/* g/n.c
**
*/
#include "all.h"

static u3_noun _n_nock_on(u3_noun bus, u3_noun fol);

/* _n_hint(): process hint.
*/
static u3_noun
_n_hint(u3_noun zep, 
        u3_noun hod,
        u3_noun bus,
        u3_noun nex)
{
  switch ( zep ) {
    default: {
      // u3m_p("weird zep", zep);
      u3a_lose(zep);
      u3a_lose(hod);

      return _n_nock_on(bus, nex);
    }

    case c3__hunk:
    case c3__lose:
    case c3__mean:
    case c3__spot: {
      u3_noun tac = u3nc(zep, hod);
      u3_noun pro;

      u3t_push(tac);
#if 0
      if ( c3__spot == zep ) {
        printf("spot %d/%d : %d/%d\r\n",
               u3h(u3h(u3t(hod))),
               u3t(u3h(u3t(hod))),
               u3h(u3t(u3t(hod))),
               u3t(u3t(u3t(hod))));
      }
#endif
      pro = _n_nock_on(bus, nex);
      u3t_drop();

      return pro;
    }

    case c3__slog: {
      if ( !(u3C.wag_w & u3o_quiet) ) {
        u3t_off(noc_o);
        u3t_slog(hod);
        u3t_on(noc_o);
      }
      return _n_nock_on(bus, nex);
    }

    case c3__germ: {
      u3_noun pro = _n_nock_on(bus, nex);

      if ( c3y == u3r_sing(pro, hod) ) {
        u3z(pro); return hod;
      } else {
        u3z(hod); return pro;
      }
    }

    case c3__fast: {
      u3_noun pro = _n_nock_on(bus, nex);

      u3t_off(noc_o);
      u3j_mine(hod, u3k(pro));
      u3t_on(noc_o);

      return pro;
    }

    case c3__memo: {
      u3z(hod);
#if 0
      return _n_nock_on(bus, nex);
#else
      {
        u3_noun pro = u3z_find_2(c3__nock, bus, nex);

        if ( pro != u3_none ) {
          u3z(bus); u3z(nex);
          return pro;
        }
        pro = _n_nock_on(u3k(bus), u3k(nex));

        if ( u3R != &(u3H->rod_u) ) {
          u3z_save_2(c3__nock, bus, nex, pro);
        }

        u3z(bus); u3z(nex);

        return pro;
      }
#endif
    }

    case c3__sole: {
      u3z(hod);
      {
        u3_noun pro = _n_nock_on(bus, nex);

        // return u3z_uniq(pro);
        return pro;
      }
    }
  }
}

/* _n_nock_on(): produce .*(bus fol).  Do not virtualize.
*/
u3_noun
_n_nock_on(u3_noun bus, u3_noun fol)
{
  u3_noun hib, gal;

  while ( 1 ) {
    hib = u3h(fol);
    gal = u3t(fol);

    u3R->pro.nox_d += 1;

    if ( c3y == u3r_du(hib) ) {
      u3_noun poz, riv;

      poz = _n_nock_on(u3k(bus), u3k(hib));
      riv = _n_nock_on(bus, u3k(gal));

      u3a_lose(fol);
      return u3i_cell(poz, riv);
    }
    else switch ( hib ) {
      default: return u3m_bail(c3__exit);

      case 0: {
        if ( c3n == u3r_ud(gal) ) {
          return u3m_bail(c3__exit);
        }
        else {
          u3_noun pro = u3k(u3at(gal, bus));

          u3a_lose(bus); u3a_lose(fol);
          return pro;
        }
      }
      c3_assert(!"not reached");

      case 1: {
        u3_noun pro = u3k(gal);

        u3a_lose(bus); u3a_lose(fol);
        return pro;
      }
      c3_assert(!"not reached");

      case 2: {
        u3_noun nex = _n_nock_on(u3k(bus), u3k(u3t(gal)));
        u3_noun seb = _n_nock_on(bus, u3k(u3h(gal)));

        u3a_lose(fol);
        bus = seb;
        fol = nex;
        continue;
      }
      c3_assert(!"not reached");

      case 3: {
        u3_noun gof, pro;

        gof = _n_nock_on(bus, u3k(gal));
        pro = u3r_du(gof);

        u3a_lose(gof); u3a_lose(fol);
        return pro;
      }
      c3_assert(!"not reached");

      case 4: {
        u3_noun gof, pro;

        gof = _n_nock_on(bus, u3k(gal));
        pro = u3i_vint(gof);

        u3a_lose(fol);
        return pro;
      }
      c3_assert(!"not reached");

      case 5: {
        u3_noun wim = _n_nock_on(bus, u3k(gal));
        u3_noun pro = u3r_sing(u3h(wim), u3t(wim));

        u3a_lose(wim); u3a_lose(fol);
        return pro;
      }
      c3_assert(!"not reached");

      case 6: {
        u3_noun b_gal, c_gal, d_gal;

        u3x_trel(gal, &b_gal, &c_gal, &d_gal);
        {
          u3_noun tys = _n_nock_on(u3k(bus), u3k(b_gal));
          u3_noun nex;

          if ( 0 == tys ) {
            nex = u3k(c_gal);
          } else if ( 1 == tys ) {
            nex = u3k(d_gal);
          } else return u3m_bail(c3__exit);

          u3a_lose(fol);
          fol = nex;
          continue;
        }
      }
      c3_assert(!"not reached");

      case 7: {
        u3_noun b_gal, c_gal;

        u3x_cell(gal, &b_gal, &c_gal);
        {
          u3_noun bod = _n_nock_on(bus, u3k(b_gal));
          u3_noun nex = u3k(c_gal);

          u3a_lose(fol);
          bus = bod;
          fol = nex;
          continue;
        }
      }
      c3_assert(!"not reached");

      case 8: {
        u3_noun b_gal, c_gal;

        u3x_cell(gal, &b_gal, &c_gal);
        {
          u3_noun heb = _n_nock_on(u3k(bus), u3k(b_gal));
          u3_noun bod = u3nc(heb, bus);
          u3_noun nex = u3k(c_gal);

          u3a_lose(fol);
          bus = bod;
          fol = nex;
          continue;
        }
      }
      c3_assert(!"not reached");

      case 9: {
        u3_noun b_gal, c_gal;

        u3x_cell(gal, &b_gal, &c_gal);
        {
          u3_noun seb = _n_nock_on(bus, u3k(c_gal));
          u3_noun pro;
         
          u3t_off(noc_o);
          pro = u3j_kick(seb, b_gal);
          u3t_on(noc_o);

          if ( u3_none != pro ) {
            u3a_lose(fol);
            return pro;
          }
          else {
            if ( c3n == u3r_ud(b_gal) ) {
              return u3m_bail(c3__exit);
            }
            else {
              u3_noun nex = u3k(u3at(b_gal, seb));

              u3a_lose(fol);
              bus = seb;
              fol = nex;
              continue;
            }
          }
        }
      }
      c3_assert(!"not reached");

      case 10: {
        u3_noun p_gal, q_gal;

        u3x_cell(gal, &p_gal, &q_gal);
        {
          u3_noun zep, hod, nex;

          if ( c3y == u3r_du(p_gal) ) {
            u3_noun b_gal = u3h(p_gal);
            u3_noun c_gal = u3t(p_gal);
            u3_noun d_gal = q_gal;

            zep = u3k(b_gal);
            hod = _n_nock_on(u3k(bus), u3k(c_gal));
            nex = u3k(d_gal);
          }
          else {
            u3_noun b_gal = p_gal;
            u3_noun c_gal = q_gal;

            zep = u3k(b_gal);
            hod = u3_nul;
            nex = u3k(c_gal);
          }

          u3a_lose(fol);
          return _n_hint(zep, hod, bus, nex);
        }
      }

      case 11: {
        u3_noun gof = _n_nock_on(bus, u3k(gal));
        u3_noun val;

        u3t_off(noc_o);
        val = u3m_soft_esc(u3k(gof));
        u3t_on(noc_o);

        if ( !_(u3du(val)) ) {
          u3m_bail(u3nt(1, gof, 0));
        } 
        else {
          u3_noun pro;

          u3z(gof);
          u3z(fol);
          pro = u3k(u3t(val));
          u3z(val);

          return pro;
        }
      }  
      c3_assert(!"not reached");
    }
  }
}

/* u3n_nock_on(): produce .*(bus fol).  Do not virtualize.
*/
u3_noun
u3n_nock_on(u3_noun bus, u3_noun fol)
{
  u3_noun pro;

  u3t_on(noc_o);
  pro = _n_nock_on(bus, fol);
  u3t_off(noc_o);

  return pro;
}

/* u3n_kick_on(): fire `gat` without changing the sample.
*/
u3_noun
u3n_kick_on(u3_noun gat)
{
  return u3j_kink(gat, 2);
}

c3_w exc_w;

/* u3n_slam_on(): produce (gat sam).
*/
u3_noun
u3n_slam_on(u3_noun gat, u3_noun sam)
{
  u3_noun cor = u3nc(u3k(u3h(gat)), u3nc(sam, u3k(u3t(u3t(gat)))));

#if 0
  if ( &u3H->rod_u == u3R ) {
    if ( exc_w == 1 ) {
      c3_assert(0);
    } 
    exc_w++;
  }
#endif
  u3z(gat);
  return u3n_kick_on(cor);
}

/* u3n_nock_un(): produce .*(bus fol), as ++toon.
*/
u3_noun
u3n_nock_un(u3_noun bus, u3_noun fol)
{
  u3_noun fly = u3nt(u3nt(11, 0, 6), 0, 0);  //  |=(a=* .^(a))

  return u3n_nock_in(fly, bus, fol);
}

/* u3n_slam_un(): produce (gat sam), as ++toon.
*/
u3_noun
u3n_slam_un(u3_noun gat, u3_noun sam)
{
  u3_noun fly = u3nt(u3nt(11, 0, 6), 0, 0);  //  |=(a=* .^(a))

  return u3n_slam_in(fly, gat, sam);
}

/* u3n_nock_in(): produce .*(bus fol), as ++toon, in namespace.
*/
u3_noun
u3n_nock_in(u3_noun fly, u3_noun bus, u3_noun fol)
{
  return u3m_soft_run(fly, u3n_nock_on, bus, fol);
}

/* u3n_slam_in(): produce (gat sam), as ++toon, in namespace.
*/
u3_noun
u3n_slam_in(u3_noun fly, u3_noun gat, u3_noun sam)
{
  return u3m_soft_run(fly, u3n_slam_on, gat, sam);
}

/* u3n_nock_an(): as slam_in(), but with empty fly.
*/
u3_noun
u3n_nock_an(u3_noun bus, u3_noun fol)
{
  u3_noun fly = u3nt(u3nc(1, 0), 0, 0);  //  |=(a=* ~)

  return u3n_nock_in(fly, bus, fol);
}