def index(input_currency, amount, output_currency=None):
error_msg = {}
########################
# input currency check #
########################
# check if input currency is in currency list
if input_currency not in CurrencyConverter.currency_code\
and input_currency not in CurrencyConverter.currency_symbol:
error_msg['input_currency'] = "please choose input currency from this list {}"\
.format(CurrencyConverter.currency_code)
################
# amount check #
################
# check if amount is float
if not amount.replace('.', '', 1).isdigit():
error_msg['amount'] = "amount should be float {}{}".format(
amount.isdigit(), amount)
else:
amount = float(amount)
#########################
# output currency check #
#########################
# check if output currency is in currency list
if output_currency and output_currency not in CurrencyConverter.currency_code\
and output_currency not in CurrencyConverter.currency_symbol:
error_msg['output_currency'] = "please choose output currency from this list {}"\
.format(CurrencyConverter.currency_code)
# return error message if input is invalid
if len(error_msg) > 0:
return jsonify({'Error': error_msg})
else:
# get currency rate
rates = CurrencyConverter.get_rates(input_currency, output_currency)
# generate output dictionary
results = CurrencyConverter.generate_results(amount, rates)
# output result in json
return jsonify(results)
else:
amount = float(args.amount)
########################################
# validation check for output currency #
########################################
# check if output currency is in currency list
if args.output_currency and args.output_currency not in CurrencyConverter.currency_code\
and args.output_currency not in CurrencyConverter.currency_symbol:
error_msg += "\n--output_currency: please choose output currency from this list {}"\
.format(CurrencyConverter.currency_code)
else:
# convert output currency to code if output currency is symbol
output_currency = CurrencyConverter.currency_symbol[args.output_currency]\
if args.output_currency in CurrencyConverter.currency_symbol else args.output_currency
######################################
# interrupt if there is invalid input #
######################################
if error_msg is not "":
parser.error(error_msg)
# get currency rate
rates = CurrencyConverter.get_rates(input_currency, output_currency)
# generate output dictionary
generated_results = CurrencyConverter.generate_results(amount, rates)
# output result in json
print(json.dumps(generated_results))
