#!/usr/bin/python
# -*- coding: utf-8 -*-

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# Copyright (c) 2012 Michael Hull.
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# modification, are permitted provided that the following conditions
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[docs]class ChannelApplicator(object):

[docs]    def __init__(self,):
        super(ChannelApplicator, self).__init__()
        self.target_channel = None

[docs]    def set_target_channel(self, target_channel):
        assert self.target_channel is None
        self.target_channel = target_channel

        # Check that everything that is over-ridden actually exists:
        for varname in self.get_variables_overriden():
            assert varname in self.target_channel.get_variables(), 'unexpected setting of %s' % varname


[docs]    def get_variable_value_for_section(self, variablename, section):
        raise NotImplementedError()

[docs]    def get_description(self):
        raise NotImplementedError()

[docs]    def get_variables_overriden(self):
        raise NotImplementedError()


[docs]class ChannelApplicatorUniform(ChannelApplicator):

[docs]    def __init__(self,  parameter_multipliers=None, parameter_overrides=None):
        super(ChannelApplicatorUniform, self).__init__()
        self._parameter_multipliers =  parameter_multipliers or {}
        self._parameter_overrides = parameter_overrides or {}

        # Check  no parameters are specified twice:
        duplicate_defs = set(self._parameter_multipliers.keys()) & set(self._parameter_overrides.keys())
        assert len(duplicate_defs) == 0, 'Ambiguity: Parameter specified twice: %s' % duplicate_defs


[docs]    def get_variables_overriden(self):
        return set(self._parameter_multipliers.keys()) | set(self._parameter_overrides.keys())


[docs]    def get_variable_value_for_section(self, variable_name, section):

        assert not ( variable_name in self._parameter_multipliers and  variable_name in self._parameter_overrides)

        if variable_name in self._parameter_multipliers:
            return self._parameter_multipliers[variable_name] * self.target_channel.get_default(variable_name)
        if variable_name in self._parameter_overrides:
            return self._parameter_overrides[variable_name]
        return self.target_channel.get_default(variable_name)


[docs]    def get_description(self):
        s1 = 'Uniform Applicator: '
        s2 = ('Overrides:{%s} ' % (','.join( [ "%s=%s" % (key,value) for (key,value) in self._parameter_overrides.iteritems()] )) ) if self._parameter_overrides else ''
        s3 = ('Multipliers:{%s} ' % (','.join( [ "%s=%s" % (key,value) for (key,value) in self._parameter_multipliers.iteritems()] )) ) if self._parameter_multipliers else ''
        return (s1 + s2 + s3).strip()