import logging
from datetime import datetime

from src.ez_lan_manager.services.DatabaseService import DatabaseService
from src.ez_lan_manager.types.Transaction import Transaction

logger = logging.getLogger(__name__.split(".")[-1])

class InsufficientFundsError(Exception):
    pass

class AccountingService:
    def __init__(self, db_service: DatabaseService) -> None:
        self._db_service = db_service

    async def add_balance(self, user_id: int, balance_to_add: int, reference: str) -> int:
        await self._db_service.add_transaction(Transaction(
            user_id=user_id,
            value=balance_to_add,
            is_debit=False,
            reference=reference,
            transaction_date=datetime.now()
        ))
        logger.debug(f"Added balance of {self.make_euro_string_from_int(balance_to_add)} to user with ID {user_id}")
        return await self.get_balance(user_id)

    async def remove_balance(self, user_id: int, balance_to_remove: int, reference: str) -> int:
        current_balance = await self.get_balance(user_id)
        if (current_balance - balance_to_remove) < 0:
            raise InsufficientFundsError
        await self._db_service.add_transaction(Transaction(
            user_id=user_id,
            value=balance_to_remove,
            is_debit=True,
            reference=reference,
            transaction_date=datetime.now()
        ))
        logger.debug(f"Removed balance of {self.make_euro_string_from_int(balance_to_remove)} to user with ID {user_id}")
        return await self.get_balance(user_id)

    async def get_balance(self, user_id: int) -> int:
        balance_buffer = 0
        for transaction in await self._db_service.get_all_transactions_for_user(user_id):
            if transaction.is_debit:
                balance_buffer -= transaction.value
            else:
                balance_buffer += transaction.value
        return balance_buffer

    async def get_transaction_history(self, user_id: int) -> list[Transaction]:
        return await self._db_service.get_all_transactions_for_user(user_id)

    @staticmethod
    def make_euro_string_from_int(cent_int: int) -> str:
        """ Internally, all money values are cents as ints. Only when showing them to the user we generate a string. Prevents float inaccuracy. """
        as_str = str(cent_int)
        if as_str[0] == "-":
            is_negative = True
            as_str = as_str[1:]
        else:
            is_negative = False

        if len(as_str) == 1:
            result = f"0.0{as_str} €"
        elif len(as_str) == 2:
            result = f"0.{as_str} €"
        else:
            result = f"{as_str[:-2]}.{as_str[-2:]} €"

        if is_negative:
            result = f"-{result}"

        return result