadline, flags.timeout) ;
  else tain_add_g(&deadline, &tain_infinite_relative) ;

  if (flags.remotehost || !flags.localname)
    if (!s6dns_init_options(flags.hosts)) strerr_diefu1sys(111, "init DNS") ; 

  {
    ip46 ip[2][MAXIP] ;
    unsigned int j = 0 ;
    size_t n[2] = { 0, 0 } ;
    if (!**argv || ((**argv == '0') && !argv[0][1]))
    {
#ifdef SKALIBS_IPV6_ENABLED
      ip46_from_ip6(&ip[0][n[0]++], IP6_LOCAL) ; 
#endif
      ip46_from_ip4(&ip[0][n[0]++], IP4_LOCAL) ; 
    }
    else
    {
      if (!flags.remotehost)
      {
#ifdef SKALIBS_IPV6_ENABLED
        if (flags.ip6 && !flags.ip4)
        {
          char ip6[MAXIP << 4] ;
          size_t i = 0 ;
          if (!ip6_scanlist(ip6, MAXIP, argv[0], &n[0])) usage() ;
          for (; i < n[0] ; i++) ip46_from_ip6(&ip[0][i], ip6 + (i << 4)) ;
        }
        else if (!flags.ip6)
        {
          char ip4[MAXIP << 2] ;
          size_t i = 0 ;
          if (!ip4_scanlist(ip4, MAXIP, argv[0], &n[0])) usage() ;
          for (; i < n[0] ; i++) ip46_from_ip4(&ip[0][i], ip4 + (i << 2)) ;
        }
        else
#endif
        if (!ip46_scanlist(ip[0], MAXIP, argv[0], &n[0])) usage() ;
      }
      else
      {
#ifdef SKALIBS_IPV6_ENABLED
        if (flags.ip6 && flags.ip4)
        {
          if (!ip46_scanlist(ip[0], MAXIP, argv[0], &n[0]))
          {
            genalloc ips = STRALLOC_ZERO ;
            size_t i = 0 ;
            int r = 0 ;
            if (flags.hosts)
            {
              r = flags.qualif ? s6dns_hosts_aaaaa_q(argv[0], &ips) : s6dns_hosts_aaaaa_noq(argv[0], &ips) ;
              if (r == -1) strerr_diefu3sys(111, "look up ", argv[0], " in hosts database") ;
            }
            if (!r && s6dns_resolve_aaaaa_g(&ips, argv[0], strlen(argv[0]), flags.qualif, &deadline) <= 0)
              strerr_diefu4x(111, "resolve ", argv[0], ": ", s6dns_constants_error_str(errno)) ;
            n[0] = genalloc_len(ip46, &ips) ;
            if (n[0] >= MAXIP) n[0] = MAXIP ;
            for (; i < n[0] ; i++) ip[0][i] = genalloc_s(ip46, &ips)[i] ;
            genalloc_free(ip46, &ips) ;
          }
        }
        else if (flags.ip6)
        {
          char ip6[MAXIP << 4] ;
          if (ip6_scanlist(ip6, MAXIP, argv[0], &n[0]))
            for (size_t i = 0 ; i < n[0] ; i++)
              ip46_from_ip6(&ip[0][i], ip6 + (i << 4)) ;
          else
          {
            stralloc ip6s = STRALLOC_ZERO ;
            size_t i = 0 ;
            int r = 0 ;
            if (flags.hosts)
            {
              r = flags.qualif ? s6dns_hosts_aaaa_q(argv[0], &ip6s) : s6dns_hosts_aaaa_noq(argv[0], &ip6s) ;
              if (r == -1) strerr_diefu3sys(111, "look up ", argv[0], " in hosts database") ;
            }
            if (!r && s6dns_resolve_aaaa_g(&ip6s, argv[0], strlen(argv[0]), flags.qualif, &deadline) <= 0)
              strerr_diefu4x(111, "resolve ", argv[0], ": ", s6dns_constants_error_str(errno)) ;
            n[0] = ip6s.len >> 4 ;
            if (n[0] >= MAXIP) n[0] = MAXIP ;
            for (; i < n[0] ; i++) ip46_from_ip6(&ip[0][i], ip6s.s + (i << 4)) ;
            stralloc_free(&ip6s) ;
          }
        }
        else
#endif
        {
          char ip4[MAXIP << 2] ;
          if (ip4_scanlist(ip4, MAXIP, argv[0], &n[0]))
            for (size_t i = 0 ; i < n[0] ; i++)
              ip46_from_ip4(&ip[0][i], ip4 + (i << 2)) ;
          else
          {
            stralloc ip4s = STRALLOC_ZERO ;
            size_t i = 0 ;
            int r = 0 ;
            if (flags.hosts)
            {
              r = flags.qualif ? s6dns_hosts_a_q(argv[0], &ip4s) : s6dns_hosts_a_noq(argv[0], &ip4s) ;
              if (r == -1) strerr_diefu3sys(111, "look up ", argv[0], " in hosts database") ;
            }
            if (!r && s6dns_resolve_a_g(&ip4s, argv[0], strlen(argv[0]), flags.qualif, &deadline) <= 0)
              strerr_diefu4x(111, "resolve ", argv[0], ": ", s6dns_constants_error_str(errno)) ;
            n[0] = ip4s.len >> 2 ;
            if (n[0] >= MAXIP) n[0] = MAXIP ;
            for (; i < n[0] ; i++) ip46_from_ip4(&ip[0][i], ip4s.s + (i << 2)) ;
            stralloc_free(&ip4s) ;
          }
        } 
      }
      if (!n[0]) strerr_dief2x(100, "no IP address for ", argv[0]) ;
    }

    if (n[0] == 1)
    {
      flags.timeoutconn[0] += flags.timeoutconn[1] ;
      flags.timeoutconn[1] = 0 ;
    }

    for (; j < 2 ; j++)
    {
      size_t i = 0 ;
      for (; i < n[j] ; i++)
      {
        tain localdeadline ;
#ifdef SKALIBS_IPV6_ENABLED
        if (!haslocalip) flags.localip.is6 = ip46_is6(&ip[j][i]) ;
#endif
        s = socket_tcp46(ip46_is6(&flags.localip));
        if (s < 0) strerr_diefu1sys(111, "create socket") ;
        if (socket_bind46(s, &flags.localip, flags.localport) < 0)
          strerr_diefu1sys(111, "bind socket") ;
        tain_addsec_g(&localdeadline, flags.timeoutconn[j]) ;
        if (tain_less(&deadline, &localdeadline)) localdeadline = deadline ;
        if (socket_deadlineconnstamp46_g(s, &ip[j][i], remoteport, &localdeadline)) goto connected ;
        fd_close(s) ;
        if (!j && flags.timeoutconn[1]) ip[1][n[1]++] = ip[0][i] ;
        else
        {
          char fmtip[IP46_FMT] ;
          char fmtport[UINT16_FMT] ;
          fmtip[ip46_fmt(fmtip, &ip[j][i])] = 0 ;
          fmtport[uint16_fmt(fmtport, remoteport)] = 0 ;
          strerr_warnwu4sys("connect to ", fmtip, " port ", fmtport) ;
        }
      }
    }
    strerr_diefu2x(111, "connect to ", "a suitable IP address") ;
  }

 connected:

  if (ndelay_off(s) == -1)
    strerr_diefu1sys(111, "ndelay_off") ;
  if (!flags.delay) socket_tcpnodelay(s) ;
  if (socket_local46(s, &flags.localip, &flags.localport) == -1)
    strerr_diefu2sys(111, "get local", " address and port") ;

  {
    ip46 remoteip ;
    char fmtip[IP46_FMT] ;
    char fmtport[UINT16_FMT] ;

    if (socket_remote46(s, &remoteip, &remoteport) == -1)
      strerr_diefu2sys(111, "get remote", " address and port") ;
    fmtip[ip46_fmt(fmtip, &remoteip)] = 0 ;
    fmtport[uint16_fmt(fmtport, remoteport)] = 0 ;
    if (flags.verbosity >= 2)
      strerr_warni4x("connected to ", fmtip, " port ", fmtport) ;
    if (!env_mexec("PROTO", "TCP")
     || !env_mexec("TCPREMOTEIP", fmtip)
     || !env_mexec("TCPREMOTEPORT", fmtport)) dienomem() ;

    fmtip[ip46_fmt(fmtip, &flags.localip)] = 0 ;
    fmtport[uint16_fmt(fmtport, flags.localport)] = 0 ;
    if (!env_mexec("TCPLOCALIP", fmtip)
     || !env_mexec("TCPLOCALPORT", fmtport)) dienomem() ;

    if (flags.localname)
    {
      if (!env_mexec("TCPLOCALHOST", flags.localname)) dienomem() ;
    }

    if (flags.hosts)
    {
      stralloc sa = STRALLOC_ZERO ;
      genalloc ga = GENALLOC_ZERO ;
      if (!flags.localname)
      {
        int r = s6dns_hosts_name(flags.localip.ip, &sa, &ga, ip46_is6(&flags.localip)) ;
        if (r == -1) strerr_diefu3sys(111, "look up name for ", "local", " ip in hosts database") ;
        if (r)
        {
          if (!env_mexec("TCPLOCALHOST", sa.s + genalloc_s(size_t, &ga)[0])) dienomem() ;
          genalloc_setlen(size_t, &ga, 0) ;
          sa.len = 0 ;
          flags.localname = "" ;
        }
      }
      if (flags.remotehost)
      {
        int r = s6dns_hosts_name(remoteip.ip, &sa, &ga, ip46_is6(&remoteip)) ;
        if (r == -1) strerr_diefu3sys(111, "look up name for ", "remote", " ip in hosts database") ;
        if (r)
        {
          if (!env_mexec("TCPREMOTEHOST", sa.s + genalloc_s(size_t, &ga)[0])) dienomem() ;
          flags.remotehost = 0 ;
        }
      }
      genalloc_free(size_t, &ga) ;
      stralloc_free(&sa) ;
    }


 /* DNS resolution for TCPLOCALHOST and TCPREMOTEHOST */

    if (!flags.localname || flags.remotehost)
    {
      s6dns_resolve_t blob[2] ;
      s6dns_dpag_t data[2] = { S6DNS_DPAG_ZERO, S6DNS_DPAG_ZERO } ;
      if (!flags.localname)
      {
        s6dns_domain_arpafromip46(&blob[0].q, &flags.localip) ;
        s6dns_domain_encode(&blob[0].q) ;
        blob[0].qtype = S6DNS_T_PTR ;
        blob[0].deadline = deadline ;
        blob[0].parsefunc = &s6dns_message_parse_answer_domain ;
        blob[0].data = &data[0] ;
        blob[0].options = S6DNS_O_RECURSIVE ;
        data[0].rtype = S6DNS_T_PTR ;
      }
      if (flags.remotehost)
      {
        s6dns_domain_arpafromip46(&blob[1].q, &remoteip) ;
        s6dns_domain_encode(&blob[1].q) ;
        blob[1].qtype = S6DNS_T_PTR ;
        blob[1].deadline = deadline ;
        blob[1].parsefunc = &s6dns_message_parse_answer_domain ;
        blob[1].data = &data[1] ;
        blob[1].options = S6DNS_O_RECURSIVE ;
        data[1].rtype = S6DNS_T_PTR ;
      }
      {
        tain infinite = TAIN_INFINITE ;
        if (!s6dns_resolven_parse_g(blob + !!flags.localname, !flags.localname + !!flags.remotehost, &infinite))
          strerr_diefu2x(111, "resolve IP addresses: ", s6dns_constants_error_str(errno)) ;
      }
      if (!flags.localname)
      {
        if (blob[0].status)
        {
          if (!env_mexec("TCPLOCALHOST", 0)) dienomem() ;
        }
        else
        {
          char s[256] ;
          unsigned int len = 0 ;
          if (genalloc_len(s6dns_domain_t, &data[0].ds))
           len = s6dns_domain_tostring(s, 255, genalloc_s(s6dns_domain_t, &data[0].ds)) ;
          genalloc_free(s6dns_domain_t, &data[0].ds) ;
          s[len] = 0 ;
          if (!env_mexec("TCPLOCALHOST", s)) dienomem() ;
        }
      }
      if (flags.remotehost)
      {
        if (blob[1].status)
        {
          if (!env_mexec("TCPREMOTEHOST", 0)) dienomem() ;
        }
        else
        {
          char s[256] ;
          unsigned int len = 0 ;
          if (genalloc_len(s6dns_domain_t, &data[1].ds))
           len = s6dns_domain_tostring(s, 255, genalloc_s(s6dns_domain_t, &data[1].ds)) ;
          genalloc_free(s6dns_domain_t, &data[1].ds) ;
          s[len] = 0 ;
          if (!env_mexec("TCPREMOTEHOST", s)) dienomem() ;
        }
      }
    }


 /* TCPREMOTEINFO */
 /*
    Yes, I should have made all the network queries in parallel,
    not only the DNS ones, but the IDENT one too. Well, that was
    too much work for an obsolete protocol. Sue me.
 */
    {
      char idbuf[S6NET_IDENT_ID_SIZE] ;
      if (flags.remoteinfo)
      {
        ssize_t r = s6net_ident_client_g(idbuf, S6NET_IDENT_ID_SIZE, &remoteip, remoteport, &flags.localip, flags.localport, &deadline) ;
        if (r <= 0)
        {
          if (flags.verbosity)
          {
            if (r < 0) strerr_warnwu1sys("s6net_ident_client") ;
            else strerr_warnw2x("ident server replied: ", s6net_ident_error_str(errno)) ;
          }
          if (!env_mexec("TCPREMOTEINFO", "")) dienomem() ;
        }
        else if (!env_mexec("TCPREMOTEINFO", idbuf)) dienomem() ;
      }
    }
  }

  if (fd_move(6, s) < 0) strerr_diefu2sys(111, "set up fd ", "6") ;
  if (fd_copy(7, 6) < 0) strerr_diefu2sys(111, "set up fd ", "7") ;
  xmexec(argv+2) ;
}