class WMA:
  def __init__(self, unit, width):
    self._unit         = unit
    self._width        = width

    self._period_short = 7
    self._period_mid   = 15
    self._period_long  = 60

    self._posi_amp = 0.1

  def judge(self, status):
    cands = status.candles[self._unit]
    short = self._wma(cands, self._period_short)
    mid   = self._wma(cands, self._period_mid)
    long  = self._wma(cands, self._period_long)

    width = mid * self._width
    posi  = max(-1, min((short-long)/width, 1)) * self._posi_amp

    diff  = short - mid
    if diff < 0:
      return max(-1, diff/width+posi)  # sell
    else:
      return min(1, diff/width+posi)  # buy

  def _wma(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