# 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,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from fun_text_processing.inverse_text_normalization.zh.graph_utils import (
    DAMO_NOT_QUOTE,
    GraphFst,
    delete_extra_space,
    delete_space,
)

import pynini
from pynini.lib import pynutil

class FractionFst(GraphFst):
    """
    Finite state transducer for verbalizing fraction, 
    """

    def __init__(self):
        super().__init__(name="fraction", kind="verbalize")
        optional_sign = pynini.closure(pynini.cross('negative: "true"', "-") + delete_space, 0, 1)
        numerator = (
            pynutil.delete('numerator:')
            + delete_space
            + pynutil.delete("\"")
            + pynini.closure(DAMO_NOT_QUOTE, 1)
            + pynutil.delete("\"")
        )

        denominator = (
            pynutil.delete('denominator:')
            + delete_space
            + pynutil.delete("\"")
            + pynini.closure(DAMO_NOT_QUOTE, 1)
            + pynutil.delete("\"")
        )

        graph = (optional_sign + numerator + delete_space + pynutil.insert("/") + denominator).optimize()
        self.numbers = graph
        delete_tokens = self.delete_tokens(optional_sign + graph)
        self.fst = delete_tokens.optimize()