from datetime import datetime
from decimal import Decimal as D

from core.exchanges import common
from core.exchanges.convert import get_price, side_to_direction
from core.lib.notify import sendmsg
from core.models import Account, Strategy, Trade
from core.trading import assetfilter, checks
from core.trading.crossfilter import crossfilter
from core.trading.risk import check_risk
from core.util import logs

log = logs.get_logger(__name__)


def convert_trades_to_usd(account, trades):
    """
    Convert a list of trades to USD. Input will also be mutated.
    :param account: Account object
    :param trades: List of trades
    :return: List of trades, with amount_usd added
    """
    for trade in trades:
        amount = trade["amount"]
        symbol = trade["symbol"]
        side = trade["side"]
        direction = side_to_direction(side)
        base, quote = get_base_quote(account.exchange, symbol)
        amount_usd = common.to_currency(direction, account, amount, base, "USD")
        trade["trade_amount_usd"] = amount_usd
        if "stop_loss_percent" in trade:
            trade["stop_loss_usd"] = (trade["stop_loss_percent"] / 100) * amount_usd
        if "take_profit_percent" in trade:
            trade["take_profit_usd"] = (trade["take_profit_percent"] / 100) * amount_usd
        if "trailing_stop_loss_percent" in trade:
            trade["trailing_stop_loss_usd"] = (
                trade["trailing_stop_loss_percent"] / 100
            ) * amount_usd

    return trades


def get_base_quote(exchange, symbol):
    """
    Get the base and quote currencies from a symbol.
    :param exchange: Exchange name
    :param symbol: Symbol
    :return: Tuple of base and quote currencies
    """
    if exchange == "alpaca":
        separator = "/"
    elif exchange == "oanda":
        separator = "_"
    base, quote = symbol.split(separator)
    return (base, quote)


def get_trade_size_in_base(direction, account, strategy, cash_balance, base):
    """
    Get the trade size in the base currency.
    :param direction: Direction of the trade
    :param account: Account object
    :param strategy: Strategy object
    :param cash_balance: Cash balance in the Account's base currency
    :param base: Base currency
    :return: Trade size in the base currency
    """

    # Convert the trade size in percent to a ratio
    trade_size_as_ratio = D(strategy.order_settings.trade_size_percent) / D(100)
    log.debug(f"Trade size as ratio: {trade_size_as_ratio}")

    # Multiply with cash balance to get the trade size in the account's
    # base currency
    amount_fiat = D(trade_size_as_ratio) * D(cash_balance)
    log.debug(f"Trade size: {amount_fiat}")

    # Convert the trade size to the base currency
    if account.currency.lower() == base.lower():
        trade_size_in_base = amount_fiat
    else:
        trade_size_in_base = common.to_currency(
            direction, account, amount_fiat, account.currency, base
        )
    log.debug(f"Trade size in base: {trade_size_in_base}")

    return trade_size_in_base


def get_tp(direction, take_profit_percent, price):
    """
    Get the take profit price.
    :param direction: Direction of the trade
    :param strategy: Strategy object
    :param price: Entry price
    """
    # Convert to ratio
    take_profit_as_ratio = D(take_profit_percent) / D(100)
    log.debug(f"Take profit as ratio: {take_profit_as_ratio}")

    take_profit_var = D(price) * D(take_profit_as_ratio)
    log.debug(f"Take profit var: {take_profit_var}")

    if direction == "buy":
        take_profit = D(price) + D(take_profit_var)
    elif direction == "sell":
        take_profit = D(price) - D(take_profit_var)

    log.debug(f"Take profit: {take_profit}")
    return take_profit


def get_sl(direction, stop_loss_percent, price, return_var=False):
    """
    Get the stop loss price.
    Also used for trailing stop loss.
    :param direction: Direction of the trade
    :param strategy: Strategy object
    :param price: Entry price
    """
    # Convert to ratio
    stop_loss_as_ratio = D(stop_loss_percent) / D(100)
    log.debug(f"Stop loss as ratio: {stop_loss_as_ratio}")

    stop_loss_var = D(price) * D(stop_loss_as_ratio)
    log.debug(f"Stop loss var: {stop_loss_var}")

    if return_var:
        return stop_loss_var

    if direction == "buy":
        stop_loss = D(price) - D(stop_loss_var)
    elif direction == "sell":
        stop_loss = D(price) + D(stop_loss_var)

    log.debug(f"Stop loss: {stop_loss}")
    return stop_loss


def get_tp_sl(direction, strategy, price, round_to=None):
    """
    Get the take profit and stop loss prices.
    :param direction: Direction of the trade
    :param strategy: Strategy object
    :param price: Price of the trade
    :return: Take profit and stop loss prices
    """
    cast = {}
    if strategy.order_settings.take_profit_percent != 0:
        cast["take_profit"] = get_tp(
            direction, strategy.order_settings.take_profit_percent, price
        )

    if strategy.order_settings.stop_loss_percent != 0:
        cast["stop_loss"] = get_sl(
            direction, strategy.order_settings.stop_loss_percent, price
        )

    # Look up the TSL if required by the strategy
    if strategy.order_settings.trailing_stop_loss_percent != 0:
        cast["trailing_stop_loss"] = get_sl(
            direction,
            strategy.order_settings.trailing_stop_loss_percent,
            price,
            return_var=True,
        )

    if round_to:
        for key in cast:
            cast[key] = float(round(cast[key], round_to))

    return cast


def get_price_bound(direction, strategy, price, current_price):
    """
    Get the price bound for a given price using the slippage from the strategy.
    * Check that the price of the callback is within the callback price deviation of the
    current price
    * Calculate the price bounds such that the maximum slippage should be within the
    price slippage relative to the current price.
    Note that the maximum actual slippage may be as high as the sum of these two values.
    :param direction: Direction of the trade
    :param strategy: Strategy object
    :param price: Price of the trade
    :param current_price: current price from the exchange
    :return: Price bound
    """

    # Convert the callback price deviation to a ratio
    if strategy.risk_model is not None:
        callback_price_deviation_as_ratio = D(
            strategy.risk_model.callback_price_deviation_percent
        ) / D(100)
    else:
        callback_price_deviation_as_ratio = D(0.5) / D(100)
    log.debug(f"Callback price deviation as ratio: {callback_price_deviation_as_ratio}")

    maximum_price_deviation = D(current_price) * D(callback_price_deviation_as_ratio)

    # Ensure the current price is within price_slippage_as_ratio of the callback price
    if abs(current_price - price) <= maximum_price_deviation:
        log.debug("Current price is within price deviation of callback price")
    else:
        log.error("Current price is not within price deviation of callback price")
        log.debug(f"Difference: {abs(current_price - price)}")
        return None

    # Convert the maximum price slippage to a ratio
    if strategy.risk_model is not None:
        price_slippage_as_ratio = D(strategy.risk_model.price_slippage_percent) / D(100)
    else:
        # Pretty liberal default
        price_slippage_as_ratio = D(2.5) / D(100)
    log.debug(f"Maximum price slippage as ratio: {price_slippage_as_ratio}")

    # Calculate the price bound by multiplying with the price
    # The price bound is the worst price we are willing to pay for the trade
    price_slippage = D(current_price) * D(price_slippage_as_ratio)
    log.debug(f"Maximum deviation from callback price: {price_slippage}")

    current_price_slippage = D(current_price) * D(price_slippage_as_ratio)
    log.debug(f"Maximum deviation from current price: {current_price_slippage}")

    # Price bound is the worst price we are willing to pay for the trade
    # For buys, a higher price is worse
    if direction == "buy":
        price_bound = D(current_price) + D(price_slippage)

    # For sells, a lower price is worse
    elif direction == "sell":
        price_bound = D(current_price) - D(price_slippage)

    log.debug(f"Price bound: {price_bound}")
    return price_bound


def get_precision(account, symbol):
    instruments = account.instruments
    if not instruments:
        log.error(f"No instruments found for {account}")
        sendmsg(account.user, f"No instruments found for {account}", title="Error")
        return (None, None)
    # Extract the information for the symbol
    instrument = account.client.extract_instrument(instruments, symbol)
    if not instrument:
        sendmsg(account.user, f"Symbol not found: {symbol}", title="Error")
        log.error(f"Symbol not found: {symbol}")
        return (None, None)
    # Get the required precision
    try:
        trade_precision = instrument["tradeUnitsPrecision"]
        display_precision = instrument["displayPrecision"]
        return (trade_precision, display_precision)
    except KeyError:
        sendmsg(
            account.user,
            f"Precision not found for {symbol} from {instrument}",
            title="Error",
        )
        log.error(f"Precision not found for {symbol} from {instrument}")
        return (None, None)


# TODO: create_trade helper
# account, strategy, base, quote, direction
# pull all data to create the trade from the strategy
# complete all crossfilter and risk management checks, etc.


def execute_strategy(callback, strategy, func):
    """
    Execute a strategy.
    :param callback: Callback object
    :param strategy: Strategy object
    """

    # Only check times for entries. We can always exit trades and set trends.
    if func == "entry":
        # Check if we can trade now!
        now_utc = datetime.utcnow()
        trading_times = strategy.trading_times.all()
        if not trading_times:
            log.error("No trading times set for strategy")
            return
        matches = [x.within_range(now_utc) for x in trading_times]
        if not any(matches):
            log.debug("Not within trading time range")
            return

    # Don't touch the account if it's disabled.
    # We still want to set trends, though.
    if func in ("entry", "exit"):
        if not strategy.account.enabled:
            log.debug("Account is disabled, exiting")
            return

    # Instruments supported by the account
    if not strategy.account.instruments:
        strategy.account.update_info()
        # Refresh account object
        strategy.account = Account.objects.get(id=strategy.account.id)

    # Shorten some hook, strategy and callback vars for convenience
    user = strategy.user
    account = strategy.account
    hook = callback.hook
    signal = callback.signal
    base = callback.base
    quote = callback.quote
    direction = signal.direction

    # Don't be silly
    if callback.exchange != account.exchange:
        log.error("Market exchange differs from account exchange.")
        sendmsg(user, "Market exchange differs from account exchange.", title="Error")
        return

    # Get the pair we are trading
    symbol = common.get_pair(account, base, quote)
    if not symbol:
        sendmsg(user, f"Symbol not supported by account: {symbol}", title="Error")
        log.error(f"Symbol not supported by account: {symbol}")
        return

    # Get the precision for the symbol
    trade_precision, display_precision = get_precision(account, symbol)
    if trade_precision is None or display_precision is None:
        # sendmsg(user, f"Precision not found for {symbol}", title="Error")
        log.error(f"Market precision not found for {symbol} from {account}")
        return

    # Round the received price to the display precision
    price = round(D(callback.price), display_precision)
    log.debug(f"Extracted price of quote: {price}")

    current_price = get_price(account, direction, symbol)
    log.debug(f"Callback price: {price}")
    log.debug(f"Current price: {current_price}")

    # Calculate price bound and round to the display precision
    price_bound = get_price_bound(direction, strategy, price, current_price)
    if not price_bound:
        return
    price_bound = round(price_bound, display_precision)

    # Callback now verified

    # Check against the asset groups
    if func == "entry" and strategy.asset_group is not None:
        allowed = assetfilter.get_allowed(strategy.asset_group, base, quote, direction)
        log.debug(f"Asset filter allowed for {strategy.asset_group}: {allowed}")
        if not allowed:
            log.debug(
                f"Denied trading {symbol} due to asset filter {strategy.asset_group}"
            )
            sendmsg(
                user,
                f"Denied trading {symbol} due to asset filter {strategy.asset_group}",
                title="Asset filter denied",
            )
            return

    if func == "exit":
        check_exit = crossfilter(account, symbol, direction, func)
        if check_exit is None:
            return
        if not check_exit:
            log.debug("Exit conditions not met.")
            return
        if check_exit["action"] == "close":
            log.debug(f"Closing position on exit signal: {symbol}")
            side = check_exit["side"]
            response = account.client.close_position(side, symbol)
            log.debug(f"Close position response: {response}")
            sendmsg(
                user,
                f"Closing {side} position on exit signal: {symbol}",
                title="Exit signal",
            )
            return

    # Set the trend
    elif func == "trend":
        if strategy.trends is None:
            strategy.trends = {}
        strategy.trends[symbol] = direction
        strategy.save()
        log.debug(f"Set trend for {symbol}: {direction}")
        return

    # Check if we are trading against the trend
    if strategy.trend_signals.exists():
        if strategy.trends is None:
            log.debug("Refusing to trade with no trend signals received")
            sendmsg(
                user,
                f"Refusing to trade {symbol} with no trend signals received",
                title="Trend not ready",
            )
            return
        if symbol not in strategy.trends:
            log.debug("Refusing to trade asset without established trend")
            sendmsg(
                user,
                f"Refusing to trade {symbol} without established trend",
                title="Trend not ready",
            )
            return
        else:
            if strategy.trends[symbol] != direction:
                log.debug("Refusing to trade against the trend")
                sendmsg(
                    user,
                    f"Refusing to trade {symbol} against the trend",
                    title="Trend rejection",
                )
                return
            else:
                log.debug(f"Trend check passed for {symbol} - {direction}")

    type = strategy.order_settings.order_type

    # Get the account's balance in the native account currency
    cash_balance = strategy.account.client.get_balance()
    log.debug(f"Cash balance: {cash_balance}")

    # Convert the trade size, which is currently in the account's base currency,
    # to the base currency of the pair we are trading
    trade_size_in_base = get_trade_size_in_base(
        direction, account, strategy, cash_balance, base
    )

    # Calculate TP/SL/TSL
    protection = get_tp_sl(
        direction, strategy, current_price, round_to=display_precision
    )
    # protection_cast = {}
    # if "sl" in protection:
    #     protection_cast["stop_loss"] = float(round(protect
    # ion["sl"], display_precision))
    # if "tp" in protection:
    #     protection_cast["take_profit"] = float(
    #         round(protection["tp"], display_precision)
    #     )
    # if "tsl" in protection:
    #     protection_cast["trailing_stop_loss"] = float(
    #         round(protection["tsl"], display_precision)
    #     )

    # Create object, note that the amount is rounded to the trade precision
    amount_rounded = float(round(trade_size_in_base, trade_precision))
    new_trade = Trade.objects.create(
        user=user,
        account=account,
        hook=hook,
        signal=signal,
        symbol=symbol,
        type=type,
        time_in_force=strategy.order_settings.time_in_force,
        # amount_fiat=amount_fiat,
        amount=amount_rounded,
        # price=price_bound,
        price=price_bound,
        direction=direction,
        **protection,
    )
    new_trade.save()

    if strategy.risk_model is not None:
        allowed = check_risk(strategy.risk_model, account, new_trade)
        if not allowed["allowed"]:
            new_trade.status = "rejected"
            new_trade.information = allowed["reason"]
            new_trade.save()
            sendmsg(
                user,
                f"Trade rejected due to risk model: {allowed['reason']}",
                title="Trade rejected",
            )
            return

    # Run the crossfilter to ensure we don't trade the same pair in opposite directions
    filtered = crossfilter(account, symbol, direction, func)

    # TP/SL calculation and get_trade_size_in_base are wasted here, but it's important
    # to record the decision in the Trade object. We can only get it after we do those.
    # It shows what would be done.
    if filtered:
        log.debug(f"Trade filtered. Action: {filtered['action']}")
        if filtered["action"] == "rejected":
            new_trade.status = "rejected"
            new_trade.save()
            sendmsg(
                user,
                (
                    f"{direction} on {symbol} rejected due to conflicting position: "
                    f"{filtered['positions']}"
                ),
                title="Trade rejected",
            )
    else:
        info = new_trade.post()
        log.debug(f"Posted trade: {info}")

        # Send notification with limited number of fields
        wanted_fields = ["requestID", "type", "symbol", "units", "reason"]
        sendmsg(
            user,
            ", ".join([str(v) for k, v in info.items() if k in wanted_fields]),
            title=f"{direction} {amount_rounded} on {symbol}",
        )


def process_callback(callback):
    log.info(f"Received callback for {callback.hook} - {callback.signal}")

    # Scan for trend
    log.debug("Scanning for trend strategies...")
    strategies = Strategy.objects.filter(
        trend_signals=callback.signal, signal_trading_enabled=True, enabled=True
    )
    log.debug(f"Matched strategies: {strategies}")
    for strategy in strategies:
        log.debug(f"Executing strategy {strategy}")
        if callback.hook.user != strategy.user:
            log.error("Ownership differs between callback and strategy.")
            continue
        execute_strategy(callback, strategy, func="trend")

    # Scan for entry
    log.debug("Scanning for entry strategies...")
    strategies = Strategy.objects.filter(
        entry_signals=callback.signal, signal_trading_enabled=True, enabled=True
    )
    log.debug(f"Matched strategies: {strategies}")
    for strategy in strategies:
        log.debug(f"Executing strategy {strategy}")
        if callback.hook.user != strategy.user:
            log.error("Ownership differs between callback and strategy.")
            continue
        execute_strategy(callback, strategy, func="entry")

    # Scan for exit
    log.debug("Scanning for exit strategies...")
    strategies = Strategy.objects.filter(
        exit_signals=callback.signal, signal_trading_enabled=True, enabled=True
    )
    log.debug(f"Matched strategies: {strategies}")
    for strategy in strategies:
        log.debug(f"Executing strategy {strategy}")
        if callback.hook.user != strategy.user:
            log.error("Ownership differs between callback and strategy.")
            continue
        execute_strategy(callback, strategy, func="exit")