import subprocess
import spacy
import pyinflect
import pandas as pd
from typing import Tuple, Union, Any

class Parser:
    def __init__(
        self
    ) -> None:
        
        self.parser = self.__init_parser("en_core_web_sm")
        self.__overrides = self.__load_overrides("data/overrides.csv")
    
    def __load_overrides(
        self,
        file_path: str
    ) -> Any:

        dic = pd.read_csv(file_path).set_index('VB').to_dict()
        fun = lambda verb, tag: dic[tag].get(verb, False)
        return fun

    def __init_parser(
        self,
        model: str
    ) -> spacy.language:

        parser = None
        try:
            parser = spacy.load(model)
        except:
            print(f"* Downloading {model} model...")
            _ = subprocess.Popen(
                f"python -m spacy download {model}", 
                stdout=subprocess.PIPE, 
                shell=True
            ).communicate()

            parser = spacy.load(model)
        
        return parser
    
    def __format_error(
        self,
        error: str
    ) -> str:

        template = """
            <center>
                <div class="alert alert-warning" role="alert">
                    <h6><b>{}</b></h6>
                </div>
            </center>
        """
        return template.format(error)

    def __format_output(
        self,
        infinitive: str,
        past: str,
        participle: str,
    ) -> str:

        template = """
            |Infinitive| Simple Past | Past Participle |
            | :----: | :----: | :----: |
            |{} | {}| {}|
        """
        return template.format(infinitive, past, participle)

    def is_in_overrides(
        self,
        verb: str,
        tense: str
    ) -> Tuple[str, bool]:

        res = self.__overrides(verb, tense)
        if isinstance(res, bool):
            return res, ""

        return True, res

    def __get_inflections(
        self, 
        infinitive: spacy.tokens.token.Token,
        tense: str
    ) -> Union[str, None]:
        
        # Check if verb is in overrides file
        res, inflections = self.is_in_overrides(infinitive.text, tense)

        if not res:
            form1 = infinitive._.inflect(tense, form_num=0)
            form2 = infinitive._.inflect(tense, form_num=1)
            inflections = list(set([form1, form2]))

            if len(inflections) == 1 and inflections[0] == None:
                return None
            
            inflections = '/'.join(inflections)

        return inflections

    def __getAllTenses(
        self, 
        tk_verb: spacy.tokens.token.Token
    ) -> Tuple[str,str,str,str]:

        infinitive  = tk_verb._.inflect('VB')
        past        = self.__get_inflections(tk_verb, 'VBD')
        participle  = self.__get_inflections(tk_verb, 'VBN')

        return infinitive, past, participle

    def __tokenizer(
        self,
        verb: str
    ) -> spacy.tokens.token.Token:

        return self.parser(verb)[0]

    def get(
        self,
        verb: str
    ) -> Tuple[str,str]:

        verb = verb.strip().lower()
        error, output = "", ""

        if verb == "":
            error = self.__format_error(
                f"Error: The Verb field can not be empty!"
            )
            return error, output

        tk_verb = self.__tokenizer(verb)
        infinitive, past, participle = self.__getAllTenses(tk_verb)

        if infinitive is None or past is None or participle is None:
            error = self.__format_error(
                f"Error: The verb '<b>{verb}</b>' has not been found or not spelled correctly!"
            )
            return error, output

        print(f"{verb} -> {infinitive},{past},{participle}")
        output = self.__format_output(infinitive, past, participle)

        return error, output