class SMA:
  def __init__(self):
    return

  def calc(self, cands, period):
    sum = 0
    n   = min(period, len(cands))
    for i in range(n):
      sum += cands[i][3]
    return sum / n

class EMA:
  def __init__(self):
    return

  def calc(self, cands, period):
    n   = min(period, len(cands))
    ret = 0
    for i in range(n):
      ret += cands[i][3]
    ret /= n
    for i in range(n):
      ret = (2/(1+n))*(cands[n-i-1][3] - ret) + ret
    return ret

class WMA:
  def __init__(self):
    return

  def calc(self, cands, period):
    sum = 0
    den = 0
    for i in range(min(period, len(cands))):
      sum += cands[i][3] * (i+1)
      den += i+1
    return sum / den


class MA_Cross:
  def __init__(self, ma, unit):
    self._ma    = ma
    self._unit  = unit

    self._period_short = 21
    self._period_mid   = 55

  def judge(self, status):
    cands = status.candles[self._unit]
    short = self._ma.calc(cands, self._period_short)
    mid   = self._ma.calc(cands, self._period_mid)

    diff  = short - mid
    if diff < 0:
      return -1  # sell
    else:
      return 1  # buy