// fstconcat.cc

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Copyright 2005-2010 Google, Inc.
// Author: riley@google.com (Michael Riley)
// Modified: jpr@google.com (Jake Ratkiewicz) to use FstClass
//
// \file
// Concatenates two FSTs.
//

#include <string>

#include <fst/script/concat.h>

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

  string usage = "Concatenates two FSTs.\n\n  Usage: ";
  usage += argv[0];
  usage += " in1.fst in2.fst [out.fst]\n";

  std::set_new_handler(FailedNewHandler);
  SetFlags(usage.c_str(), &argc, &argv, true);
  if (argc < 3 || argc > 4) {
    ShowUsage();
    return 1;
  }

  string in1_name = strcmp(argv[1], "-") == 0 ? "" : argv[1];
  string in2_name = strcmp(argv[2], "-") == 0 ? "" : argv[2];
  string out_fname = argc > 3 ? argv[3] : "";

  if (in1_name.empty() && in2_name.empty()) {
    LOG(ERROR) << argv[0] << ": Can't take both inputs from standard input.";
    return 1;
  }

  MutableFstClass *fst1 = MutableFstClass::Read(in1_name, true);
  if (!fst1) return 1;

  FstClass *fst2 = FstClass::Read(in2_name);
  if (!fst2) return 1;

  s::Concat(fst1, *fst2);
  fst1->Write(out_fname);

  return 0;
}