# 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, delete_preserve_order


class DateFst(GraphFst):
    """
    Finite state transducer for verbalizing date, e.g.
        date { year: "kettőezer-tíz" month: "szeptember" day: "harmincegyedike" preserve_order: true } -> "kettőezer-tíz szeptember harmincegyedike"

    Args:
        ordinal: ordinal verbalizer GraphFst
        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="date", kind="verbalize", deterministic=deterministic)

        month = pynutil.delete("month: \"") + pynini.closure(NEMO_NOT_QUOTE, 1) + pynutil.delete("\"")

        year = pynutil.delete("year: \"") + pynini.closure(NEMO_NOT_QUOTE, 1) + pynutil.delete("\"")

        day = pynutil.delete("day: \"") + pynini.closure(NEMO_NOT_QUOTE, 1) + pynutil.delete("\"")

        # day month year
        graph_ymd = pynini.closure(year + pynini.accep(" "), 0, 1) + month + pynini.accep(" ") + day

        self.graph = graph_ymd
        final_graph = self.graph + delete_preserve_order

        delete_tokens = self.delete_tokens(final_graph)
        self.fst = delete_tokens.optimize()