import dataset
import scipy

class Project:
    def __init__(self,name="Testing"):
        self.name = name
        self.dim_names = []
        self._observers = {}
        self.current_data=None
        self.datasets=[]
        self.sel_obj = dataset.Selection()
        
    def attach(self,observer,key):
        """Attach observer for selection updates"""
        if not self._observers.has_key(key):
            self._observers[key]=[]        
        if not observer in self._observers[key]:
            self._observers[key].append(observer)

    def detach(self,observer,key):
        """Detach observer for selection updates"""
        try:
            self._observers[key].remove(observer)
        except ValueError:
            pass

    def notify(self,key,modifier=None):
        """Notifies observers"""
        for observer in self._observers[key]:
            if modifier != observer:
                observer.update(self,key)

    def set_selection(self,dim_name,selection):
        """Sets a current selection and notify observers"""
        self.sel_obj.current_selection[dim_name] = set(selection)
        self.notify('selection_update')

    def get_selection(self):
        """Returns the current selection object"""
        return self.sel_obj.current_selection
    
    def add_dataset(self,dataset):
        """Appends a new Dataset to the project."""
        self.datasets.append(dataset)
        for dim_name in dataset.ids.keys():
            if dim_name not in self.dim_names:
                self.dim_names.append(dim_name)

    def suggest_dim_name(self,dim_name):
        """Creates an arbitrary unique name for a new dimension."""
        while dim_name in self.dim_names:
            dim_name = dim_name + "_t" 
        return dim_name