First part of a massive refactoring. Also Configuration class that'll be used to store a default currency in a config file was added.

piggybank/__init__.py

@@ -1,8 +1,8 @@
-__date__ = "29 December 2019"
+__date__ = "4 June 2020"
 __version__ = "1.0.0"
 __author__ = "Alexander \"Arav\" Andreev"
-__email__ = "me@aravs.ru"
+__email__ = "me@arav.top"
-__copyright__ = f"Copyright (c) 2019 {__author__} <{__email__}>"
+__copyright__ = f"Copyright (c) 2020 {__author__} <{__email__}>"
 __license__ = \
 """This program is free software. It comes without any warranty, to
 the extent permitted by applicable law. You can redistribute it
@@ -12,7 +12,6 @@ http://www.wtfpl.net/ for more details."""
 
 
 PIGGYBANK_FILE_EXTENSION = ".pb"
-PIGGYBANK_CONFIGURATION_FILE = "piggybank.conf"
 
 
 def print_program_version() -> None:

piggybank/configuration.py

@@ -0,0 +1,50 @@
+"""An implementation of a simple key=value configuration."""
+
+from os import getenv
+from os.path import exists, join
+from platform import system
+from typing import Union
+
+__all__ = ["Configuration", "get_configuration_path"]
+
+
+DEFAULT_CONFIGURATION = {
+    "default-currency": "SRUB"
+}
+DEFAULT_CONFIGURATION_FILE = join(get_configuration_path(), "piggybank.conf")
+
+
+def get_configuration_path():
+    if system() == "Linux":
+        return getenv("XDG_CONFIG_HOME") or f"{getenv('HOME')}/.config"
+    elif system() == "Windows":
+        return getenv("APPDATA")
+
+
+class Configuration:
+    def __init__(self, configuration_file: str = DEFAULT_CONFIGURATION_FILE,
+                 default_configuration: dict = DEFAULT_CONFIGURATION) -> None:
+        self._configuration_file = configuration_file
+        self._configuration = dict()
+
+        if exists(self._configuration_file):
+            self.load()
+        elif not default_configuration is None:
+            self._configuration = default_configuration
+            self.save()
+
+    def load(self) -> None:
+        for line in open(self._configuration_file, 'r'):
+            key, value = line.split(" = ")
+            self._configuration[key] = value
+
+    def save(self) -> None:
+        with open(self._configuration_file, 'w') as cf:
+            for key, value in self._configuration.items():
+                cf.write(f"{key} = {value}\n")
+
+    def __getitem__(self, key: str) -> Union[int, str, bool]:
+        return self._configuration[key]
+
+    def __setitem__(self, key: str, value: Union[int, str, bool]) -> None:
+        self._configuration[key] = value

piggybank/piggybank.py

@@ -5,105 +5,52 @@ from os.path import exists
 from typing import List
 
 from piggybank import PIGGYBANK_FILE_EXTENSION
-from piggybank.currencies import CURRENCIES, DEFAULT_CURRENCY, \
+from piggybank.currencies import CURRENCIES, \
     CurrencyIsNotSupportedError, CurrenciesCoinCountMismatchError, \
     CurrencyMismatchError
-from piggybank.transaction import Transaction, TYPE_INCOME
+from piggybank.transaction import Transaction, sum_transactions, TYPE_INCOME
 
 __all__ = ["PiggyBank"]
 
 
 class PiggyBank:
     """This class stores array of transactions and perform some actions on it."""
-    def __init__(self, currency: str = DEFAULT_CURRENCY) -> None:
+    def __init__(self, currency: str = None) -> None:
-        if currency.upper() in CURRENCIES:
+        if not currency is None:
-            self._currency = currency.upper()
+            self.currency = currency
-        else:
-            raise CurrencyIsNotSupportedError
-
         self._transactions = []
+        self._last_transaction = None
 
     def transact(self, coins: List[int], direction: str = TYPE_INCOME) -> None:
         """Make a transaction."""
-        if len(coins) != CURRENCIES[self.currency]["count"]:
+        if len(coins) != CURRENCIES[self._currency]["count"]:
-            raise ValueError("Length of passed coins list doesn't match the "
+            raise ValueError("Length of passed coins list doesn't match the " \
-                             f"currency's coins count. ({len(coins)} "
+                             f"currency's coins count. ({len(coins)} " \
-                             f"!= {CURRENCIES[self.currency]['count']})")
+                             f"!= {CURRENCIES[self._currency]['count']})")
-
+        self._last_transaction = Transaction(coins, direction)
-        self._transactions.append(Transaction(coins, direction))
+        self._transactions.append(self._last_transaction)
-
+        for coin_count in sum_transactions(self._transactions):
-        for coin_count in self.count:
             if coin_count < 0:
                 del self._transactions[-1]
+                self._last_transaction = None
                 raise ValueError(
                     "You can't take out more than you have.")
 
-    @property
-    def count(self) -> List[int]:
-        """Returns a list of counts for each face value in total."""
-        count = [0] * CURRENCIES[self.currency]["count"]
-        for tr in self.transactions:
-            count = [x + y if tr.direction == TYPE_INCOME
-                     else x - y for x, y in zip(count, tr.coins)]
-        return count
-
-    @property
-    def sum(self) -> List[int]:
-        """Returns a list of sums for each face value multiplied by its
-        currency's multipilers."""
-        return [x * y for x, y
-                in zip(self.count, CURRENCIES[self.currency]["multipliers"])]
-
-    @property
-    def total(self) -> int:
-        """Returns a total amount of money stored in a PiggyBank."""
-        return sum(self.sum)
-
-    @staticmethod
-    def from_file(filename: str) -> PiggyBank:
-        """Returns a PiggyBank object loaded from a file with name
-        `filename`."""
-        piggybank = PiggyBank()
-        piggybank.load(filename)
-        return piggybank
-
-    def save(self, filename: str) -> None:
-        """Writes a PiggyBank object to a file with name `filename`."""
-        if not filename.endswith(PIGGYBANK_FILE_EXTENSION):
-            filename += PIGGYBANK_FILE_EXTENSION
-        with open(filename, 'w') as _file:
-            _file.write(f"{self.currency}\n")
-            for transaction in self.transactions:
-                _file.write(f"{str(transaction)}\n")
-
-    def load(self, filename: str) -> None:
-        """Loads a PiggyBank from a file with name `filename`."""
-        if not filename.endswith(PIGGYBANK_FILE_EXTENSION):
-            filename += PIGGYBANK_FILE_EXTENSION
-        if not exists(filename):
-            raise FileNotFoundError(filename)
-        with open(filename, 'r') as _file:
-            currency = _file.readline()[:-1]
-            if currency not in CURRENCIES:
-                raise CurrencyIsNotSupportedError
-            else:
-                self.currency = currency
-            for transaction in _file:
-                self._transactions.append(Transaction.from_string(transaction))
-
     @property
     def currency(self) -> str:
         """Returns a currency of a PiggyBank."""
         return self._currency
 
     @currency.setter
-    def currency(self, currency: str) -> None:
+    def currency(self, currency: str = None) -> None:
         """Sets a currency of a PiggyBank with check for support. And if count
         of coins doesn't match the old currency it won't set a new one."""
         currency = currency.upper()
-        if currency not in CURRENCIES:
+        if not currency in CURRENCIES:
             raise CurrencyIsNotSupportedError
-        if CURRENCIES[currency]["count"] != CURRENCIES[self.currency]["count"]:
+        if not self._currency is None and \
+            CURRENCIES[currency]["count"] \
+            != CURRENCIES[self._currency]["count"]:
             raise CurrenciesCoinCountMismatchError
         self._currency = currency
 
@@ -112,13 +59,49 @@ class PiggyBank:
         """Returns a list of transactions."""
         return self._transactions
 
+    @staticmethod
+    def from_file(filename: str) -> PiggyBank:
+        """Returns a PiggyBank object loaded from a file."""
+        piggybank = PiggyBank()
+        piggybank.load(filename)
+        return piggybank
+
+    def save(self, filename: str) -> None:
+        """Appends last successful transaction to a file. File will be created
+        if not exist yet."""
+        if self._last_transaction is None:
+            raise ValueError("No successful transaction found.")
+        if not filename.endswith(PIGGYBANK_FILE_EXTENSION):
+            filename += PIGGYBANK_FILE_EXTENSION
+        if not exists(filename):
+            with open(filename, 'w') as pbf:
+                pbf.write(f"{self.currency}\n{self._last_transaction}\n")
+        else:
+            with open(filename, 'a') as pbf:
+                pbf.write(f"{self._last_transaction}\n")
+
+    def load(self, filename: str) -> None:
+        """Loads a PiggyBank from a file."""
+        if not filename.endswith(PIGGYBANK_FILE_EXTENSION):
+            filename += PIGGYBANK_FILE_EXTENSION
+        if not exists(filename):
+            raise FileNotFoundError(filename)
+        with open(filename, 'r') as pbf:
+            currency = pbf.readline()[:-1]
+            if currency not in CURRENCIES:
+                raise CurrencyIsNotSupportedError
+            else:
+                self._currency = currency
+            for line in pbf:
+                self._transactions.append(Transaction.from_string(line))
+
     def __eq__(self, piggybank: PiggyBank) -> str:
-        """It compares only currency."""
+        """Compares only currency."""
-        return self.currency == piggybank._currency
+        return self._currency == piggybank.currency
 
     def __add__(self, piggybank: PiggyBank) -> PiggyBank:
         if self != piggybank:
             raise CurrencyMismatchError
-        new = PiggyBank(self.currency)
+        new = PiggyBank(self._currency)
-        new._transactions = self.transactions + piggybank._transactions
+        new._transactions = self._transactions + piggybank._transactions
         return new

piggybank/transaction.py

@@ -1,18 +1,44 @@
 """Transaction class implementation."""
 
 from __future__ import annotations
+from operator import add, sub, mul
 from time import strftime, strptime, gmtime
-from typing import Optional, List
+from typing import Optional, List, Union
 
-__all__ = ["Transaction", "TYPE_INCOME", "TYPE_OUTCOME", "TIME_FORMAT"]
+from piggybank.currencies import CURRENCIES
 
-TYPE_INCOME = "in"
+__all__ = ["Transaction", "sum_transactions", "multiply_transactions",
-TYPE_OUTCOME = "out"
+           "TYPE_INCOME", "TYPE_OUTCOME", "TIME_FORMAT"]
+
+TYPE_INCOME = "i"
+TYPE_OUTCOME = "o"
 TIME_FORMAT = "%Y-%m-%dT%H:%M:%S"
 
 
+def sum_transactions(transactions: List[Transaction]) -> List[int]:
+    """Sums all the coins and returns resulting list. All transactions must have
+    same length of coins' list."""
+    coins = [0] * len(transactions[0].coins)
+    for transaction in transactions:
+        if transaction.direction == TYPE_INCOME:
+            coins = list(map(add, transaction.coins, coins))
+        else:
+            coins = list(map(sub, transaction.coins, coins))
+    return coins
+
+def multiply_transactions(transactions: Union[List[Transaction], Transaction],
+                          currency: str) -> List[int]:
+    """Multiplies coins' counts by currency."""
+    if type(transactions) is Transaction:
+        return list(map(mul, transactions.coins, \
+            CURRENCIES[currency]["multipliers"]))
+    else:
+        coins = sum_transactions(transactions)
+        return list(map(mul, coins, CURRENCIES[currency]["multipliers"]))
+
+
 class Transaction:
-    """An object that holds a transaction.
+    """An object that holds a single transaction.
 
     Arguments:
         - coins     -- a list of numbers represent count for each face value;
@@ -22,33 +48,55 @@ class Transaction:
     def __init__(self, coins: List[int], direction: str = TYPE_INCOME,
                  timestamp: Optional[str] = None) -> None:
         self.coins = coins
-        if direction in [TYPE_INCOME, TYPE_OUTCOME]:
         self.direction = direction
+        self.timestamp = timestamp
+
+    @property
+    def coins(self) -> List[int]:
+        return self._coins
+
+    @coins.setter
+    def coins(self, coins: List[int]) -> None:
+        if coins is list:
+            self._coins = coins
         else:
-            raise ValueError(f"Direction may only be"
+            raise TypeError("Coins must be of type 'list'.")
-                             f"'{TYPE_INCOME}' or '{TYPE_OUTCOME}'")
+
+    @property
+    def direction(self) -> str:
+        return self._direction
+
+    @direction.setter
+    def direction(self, direction: str = TYPE_INCOME) -> None:
+        if direction in [TYPE_INCOME, TYPE_OUTCOME]:
+            self._direction = direction
+        else:
+            raise ValueError("Direction may only be of TYPE_INCOME(\"i\") " \
+                             "or TYPE_OUTCOME(\"o\").")
+
+    @property
+    def timestamp(self) -> str:
+        return self._timestamp
+
+    @timestamp.setter
+    def timestamp(self, timestamp: str = None) -> None:
         if timestamp is None:
-            self.timestamp = strftime(TIME_FORMAT, gmtime())
+            self._timestamp = strftime(TIME_FORMAT, gmtime())
         else:
             try:
                 strptime(timestamp, TIME_FORMAT)
             except ValueError:
-                raise ValueError(f"Timestamp {timestamp} has wrong format. "
+                raise ValueError(f"Timestamp {timestamp} has wrong format. " \
-                                 f"The right one is '{TIME_FORMAT}''")
+                                 f"The right one is \"{TIME_FORMAT}\".")
-            self.timestamp = timestamp
+            self._timestamp = timestamp
 
     @staticmethod
     def from_string(transaction: str) -> Transaction:
         """Makes a Transaction object from its string output."""
         timestamp, direction, coins = transaction.split()
-
         coins = list(map(int, coins.split(",")))
         return Transaction(coins, direction, timestamp)
 
     def __str__(self) -> str:
         return f"{self.timestamp} {self.direction} " \
-            f"{','.join(str(c) for c in self.coins)}"
+            f"{','.join(map(str, self.coins))}"
-
-    def __repr__(self) -> str:
-        return f"Transaction(coins={self.coins!r}," \
-            f"direction={self.direction!r}, timestamp={self.timestamp!r})"