// Copyright (c) 2017-2022, Lawrence Livermore National Security, LLC and other CEED contributors.
// All Rights Reserved. See the top-level LICENSE and NOTICE files for details.
//
// SPDX-License-Identifier: BSD-2-Clause
//
// This file is part of CEED:  http://github.com/ceed

#ifndef bp1_h
#define bp1_h

/// A structure used to pass additional data to f_build_mass
struct BuildContext { CeedInt dim, space_dim; };

/// libCEED Q-function for building quadrature data for a mass operator
CEED_QFUNCTION(f_build_mass)(void *ctx, const CeedInt Q,
                             const CeedScalar *const *in, CeedScalar *const *out) {
  // in[0] is Jacobians with shape [dim, nc=dim, Q]
  // in[1] is quadrature weights, size (Q)
  BuildContext *bc = (BuildContext *)ctx;
  const CeedScalar *J = in[0], *w = in[1];
  CeedScalar *qdata = out[0];

  switch (bc->dim + 10*bc->space_dim) {
  case 11:
    // Quadrature Point Loop
    CeedPragmaSIMD
    for (CeedInt i=0; i<Q; i++) {
      qdata[i] = J[i] * w[i];
    }
    break;
  case 22:
    // Quadrature Point Loop
    CeedPragmaSIMD
    for (CeedInt i=0; i<Q; i++) {
      // 0 2
      // 1 3
      qdata[i] = (J[i+Q*0]*J[i+Q*3] - J[i+Q*1]*J[i+Q*2]) * w[i];
    }
    break;
  case 33:
    // Quadrature Point Loop
    CeedPragmaSIMD
    for (CeedInt i=0; i<Q; i++) {
      // 0 3 6
      // 1 4 7
      // 2 5 8
      qdata[i] = (J[i+Q*0]*(J[i+Q*4]*J[i+Q*8] - J[i+Q*5]*J[i+Q*7]) -
                  J[i+Q*1]*(J[i+Q*3]*J[i+Q*8] - J[i+Q*5]*J[i+Q*6]) +
                  J[i+Q*2]*(J[i+Q*3]*J[i+Q*7] - J[i+Q*4]*J[i+Q*6])) * w[i];
    }
    break;
  }
  return 0;
}

/// libCEED Q-function for applying a mass operator
CEED_QFUNCTION(f_apply_mass)(void *ctx, const CeedInt Q,
                             const CeedScalar *const *in, CeedScalar *const *out) {
  const CeedScalar *u = in[0], *qdata = in[1];
  CeedScalar *v = out[0];

  // Quadrature Point Loop
  CeedPragmaSIMD
  for (CeedInt i=0; i<Q; i++) {
    v[i] = qdata[i] * u[i];
  }
  return 0;
}

#endif // bp1_h