from otree.api import *
import string
import numpy as np
import random
c = cu


doc = 'Payment processing'


class Constants(BaseConstants):

    name_in_url = 'payment'

    players_per_group = None

    num_rounds=1

    
    LETTERS_DICT={}

    #generates dictionary to translate letters (from ascii values) into numerical values according to IBAN verification algorithm (A=10, ...)
    for i,d in enumerate(string.digits + string.ascii_uppercase):
        LETTERS_DICT[ord(d)] = str(i)

    
    choice_set=[]

    for i in string.digits:
        choice_set.append(ord(i))
    for i in range(ord('A'), ord('Z')+1):
        choice_set.append(i)


def generate_random_id():
    '''Generates a random (non-secure) identifier out of uppercase latters and numbers'''

    random_string = ''
 
    for i in range(10):
        random_char = random.choice(Constants.choice_set)
        # Keep appending random characters using chr(x)
        random_string += (chr(random_char))

    return random_string

class Subsession(BaseSubsession):
    pass


def creating_session(subsession):
    for players in subsession.get_players():
        players.payout_id = generate_random_id()

class Group(BaseGroup):
    pass


class Player(BasePlayer):

    payout_id = models.StringField(initial='') #for reference in case participant needs to contact experimenters
    iban_number = models.StringField(label='IBAN (account number)')
    iban_name = models.StringField(label='Name of account holder')



class Payment(Page):
    #payment details page
    form_model = 'player'
    form_fields=['iban_number', 'iban_name']

    @staticmethod
    def error_message(player, values):
        if check_iban(values['iban_number']) !=1:
            return 'IBAN invalid - please check your account number'

    @staticmethod
    def before_next_page(player, timeout_happened):
        player.iban_number = ''.join(player.iban_number.split())
        player.iban_number = player.iban_number.upper()


class Thanks(Page):
    #final summary page
    form_model = 'player'



def iban_letter_replacement(iban_string):
    '''Replaces letters in a string with numerical values defined in LETTERS_DICT'''
    iban_numeric = iban_string.translate(Constants.LETTERS_DICT)

    return iban_numeric


def iban_valid(iban_string):
    '''IBAN mod 97 verification check, returns TRUE if IBAN valid according to this check'''
    inverted_iban = iban_string[4:] + iban_string[:4]
    inverted_numeric = int(iban_letter_replacement(inverted_iban))
    return (inverted_numeric % 97) ==1


def iban_char_verify(iban_string):
    '''Generates IBAN verification characters and compares them with the given ones, returns TRUE if identical'''
    iban_nc =  iban_string[4:] + iban_string[:2] + '00' 

    iban_nc_inv_num = int(iban_letter_replacement(iban_nc))

    return '{:02}'.format(98 - iban_nc_inv_num % 97)==iban_string[2:4]
    

def check_iban(iban_string):
    '''Verfies IBAN validity with mod97 check as well as the verification characters'''

    iban_string = iban_string.upper()
    iban_string = ''.join(iban_string.split()) #removes all type of whitespaces

    try:
        return iban_char_verify(iban_string) and iban_valid(iban_string)
    except:
        return False
    

page_sequence = [Payment, Thanks]