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#
# 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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import pynini
from pynini.lib import pynutil

from nemo_text_processing.text_normalization.en.graph_utils import (
    NEMO_NOT_QUOTE,
    GraphFst,
    delete_preserve_order,
    delete_space,
    insert_space,
)


class DecimalFst(GraphFst):
    """
    Finite state transducer for verbalizing decimal, e.g.
        decimal { integer_part: "հինգ" quantity: "միլիոն" } -> 5 միլիոն

    """

    def __init__(self, deterministic: bool = True):
        super().__init__(name="decimal", kind="classify", deterministic=deterministic)

        integer = pynutil.delete("integer_part: \"") + pynini.closure(NEMO_NOT_QUOTE, 1) + pynutil.delete("\"")
        fractional_default = (
            pynutil.delete("fractional_part: \"") + pynini.closure(NEMO_NOT_QUOTE, 1) + pynutil.delete("\"")
        )

        conjunction = pynutil.insert(" ամբողջ ")
        fractional = conjunction + fractional_default

        quantity = (
            delete_space
            + insert_space
            + pynutil.delete("quantity: \"")
            + pynini.closure(NEMO_NOT_QUOTE, 1)
            + pynutil.delete("\"")
        )
        optional_quantity = pynini.closure(quantity, 0, 1)

        graph = pynini.union((integer + quantity), (integer + delete_space + fractional + optional_quantity))

        self.numbers_only_quantity = pynini.union(
            (integer + quantity), (integer + delete_space + fractional + quantity)
        ).optimize()

        graph += delete_preserve_order
        self.numbers = graph
        delete_tokens = self.delete_tokens(graph)
        self.fst = delete_tokens.optimize()