from matplotlib.artist import Artist
import matplotlib.cbook as cbook


class Container(tuple):
    """
    Base class for containers.

    Containers are classes that collect semantically related Artists such as
    the bars of a bar plot.
    """

    def __repr__(self):
        return ("<{} object of {} artists>"
                .format(type(self).__name__, len(self)))

    def __new__(cls, *args, **kwargs):
        return tuple.__new__(cls, args[0])

    def __init__(self, kl, label=None):
        self.eventson = False  # fire events only if eventson
        self._oid = 0  # an observer id
        self._propobservers = {}  # a dict from oids to funcs
        self._remove_method = None
        self.set_label(label)

    def remove(self):
        for c in cbook.flatten(
                self, scalarp=lambda x: isinstance(x, Artist)):
            if c is not None:
                c.remove()

        if self._remove_method:
            self._remove_method(self)

    def get_children(self):
        return [child for child in cbook.flatten(self) if child is not None]

    get_label = Artist.get_label
    set_label = Artist.set_label
    add_callback = Artist.add_callback
    remove_callback = Artist.remove_callback
    pchanged = Artist.pchanged


class BarContainer(Container):
    """
    Container for the artists of bar plots (e.g. created by `.Axes.bar`).

    The container can be treated as a tuple of the *patches* themselves.
    Additionally, you can access these and further parameters by the
    attributes.

    Attributes
    ----------
    patches : list of :class:`~matplotlib.patches.Rectangle`
        The artists of the bars.

    errorbar : None or :class:`~matplotlib.container.ErrorbarContainer`
        A container for the error bar artists if error bars are present.
        *None* otherwise.

    """

    def __init__(self, patches, errorbar=None, **kwargs):
        self.patches = patches
        self.errorbar = errorbar
        Container.__init__(self, patches, **kwargs)


class ErrorbarContainer(Container):
    """
    Container for the artists of error bars (e.g. created by `.Axes.errorbar`).

    The container can be treated as the *lines* tuple itself.
    Additionally, you can access these and further parameters by the
    attributes.

    Attributes
    ----------
    lines : tuple
        Tuple of ``(data_line, caplines, barlinecols)``.

        - data_line : :class:`~matplotlib.lines.Line2D` instance of
          x, y plot markers and/or line.
        - caplines : tuple of :class:`~matplotlib.lines.Line2D` instances of
          the error bar caps.
        - barlinecols : list of :class:`~matplotlib.collections.LineCollection`
          with the horizontal and vertical error ranges.

    has_xerr, has_yerr : bool
        ``True`` if the errorbar has x/y errors.

    """

    def __init__(self, lines, has_xerr=False, has_yerr=False, **kwargs):
        self.lines = lines
        self.has_xerr = has_xerr
        self.has_yerr = has_yerr
        Container.__init__(self, lines, **kwargs)


class StemContainer(Container):
    """
    Container for the artists created in a :meth:`.Axes.stem` plot.

    The container can be treated like a namedtuple ``(markerline, stemlines,
    baseline)``.

    Attributes
    ----------
    markerline :  :class:`~matplotlib.lines.Line2D`
        The artist of the markers at the stem heads.

    stemlines : list of :class:`~matplotlib.lines.Line2D`
        The artists of the vertical lines for all stems.

    baseline : :class:`~matplotlib.lines.Line2D`
        The artist of the horizontal baseline.
    """
    def __init__(self, markerline_stemlines_baseline, **kwargs):
        """
        Parameters
        ----------
        markerline_stemlines_baseline : tuple
            Tuple of ``(markerline, stemlines, baseline)``.
            ``markerline`` contains the `LineCollection` of the markers,
            ``stemlines`` is a `LineCollection` of the main lines,
            ``baseline`` is the `Line2D` of the baseline.
        """
        markerline, stemlines, baseline = markerline_stemlines_baseline
        self.markerline = markerline
        self.stemlines = stemlines
        self.baseline = baseline
        Container.__init__(self, markerline_stemlines_baseline, **kwargs)
