#include <cctk.h>
#include <cctk_Parameters.h>

#include <loopcontrol.h>

#include <algorithm>
#include <cassert>
#include <cmath>

#include "gdata.hh"
#include "operator_prototypes_3d.hh"
#include "typeprops.hh"

using namespace std;



namespace CarpetLib {


  
#define SRCIND3(i,j,k)                                  \
  index3 (srcioff + (i), srcjoff + (j), srckoff + (k),  \
          srcipadext, srcjpadext, srckpadext,           \
          srciext, srcjext, srckext)
#define DSTIND3(i,j,k)                                  \
  index3 (dstioff + (i), dstjoff + (j), dstkoff + (k),  \
          dstipadext, dstjpadext, dstkpadext,           \
          dstiext, dstjext, dstkext)
#define SRCOFF3(i,j,k)                                  \
  offset3 (srcioff + (i), srcjoff + (j), srckoff + (k), \
           srciext, srcjext, srckext)
#define DSTOFF3(i,j,k)                                  \
  offset3 (dstioff + (i), dstjoff + (j), dstkoff + (k), \
           dstiext, dstjext, dstkext)
  
  
  
// This operator offers fifth-order accurate restriction operators for cell
// centered grids when use_higher_order_restriction is set. This interpolation
// is done for samples at the cell centres (so this is not a ppm scheme or
// anything like that).  It really only fits a polynomial of the form
//    f(x,y,z) = \sum_{i,j,k=0}^5 a_{i,j,k} x^i y^j z^k
// to the fine cells and evaluates at x=y=z=0. So it is good for the metric,
// but bad for matter (since it will destroy the conservation).  Because of
// this it should not be used for grid functions whose transport operator is
// not WENO or ENO which hopefully excludes all matter variables.
// TODO: use prolongate_3d_rf2 instead of writing new operators, its the same
// interpolation.

  namespace {

  // 1D restriction
  template <typename T>
    inline T restrict1 (T const * restrict const p,
                        size_t const d1)
    {
      typedef typename typeprops<T>::real RT;
      RT const den = 256;
      RT const f2 = 3/den, f1 = 25/den, f0 = 150/den;
      T const res =
        + f2 * p[- 2]
        - f1 * p[- 1]
        + f0 * p[- 0]
        + f0 * p[+ 1]
        - f1 * p[+ 2]
        + f2 * p[+ 3];
      return res;
    }
  
  // 2D restriction
  template <typename T>
    inline T restrict2 (T const * restrict const p,
                        size_t const d1, size_t const d2)
    {
      typedef typename typeprops<T>::real RT;
      RT const den = 256;
      RT const f2 = 3/den, f1 = 25/den, f0 = 150/den;
      T const res =
        + f2 * restrict1 (p - 2*d2, d1)
        - f1 * restrict1 (p - 1*d2, d1)
        + f0 * restrict1 (p - 0*d2, d1)
        + f0 * restrict1 (p + 1*d2, d1)
        - f1 * restrict1 (p + 2*d2, d1)
        + f2 * restrict1 (p + 3*d2, d1);
      return res;
    }
  
  // 3D restriction
  template <typename T>
    inline T restrict3 (T const * restrict const p,
                        size_t const d1, size_t const d2, size_t const d3)
    {
      typedef typename typeprops<T>::real RT;
      RT const den = 256;
      RT const f2 = 3/den, f1 = 25/den, f0 = 150/den;
      T const res =
        + f2 * restrict2 (p - 2*d3, d1, d2)
        - f1 * restrict2 (p - 1*d3, d1, d2)
        + f0 * restrict2 (p - 0*d3, d1, d2)
        + f0 * restrict2 (p + 1*d3, d1, d2)
        - f1 * restrict2 (p + 2*d3, d1, d2)
        + f2 * restrict2 (p + 3*d3, d1, d2);
      return res;
    }
  
  } // namespace



  template <typename T>
  void
  restrict_3d_cc_o5_rf2 (T const * restrict const src,
                         ivect3 const & restrict srcpadext,
                         ivect3 const & restrict srcext,
                         T * restrict const dst,
                         ivect3 const & restrict dstpadext,
                         ivect3 const & restrict dstext,
                         ibbox3 const & restrict srcbbox,
                         ibbox3 const & restrict dstbbox,
                         ibbox3 const & restrict,
                         ibbox3 const & restrict regbbox,
                         void * extraargs)
  {
    assert (not extraargs);
    
    DECLARE_CCTK_PARAMETERS;
    
    
    
    if (any (srcbbox.stride() >= regbbox.stride() or
             dstbbox.stride() != regbbox.stride()))
    {
      CCTK_WARN (0, "Internal error: strides disagree");
    }
    
    if (any (reffact2 * srcbbox.stride() != dstbbox.stride())) {
      CCTK_WARN (0, "Internal error: destination strides are not twice the source strides");
    }
    
    // This could be handled, but is likely to point to an error
    // elsewhere
    if (regbbox.empty()) {
      CCTK_WARN (0, "Internal error: region extent is empty");
    }
    
    if (not regbbox.expanded_for(srcbbox).expand(1,1).is_contained_in(srcbbox) or
        not regbbox.is_contained_in(dstbbox))
    {
      cerr << "srcbbox: " << srcbbox << endl
           << "dstbbox: " << dstbbox << endl
           << "regbbox: " << regbbox << endl;
      CCTK_WARN (0, "Internal error: region extent is not contained in array extent");
    }
    
    
    
    ivect3 const regext = regbbox.shape() / regbbox.stride();
    assert (all (srcbbox.stride() % 2 == 0));
    assert (all ((regbbox.lower() - srcbbox.lower() - srcbbox.stride() / 2) %
                 srcbbox.stride() == 0));
    ivect3 const srcoff =
      (regbbox.lower() - srcbbox.lower() - srcbbox.stride() / 2) /
      srcbbox.stride();
    assert (all ((regbbox.lower() - dstbbox.lower()) % dstbbox.stride() == 0));
    ivect3 const dstoff =
      (regbbox.lower() - dstbbox.lower()) / dstbbox.stride();
    
    
    
    int const srcipadext = srcpadext[0];
    int const srcjpadext = srcpadext[1];
    int const srckpadext = srcpadext[2];
    
    int const dstipadext = dstpadext[0];
    int const dstjpadext = dstpadext[1];
    int const dstkpadext = dstpadext[2];
    
    int const srciext = srcext[0];
    int const srcjext = srcext[1];
    int const srckext = srcext[2];
    
    int const dstiext = dstext[0];
    int const dstjext = dstext[1];
    int const dstkext = dstext[2];
    
    int const regiext = regext[0];
    int const regjext = regext[1];
    int const regkext = regext[2];
    
    int const srcioff = srcoff[0];
    int const srcjoff = srcoff[1];
    int const srckoff = srcoff[2];
    
    int const dstioff = dstoff[0];
    int const dstjoff = dstoff[1];
    int const dstkoff = dstoff[2];
    
    // size_t const srcdi == SRCOFF3(1,0,0) - SRCOFF3(0,0,0);
    size_t const srcdi = 1;
    assert (srcdi == SRCOFF3(1,0,0) - SRCOFF3(0,0,0));
    size_t const srcdj = SRCOFF3(0,1,0) - SRCOFF3(0,0,0);
    size_t const srcdk = SRCOFF3(0,0,1) - SRCOFF3(0,0,0);
    
    
    
    if (not use_loopcontrol_in_operators) {

    // Loop over coarse region
#pragma omp parallel for collapse(3)
    for (int k=0; k<regkext; ++k) {
      for (int j=0; j<regjext; ++j) {
        for (int i=0; i<regiext; ++i) {
          
#ifdef CARPET_DEBUG
    if(not (2 * k + 3 + srckoff < srckext and
            2 * j + 3 + srcjoff < srcjext and
            2 * i + 3 + srcioff < srciext and
            2 * k - 2 + srckoff >= 0 and
            2 * j - 2 + srcjoff >= 0 and
            2 * i - 2 + srcioff >= 0))
    {
      cout << "restrict_3d_cc_o3_rf2.cc\n";
      cout << "regext " << regext << "\n";
      cout << "srcext " << srcext << "\n";
      cout << "srcbbox=" << srcbbox << "\n";
      cout << "dstbbox=" << dstbbox << "\n";
      cout << "regbbox=" << regbbox << "\n";
      cout << "i,j,k=" << i << " " << j << " " << k << "\n";
      assert(2 * k + 2 + srckoff < srckext);
      assert(2 * j + 2 + srcjoff < srcjext);
      assert(2 * i + 2 + srcioff < srciext);
      assert(2 * k - 1 + srckoff >= 0);
      assert(2 * j - 1 + srcjoff >= 0);
      assert(2 * i - 1 + srcioff >= 0);
    }
#endif    
          dst [DSTIND3(i, j, k)] =
            CarpetLib::restrict3
            (& src[SRCIND3(2*i, 2*j, 2*k)], srcdi, srcdj, srcdk);

        }
      }
    }

    } else {

    // Loop over coarse region
#pragma omp parallel
    CCTK_LOOP3(restrict_3d_cc_o5_rf2,
               i,j,k, 0,0,0, regiext,regjext,regkext,
               dstipadext,dstjpadext,dstkpadext)
    {
          
#ifdef CARPET_DEBUG
      if(not (2 * k + 3 + srckoff < srckext and
              2 * j + 3 + srcjoff < srcjext and
              2 * i + 3 + srcioff < srciext and
              2 * k - 2 + srckoff >= 0 and
              2 * j - 2 + srcjoff >= 0 and
              2 * i - 2 + srcioff >= 0))
      {
        cout << "restrict_3d_cc_o3_rf2.cc\n";
        cout << "regext " << regext << "\n";
        cout << "srcext " << srcext << "\n";
        cout << "srcbbox=" << srcbbox << "\n";
        cout << "dstbbox=" << dstbbox << "\n";
        cout << "regbbox=" << regbbox << "\n";
        cout << "i,j,k=" << i << " " << j << " " << k << "\n";
        assert(2 * k + 2 + srckoff < srckext);
        assert(2 * j + 2 + srcjoff < srcjext);
        assert(2 * i + 2 + srcioff < srciext);
        assert(2 * k - 1 + srckoff >= 0);
        assert(2 * j - 1 + srcjoff >= 0);
        assert(2 * i - 1 + srcioff >= 0);
      }
#endif    
      dst [DSTIND3(i, j, k)] =
        CarpetLib::restrict3
        (& src[SRCIND3(2*i, 2*j, 2*k)], srcdi, srcdj, srcdk);

    } CCTK_ENDLOOP3(restrict_3d_cc_o5_rf2);
    
    }

  }
  
  
  
#define TYPECASE(N,T)                                           \
  template                                                      \
  void                                                          \
  restrict_3d_cc_o5_rf2 (T const * restrict const src,          \
                         ivect3 const & restrict srcpadext,     \
                         ivect3 const & restrict srcext,        \
                         T * restrict const dst,                \
                         ivect3 const & restrict dstpadext,     \
                         ivect3 const & restrict dstext,        \
                         ibbox3 const & restrict srcbbox,       \
                         ibbox3 const & restrict dstbbox,       \
                         ibbox3 const & restrict,               \
                         ibbox3 const & restrict regbbox,       \
                         void * extraargs);
#include "typecase.hh"
#undef TYPECASE
  
  
  
} // namespace CarpetLib