from string import ascii_lowercase
from string import ascii_uppercase
from numbers import Number
from sys import stdin
import unittest


class Node:
    def __init__(self, next, newnode):
        self.next = next
        self.newnode = newnode


class LinkedQ:
    def __init__(self):
        self._first = None
        self._last = None

    def enqueue(self, value):  # lägger till element i slutet av listan
        newn = Node(None, value)
        if self._first is None:
            self._first = newn
            self._last = newn
        else:
            self._last.next = newn
            self._last = newn

    def dequeue(self):  # plockar ut och returnerar första elementet

        if self._first is None:
            return None
        else:
            value = self._first.newnode
            self._first = self._first.next
            return value

    def peek(self):
        if not self._first:
            return
        return self._first.newnode

    def isEmpty(self):
        if self._first is None:  # kollar om listan är tom eller inte
            return True
        else:
            return False
            # def __str__(self):
            # return self


atomer = ['H', 'He', 'Li', 'Be', 'B', 'C', 'N', 'O', 'F', 'Ne', 'Na', 'Mg', 'Al', 'Si', 'P', 'S', 'Cl', 'Ar', 'K', 'Ca',
          'Sc', 'Ti', 'V', 'Cr', 'Mn', 'Fe', 'Co', 'Ni', 'Cu', 'Zn', 'Ga', 'Ge', 'As', 'Se', 'Br', 'Kr', 'Rb', 'Sr',
          'Y', 'Zr', 'Nb', 'Mo', 'Tc', 'Ru', 'Rh', 'Pd', 'Ag', 'Cd', 'In', 'Sn', 'Sb', 'Te', 'I', 'Xe', 'Cs', 'Ba',
          'La', 'Ce', 'Pr', 'Nd', 'Pm', 'Sm', 'Eu', 'Gd', 'Tb', 'Dy', 'Ho', 'Er', 'Tm', 'Yb', 'Lu', 'Hf', 'Ta', 'W',
          'Re', 'Os', 'Ir', 'Pt', 'Au', 'Hg', 'Tl', 'Pb', 'Bi', 'Po', 'At', 'Rn', 'Fr', 'Ra', 'Ac', 'Th', 'Pa', 'U',
          'Np', 'Pu', 'Am', 'Cm', 'Bk', 'Cf', 'Es', 'Fm', 'Md', 'No', 'Lr', 'Rf', 'Db', 'Sg', 'Bh', 'Hs', 'Mt', 'Ds',
          'Rg', 'Cn', 'Fl', 'Lv']


# Syntaxkontroll


class Syntaxfel(Exception):
    pass


gemener = list(ascii_lowercase)
versaler = list(ascii_uppercase)
lista1 = "0 1 2 3 4 5 6 7 8 9".split()
lista2 = "1 2 3 4 5 6 7 8 9".split()
lista3 = "2 3 4 5 6 7 8 9".split()


def readMolekyl(q):
    return readAtom(q)


def readAtom(q):
    return readLetter(q)


def readLetter(q):
    tecken = q.dequeue()
    if tecken == "(":
        return readAtom(q)
    if tecken in versaler:
        if tecken + q.peek() in atomer:
            q.dequeue()
            return readnum(q)
        if tecken in atomer:
            return readnum(q)
        return Syntaxfel("Okänd atom vid radslutet " + radslut(q))
    if tecken == ")":
        if q.peek() not in lista3:
            return Syntaxfel('Saknad siffra vid radslutet ' + radslut(q))
        try:
            num = int(q.dequeue())
            return readAtom(q)
        except ValueError:
            return Syntaxfel('Saknad siffra vid radslutet ' + radslut(q))
    if not tecken:
        return
    if tecken in gemener:
        return Syntaxfel("Saknad stor bokstav vid radslutet " + radslut(q))
    return Syntaxfel('Felaktig gruppstart vid radslutet ' + radslut(q))

def readnum(q):
    if q.isEmpty():
        return
    try:
        num = int(q.dequeue())
    except ValueError:
        return readAtom(q)
    if num == 1 and not q.peek() or num < 1:
        return Syntaxfel('För litet tal vid radslutet ' + radslut(q))

    else:
        while not q.isEmpty():
            num = q.dequeue()
            try:
                if int(num) < 0:
                    return Syntaxfel('För litet tal vid radslutet ' + radslut(q))
            except ValueError:
                return readAtom(q)

def printQueue(q):
    while not q.isEmpty():
        word = q.dequeue()
        print(word, end=" ")
    print()
def radslut(q):
    q.dequeue()
    word = ''
    while not q.isEmpty():
        word += q.dequeue()
    return str(word)


def storeSentence(mening):
    q = LinkedQ()
    mening = list(mening)
    for ordet in mening:
        q.enqueue(ordet)
    return q


def kollaMolekylen(mening):
    q = storeSentence(mening)
    return readMolekyl(q)




def main():
    #meningar = ["C(Xx4)5", "C(OH4)C", "C(OH4C", "H2O)Fe", "H0", "H1C", "H02C", "Nacl" "a", "(Cl)2)3)2"]
    #for mening in meningar:
    mening = "C(OH4C"
    syntaxfel = kollaMolekylen(mening)
    if not syntaxfel:
        print('Formeln är syntaktiskt korrekt')
    else:
        print(syntaxfel)



main()


if __name__ == "__main__":
   unittest.main()


class Test(unittest.TestCase):
   def test_kollaMolekylen1(self):
       self.assertIsNone(kollaMolekylen('Na'))
       self.assertIsNone(kollaMolekylen('H2O'))
       self.assertIsNone(kollaMolekylen('Si(C3(COOH)2)4(H2O)7'))
       self.assertIsNone(kollaMolekylen('Na332'))

   def test_kollaMolekylen2(self):
       with self.assertRaises(Syntaxfel):
           kollaMolekylen('C(Xx4)5')
       with self.assertRaises(Syntaxfel):
           kollaMolekylen('C(OH4)C')
       with self.assertRaises(Syntaxfel):
           kollaMolekylen('C(OH4C')
       with self.assertRaises(Syntaxfel):
           kollaMolekylen('H2O)Fe')
       with self.assertRaises(Syntaxfel):
           kollaMolekylen('H0')
       with self.assertRaises(Syntaxfel):
           kollaMolekylen('H1C')
       with self.assertRaises(Syntaxfel):
           kollaMolekylen('H02C')
       with self.assertRaises(Syntaxfel):
           kollaMolekylen('Nacl')
       with self.assertRaises(Syntaxfel):
           kollaMolekylen('a')
       with self.assertRaises(Syntaxfel):
           kollaMolekylen('(Cl)2)3')
       with self.assertRaises(Syntaxfel):
           kollaMolekylen(')')
       with self.assertRaises(Syntaxfel):
           kollaMolekylen('2')