import config
from config import *
from parse import *

interactive_grammar = r"""
    ?start: imply
        | initial_fact | query

    ?imply: xor "=>" xor    -> imply
        | xor "<=>" xor     -> iff
    ?xor: or
        | xor "^" or        -> ft_xor
    ?or: and
        | or "|" and        -> ft_or
    ?and: atom
        | and "+" atom      -> ft_and
    ?atom: UCASE_LETTER     -> var
        | "!" atom         -> ft_not
        | "(" xor ")"

    ?initial_fact: "=" UCASE_LETTER* -> set_fact
    ?query: "?" UCASE_LETTER+ ->query

    _LI: (_COMMENT | LF+)
    _COMMENT: /#[^\n].*\n/

    %import common.UCASE_LETTER
    %import common.NUMBER
    %import common.WS_INLINE
    %import common.LF
    %ignore WS_INLINE
    %ignore _COMMENT
"""


def reset_states():
        for idx in fact_dict:
            fact_dict[idx].state = False
            fact_dict[idx].is_set = False
            
def interactive():
        print('Welcome to the best expert system in the world wide web')
        calc_parser = Lark(interactive_grammar, parser='lalr',
        debug=True, transformer=computer)
        while True:
           try:
               s = input('> ')
           except EOFError:
               break
           if (s == 'exit'):
               exit('Good bye')
               continue
           elif (s == 'reset'):
                reset_states()
                continue
           elif (s == 'reset --hard'):
                config.fact_dict = {}
                continue
                
           try:
               tree = calc_parser.parse(s)
           except UnexpectedInput as e:
               print(e)
               continue
           if (tree == None):
             continue
           if (tree.data == "imply" or tree.data == "iff"):
                set_trees(tree)
           else:
                query(tree)