# vim: set fileencoding=utf-8 :

import yaml

class WorkerSlotModel:
    def __init__ (self, slots, worker, env):
        self._slots = slots
        self._worker = worker
        self._env = env

        # generated properties, public, read-only
        self.slotNames = set (slots.keys ())
        assert len (self.slotNames) == len (slots.keys ()), "slot names must be unique"
        self.workerNames = set (worker.keys ())
        assert len (self.workerNames) == len (worker.keys ()), "worker names must be unique"
        self.minTotalSlots = self._env.get ('minSlots', 0)
        self.maxTotalSlots = self._env.get ('maxSlots', len (self.slotNames))

        # sanity-checks
        # min workers per slot must be smaller than total number of workers
        for s in self.slotNames:
            assert self.minWorker (s) <= len (self.workerNames), "Min workers per slot must be <= total workers"

    @classmethod
    def fromYaml (obj, fd):
        """
        Import from YAML file. Structured like this:

        """
        data = yaml.load (fd)
        o = obj (data['slots'], data['worker'], data.get ('env', {}))
        return o

    def available (self, worker, slot):
        """
        Is worker available for slot?
        """
        return self.priority (worker, slot) is not None

    def priority (self, worker, slot):
        """
        Get worker’s preferences/priority for slot, priority is higher for
        smaller numbers and must be >= 1
        """
        return self._worker[worker]['prio'].get (slot, None)

    def maxSlots (self, worker):
        """
        Get max number of slots to assign to worker. Defaults to 1.
        """
        return self._worker[worker].get ('slots', {}).get ('max', 1)

    def minSlots (self, worker):
        """
        Get min number of slots to assign to worker. Defaults to 1.
        """
        return self._worker[worker].get ('slots', {}).get ('min', 1)

    def maxWorker (self, slot):
        """
        Get max number of worker for slot, defaults to #worker
        """
        return self._slots[slot].get ('max', len (self.workerNames))

    def minWorker (self, slot):
        """
        Get min number of worker for slot. Defaults to 0.
        """
        return self._slots[slot].get ('min', 0)

    def dump (self, fd):
        yaml.dump ({'worker': self._worker, 'slots': self._slots, 'env': self._env}, fd)