// See www.openfst.org for extensive documentation on this weighted
// finite-state transducer library.
//
// Sorts arcs of an FST.

#include <cstring>

#include <memory>
#include <string>

#include <fst/flags.h>
#include <fst/log.h>
#include <fst/script/arcsort.h>
#include <fst/script/getters.h>

DECLARE_string(sort_type);

int fstarcsort_main(int argc, char **argv) {
  namespace s = fst::script;
  using fst::script::MutableFstClass;

  string usage = "Sorts arcs of an FST.\n\n  Usage: ";
  usage += argv[0];
  usage += " [in.fst [out.fst]]\n";

  std::set_new_handler(FailedNewHandler);
  SET_FLAGS(usage.c_str(), &argc, &argv, true);

  if (argc > 3) {
    ShowUsage();
    return 1;
  }

  const string in_name =
      (argc > 1 && (strcmp(argv[1], "-") != 0)) ? argv[1] : "";
  const string out_name = argc > 2 ? argv[2] : "";

  std::unique_ptr<MutableFstClass> fst(MutableFstClass::Read(in_name, true));
  if (!fst) return 1;

  s::ArcSortType sort_type;
  if (!s::GetArcSortType(FLAGS_sort_type, &sort_type)) {
    LOG(ERROR) << argv[0] << ": Unknown or unsupported sort type: "
               << FLAGS_sort_type;
    return 1;
  }

  s::ArcSort(fst.get(), sort_type);

  return !fst->Write(out_name);
}