from decimal import Decimal as D

from core.exchanges import GenericAPIError
from core.lib.elastic import store_msg
from core.util import logs

log = logs.get_logger(__name__)


def get_balance_hook(user_id, user_name, account_id, account_name, balance):
    """
    Called every time the balance is fetched on an account.
    Store this into Elasticsearch.
    """
    store_msg(
        "balances",
        {
            "user_id": user_id,
            "user_name": user_name,
            "account_id": account_id,
            "account_name": account_name,
            "balance": balance,
        },
    )


def get_pair(account, base, quote, invert=False):
    """
    Get the pair for the given account and currencies.
    :param account: Account object
    :param base: Base currency
    :param quote: Quote currency
    :param invert: Invert the pair
    :return: currency symbol, e.g. BTC_USD, BTC/USD, etc.
    """
    # Currently we only have two exchanges with different pair separators
    if account.exchange == "alpaca":
        separator = "/"
    elif account.exchange == "oanda":
        separator = "_"

    # Flip the pair if needed
    if invert:
        symbol = f"{quote.upper()}{separator}{base.upper()}"
    else:
        symbol = f"{base.upper()}{separator}{quote.upper()}"
    # Check it exists
    if symbol not in account.supported_symbols:
        return False
    return symbol


def to_currency(direction, account, amount, from_currency, to_currency):
    """
    Convert an amount from one currency to another.
    :param direction: Direction of the trade
    :param account: Account object
    :param amount: Amount to convert
    :param from_currency: Currency to convert from
    :param to_currency: Currency to convert to
    :return: Converted amount
    """
    # If we're converting to the same currency, just return the amount
    if from_currency == to_currency:
        return amount
    inverted = False

    # This is needed because OANDA has different values for bid and ask
    if direction == "buy":
        price_index = "bids"
    elif direction == "sell":
        price_index = "asks"
    symbol = get_pair(account, from_currency, to_currency)
    if not symbol:
        symbol = get_pair(account, from_currency, to_currency, invert=True)
        inverted = True

        # Bit of a hack but it works
        if not symbol:
            log.error(f"Could not find symbol for {from_currency} -> {to_currency}")
            raise Exception("Could not find symbol")
    try:
        prices = account.client.get_currencies([symbol])
    except GenericAPIError as e:
        log.error(f"Error getting currencies and inverted currencies: {e}")
        return None
    price = D(prices["prices"][0][price_index][0]["price"])

    # If we had to flip base and quote, we need to use the reciprocal of the price
    if inverted:
        price = D(1.0) / price

    # Convert the amount to the destination currency
    converted = D(amount) * price

    return converted