infixcalc.py

#!/usr/bin/env python3
""" Calculadora infix

Funcionamento:

[operação] [n1] [n2]

Operações: 
sum -> +
sub -> -
mul -> *
div -> /

Uso:
$ infixcalc.py sum 5 2
7

$ infixcalc.py mul 10 5
50

$ infixcalc.py 
operação: sum
n1: 5
n2: 4
9

Os resultados serão salvos em "infixcalc.log"
"""
__version__ = "0.1.0"

import os
import sys
from datetime import datetime
import logging

log_level = os.getenv("LOG_LEVEL", "WARNING").upper()
log = logging.Logger("logs.py", log_level)
ch = logging.StreamHandler()
ch.setLevel(log_level)
fmt = logging.Formatter(
    '%(asctime)s %(name)s %(levelname)s'
    'l:%(lineno)d f:%(filename)s: %(message)s'
)
ch.setFormatter(fmt)
log.addHandler(ch)

arguments = sys.argv[1:]

# validação
if not arguments:
    operation = input("operação:")
    n1 = input("n1")
    n2 = input("n2")
    arguments = [operation, n1, n2]
    
elif len(arguments) != 3:
    print("Número de argumentos inválidos")
    print("ex: 'sum 5 5'")
    sys.exit(1)

operation, *nums = arguments
valid_operations = ("sum", "sub", "mul", "div")

if operation not in valid_operations:
    print("Operação inválida")
    print(valid_operations)
    sys.exit(1)

validated_nums = []

for num in nums:
    if not num.replace(".", "").isdigit():
        print(f"Número inválido {num}")
        sys.exit(1)
    if "." in num:
        num = float(num)
    else:
        num = int(num)
    validated_nums.append(num)

try:        
    n1, n2 = validated_nums
except ValueError as e:
    print(str(e))
    sys.exit(1)
    
# TODO: Usar dicionário de funções
if operation == "sum":
    result = n1 + n2
elif operation == "sub":
    result = n1 - n2
elif operation == "mul":
    result = n1 * n2
elif operation == "div":
    result = n1 / n2

path = os.curdir
filepath = os.path.join(path, "infixcalc.log")
timestamp = datetime.now().isoformat()
user = os.getenv("USER", "anonymous")

print(f'O resultado é {result}')

try:
    with open(filepath, "a") as file_:
        file_.write(f'{timestamp} - {user} - {operation}, {n1}, {n2} = {result}\n')
except PermissionError as e:
    log.error(
        str(e)
    )
    
    sys.exit(1)