# Copyright (c) 2021, NVIDIA CORPORATION & AFFILIATES.  All rights reserved.
#
# 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,
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import pynini
from pynini.lib import pynutil

from nemo_text_processing.text_normalization.en.graph_utils import NEMO_NOT_QUOTE, GraphFst


class CardinalFst(GraphFst):
    """
    Finite state transducer for verbalizing cardinals
        e.g. cardinal { integer: "zwei" } -> "zwei"

    Args:
        deterministic: if True will provide a single transduction option,
            for False multiple transduction are generated (used for audio-based normalization)
    """

    def __init__(self, deterministic: bool = True):
        super().__init__(name="cardinal", kind="verbalize", deterministic=deterministic)
        optional_sign = pynini.closure(pynini.cross("negative: \"true\" ", "minus "), 0, 1)
        self.optional_sign = optional_sign
        integer = pynini.closure(NEMO_NOT_QUOTE, 1)

        self.integer = pynutil.delete(" \"") + integer + pynutil.delete("\"")

        integer = pynutil.delete("integer:") + self.integer
        self.numbers = integer
        graph = optional_sign + self.numbers
        delete_tokens = self.delete_tokens(graph)
        self.fst = delete_tokens.optimize()