/// @file
/// Test creation, action, and destruction for mass matrix operator with multigrid level, nontensor basis
/// \test Test creation, action, and destruction for mass matrix operator with multigrid level, nontensor basis
#include <ceed.h>
#include <stdlib.h>
#include <math.h>

int main(int argc, char **argv) {
  Ceed ceed;
  CeedElemRestriction elem_restr_x, elem_restr_qd,
                      elem_restr_u_c, elem_restr_u_f;
  CeedBasis basis_x, basis_u;
  CeedQFunction qf_setup, qf_mass;
  CeedOperator op_setup, op_mass_c, op_mass_f,
               op_prolong, op_restrict;
  CeedVector q_data, X, U_c, U_f,
             V_c, V_f, p_mult_f;
  const CeedScalar *hv;
  CeedInt num_elem = 15, P_c = 3, P_f = 5, Q = 8;
  CeedInt num_dofs_x = num_elem+1, num_dofs_u_c = num_elem*(P_c-1)+1,
          num_dofs_u_f = num_elem*(P_f-1)+1;
  CeedInt ind_u_c[num_elem*P_c], ind_u_f[num_elem*P_f],
          ind_x[num_elem*2];
  CeedScalar x[num_dofs_x];
  CeedScalar sum;

  CeedInit(argv[1], &ceed);

  for (CeedInt i=0; i<num_dofs_x; i++)
    x[i] = (CeedScalar) i / (num_dofs_x - 1);
  for (CeedInt i=0; i<num_elem; i++) {
    ind_x[2*i+0] = i;
    ind_x[2*i+1] = i+1;
  }
  // Restrictions
  CeedElemRestrictionCreate(ceed, num_elem, 2, 1, 1, num_dofs_x, CEED_MEM_HOST,
                            CEED_USE_POINTER, ind_x, &elem_restr_x);

  for (CeedInt i=0; i<num_elem; i++) {
    for (CeedInt j=0; j<P_c; j++) {
      ind_u_c[P_c*i+j] = i*(P_c-1) + j;
    }
  }
  CeedElemRestrictionCreate(ceed, num_elem, P_c, 1, 1, num_dofs_u_c,
                            CEED_MEM_HOST,
                            CEED_USE_POINTER, ind_u_c, &elem_restr_u_c);

  for (CeedInt i=0; i<num_elem; i++) {
    for (CeedInt j=0; j<P_f; j++) {
      ind_u_f[P_f*i+j] = i*(P_f-1) + j;
    }
  }
  CeedElemRestrictionCreate(ceed, num_elem, P_f, 1, 1, num_dofs_u_f,
                            CEED_MEM_HOST,
                            CEED_USE_POINTER, ind_u_f, &elem_restr_u_f);

  CeedInt strides_qd[3] = {1, Q, Q};
  CeedElemRestrictionCreateStrided(ceed, num_elem, Q, 1, Q*num_elem, strides_qd,
                                   &elem_restr_qd);

  // Bases
  CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, 2, Q, CEED_GAUSS, &basis_x);
  CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, P_f, Q, CEED_GAUSS, &basis_u);

  // QFunctions
  CeedQFunctionCreateInteriorByName(ceed, "Mass1DBuild", &qf_setup);
  CeedQFunctionCreateInteriorByName(ceed, "MassApply", &qf_mass);

  // Operators
  CeedOperatorCreate(ceed, qf_setup, CEED_QFUNCTION_NONE, CEED_QFUNCTION_NONE,
                     &op_setup);
  CeedOperatorCreate(ceed, qf_mass, CEED_QFUNCTION_NONE, CEED_QFUNCTION_NONE,
                     &op_mass_f);

  CeedVectorCreate(ceed, num_dofs_x, &X);
  CeedVectorSetArray(X, CEED_MEM_HOST, CEED_USE_POINTER, x);
  CeedVectorCreate(ceed, num_elem*Q, &q_data);

  CeedOperatorSetField(op_setup, "weights", CEED_ELEMRESTRICTION_NONE, basis_x,
                       CEED_VECTOR_NONE);
  CeedOperatorSetField(op_setup, "dx", elem_restr_x, basis_x, CEED_VECTOR_ACTIVE);
  CeedOperatorSetField(op_setup, "qdata", elem_restr_qd, CEED_BASIS_COLLOCATED,
                       CEED_VECTOR_ACTIVE);

  CeedOperatorSetField(op_mass_f, "qdata", elem_restr_qd, CEED_BASIS_COLLOCATED,
                       q_data);
  CeedOperatorSetField(op_mass_f, "u", elem_restr_u_f, basis_u,
                       CEED_VECTOR_ACTIVE);
  CeedOperatorSetField(op_mass_f, "v", elem_restr_u_f, basis_u,
                       CEED_VECTOR_ACTIVE);

  CeedOperatorApply(op_setup, X, q_data, CEED_REQUEST_IMMEDIATE);

  // Create multigrid level
  CeedVectorCreate(ceed, num_dofs_u_f, &p_mult_f);
  CeedVectorSetValue(p_mult_f, 1.0);
  CeedBasis basis_u_c, basis_c_to_f;
  CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, P_c, Q, CEED_GAUSS, &basis_u_c);
  CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, P_c, P_f, CEED_GAUSS_LOBATTO,
                                  &basis_c_to_f);
  const CeedScalar *interp_c_to_f;
  CeedBasisGetInterp1D(basis_c_to_f, &interp_c_to_f);
  CeedOperatorMultigridLevelCreateH1(op_mass_f, p_mult_f, elem_restr_u_c,
                                     basis_u_c, interp_c_to_f, &op_mass_c,
                                     &op_prolong, &op_restrict);

  // Coarse problem
  CeedVectorCreate(ceed, num_dofs_u_c, &U_c);
  CeedVectorSetValue(U_c, 1.0);
  CeedVectorCreate(ceed, num_dofs_u_c, &V_c);
  CeedOperatorApply(op_mass_c, U_c, V_c, CEED_REQUEST_IMMEDIATE);

  // Check output
  CeedVectorGetArrayRead(V_c, CEED_MEM_HOST, &hv);
  sum = 0.;
  for (CeedInt i=0; i<num_dofs_u_c; i++) {
    sum += hv[i];
  }
  if (fabs(sum-1.)>1000.*CEED_EPSILON)
    // LCOV_EXCL_START
    printf("Computed Area Coarse Grid: %f != True Area: 1.0\n", sum);
  // LCOV_EXCL_STOP
  CeedVectorRestoreArrayRead(V_c, &hv);

  // Prolong coarse u
  CeedVectorCreate(ceed, num_dofs_u_f, &U_f);
  CeedOperatorApply(op_prolong, U_c, U_f, CEED_REQUEST_IMMEDIATE);

  // Fine problem
  CeedVectorCreate(ceed, num_dofs_u_f, &V_f);
  CeedOperatorApply(op_mass_f, U_f, V_f, CEED_REQUEST_IMMEDIATE);

  // Check output
  CeedVectorGetArrayRead(V_f, CEED_MEM_HOST, &hv);
  sum = 0.;
  for (CeedInt i=0; i<num_dofs_u_f; i++) {
    sum += hv[i];
  }
  if (fabs(sum-1.)>1000.*CEED_EPSILON)
    // LCOV_EXCL_START
    printf("Computed Area Fine Grid: %f != True Area: 1.0\n", sum);
  // LCOV_EXCL_STOP
  CeedVectorRestoreArrayRead(V_f, &hv);

  // Restrict state to coarse grid
  CeedOperatorApply(op_restrict, V_f, V_c, CEED_REQUEST_IMMEDIATE);

  // Check output
  CeedVectorGetArrayRead(V_c, CEED_MEM_HOST, &hv);
  sum = 0.;
  for (CeedInt i=0; i<num_dofs_u_c; i++) {
    sum += hv[i];
  }
  if (fabs(sum-1.)>1000.*CEED_EPSILON)
    // LCOV_EXCL_START
    printf("Computed Area Coarse Grid: %f != True Area: 1.0\n", sum);
  // LCOV_EXCL_STOP
  CeedVectorRestoreArrayRead(V_c, &hv);

  // Cleanup
  CeedQFunctionDestroy(&qf_setup);
  CeedQFunctionDestroy(&qf_mass);
  CeedOperatorDestroy(&op_setup);
  CeedOperatorDestroy(&op_mass_c);
  CeedOperatorDestroy(&op_mass_f);
  CeedOperatorDestroy(&op_prolong);
  CeedOperatorDestroy(&op_restrict);
  CeedElemRestrictionDestroy(&elem_restr_u_c);
  CeedElemRestrictionDestroy(&elem_restr_u_f);
  CeedElemRestrictionDestroy(&elem_restr_x);
  CeedElemRestrictionDestroy(&elem_restr_qd);
  CeedBasisDestroy(&basis_u);
  CeedBasisDestroy(&basis_u_c);
  CeedBasisDestroy(&basis_c_to_f);
  CeedBasisDestroy(&basis_x);
  CeedVectorDestroy(&X);
  CeedVectorDestroy(&U_c);
  CeedVectorDestroy(&U_f);
  CeedVectorDestroy(&V_c);
  CeedVectorDestroy(&V_f);
  CeedVectorDestroy(&p_mult_f);
  CeedVectorDestroy(&q_data);
  CeedDestroy(&ceed);
  return 0;
}