# coding=utf-8
from BTrees.OOBTree import OOBTree
from persistent import Persistent

class MBase(Persistent):
    """
    BASE Class for all classes of Playground System
    -----------------------------------------------
    """
    def __init__(self):
        self.name = None # main folder name (this can change after folder creation)
        self.path = None # main folder path
        self.children = OOBTree() # children list
        self.data = OOBTree() # data list
    # Maybe some global methods here
    # for example:
    # getting all children or all data
    # with index vs vs. (list comprehensions here)


class MContainer(MBase):
    """
    BASE MContainer CLASS
    ---------------------
    MContainer class represents folders that has
    same base-typed children and children grouping attributes
    ...
    a MContainer based object can have MAsset based objects only
    for parenting.
    ...
    a MContainer object have children data and methods to access them
    ...
    EXAMPLE 1:
        - Episode(s) is a MContainer class object (it's plural)
        - an Episode(s) class object can contain only Episode(MAsset) class objects
        - an MContainer has grouping attributes
        - so, we can group its children. (episode 1-13, episode 14-26 etc...)

    EXAMPLE 2:
        - Asset(s) is a MContainer object
        - it can only have Asset objects
        - so, we can group them like CHARACTERS, VEHICLES and so on...
    """
    def __init__(self):
        super(MContainer, self).__init__()
        self.group_data = OOBTree() # data needed for grouping (keys: Group names, values

    def append(self, asset):
        """Adds MAsset object to self.children"""
        if isinstance(asset, MAsset):
            if self.children.insert(asset.name, asset):
                return True
            else:
                # if already have a same named child don't contain it
                # and return false. this is the default behaviour of BTrees
                # it simply ignores it, so i need to raise exception
                raise KeyError('{} is already exists. Try different name.'.format(asset.name))
        else:
            # asset object is not MAsset object
            raise TypeError('Passed object is not a <MAsset> object.')
    # maybe we need grouping methods here


class MAsset(MBase):
    """
    BASE MAsset CLASS
    -----------------
    MAsset class represents folders that has
    same base-typed children but unlike MContainer class
    has no children grouping attributes.
    ...
    MAsset class can only have MContainer class objects
    or some special type. (maya scene files, textures, organization etc.)
    ...
    EXAMPLE 1:
        - Shot (no plural) is a MAsset base-typed object
        - it has some special attributes

    This class is almost identical with MContainer class
    it's a seperate class because both have methods for
    allowed children control. so this class can only allow
    MContainer object, a MContainer object can only have this type...
    """
    def __init__(self):
        super(MAsset, self).__init__()

    def append(self, container):
        """Adds MContainer object to self.children"""
        if isinstance(container, MContainer):
            if self.children.insert(container.name, container):
                return True
            else:
                # if already have a same named child don't contain it
                # and return false. this is the default behaviour of BTrees
                # it simply ignores it, so i need to raise exception
                raise KeyError('{} is already exists. Try different name.'.format(container.name))
        else:
            # container object is not MContainer object
            raise TypeError('Passed object is not a <MContainer> object.')