'''
This module defines :class:`Unit`, a container of :class:`SpikeTrain` objects
from a unit.

:class:`Unit` derives from :class:`Container`,
from :module:`neo.core.container`.
'''

from neo.core.container import Container


class Unit(Container):
    '''
    A container of :class:`SpikeTrain` objects from a unit.

    Use of :class:`Unit` is deprecated. It can be replaced by the :class:`Group`.

    A :class:`Unit` regroups all the :class:`SpikeTrain`
    objects that were emitted by a single spike source during a :class:`Block`.
    A spike source is often a single neuron but doesn't have to be.  The spikes
    may come from different :class:`Segment` objects within the :class:`Block`,
    so this object is not contained in the usual :class:`Block`/
    :class:`Segment`/:class:`SpikeTrain` hierarchy.

    A :class:`Unit` is linked to :class:`ChannelIndex` objects from
    which it was detected. With tetrodes, for instance, multiple channels may
    record the same :class:`Unit`.

    *Usage*::

        >>> from neo.core import Unit, SpikeTrain
        >>>
        >>> unit = Unit(name='pyramidal neuron')
        >>>
        >>> train0 = SpikeTrain(times=[.01, 3.3, 9.3], units='sec', t_stop=10)
        >>> unit.spiketrains.append(train0)
        >>>
        >>> train1 = SpikeTrain(times=[100.01, 103.3, 109.3], units='sec',
        ...                  t_stop=110)
        >>> unit.spiketrains.append(train1)

    *Required attributes/properties*:
        None

    *Recommended attributes/properties*:
        :name: (str) A label for the dataset.
        :description: (str) Text description.
        :file_origin: (str) Filesystem path or URL of the original data file.

    Note: Any other additional arguments are assumed to be user-specific
            metadata and stored in :attr:`annotations`.

    *Container of*:
        :class:`SpikeTrain`

    '''

    _data_child_objects = ('SpikeTrain',)
    _single_parent_objects = ('ChannelIndex',)
    _recommended_attrs = Container._recommended_attrs

    def __init__(self, name=None, description=None, file_origin=None,
                 **annotations):
        '''
        Initialize a new :clas:`Unit` instance (spike source)
        '''
        super().__init__(name=name, description=description,
                                   file_origin=file_origin, **annotations)
        self.channel_index = None

    def get_channel_indexes(self):
        """
        """
        if self.channel_index:
            return self.channel_index.index
        else:
            return None