# for empty grouping / categories
    placeholder = [dict(genre="./.", title="Subcategory placeholder", playing="./.", url="none:", listeners=0, bitrate=0, homepage="", state="gtk-folder")]
    empty_stub = [dict(genre="./.", title="No categories found (HTTP error)", playing="Try Channel→Reload Categories later..", url="none:", listeners=0, bitrate=0, homepage="", state="gtk-stop")]
    
    # regex            
    rx_www_url = re.compile("""(www(\.\w+[\w-]+){2,}|(\w+[\w-]+[ ]?\.)+(com|FM|net|org|de|PL|fr|uk))""", re.I)



    #--------------------------- initialization --------------------------------


    # constructor
    def __init__(self, parent=None):
    
        #self.streams = {}
        self.gtk_list = None
        self.gtk_cat = None

        self.parent = stub_parent(None)

        # only if streamtuner2 is run in graphical mode        
        if (parent):
            self.cache()
            self.gui(parent)
        pass



























        
    # initialize Gtk widgets / data objects
    def gui(self, parent):
        #print(self.module + ".gui()")

        # save reference to main window/glade API

            self.load(self.current)
        else:
            uikit.columns(self.gtk_list, self.datamap, [])
            
        # add to main menu
        uikit.add_menu([parent.channelmenuitems], self.meta["title"], lambda w: parent.channel_switch_by_name(self.module) or 1)


    # Statusbar stub (defers to parent/main window, if in GUI mode)
    def status(self, *v):
        if self.parent: self.parent.status(*v)
        else: __print__(dbg.INFO, "status():", *v)


        
    #--------------------- streams/model data accesss ---------------------------
        
    # Get list of stations in current category
    def stations(self):
        return self.streams.get(self.current, [])

    # Convert ListStore iter to row number
    def rowno(self):
        (model, iter) = self.model_iter()
        return model.get_path(iter)[0]

    # Return ListStore object and Iterator for currently selected row in gtk.TreeView station list
    def model_iter(self):
        return self.gtk_list.get_selection().get_selected()

    # Currently selected entry in stations list, return complete data dict
    def row(self):
        return self.stations() [self.rowno()]
        
    # Fetches a single varname from currently selected station entry
    def selected(self, name="url"):
        return self.row().get(name)
    
    # Inject status icon into currently selected row (used by main.bookmark() call)
    def row_icon(self, gtkIcon = gtk.STOCK_ABOUT):
        try:
            # Updates gtk_list store, set icon in current display.
            # Since it is used by bookmarks, would be reshown with next display() anyhow,
            # and there's no need to invalidate the ls cache, because that's referenced by model anyhow.
            (model,iter) = self.model_iter()
            model.set_value(iter, 0, gtkIcon)
        except:
             pass

    

    #------------------------ base implementations -----------------------------

    # read previous channel/stream data, if there is any
    def cache(self):
        # stream list
        cache = conf.load("cache/" + self.module)
        if (cache):
            self.streams = cache
        # categories
        cache = conf.load("cache/categories_" + self.module)
        if (cache):
            self.categories = cache
        # catmap (optional)
        cache = conf.load("cache/catmap_" + self.module)
        if (cache):
            self.catmap = cache
        pass

        
    # make private copy of .datamap and modify field (title= only ATM)
    def update_datamap(self, search="name", title=None):
        if self.datamap == GenericChannel.datamap:
            self.datamap = copy.deepcopy(self.datamap)
        for i,row in enumerate(self.datamap):
            if row[2][0] == search:

        return self.current




    #--------------------------- actions ---------------------------------

    # Invoke action.play() for current station.
    # Can be overridden to provide channel-specific "play" alternative
    def play(self):
        row = self.row()
        if row:
            # playlist and audio type

            audioformat = row.get("format", self.audioformat)
            listformat = row.get("listformat", self.listformat)

            # invoke audio player
            action.play(row["url"], audioformat, listformat, row)
        else:
            self.status("No station selected for playing.")
        return row

    # Start streamripper/youtube-dl/etc
    def record(self):
        row = self.row()
        if row:
            audioformat = row.get("format", self.audioformat)
            listformat = row.get("listformat", self.listformat)
            action.record(row.get("url"), audioformat, listformat, row=row)
        return row



    #--------------------------- utility functions -----------------------