"""Abstract protocols for managing communications for Dragonframe remote operation.

Copyright (c) 2018, Garth Zeglin.  All rights reserved. Licensed under the terms
of the BSD 3-clause license.
"""

# Enable basic compatibility features to work with either Python 2 or 3.
from __future__ import print_function, absolute_import, unicode_literals

# Standard library modules.
import logging, collections

# Import modules from the course library.
import ase.base

################################################################
[docs]class DFRemoteServerProtocol(ase.base.Protocol):
    """Communicate as a remote control with Dragonframe using the Simple
    Interface/TCP protocol.
    """

    def __init__(self):
        self.transport = None
        self._buffer = b''

        # configure logging
        self.logger = logging.getLogger(__name__) #: logging object for controlling or capturing an event log
        self.logger.setLevel(logging.DEBUG)
        return

[docs]    def data_received(self, data):
        self.logger.debug('Message received: %r', data)

        # Manage the possibility of partial reads by appending new data to any previously received partial line.
        self._buffer += data

        # If at least one full line has been received:
        if b'\r\n' in self._buffer:
            # Split out each line on CRLF; the last element will be any remainder.
            lines = self._buffer.split(b'\r\n')
            for line in lines[:-1]:
                self.process_line(line.decode().split())

            # Any extra text (possibly empty) will be saved for the next receive.
            self._buffer = lines[-1]
        return

    # Transmit a status string to the client.  It is encoded as UTF-8 and a CRLF ending appended.
    def _send(self, status):
        data = status.encode() + b'\r\n'
        self.transport.write(data)
        self.transport.flush()
        self.logger.debug('Message sent: %r', data)
        return

    # Main entry point for interpreting the DFRemote protocol.
[docs]    def process_line(self, tokens):
        num_tokens = len(tokens)
        if num_tokens > 0:
            # Shoot Frame message, e.g. 'SH 1 1 X1 0'
            # This indicates the frame/exposure combination which was just shot.
            if tokens[0] == 'SH':
                if num_tokens >= 5:
                    frame = int(tokens[1])
                    exposure = int(tokens[2])
                    exposure_name = tokens[3]
                    stereo_position = int(tokens[4])
                    self.shot_taken(frame, exposure, exposure_name, stereo_position)
                    
            # Position Frame message, e.g. 'PF 2 1 X1 0'
            # This appears to indicate the frame/exposure combination to which to move after a shot.
            elif tokens[0] == 'PF':
                if num_tokens >= 5:
                    frame = int(tokens[1])
                    exposure = int(tokens[2])
                    exposure_name = tokens[3]
                    stereo_position = int(tokens[4])
                    self.position_requested(frame, exposure, exposure_name, stereo_position)
                    
            # Capture Complete message, e.g. 'CC 1 1 X1 0'
            # This is the final stage of a common SH, PF, CC sequence during a shot.
            elif tokens[0] == 'CC':
                if num_tokens >= 5:
                    frame = int(tokens[1])
                    exposure = int(tokens[2])
                    exposure_name = tokens[3]
                    stereo_position = int(tokens[4])
                    
            # Delete message, e.g. 'DE'
            elif tokens[0] == 'DE':
                self.frame_deleted()
                
        return

    # Methods to transmit messages to Dragonframe.
[docs]    def send_shoot_frames(self, count=1):
        self._send('S %d' % (count))
        return

[docs]    def send_delete_frame(self):
        self._send('D')
        return
    
[docs]    def send_toggle_play(self):
        self._send('P')
        return
    
[docs]    def send_live_view(self):
        self._send('L')
        return

    # Overridable methods to handle specific client requests.
[docs]    def shot_taken(self, frame, exposure, exposure_name, stereo_position):
        self.logger.info("Shot taken: frame %d, exposure %d, exposure_name %s, stereo_position %d", frame, exposure, exposure_name, stereo_position)

[docs]    def position_requested(self, frame, exposure, exposure_name, stereo_position):
        self.logger.info("Position requested: frame %d, exposure %d, exposure_name %s, stereo_position %d", frame, exposure, exposure_name, stereo_position)

[docs]    def frame_deleted(self):
        self.logger.info("Frame deleted")
        

################################################################