// 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

/// @file
/// Utility functions for setting up problems using the Newtonian Qfunction

#include "../qfunctions/newtonian.h"

#include "../navierstokes.h"
#include "../qfunctions/setupgeo.h"

// For use with PetscOptionsEnum
static const char *const StateVariables[] = {"CONSERVATIVE", "PRIMITIVE", "StateVariable", "STATEVAR_", NULL};

// Compute relative error |a - b|/|s|
static PetscErrorCode CheckPrimitiveWithTolerance(StatePrimitive sY, StatePrimitive aY, StatePrimitive bY, const char *name, PetscReal rtol_pressure,
                                                  PetscReal rtol_velocity, PetscReal rtol_temperature) {
  PetscFunctionBeginUser;
  StatePrimitive eY;  // relative error
  eY.pressure   = (aY.pressure - bY.pressure) / sY.pressure;
  PetscScalar u = sqrt(Square(sY.velocity[0]) + Square(sY.velocity[1]) + Square(sY.velocity[2]));
  for (int j = 0; j < 3; j++) eY.velocity[j] = (aY.velocity[j] - bY.velocity[j]) / u;
  eY.temperature = (aY.temperature - bY.temperature) / sY.temperature;
  if (fabs(eY.pressure) > rtol_pressure) printf("%s: pressure error %g\n", name, eY.pressure);
  for (int j = 0; j < 3; j++) {
    if (fabs(eY.velocity[j]) > rtol_velocity) printf("%s: velocity[%d] error %g\n", name, j, eY.velocity[j]);
  }
  if (fabs(eY.temperature) > rtol_temperature) printf("%s: temperature error %g\n", name, eY.temperature);
  PetscFunctionReturn(0);
}

static PetscErrorCode UnitTests_Newtonian(User user, NewtonianIdealGasContext gas) {
  Units            units = user->units;
  const CeedScalar eps   = 1e-6;
  const CeedScalar kg = units->kilogram, m = units->meter, sec = units->second, Pascal = units->Pascal;
  PetscFunctionBeginUser;
  const CeedScalar rho = 1.2 * kg / (m * m * m), u = 40 * m / sec;
  CeedScalar       U[5] = {rho, rho * u, rho * u * 1.1, rho * u * 1.2, 250e3 * Pascal + .5 * rho * u * u};
  const CeedScalar x[3] = {.1, .2, .3};
  State            s    = StateFromU(gas, U, x);
  for (int i = 0; i < 8; i++) {
    CeedScalar dU[5] = {0}, dx[3] = {0};
    if (i < 5) dU[i] = U[i];
    else dx[i - 5] = x[i - 5];
    State ds = StateFromU_fwd(gas, s, dU, x, dx);
    for (int j = 0; j < 5; j++) dU[j] = (1 + eps * (i == j)) * U[j];
    for (int j = 0; j < 3; j++) dx[j] = (1 + eps * (i == 5 + j)) * x[j];
    State          t = StateFromU(gas, dU, dx);
    StatePrimitive dY;
    dY.pressure = (t.Y.pressure - s.Y.pressure) / eps;
    for (int j = 0; j < 3; j++) dY.velocity[j] = (t.Y.velocity[j] - s.Y.velocity[j]) / eps;
    dY.temperature = (t.Y.temperature - s.Y.temperature) / eps;
    char buf[128];
    snprintf(buf, sizeof buf, "StateFromU_fwd i=%d", i);
    PetscCall(CheckPrimitiveWithTolerance(dY, ds.Y, dY, buf, 5e-6, 1e-6, 1e-6));
  }
  PetscFunctionReturn(0);
}

PetscErrorCode NS_NEWTONIAN_IG(ProblemData *problem, DM dm, void *ctx, SimpleBC bc) {
  SetupContext             setup_context;
  User                     user   = *(User *)ctx;
  CeedInt                  degree = user->app_ctx->degree;
  StabilizationType        stab;
  StateVariable            state_var;
  MPI_Comm                 comm = PETSC_COMM_WORLD;
  PetscBool                implicit;
  PetscBool                has_curr_time = PETSC_FALSE, unit_tests;
  NewtonianIdealGasContext newtonian_ig_ctx;
  CeedQFunctionContext     newtonian_ig_context;

  PetscFunctionBeginUser;
  PetscCall(PetscCalloc1(1, &setup_context));
  PetscCall(PetscCalloc1(1, &newtonian_ig_ctx));

  // ------------------------------------------------------
  //           Setup Generic Newtonian IG Problem
  // ------------------------------------------------------
  problem->dim                     = 3;
  problem->q_data_size_vol         = 10;
  problem->q_data_size_sur         = 10;
  problem->jac_data_size_sur       = 11;
  problem->setup_vol.qfunction     = Setup;
  problem->setup_vol.qfunction_loc = Setup_loc;
  problem->setup_sur.qfunction     = SetupBoundary;
  problem->setup_sur.qfunction_loc = SetupBoundary_loc;
  problem->bc                      = NULL;
  problem->bc_ctx                  = setup_context;
  problem->non_zero_time           = PETSC_FALSE;
  problem->print_info              = PRINT_NEWTONIAN;

  // ------------------------------------------------------
  //             Create the libCEED context
  // ------------------------------------------------------
  CeedScalar cv         = 717.;           // J/(kg K)
  CeedScalar cp         = 1004.;          // J/(kg K)
  CeedScalar g[3]       = {0, 0, -9.81};  // m/s^2
  CeedScalar lambda     = -2. / 3.;       // -
  CeedScalar mu         = 1.8e-5;         // Pa s, dynamic viscosity
  CeedScalar k          = 0.02638;        // W/(m K)
  CeedScalar c_tau      = 0.5 / degree;   // -
  CeedScalar Ctau_t     = 1.0;            // -
  CeedScalar Cv_func[3] = {36, 60, 128};
  CeedScalar Ctau_v     = Cv_func[(CeedInt)Min(3, degree) - 1];
  CeedScalar Ctau_C     = 0.25 / degree;
  CeedScalar Ctau_M     = 0.25 / degree;
  CeedScalar Ctau_E     = 0.125;
  PetscReal  domain_min[3], domain_max[3], domain_size[3];
  PetscCall(DMGetBoundingBox(dm, domain_min, domain_max));
  for (PetscInt i = 0; i < 3; i++) domain_size[i] = domain_max[i] - domain_min[i];

  // ------------------------------------------------------
  //             Create the PETSc context
  // ------------------------------------------------------
  PetscScalar meter    = 1;  // 1 meter in scaled length units
  PetscScalar kilogram = 1;  // 1 kilogram in scaled mass units
  PetscScalar second   = 1;  // 1 second in scaled time units
  PetscScalar Kelvin   = 1;  // 1 Kelvin in scaled temperature units
  PetscScalar W_per_m_K, Pascal, J_per_kg_K, m_per_squared_s;

  // ------------------------------------------------------
  //              Command line Options
  // ------------------------------------------------------
  PetscOptionsBegin(comm, NULL, "Options for Newtonian Ideal Gas based problem", NULL);
  // -- Conservative vs Primitive variables
  PetscCall(PetscOptionsEnum("-state_var", "State variables used", NULL, StateVariables, (PetscEnum)(state_var = STATEVAR_CONSERVATIVE),
                             (PetscEnum *)&state_var, NULL));

  switch (state_var) {
    case STATEVAR_CONSERVATIVE:
      problem->ics.qfunction                        = ICsNewtonianIG;
      problem->ics.qfunction_loc                    = ICsNewtonianIG_loc;
      problem->apply_vol_rhs.qfunction              = RHSFunction_Newtonian;
      problem->apply_vol_rhs.qfunction_loc          = RHSFunction_Newtonian_loc;
      problem->apply_vol_ifunction.qfunction        = IFunction_Newtonian_Conserv;
      problem->apply_vol_ifunction.qfunction_loc    = IFunction_Newtonian_Conserv_loc;
      problem->apply_vol_ijacobian.qfunction        = IJacobian_Newtonian_Conserv;
      problem->apply_vol_ijacobian.qfunction_loc    = IJacobian_Newtonian_Conserv_loc;
      problem->apply_inflow.qfunction               = BoundaryIntegral_Conserv;
      problem->apply_inflow.qfunction_loc           = BoundaryIntegral_Conserv_loc;
      problem->apply_inflow_jacobian.qfunction      = BoundaryIntegral_Jacobian_Conserv;
      problem->apply_inflow_jacobian.qfunction_loc  = BoundaryIntegral_Jacobian_Conserv_loc;
      problem->apply_outflow.qfunction              = PressureOutflow_Conserv;
      problem->apply_outflow.qfunction_loc          = PressureOutflow_Conserv_loc;
      problem->apply_outflow_jacobian.qfunction     = PressureOutflow_Jacobian_Conserv;
      problem->apply_outflow_jacobian.qfunction_loc = PressureOutflow_Jacobian_Conserv_loc;
      break;

    case STATEVAR_PRIMITIVE:
      problem->ics.qfunction                        = ICsNewtonianIG_Prim;
      problem->ics.qfunction_loc                    = ICsNewtonianIG_Prim_loc;
      problem->apply_vol_ifunction.qfunction        = IFunction_Newtonian_Prim;
      problem->apply_vol_ifunction.qfunction_loc    = IFunction_Newtonian_Prim_loc;
      problem->apply_vol_ijacobian.qfunction        = IJacobian_Newtonian_Prim;
      problem->apply_vol_ijacobian.qfunction_loc    = IJacobian_Newtonian_Prim_loc;
      problem->apply_inflow.qfunction               = BoundaryIntegral_Prim;
      problem->apply_inflow.qfunction_loc           = BoundaryIntegral_Prim_loc;
      problem->apply_inflow_jacobian.qfunction      = BoundaryIntegral_Jacobian_Prim;
      problem->apply_inflow_jacobian.qfunction_loc  = BoundaryIntegral_Jacobian_Prim_loc;
      problem->apply_outflow.qfunction              = PressureOutflow_Prim;
      problem->apply_outflow.qfunction_loc          = PressureOutflow_Prim_loc;
      problem->apply_outflow_jacobian.qfunction     = PressureOutflow_Jacobian_Prim;
      problem->apply_outflow_jacobian.qfunction_loc = PressureOutflow_Jacobian_Prim_loc;
      break;
  }

  // -- Physics
  PetscCall(PetscOptionsScalar("-cv", "Heat capacity at constant volume", NULL, cv, &cv, NULL));
  PetscCall(PetscOptionsScalar("-cp", "Heat capacity at constant pressure", NULL, cp, &cp, NULL));
  PetscCall(PetscOptionsScalar("-lambda", "Stokes hypothesis second viscosity coefficient", NULL, lambda, &lambda, NULL));
  PetscCall(PetscOptionsScalar("-mu", "Shear dynamic viscosity coefficient", NULL, mu, &mu, NULL));
  PetscCall(PetscOptionsScalar("-k", "Thermal conductivity", NULL, k, &k, NULL));

  PetscInt dim = problem->dim;
  PetscCall(PetscOptionsRealArray("-g", "Gravitational acceleration", NULL, g, &dim, NULL));
  PetscCall(PetscOptionsEnum("-stab", "Stabilization method", NULL, StabilizationTypes, (PetscEnum)(stab = STAB_NONE), (PetscEnum *)&stab, NULL));
  PetscCall(PetscOptionsScalar("-c_tau", "Stabilization constant", NULL, c_tau, &c_tau, NULL));
  PetscCall(PetscOptionsScalar("-Ctau_t", "Stabilization time constant", NULL, Ctau_t, &Ctau_t, NULL));
  PetscCall(PetscOptionsScalar("-Ctau_v", "Stabilization viscous constant", NULL, Ctau_v, &Ctau_v, NULL));
  PetscCall(PetscOptionsScalar("-Ctau_C", "Stabilization continuity constant", NULL, Ctau_C, &Ctau_C, NULL));
  PetscCall(PetscOptionsScalar("-Ctau_M", "Stabilization momentum constant", NULL, Ctau_M, &Ctau_M, NULL));
  PetscCall(PetscOptionsScalar("-Ctau_E", "Stabilization energy constant", NULL, Ctau_E, &Ctau_E, NULL));
  PetscCall(PetscOptionsBool("-implicit", "Use implicit (IFunction) formulation", NULL, implicit = PETSC_FALSE, &implicit, NULL));
  PetscCall(PetscOptionsBool("-newtonian_unit_tests", "Run Newtonian unit tests", NULL, unit_tests = PETSC_FALSE, &unit_tests, NULL));

  // -- Units
  PetscCall(PetscOptionsScalar("-units_meter", "1 meter in scaled length units", NULL, meter, &meter, NULL));
  meter = fabs(meter);
  PetscCall(PetscOptionsScalar("-units_kilogram", "1 kilogram in scaled mass units", NULL, kilogram, &kilogram, NULL));
  kilogram = fabs(kilogram);
  PetscCall(PetscOptionsScalar("-units_second", "1 second in scaled time units", NULL, second, &second, NULL));
  second = fabs(second);
  PetscCall(PetscOptionsScalar("-units_Kelvin", "1 Kelvin in scaled temperature units", NULL, Kelvin, &Kelvin, NULL));
  Kelvin = fabs(Kelvin);

  // -- Warnings
  if (stab == STAB_SUPG && !implicit) {
    PetscCall(PetscPrintf(comm, "Warning! Use -stab supg only with -implicit\n"));
  }
  if (state_var == STATEVAR_PRIMITIVE && !implicit) {
    SETERRQ(comm, PETSC_ERR_ARG_NULL, "RHSFunction is not provided for primitive variables (use -state_var primitive only with -implicit)\n");
  }
  PetscOptionsEnd();

  // ------------------------------------------------------
  //           Set up the PETSc context
  // ------------------------------------------------------
  // -- Define derived units
  Pascal          = kilogram / (meter * PetscSqr(second));
  J_per_kg_K      = PetscSqr(meter) / (PetscSqr(second) * Kelvin);
  m_per_squared_s = meter / PetscSqr(second);
  W_per_m_K       = kilogram * meter / (pow(second, 3) * Kelvin);

  user->units->meter           = meter;
  user->units->kilogram        = kilogram;
  user->units->second          = second;
  user->units->Kelvin          = Kelvin;
  user->units->Pascal          = Pascal;
  user->units->J_per_kg_K      = J_per_kg_K;
  user->units->m_per_squared_s = m_per_squared_s;
  user->units->W_per_m_K       = W_per_m_K;

  // ------------------------------------------------------
  //           Set up the libCEED context
  // ------------------------------------------------------
  // -- Scale variables to desired units
  cv *= J_per_kg_K;
  cp *= J_per_kg_K;
  mu *= Pascal * second;
  k *= W_per_m_K;
  for (PetscInt i = 0; i < 3; i++) domain_size[i] *= meter;
  for (PetscInt i = 0; i < 3; i++) g[i] *= m_per_squared_s;
  problem->dm_scale = meter;

  // -- Setup Context
  setup_context->cv   = cv;
  setup_context->cp   = cp;
  setup_context->lx   = domain_size[0];
  setup_context->ly   = domain_size[1];
  setup_context->lz   = domain_size[2];
  setup_context->time = 0;
  PetscCall(PetscArraycpy(setup_context->g, g, 3));

  // -- Solver Settings
  user->phys->stab          = stab;
  user->phys->implicit      = implicit;
  user->phys->state_var     = state_var;
  user->phys->has_curr_time = has_curr_time;

  // -- QFunction Context
  newtonian_ig_ctx->lambda        = lambda;
  newtonian_ig_ctx->mu            = mu;
  newtonian_ig_ctx->k             = k;
  newtonian_ig_ctx->cv            = cv;
  newtonian_ig_ctx->cp            = cp;
  newtonian_ig_ctx->c_tau         = c_tau;
  newtonian_ig_ctx->Ctau_t        = Ctau_t;
  newtonian_ig_ctx->Ctau_v        = Ctau_v;
  newtonian_ig_ctx->Ctau_C        = Ctau_C;
  newtonian_ig_ctx->Ctau_M        = Ctau_M;
  newtonian_ig_ctx->Ctau_E        = Ctau_E;
  newtonian_ig_ctx->stabilization = stab;
  newtonian_ig_ctx->is_implicit   = implicit;
  newtonian_ig_ctx->state_var     = state_var;
  PetscCall(PetscArraycpy(newtonian_ig_ctx->g, g, 3));

  if (bc->num_freestream > 0) PetscCall(FreestreamBCSetup(problem, dm, ctx, newtonian_ig_ctx));

  CeedQFunctionContextCreate(user->ceed, &problem->ics.qfunction_context);
  CeedQFunctionContextSetData(problem->ics.qfunction_context, CEED_MEM_HOST, CEED_USE_POINTER, sizeof(*setup_context), setup_context);
  CeedQFunctionContextSetDataDestroy(problem->ics.qfunction_context, CEED_MEM_HOST, FreeContextPetsc);
  CeedQFunctionContextRegisterDouble(problem->ics.qfunction_context, "evaluation time", (char *)&setup_context->time - (char *)setup_context, 1,
                                     "Time of evaluation");

  CeedQFunctionContextCreate(user->ceed, &newtonian_ig_context);
  CeedQFunctionContextSetData(newtonian_ig_context, CEED_MEM_HOST, CEED_USE_POINTER, sizeof(*newtonian_ig_ctx), newtonian_ig_ctx);
  CeedQFunctionContextSetDataDestroy(newtonian_ig_context, CEED_MEM_HOST, FreeContextPetsc);
  CeedQFunctionContextRegisterDouble(newtonian_ig_context, "timestep size", offsetof(struct NewtonianIdealGasContext_, dt), 1,
                                     "Size of timestep, delta t");
  CeedQFunctionContextRegisterDouble(newtonian_ig_context, "ijacobian time shift", offsetof(struct NewtonianIdealGasContext_, ijacobian_time_shift),
                                     1, "Shift for mass matrix in IJacobian");
  problem->apply_vol_rhs.qfunction_context = newtonian_ig_context;
  CeedQFunctionContextReferenceCopy(newtonian_ig_context, &problem->apply_vol_ifunction.qfunction_context);
  CeedQFunctionContextReferenceCopy(newtonian_ig_context, &problem->apply_vol_ijacobian.qfunction_context);
  CeedQFunctionContextReferenceCopy(newtonian_ig_context, &problem->apply_inflow.qfunction_context);
  CeedQFunctionContextReferenceCopy(newtonian_ig_context, &problem->apply_inflow_jacobian.qfunction_context);
  CeedQFunctionContextReferenceCopy(newtonian_ig_context, &problem->apply_outflow.qfunction_context);
  CeedQFunctionContextReferenceCopy(newtonian_ig_context, &problem->apply_outflow_jacobian.qfunction_context);

  if (unit_tests) {
    PetscCall(UnitTests_Newtonian(user, newtonian_ig_ctx));
  }
  PetscFunctionReturn(0);
}

PetscErrorCode PRINT_NEWTONIAN(ProblemData *problem, AppCtx app_ctx) {
  MPI_Comm                 comm = PETSC_COMM_WORLD;
  NewtonianIdealGasContext newtonian_ctx;

  PetscFunctionBeginUser;
  CeedQFunctionContextGetData(problem->apply_vol_rhs.qfunction_context, CEED_MEM_HOST, &newtonian_ctx);
  PetscCall(PetscPrintf(comm,
                        "  Problem:\n"
                        "    Problem Name                       : %s\n"
                        "    Stabilization                      : %s\n",
                        app_ctx->problem_name, StabilizationTypes[newtonian_ctx->stabilization]));
  CeedQFunctionContextRestoreData(problem->apply_vol_rhs.qfunction_context, &newtonian_ctx);
  PetscFunctionReturn(0);
}