"""
Tools for IO coder:
  * Creating RecordingChannel and making links with AnalogSignals and
    SPikeTrains
"""

try:
    from collections.abc import MutableSequence
except ImportError:
    from collections import MutableSequence

import numpy as np

from neo.core import (AnalogSignal, Block,
                      Epoch, Event,
                      IrregularlySampledSignal,
                      ChannelIndex, Group, ChannelView,
                      Segment, SpikeTrain, Unit)


# def finalize_block(block):
#    populate_RecordingChannel(block)
#    block.create_many_to_one_relationship()

# Special case this tricky many-to-many relationship
# we still need links from recordingchannel to analogsignal
#    for chx in block.channel_indexes:
#        for rc in chx.recordingchannels:
#            rc.create_many_to_one_relationship()


# def populate_RecordingChannel(bl, remove_from_annotation=True):
#     """
#     When a Block is
#     Block>Segment>AnalogSIgnal
#     this function auto create all RecordingChannel following these rules:
#       * when 'channel_index ' is in AnalogSIgnal the corresponding
#         RecordingChannel is created.
#       * 'channel_index ' is then set to None if remove_from_annotation
#       * only one ChannelIndex is created
#
#     It is a utility at the end of creating a Block for IO.
#
#     Usage:
#     >>> populate_RecordingChannel(a_block)
#     """
#     recordingchannels = {}
#     for seg in bl.segments:
#         for anasig in seg.analogsignals:
#             if getattr(anasig, 'channel_index', None) is not None:
#                 ind = int(anasig.channel_index)
#                 if ind not in recordingchannels:
#                     recordingchannels[ind] = RecordingChannel(index=ind)
#                     if 'channel_name' in anasig.annotations:
#                         channel_name = anasig.annotations['channel_name']
#                         recordingchannels[ind].name = channel_name
#                         if remove_from_annotation:
#                             anasig.annotations.pop('channel_name')
#                 recordingchannels[ind].analogsignals.append(anasig)
#                 anasig.recordingchannel = recordingchannels[ind]
#                 if remove_from_annotation:
#                     anasig.channel_index = None
#
#     indexes = np.sort(list(recordingchannels.keys())).astype('i')
#     names = np.array([recordingchannels[idx].name for idx in indexes],
#                      dtype='S')
#     chx = ChannelIndex(name='all channels',
#                        index=indexes,
#                        channel_names=names)
#     bl.channel_indexes.append(chx)
#     for ind in indexes:
#         # many to many relationship
#         chx.recordingchannels.append(recordingchannels[ind])
#         recordingchannels[ind].channel_indexes.append(chx)


# def iteritems(D):
#    try:
#        return D.iteritems()  # Python 2
#    except AttributeError:
#        return D.items()  # Python 3


class LazyList(MutableSequence):
    """ An enhanced list that can load its members on demand. Behaves exactly
    like a regular list for members that are Neo objects. Each item should
    contain the information that ``load_lazy_cascade`` needs to load the
    respective object.
    """
    _container_objects = {
        Block, Segment, ChannelIndex, Unit, Group}
    _neo_objects = _container_objects.union(
        [AnalogSignal, Epoch, Event, ChannelView,
         IrregularlySampledSignal, SpikeTrain])

    def __init__(self, io, lazy, items=None):
        """
        :param io: IO instance that can load items.
        :param lazy: Lazy parameter with which the container object
            using the list was loaded.
        :param items: Optional, initial list of items.
        """
        if items is None:
            self._data = []
        else:
            self._data = items
        self._lazy = lazy
        self._io = io

    def __getitem__(self, index):
        item = self._data.__getitem__(index)
        if isinstance(index, slice):
            return LazyList(self._io, item)

        if type(item) in self._neo_objects:
            return item

        loaded = self._io.load_lazy_cascade(item, self._lazy)
        self._data[index] = loaded
        return loaded

    def __delitem__(self, index):
        self._data.__delitem__(index)

    def __len__(self):
        return self._data.__len__()

    def __setitem__(self, index, value):
        self._data.__setitem__(index, value)

    def insert(self, index, value):
        self._data.insert(index, value)

    def append(self, value):
        self._data.append(value)

    def reverse(self):
        self._data.reverse()

    def extend(self, values):
        self._data.extend(values)

    def remove(self, value):
        self._data.remove(value)

    def __str__(self):
        return '<' + self.__class__.__name__ + '>' + self._data.__str__()

    def __repr__(self):
        return '<' + self.__class__.__name__ + '>' + self._data.__repr__()