summary.py

from aiovelib.service import IntegerItem

class Summary(object):
	def __init__(self, path, item=None):
		self.make_item = IntegerItem if item is None else item
		self.path = path

	def summarise(self, leader):
		raise NotImplementedError("summarise")

	def initial(self, v):
		""" Initial value for the summary. Uses `v` as a hunt, but can
		    replace it with something else. This is so we can override
		    the behaviour for some summaries and delay the decision
		    instead of starting with the first value from the first
		    RS device."""
		return v

class SummaryAll(Summary):
	def summarise(self, leader):
		return int(all(x.get_value(self.path) for x in leader.subservices))

class SummaryAny(Summary):
	def summarise(self, leader):
		return int(any(x.get_value(self.path) for x in leader.subservices))

class SummaryMax(Summary):
	def summarise(self, leader):
		try:
			return max(y for y in (x.get_value(self.path) for x in leader.subservices) if y is not None)
		except ValueError:
			return None

class SummaryFirst(Summary):
	def summarise(self, leader):
		for x in leader.subservices:
			return x.get_value(self.path)
		return None

class SettingMixin(object):
	""" Enherit from this, and one of the other Summary methods to make
	    one dependent on a setting.
	    Eg: class SummarySomething(SettingMixin, SummaryMax): pass """
	_default = None
	def __init__(self, setting, path, item=None):
		self.setting = setting
		super().__init__(path, item)

	def summarise(self, leader):
		if leader.settings.get_value(self.setting) == 1:
			return super().summarise(leader)
		return self._default

	def initial(self, v):
		return self._default

class SummaryOptionalAlarm(SettingMixin, SummaryMax):
	_default = 0