// fstbin/fstaddselfloops.cc

// Copyright 2009-2011  Microsoft Corporation

// See ../../COPYING for clarification regarding multiple authors
//
// 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
//
// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
// MERCHANTABLITY OR NON-INFRINGEMENT.
// See the Apache 2 License for the specific language governing permissions and
// limitations under the License.

#include "base/kaldi-common.h"
#include "fst/fstlib.h"
#include "fstext/determinize-star.h"
#include "fstext/fstext-utils.h"
#include "fstext/kaldi-fst-io.h"
#include "util/parse-options.h"
#include "util/simple-io-funcs.h"

/* some test examples:
  pushd ~/tmpdir
 ( echo 3; echo  4) > in.list
 ( echo 5; echo  6) > out.list
 ( echo "0 0 0 0"; echo "0 0" ) | fstcompile | fstaddselfloops in.list out.list
 | fstprint ( echo "0 1 0 1"; echo " 0 2 1 0"; echo "1 0"; echo "2 0"; ) |
 fstcompile | fstaddselfloops in.list out.list | fstprint
*/

int main(int argc, char *argv[]) {
    try {
        using namespace kaldi;  // NOLINT
        using namespace fst;    // NOLINT
        using kaldi::int32;

        const char *usage =
            "Adds self-loops to states of an FST to propagate disambiguation "
            "symbols through it\n"
            "They are added on each final state and each state with "
            "non-epsilon "
            "output symbols\n"
            "on at least one arc out of the state.  Useful in conjunction with "
            "predeterminize\n"
            "\n"
            "Usage:  fstaddselfloops in-disambig-list out-disambig-list  "
            "[in.fst "
            "[out.fst] ]\n"
            "E.g:  fstaddselfloops in.list out.list < in.fst > withloops.fst\n"
            "in.list and out.list are lists of integers, one per line, of the\n"
            "same length.\n";

        ParseOptions po(usage);
        po.Read(argc, argv);

        if (po.NumArgs() < 2 || po.NumArgs() > 4) {
            po.PrintUsage();
            exit(1);
        }

        std::string disambig_in_rxfilename = po.GetArg(1),
                    disambig_out_rxfilename = po.GetArg(2),
                    fst_in_filename = po.GetOptArg(3),
                    fst_out_filename = po.GetOptArg(4);

        VectorFst<StdArc> *fst = ReadFstKaldi(fst_in_filename);

        std::vector<int32> disambig_in;
        if (!ReadIntegerVectorSimple(disambig_in_rxfilename, &disambig_in))
            KALDI_ERR << "fstaddselfloops: Could not read disambiguation "
                         "symbols from "
                      << kaldi::PrintableRxfilename(disambig_in_rxfilename);

        std::vector<int32> disambig_out;
        if (!ReadIntegerVectorSimple(disambig_out_rxfilename, &disambig_out))
            KALDI_ERR << "fstaddselfloops: Could not read disambiguation "
                         "symbols from "
                      << kaldi::PrintableRxfilename(disambig_out_rxfilename);

        if (disambig_in.size() != disambig_out.size())
            KALDI_ERR << "fstaddselfloops: mismatch in size of disambiguation "
                         "symbols";

        AddSelfLoops(fst, disambig_in, disambig_out);

        WriteFstKaldi(*fst, fst_out_filename);

        delete fst;

        return 0;
    } catch (const std::exception &e) {
        std::cerr << e.what();
        return -1;
    }
    return 0;
}