/***************************************************************************
                                base_amoeba.h
                             -------------------
                        Trung Dac Nguyen (Northwestern)

  Base class for pair styles needing per-particle data for position,
  charge, and type.

 __________________________________________________________________________
    This file is part of the LAMMPS Accelerator Library (LAMMPS_AL)
 __________________________________________________________________________

    begin                :
    email                : trung.nguyen@northwestern.edu
 ***************************************************************************/

#ifndef LAL_BASE_AMOEBA_H
#define LAL_BASE_AMOEBA_H

#include "lal_device.h"
#include "lal_balance.h"
#include "mpi.h"

#if defined(USE_OPENCL)
#include "geryon/ocl_texture.h"
#elif defined(USE_CUDART)
#include "geryon/nvc_texture.h"
#elif defined(USE_HIP)
#include "geryon/hip_texture.h"
#else
#include "geryon/nvd_texture.h"
#endif

//#define ASYNC_DEVICE_COPY

#if !defined(USE_OPENCL) && !defined(USE_HIP)
// temporary workaround for int2 also defined in cufft
#ifdef int2
#undef int2
#endif
#include "cufft.h"
#endif

namespace LAMMPS_AL {

template <class numtyp, class acctyp>
class BaseAmoeba {
 public:
  BaseAmoeba();
  virtual ~BaseAmoeba();

  /// Clear any previous data and set up for a new LAMMPS run
  /** \param max_nbors initial number of rows in the neighbor matrix
    * \param cell_size cutoff + skin
    * \param gpu_split fraction of particles handled by device
    * \param k_name name for the kernel for force calculation
    *
    * Returns:
    * -  0 if successful
    * - -1 if fix gpu not found
    * - -3 if there is an out of memory error
    * - -4 if the GPU library was not compiled for GPU
    * - -5 Double precision is not supported on card **/
  int init_atomic(const int nlocal, const int nall, const int max_nbors,
                  const int maxspecial, const int maxspecial15, const double cell_size,
                  const double gpu_split, FILE *screen, const void *pair_program,
                  const char *kname_multipole, const char *kname_udirect2b,
                  const char *kname_umutual2b, const char *kname_polar,
                  const char *kname_fphi_uind, const char *kname_fphi_mpole,
                  const char *kname_short_nbor, const char* kname_special15);

  /// Estimate the overhead for GPU context changes and CPU driver
  void estimate_gpu_overhead(const int add_kernels=0);

  /// Check if there is enough storage for atom arrays and realloc if not
  /** \param success set to false if insufficient memory **/
  inline void resize_atom(const int inum, const int nall, bool &success) {
    if (atom->resize(nall, success)) {
      pos_tex.bind_float(atom->x,4);
      q_tex.bind_float(atom->q,1);
    }
    ans->resize(inum,success);
  }

  /// Check if there is enough storage for neighbors and realloc if not
  /** \param nlocal number of particles whose nbors must be stored on device
    * \param host_inum number of particles whose nbors need to copied to host
    * \param current maximum number of neighbors
    * \note olist_size=total number of local particles **/
  inline void resize_local(const int inum, const int max_nbors, bool &success) {
    nbor->resize(inum,max_nbors,success);
  }

  /// Check if there is enough storage for neighbors and realloc if not
  /** \param nlocal number of particles whose nbors must be stored on device
    * \param host_inum number of particles whose nbors need to copied to host
    * \param current maximum number of neighbors
    * \note host_inum is 0 if the host is performing neighboring
    * \note nlocal+host_inum=total number local particles
    * \note olist_size=0 **/
  inline void resize_local(const int inum, const int host_inum,
                           const int max_nbors, bool &success) {
    nbor->resize(inum,host_inum,max_nbors,success);
  }

  /// Clear all host and device data
  /** \note This is called at the beginning of the init() routine **/
  void clear_atomic();

  /// Returns memory usage on device per atom
  int bytes_per_atom_atomic(const int max_nbors) const;

  /// Total host memory used by library for pair style
  double host_memory_usage_atomic() const;

  /// Accumulate timers
  inline void acc_timers() {
    if (device->time_device()) {
      nbor->acc_timers(screen);
      time_pair.add_to_total();
      atom->acc_timers();
      ans->acc_timers();
    }
  }

  /// Zero timers
  inline void zero_timers() {
    time_pair.zero();
    atom->zero_timers();
    ans->zero_timers();
  }

  /// Copy neighbor list from host
  int * reset_nbors(const int nall, const int inum, int *ilist, int *numj,
                    int **firstneigh, bool &success);

  /// Build neighbor list on device
  int build_nbor_list(const int inum, const int host_inum,
                       const int nall, double **host_x, int *host_type,
                       double *sublo, double *subhi, tagint *tag, int **nspecial,
                       tagint **special, int *nspecial15, tagint **special15,
                       bool &success);

  /// Reallocate per-atom arrays if needed, and build neighbor lists once, if needed
  virtual int** precompute(const int ago, const int inum_full, const int nall,
                double **host_x, int *host_type, int *host_amtype,
                int *host_amgroup, double **host_rpole, double **host_uind,
                double **host_uinp, double *host_pval, double *sublo, double *subhi,
                tagint *tag, int **nspecial, tagint **special,
                int *nspecial15, tagint **special15,
                const bool eflag, const bool vflag,
                const bool eatom, const bool vatom, int &host_start,
                int **&ilist, int **&numj, const double cpu_time, bool &success,
                double *charge, double *boxlo, double *prd);

  /// Compute multipole real-space with device neighboring
  virtual void compute_multipole_real(const int ago, const int inum_full, const int nall,
                double **host_x, int *host_type, int *host_amtype,
                int *host_amgroup, double **host_rpole, double *host_pval,
                double *sublo, double *subhi, tagint *tag,
                int **nspecial, tagint **special, int *nspecial15, tagint **special15,
                const bool eflag, const bool vflag, const bool eatom, const bool vatom,
                int &host_start, int **ilist, int **numj, const double cpu_time,
                bool &success, const double aewald, const double felec,
                const double off2_mpole, double *charge, double *boxlo,
                double *prd, void **tep_ptr);

  /// Compute the real space part of the permanent field (udirect2b) with device neighboring
  virtual void compute_udirect2b(int *host_amtype, int *host_amgroup, double **host_rpole,
                double **host_uind, double **host_uinp, double *host_pval,
                const double aewald, const double off2_polar, void **fieldp_ptr);

  /// Compute the real space part of the induced field (umutual2b) with device neighboring
  virtual void compute_umutual2b(int *host_amtype, int *host_amgroup, double **host_rpole,
                double **host_uind, double **host_uinp, double *host_pval,
                const double aewald, const double off2_polar, void **fieldp_ptr);

  /// Allocate/resize per-atom arrays before the kspace parts in induce() and polar
  virtual void precompute_kspace(const int inum_full, const int bsorder,
                                 double ***host_thetai1, double ***host_thetai2,
                                 double ***host_thetai3, int** igrid,
                                 const int nzlo_out, const int nzhi_out,
                                 const int nylo_out, const int nyhi_out,
                                 const int nxlo_out, const int nxhi_out);
  /// Interpolate the induced potential from the grid
  virtual void compute_fphi_uind(double ****host_grid_brick,
                                 void **host_fdip_phi1, void **host_fdip_phi2,
                                 void **host_fdip_sum_phi);

  /// Interpolate the multipolar potential from the grid
  virtual void compute_fphi_mpole(double ***host_grid_brick, void **host_fphi,
                                  const double felec);

  /// Compute polar real-space with device neighboring
  virtual void compute_polar_real(int *host_amtype, int *host_amgroup, double **host_rpole,
                double **host_uind, double **host_uinp, double *host_pval,
                const bool eflag, const bool vflag,
                const bool eatom, const bool vatom,
                const double aewald, const double felec, const double off2_polar,
                void **tep_ptr);

  // copy field and fieldp from device to host after umutual2b
  virtual void update_fieldp(void **fieldp_ptr) {
    *fieldp_ptr=_fieldp.host.begin();
     // _fieldp store both arrays, one after another
    _fieldp.update_host(_max_fieldp_size*6,false);
  }

  /// setup a plan for FFT, where size is the number of elements

  void setup_fft(const int size, const int element_type=0);

  /// compute forward/backward FFT on the device

  void compute_fft1d(void* in, void* out, const int numel, const int mode);

  // -------------------------- DEVICE DATA -------------------------

  /// Device Properties and Atom and Neighbor storage
  Device<numtyp,acctyp> *device;

  /// Geryon device
  UCL_Device *ucl_device;

  /// Device Timers
  UCL_Timer time_pair;

  /// Host device load balancer
  Balance<numtyp,acctyp> hd_balancer;

  /// LAMMPS pointer for screen output
  FILE *screen;

  // --------------------------- ATOM DATA --------------------------

  /// Atom Data
  Atom<numtyp,acctyp> *atom;

  UCL_Vector<numtyp,numtyp> polar1, polar2, polar3, polar4, polar5;

  /// cast host arrays into a single array for atom->extra
  void cast_extra_data(int* amtype, int* amgroup, double** rpole,
    double** uind, double** uinp, double* pval=nullptr);

  /// Per-atom arrays
  UCL_Vector<acctyp,acctyp> _tep, _fieldp;
  int _nmax, _max_tep_size, _max_fieldp_size;

  int _bsorder;
  UCL_Vector<numtyp4,numtyp4> _thetai1, _thetai2, _thetai3;
  UCL_Vector<int,int> _igrid;
  UCL_Vector<numtyp2,numtyp2> _cgrid_brick;
  UCL_Vector<acctyp,acctyp> _fdip_phi1, _fdip_phi2, _fdip_sum_phi;
  int _max_thetai_size;
  int _nzlo_out, _nzhi_out, _nylo_out, _nyhi_out, _nxlo_out, _nxhi_out;
  int _ngridx, _ngridy, _ngridz, _num_grid_points;

  int _end_command_queue;

  // ------------------------ FORCE/ENERGY DATA -----------------------

  Answer<numtyp,acctyp> *ans;

  // --------------------------- NBOR DATA ----------------------------

  /// Neighbor data
  Neighbor *nbor;
  /// Device storage for 1-5 special neighbor counts
  UCL_D_Vec<int> dev_nspecial15;
  /// Device storage for special neighbors
  UCL_D_Vec<tagint> dev_special15, dev_special15_t;

  int add_onefive_neighbors();

  UCL_D_Vec<int> dev_short_nbor;

  // ------------------------- DEVICE KERNELS -------------------------
  UCL_Program *pair_program;
  UCL_Kernel k_multipole, k_udirect2b, k_umutual2b, k_polar;
  UCL_Kernel k_fphi_uind, k_fphi_mpole;
  UCL_Kernel k_special15, k_short_nbor;
  inline int block_size() { return _block_size; }
  inline void set_kernel(const int /*eflag*/, const int /*vflag*/) {}

  // --------------------------- TEXTURES -----------------------------
  UCL_Texture pos_tex;
  UCL_Texture q_tex;

 protected:
  bool _compiled;
  int _block_size, _block_bio_size, _threads_per_atom;
  int _extra_fields;
  double _max_bytes, _max_an_bytes, _maxspecial, _maxspecial15, _max_nbors;
  double _gpu_overhead, _driver_overhead;
  bool short_nbor_polar_avail;
  UCL_D_Vec<int> *_nbor_data;

  numtyp _aewald,_felec;
  numtyp _off2_hal,_off2_repulse,_off2_disp,_off2_mpole,_off2_polar;

  int _eflag, _vflag;

  void compile_kernels(UCL_Device &dev, const void *pair_string,
     const char *kname_multipole, const char *kname_udirect2b,
     const char *kname_umutual2b, const char *kname_polar,
     const char *kname_fphi_uind, const char *kname_fphi_mpole,
     const char *kname_short_nbor, const char* kname_special15);

  virtual int multipole_real(const int eflag, const int vflag) = 0;
  virtual int udirect2b(const int eflag, const int vflag) = 0;
  virtual int umutual2b(const int eflag, const int vflag) = 0;
  virtual int fphi_uind();
  virtual int fphi_mpole();
  virtual int polar_real(const int eflag, const int vflag) = 0;


  #if !defined(USE_OPENCL) && !defined(USE_HIP)
  cufftHandle plan;
  #endif
  bool fft_plan_created;
};

}

#endif
