"""
Base class for all estimators.

"""
# Author: Gael Varoquaux <gael.varoquaux@normalesup.org>

# License: BSD Style
import inspect

import numpy as np


################################################################################
class BaseEstimator(object):
    """ Base class for all estimators in the scikit learn

        Note
        =====

        All estimators should specify all the parameters that can be set
        at the class level in their __init__ as explicit keyword
        arguments (no *args, **kwargs).

    """

    @classmethod
    def _get_param_names(cls):
        args, varargs, kw, default = inspect.getargspec(cls.__init__)
        assert varargs is None, (
            'scikit learn estimators should always specify their '
            'parameters in the signature of their init (no varargs).'
            )
        # Remove 'self'
        # XXX: This is going to fail if the init is a staticmethod, but
        # who would do this?
        args.pop(0)
        return args


    def _get_params(self):
        out = dict()
        for key in self._get_param_names():
            out[key] = getattr(self, key)
        return out


    def _set_params(self, **params):
        """ Set the parameters of the estimator.
        """
        valid_params = self._get_param_names()
        for key, value in params.iteritems():
            assert key in valid_params, ('Invalid parameter %s '
                'for estimator %s' %
                (key, self.__class__.__name__))
            setattr(self, key, value)


    def __repr__(self):
        options = np.get_printoptions()
        np.set_printoptions(precision=5, threshold=64, edgeitems=2)
        class_name = self.__class__.__name__
        params_str = (',\n' + (1+len(class_name))*' ').join(
                                  '%s=%s' % (k, v) 
                                  for k, v in self._get_params().iteritems())
        np.set_printoptions(**options)
        return '%s(%s)' % (
                class_name,
                params_str
            )