import jsgf
from os import listdir
from os.path import isfile, join

mypath = "./grammar/"
onlyfiles = [f for f in listdir(mypath) if isfile(join(mypath, f))]

grammars = []

for grammarFile in onlyfiles:
    grammar = jsgf.parse_grammar_file(mypath + grammarFile)
    grammars.append(grammar)

class Ajn:        
 
        
            
    def __init__(self, grammars = None):
        self.grammars = grammars

    def get_dialog_act(rule):
        slots = []
        get_slots(rule.expansion, slots)
        return {'act': rule.grammar.name, 'slots': slots}

    def get_slots(expansion, slots):
        if expansion.tag != '':
            slots.append((expansion.tag, expansion.current_match))
            return

        for child in expansion.children:
            get_slots(child, slots)

        if not expansion.children and isinstance(expansion, jsgf.NamedRuleRef):
            get_slots(expansion.referenced_rule.expansion, slots)

    def nlu(utterance):
        matched = None
        for grammar in grammars:
            matched = grammar.find_matching_rules(utterance)
            if matched:
                break

        if matched:
            return get_dialog_act(matched[0])
        else:
            return {'act': 'null', 'slots': []}


ajn = Ajn()