import backtrader

class MA_CrossOver(backtrader.Strategy):
    '''This is a long-only strategy which operates on a moving average cross

    Note:
      - Although the default

    Buy Logic:
      - No position is open on the data

      - The ``fast`` moving averagecrosses over the ``slow`` strategy to the
        upside.

    Sell Logic:
      - A position exists on the data

      - The ``fast`` moving average crosses over the ``slow`` strategy to the
        downside

    Order Execution Type:
      - Market

    '''
    alias = ('SMA_CrossOver',)

    params = (
        # period for the fast Moving Average
        ('fast', 24),
        # period for the slow moving average
        ('slow', 72),
        # moving average to use
        ('_movav', backtrader.ind.MovAv.SMA)
    )

    def __init__(self):
        sma_fast = self.p._movav(period=self.p.fast)
        sma_slow = self.p._movav(period=self.p.slow)
        self.buysig = backtrader.ind.CrossOver(sma_fast, sma_slow)

    def log(self, txt, dt=None):
        ''' Logging function fot this strategy'''
        dt = dt or self.datas[0].datetime.date(0)
        print('%s, %s' % (dt.isoformat(), txt))

    def notify_order(self, order):
        if order.status in [order.Submitted, order.Accepted]:
            return
        if order.status in [order.Completed]:
            if order.isbuy():
                self.log('BUY EXECUTED, %.6f' % order.executed.price)
            elif order.issell():
                self.log('SELL EXECUTED, %.6f' % order.executed.price)
            self.bar_executed = len(self)
        elif order.status in [order.Canceled, order.Margin, order.Rejected]:
            self.log('Order Canceled/Margin/Rejected')
        self.order = None

    def next(self):
        if self.position.size:
            if self.buysig < 0:
                self.sell()
        elif self.buysig > 0:
            self.buy()