from getpass import getpass
from robobrowser import RoboBrowser
from re import compile

url = 'https://galilei-cr-sito.registroelettronico.com/'
url_main = url + 'news'
url_login = url + 'login'
url_marks = url + 'votes/?s='

subjects = {}
br = RoboBrowser(history=False)


def login(user, password):
    '''Authenticate the user'''
    br.open(url_login)

    # Fill in the login form
    form = br.get_form(id='loginform')
    form['username'].value = user
    form['password'].value = password
    br.submit_form(form)

    # Check if authenticated
    if 'errati' in br.response.text:
        return False
    return True


def means():
    '''Compute mean for each subject'''
    for i in subjects.keys():
        yield _mean(list(get_marks(i)))


def get_name():
    '''Find the student's name from the registry'''
    br.open(url_main)

    # Get the content of 'h2' tag with ID 'student_name'
    name = br.select('h2#student_name')[0].text.split()
    return ' '.join([name[-1]] + name[:-1])


def get_subjects():
    '''Create a reversed dictionary of type (subject, id)'''
    br.open(url_main)
    links = br.get_links(href=compile('votes/\?s=\d+'))
    return {i.text.capitalize(): i.attrs['href'][-7:] for i in links}


def get_marks(subject):
    '''Returned the list of marks for a subject'''
    br.open(url_marks + str(subjects[subject]))
    res = br.find_all(text=compile(r'^(\d{1,2}(\+|-|\.\d{1,2})?) '))
    return _parse(i[0:-1] for i in res)


def _parse(marks):
    '''
    Parse marks into floats:
      NC -> 0
      A  -> nothing
      n+ -> n + 0.25
      n- -> n - 0.25
      n  -> n
    '''
    for i in marks:
        try:
            yield float(i)
        except ValueError:
            if i == 'A':
                pass
            elif i == 'NC':
                yield 0
            elif i[1] == '+':
                yield float(i[0]) + 0.25
            elif i[1] == '-':
                yield float(i[0]) - 0.25
            elif i[2] == '-':
                yield float(i[:-1]) - 0.25


def _mean(marks):
    '''Mean of a list of marks'''
    marks = list(marks)
    return sum(marks) / len(marks)


def _show_means():
    '''Show general mean and for each subject [Procedure]'''
    # Print id, subject, mean for every subject
    print('Media generale: %.2f' % _mean(means()))
    for id, (subject, voto) in enumerate(zip(subjects.keys(), means())):
        print('%d. %s: %.2f' % (id + 1, subject, voto))


def _show_marks():
    '''Prompt for a subject and show the marks [Procedure]'''
    for i, subject in enumerate(subjects.keys()):
        print('%d. %s' % (i + 1, subject))
    while True:
        print('')
        id = int(input('Materia: '))
        if id in range(15):
            name = list(subjects.keys())[id - 1]
            print(name)
            print('Voti:', *get_marks(name))
            print('Media: %.2f' % _mean(get_marks(name)))
        else:
            print('Inserire numero corretto!')


def main():
    # Authentication
    logged = False
    while not logged:
        user, password = input('Username: '), getpass('Password: ')
        logged = login(user, password)
        if not logged:
            print('Autenticazione fallita, riprovare.')
    print('Connesso come %s.\n' % get_name())

    # So we don't need to recompute every time
    global subjects
    subjects = get_subjects()

    # Menu
    while True:
        mode = input('Scegli [v]oti o [m]edie: ')
        print('')
        if mode == 'v':
            _show_marks()
        elif mode == 'm':
            _show_means()
        input()

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        print('')