class ExampleClusters:
    def __init__(self):
        self.idxs = set()
        self.lists = {}
        
    @staticmethod
    def get_key(sense, example):
        sense_idx = sense.original_idx
        structure_name = example.get_structure()
        key = "{}-{}".format(sense_idx, structure_name)
        return key
    
    def _first_empty_cluster(self):
        idx = 0
        while True:
            if idx not in self.clusters:
                self.idxs.add(idx)
                return idx
            idx += 1

    def _register_cluster(self, idx):
        if idx not in self.idxs:
            self.idxs.add(idx)
        
    def _rebuild_lists(self, model):
        self.lists = {}
        
        for sense in model.entry.senses:
            for example in sense.examples:
                structure = example.get_structure()
                key = ExampleClusters.get_key(sense, example)
                
                if key not in self.lists:
                    self.lists[key] = set()
                    
                self.lists[key].add(example.get_cluster())
                    
        for key in self.lists.keys():
            self.lists[key] = sorted(self.lists[key], key=lambda x: x)
    
    def _get_list(self, sense, example):
        key = ExampleClusters.get_key(sense, example)
        if key in self.lists:
            return self.lists[key]
        else:
            return []
    
    @staticmethod
    def first_empty_cluster():
        return ec._first_empty_cluster()
            
    @staticmethod
    def register_cluster(idx):
        return ec._register_cluster(idx)
            
    @staticmethod
    def rebuild_lists(model):
        return ec._rebuild_lists(model)
    
    @staticmethod
    def get_list(sense, example):
        return ec._get_list(sense, example)
        
    
ec = ExampleClusters()