import zmq
import threading
import logging

from robot_interface.endpoints.socket_base import SocketBase
from robot_interface.state import state
from robot_interface.core.config import settings

class VideoSender(SocketBase):
    """
    Video sender endpoint, responsible for sending video frames.

    :param zmq_context: The ZeroMQ context to use.
    :type zmq_context: zmq.Context

    :param port: The port to use for sending video frames.
    :type port: int
    """
    def __init__(self, zmq_context, port=settings.agent_settings.video_sender_port):
        super(VideoSender, self).__init__("video")
        self.create_socket(zmq_context, zmq.PUB, port, [(zmq.CONFLATE,1)])
    
    def start_video_rcv(self):
        """
        Prepares arguments for retrieving video images from Pepper and starts video loop on a separate thread.
        
        Will not start if no qi session is available.
        """
        if not state.qi_session:
            logging.info("No Qi session available. Not starting video loop.")
            return

        video = state.qi_session.service("ALVideoDevice")
        video_settings = settings.video_config
        camera_index = video_settings.camera_index
        kQVGA = video_settings.resolution
        kRGB = video_settings.color_space
        FPS = video_settings.fps
        video_name = video_settings.stream_name
        vid_stream_name = video.subscribeCamera(video_name, camera_index, kQVGA, kRGB, FPS)
        thread = threading.Thread(target=self.video_rcv_loop, args=(video, vid_stream_name))
        thread.start()

    def video_rcv_loop(self, vid_service, vid_stream_name):
        """
        The main loop of retrieving video images from the robot.

        :param vid_service: The video service object that the active Qi session is connected to. 
        :type vid_service: Object (Qi service object)

        :param vid_stream_name: The name of a camera subscription on the video service object vid_service
        :type vid_stream_name: str
        """
        while not state.exit_event.is_set():
            try:
                img = vid_service.getImageRemote(vid_stream_name)
                #Possibly limit images sent if queuing issues arise
                self.socket.send(img[settings.video_config.image_buffer])
            except:
                logging.warn("Failed to retrieve video image from robot.")