import spacy
from spacy.matcher import Matcher 


def get_entities(sent):
    ## chunk 1
    ent1 = ""
    ent2 = ""

    prv_tok_dep = ""  # dependency tag of previous token in the sentence
    prv_tok_text = ""  # previous token in the sentence

    prefix = ""
    modifier = ""

    #############################################################

    for tok in nlp(sent):
        ## chunk 2
        # if token is a punctuation mark then move on to the next token
        if tok.dep_ != "punct":
            # check: token is a compound word or not
            if tok.dep_ == "compound":
                prefix = tok.text
                # if the previous word was also a 'compound' then add the current word to it
                if prv_tok_dep == "compound":
                    prefix = prv_tok_text + " " + tok.text

            # check: token is a modifier or not
            if tok.dep_.endswith("mod") == True:
                modifier = tok.text
                # if the previous word was also a 'compound' then add the current word to it
                if prv_tok_dep == "compound":
                    modifier = prv_tok_text + " " + tok.text

            ## chunk 3
            if tok.dep_.find("subj") == True:
                ent1 = modifier + " " + prefix + " " + tok.text
                prefix = ""
                modifier = ""
                prv_tok_dep = ""
                prv_tok_text = ""

                ## chunk 4
            if tok.dep_.find("obj") == True:
                ent2 = modifier + " " + prefix + " " + tok.text

            ## chunk 5  
            # update variables
            prv_tok_dep = tok.dep_
            prv_tok_text = tok.text
    #############################################################

    return [ent1.strip(), ent2.strip()]




def get_relation(sent):
    nlp = spacy.load('en_core_web_sm')

    doc = nlp(sent)

    # Matcher class object 
    matcher = Matcher(nlp.vocab)

    #define the pattern 
    pattern = [{'DEP':'ROOT'},
            {'DEP':'prep','OP':"?"},
            {'DEP':'agent','OP':"?"},  
            {'POS':'ADJ','OP':"?"}] 

    matcher.add('matching_pattern', patterns=[pattern])
    matches = matcher(doc)
    k = len(matches) - 1

    span = doc[matches[k][1]:matches[k][2]] 

    return(span.text)