95 lines
3.6 KiB
Python
95 lines
3.6 KiB
Python
"""PiggyBank implementation."""
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from __future__ import annotations
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from os.path import exists
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from typing import List
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from piggybank import PIGGYBANK_FILE_EXTENSION, CURRENCIES
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from piggybank.currency import CurrencyIsNotSupportedError
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from piggybank.transaction import Transaction, sum_transactions, TYPE_INCOME
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__all__ = ["PiggyBank"]
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class PiggyBank:
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"""This class stores array of transactions and perform some actions on it."""
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def __init__(self, currency: str = None) -> None:
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self._currency = None
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if not currency is None:
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self.currency = currency
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self._transactions = []
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self._last_transaction = None
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def transact(self, coins: List[int], direction: str = TYPE_INCOME) -> None:
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"""Make a transaction."""
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if len(coins) != len(CURRENCIES[self._currency]):
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raise ValueError("Length of passed coins list doesn't match the " \
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f"currency's coins count. ({len(coins)} " \
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f"!= {len(CURRENCIES[self._currency])})")
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self._last_transaction = Transaction(coins, direction)
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self._transactions.append(self._last_transaction)
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for coin_count in sum_transactions(self._transactions):
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if coin_count < 0:
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del self._transactions[-1]
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self._last_transaction = None
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raise ValueError(
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"You can't take out more than you have.")
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@property
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def currency(self) -> str:
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"""Returns a currency of a PiggyBank."""
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return self._currency
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@currency.setter
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def currency(self, currency: str) -> None:
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"""Sets a currency of a PiggyBank with check for support."""
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currency = currency.upper()
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if not currency in CURRENCIES.keys():
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raise CurrencyIsNotSupportedError
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self._currency = currency
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@property
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def transactions(self) -> List[Transaction]:
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"""Returns a list of transactions."""
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return self._transactions
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@staticmethod
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def from_file(filename: str) -> PiggyBank:
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"""Returns a PiggyBank object loaded from a file."""
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piggybank = PiggyBank()
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piggybank.load(filename)
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return piggybank
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def save(self, filename: str) -> None:
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"""Appends last successful transaction to a file. File will be created
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if not exist yet."""
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if self._last_transaction is None:
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raise ValueError("No successful transaction found.")
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if not filename.endswith(PIGGYBANK_FILE_EXTENSION):
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filename += PIGGYBANK_FILE_EXTENSION
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if not exists(filename):
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with open(filename, 'w') as pbf:
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pbf.write(f"{self.currency}\n{self._last_transaction}\n")
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else:
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with open(filename, 'a') as pbf:
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pbf.write(f"{self._last_transaction}\n")
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def load(self, filename: str) -> None:
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"""Loads a PiggyBank from a file."""
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if not filename.endswith(PIGGYBANK_FILE_EXTENSION):
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filename += PIGGYBANK_FILE_EXTENSION
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if not exists(filename):
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raise FileNotFoundError(filename)
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with open(filename, 'r') as pbf:
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currency = pbf.readline()[:-1]
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if currency not in CURRENCIES:
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raise CurrencyIsNotSupportedError
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else:
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self._currency = currency
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for line in pbf:
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self._transactions.append(Transaction.from_string(line))
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def __eq__(self, piggybank: PiggyBank) -> str:
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"""Compares only currency."""
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return self._currency == piggybank.currency
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