from db import dbconn
from quantlib.indexes.api import UsdLiborSwapIsdaFixAm
from quantlib.quotes import SimpleQuote
from quantlib.time.api import Date, Period, Years, pydate_from_qldate
from quantlib.instruments.api import MakeSwaption
from quantlib.instruments.swap import SwapType
from quantlib.pricingengines.api import BlackSwaptionEngine
from quantlib.settings import Settings
from yieldcurve import YC


class IRSwaption():
    """ adapter class for the QuantLib code"""
    def __init__(self, swap_index, option_tenor, strike, option_type="payer",
                 direction="Long", notional=10_000_000, yc=None):
        self._qloption = (MakeSwaption(swap_index, option_tenor, strike).
                          with_nominal(notional).
                          with_underlying_type(SwapType[option_type.title()])())
        if type(direction) is bool:
            self._direction = 2 * direction - 1
        else:
            self.direction = direction
        self._yc = yc or swap_index.forwarding_term_structure
        self._sigma = SimpleQuote(0.218)
        self._qloption.set_pricing_engine(BlackSwaptionEngine(self._yc, self._sigma))

    @property
    def direction(self):
        if self._direction == 1.:
            return "Long"
        else:
            return "Short"

    @direction.setter
    def direction(self, d):
        if d == "Long":
            self._direction = 1.
        elif d == "Short":
            self._direction = -1.
        else:
            raise ValueError("Direction needs to be either 'Long' or 'Short'")

    @property
    def pv(self):
        return self._direction * self._qloption.npv

    @property
    def sigma(self):
        return self._sigma.value

    @sigma.setter
    def sigma(self, s):
        self._sigma.value = s

    def from_tradeid(trade_id):
        with dbconn('dawndb') as conn:
            with conn.cursor() as c:
                c.execute("SELECT * from swaptions "
                          "WHERE id = %s", (trade_id,))
                rec = c.fetchone()
        yc = YC(evaluation_date=rec['trade_date'], fixed=True)
        p = Period(int(rec['security_id'].replace("USISDA", "")), Years)
        swap_index = UsdLiborSwapIsdaFixAm(p, yc)
        instance = IRSwaption(swap_index, Date.from_datetime(rec['expiration_date']),
                              rec['strike'], rec['option_type'], rec['buysell'],
                              rec['notional'])
        return instance

    @property
    def value_date(self):
        return pydate_from_qldate(self._qloption.valuation_date)

    @value_date.setter
    def value_date(self, d):
        self.yc.link_to(YC(evaluation_date=d, fixed=True))