import queue
import sse
from exceptions import TooManyConnections

class SseStream():
    __queues = {}
    __maxConnections = 10
    __queue_size = 50

    @staticmethod
    def setMaxConnections(maxConnections = 10):
        """ Set maximum number of concurrent connections
        ---
        Paremeters:
        ------
        maxConnections: int, optional
            The number of maximum concurrent connections ( default value is 10) """
        SseStream.__maxConnections = maxConnections

    @staticmethod
    def setQueueSize(queueSize = 50):
        """ Set the queue size for stored messages
        ---
        Parementers
        ------
        queueSize: int, optional
            The number of stored messages in the queue, set to <=0 for unlimited size ( default value is 50 ) """
        SseStream.__queue_size = queueSize

    def __init__(self, id):
        """ Init a new stream
        ---
        Paremeters:
        ------
        id: string
            The unique id of the client 
        """
        if len( self.__queues ) >= self.__maxConnections:
            raise TooManyConnections

        if not self.__queues.get( id ):
            self._queue = queue.Queue( self.__queue_size )
            self.__queues[ id ] = self._queue
        
        print(f"Queue size: {self.__queue_size}; Connections: { len( self.__queues ) }/{self.__maxConnections}; ID: {id}")

    def __del__(self):
        """ Deregister client from queue - clean up """
        print( "Stream object is deleted")

    def __iter__(self):
        return self

    def __next__(self):
        """ Method which is called regular to send out the event """
        while True:
            msg = self.queue.get(block=True, timeout=None)
            if isinstance( msg, sse.Sse ):
                for data in msg:
                    yield data

    def addMessage(self, event_name, data, id = 0):
        """ 
        Adds a event to the queue so it can be sent out
        ---
        Parameters:
        ------
        event_name: str
            Name of the event
        data: string or list of strings
            Datat to be send
        id: int
            id of the event, if set to 0 no ID will be sent """
        event = sse.Sse()
        if id > 0:
            event.set_event_id(id)
        else:
            event.reset_event_id()
        event.add_message( event_name, data )

        self._queue.put(event)





def main():
    SseStream.setMaxConnections(5)
    SseStream.setQueueSize(10)
    sse = SseStream("Test")

if __name__ == "__main__":
    main()