/* -*- c++ -*- ----------------------------------------------------------
   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
   http://lammps.sandia.gov, Sandia National Laboratories
   Steve Plimpton, sjplimp@sandia.gov

   Copyright (2003) Sandia Corporation.  Under the terms of Contract
   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
   certain rights in this software.  This software is distributed under
   the GNU General Public License.

   See the README file in the top-level LAMMPS directory.
------------------------------------------------------------------------- */

/* ----------------------------------------------------------------------
   Contributing authors: Richard Berger (Temple U)
------------------------------------------------------------------------- */

#include "lammps.h"
#include "force.h"
#include "error.h"
#include "comm.h"
#include "potential_file_reader.h"
#include "utils.h"
#include "tokenizer.h"
#include "fmt/format.h"

#include <cstring>

using namespace LAMMPS_NS;

PotentialFileReader::PotentialFileReader(LAMMPS *lmp,
                                         const std::string &filename,
                                         const std::string &potential_name) : Pointers(lmp), filename(filename) {
  if (comm->me != 0) {
    error->one(FLERR, "PotentialFileReader should only be called by proc 0!");
  }

  fp = force->open_potential(filename.c_str());

  if (fp == NULL)
    error->one(FLERR,fmt::format("Cannot open {} potential file {}: {}",
                                 potential_name, filename, utils::getsyserror()));
}

PotentialFileReader::~PotentialFileReader() {
  fclose(fp);
}

void PotentialFileReader::skip_line() {
  char *ptr = fgets(line, MAXLINE, fp);
  if (ptr == nullptr)
    error->one(FLERR,fmt::format("Missing line in {} potential file!",
                                 potential_name));
}

char *PotentialFileReader::next_line(int nparams) {
  // concatenate lines until have nparams words
  int n = 0;
  int nwords = 0;

  char *ptr = fgets(line, MAXLINE, fp);

  if (ptr == nullptr) {
    // EOF
    return nullptr;
  }

  // strip comment
  if ((ptr = strchr(line, '#'))) *ptr = '\0';

  nwords = utils::count_words(line);

  if (nwords > 0) {
    n = strlen(line);
  }

  while(nwords < nparams) {
    char *ptr = fgets(&line[n], MAXLINE - n, fp);

    if (ptr == nullptr) {
      // EOF
      if (nwords > 0 && nwords < nparams)
        error->one(FLERR,fmt::format("Incorrect format in {} potential "
                                     "file! {}/{} parameters",
                                     potential_name, nwords, nparams));
      return nullptr;
    }

    // strip comment
    if ((ptr = strchr(line, '#'))) *ptr = '\0';

    nwords = utils::count_words(line);

    // skip line if blank
    if (nwords > 0) {
      n = strlen(line);
    }
  }

  return line;
}

void PotentialFileReader::next_dvector(int n, double * list) {
  int i = 0;
  while (i < n) {
    char *ptr = fgets(line, MAXLINE, fp);

    if (ptr == nullptr) {
      // EOF
      if (i < n)
        error->one(FLERR,fmt::format("Incorrect format in {} potential file! "
                                     "{}/{} values", potential_name, i, n));
    }

    ValueTokenizer values(line);
    while(values.has_next()) {
      list[i++] = values.next_double();
    }
  }
}