import numpy as np

class Joint():
    def __init__(self, name, parent=None, children=None):
        self.name = name
        self.parent = parent
        self.children = children

class MocapData():
    def __init__(self):
        self.skeleton = {}
        self.values = None
        self.channel_names = [] #TODO: Come up with a more coherent name for this on others
        self.framerate = 0.0
        self.root_name = ''
        self.metadata = {} #Note: This possibly breaks old pickles
    
    def traverse(self, j=None):
        stack = [self.root_name]
        while stack:
            joint = stack.pop()
            yield joint
            for c in self.skeleton[joint]['children']:
                stack.append(c)

    def clone(self):
        import copy
        new_data = MocapData()
        new_data.skeleton = copy.copy(self.skeleton)
        new_data.values = copy.copy(self.values)
        new_data.channel_names = copy.copy(self.channel_names)
        new_data.root_name = copy.copy(self.root_name)
        new_data.framerate = copy.copy(self.framerate)

        if hasattr(self,'metadata'):
            new_data.metadata = copy.copy(self.metadata)
        else:
            new_data.metadata = {}
        return new_data

    def get_all_channels(self):
        '''Returns all of the channels parsed from the file as a 2D numpy array'''

        frames = [f[1] for f in self.values]
        return np.asarray([[channel[2] for channel in frame] for frame in frames])

    def get_skeleton_tree(self):
        tree = []
        root_key =  [j for j in self.skeleton if self.skeleton[j]['parent']==None][0]
        
        root_joint = Joint(root_key)
    
    def get_empty_channels(self):
        #TODO
        pass

    def get_constant_channels(self):
        #TODO
        pass
