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# Copyright 2015 and onwards Google, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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#
#     http://www.apache.org/licenses/LICENSE-2.0
#
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# 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.inverse_text_normalization.mr.graph_utils import (
    NEMO_NOT_QUOTE,
    GraphFst,
    delete_extra_space,
    delete_space,
)


class DateFst(GraphFst):
    """
    Finite state transducer for verbalizing date, e.g.
        e.g. date { month: "जानेवारी" year: "२०००" preserve_order: true } -> जानेवारी २०००
        e.g. date { day: "१५" month: "फेब्रुवारी" year: "२०२३" } -> १५ फेब्रुवारी २०२३
        e.g. date { text: "इ.स.पू." year: "१९८५" preserve_order: true } -> इ.स.पू. १९८५
    """

    def __init__(self):
        super().__init__(name="date", kind="verbalize")
        month = (
            pynutil.delete("month:")
            + delete_space
            + pynutil.delete("\"")
            + pynini.closure(NEMO_NOT_QUOTE, 1)
            + pynutil.delete("\"")
        )
        day = (
            pynutil.delete("day:")
            + delete_space
            + pynutil.delete("\"")
            + pynini.closure(NEMO_NOT_QUOTE, 1)
            + pynutil.delete("\"")
        )
        year = (
            pynutil.delete("year:")
            + delete_space
            + pynutil.delete("\"")
            + pynini.closure(NEMO_NOT_QUOTE, 1)
            + delete_space
            + pynutil.delete("\"")
        )
        period = (
            pynutil.delete("text:")
            + delete_space
            + pynutil.delete("\"")
            + pynini.closure(NEMO_NOT_QUOTE, 1)
            + pynutil.delete("\"")
        )
        graph_fy = period + pynini.closure(delete_extra_space + year, 0, 1)
        # month (day) year
        graph_mdy = (
            month + pynini.closure(delete_extra_space + day, 0, 1) + pynini.closure(delete_extra_space + year, 0, 1)
        )

        # (day) month year
        graph_dmy = (
            pynini.closure(day + delete_extra_space, 0, 1) + month + pynini.closure(delete_extra_space + year, 0, 1)
        )

        optional_preserve_order = pynini.closure(
            pynutil.delete("preserve_order:") + delete_space + pynutil.delete("true") + delete_space
            | pynutil.delete("field_order:")
            + delete_space
            + pynutil.delete("\"")
            + NEMO_NOT_QUOTE
            + pynutil.delete("\"")
            + delete_space
        )

        final_graph = (graph_mdy | year | graph_dmy | graph_fy) + delete_space + optional_preserve_order | (
            graph_mdy | year | graph_dmy | graph_fy
        ) + delete_space + optional_preserve_order

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