###########################################################################
#
# Copyright (c) 2019-2020 Diality Inc. - All Rights Reserved.
#
# THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
# WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
#
# @file reservoirs.py
#
# @author (last) Sean Nash
# @date (last) 15-Oct-2020
# @author (original) Sean
# @date (original) 14-Apr-2020
#
############################################################################
import struct
from logging import Logger
from ..protocols.CAN import (DenaliMessage,
                             DenaliChannels)
from ..utils.base import _AbstractSubSystem, _publish
from ..common.msg_defs import MsgIds, MsgFieldPositions
from ..utils.conversions import integer_to_bytearray


class DGReservoirs(_AbstractSubSystem):
    """
    DG interface containing reservoir related commands.
    """

    # Reservoir IDs
    RESERVOIR1 = 0
    RESERVOIR2 = 1

    def __init__(self, can_interface, logger: Logger):
        """

        @param can_interface: The DenaliCANMessenger object
        """

        super().__init__()
        self.can_interface = can_interface
        self.logger = logger

        if self.can_interface is not None:
            channel_id = DenaliChannels.dg_sync_broadcast_ch_id
            msg_id = MsgIds.MSG_ID_DG_RESERVOIR_DATA.value
            self.can_interface.register_receiving_publication_function(channel_id, msg_id,
                                                                       self._handler_reservoirs_sync)

        self.active_reservoir = self.RESERVOIR1
        self.fill_to_vol_ml = 0
        self.drain_to_vol_ml = 0

    def get_active_reservoir(self):
        """
        Gets the active reservoir
        RESERVOIR1 = 0 \n
        RESERVOIR2 = 1 \n

        @return: 0 or 1
        """
        return self.active_reservoir

    def get_fill_to_vol(self):
        """
        Gets the fill to volume

        @return: The fill to volume (mL)
        """
        return self.fill_to_vol_ml

    def get_drain_to_vol(self):
        """
        Gets the drain to volume
        @return: The drain to volume (mL)
        """
        return self.drain_to_vol_ml

    def cmd_switch_reservoirs(self, reservoir: int) -> bool:
        """
        Sends a command to the DG to switch reservoirs
        @param reservoir: (int) the new reservoir number
        @return: True if command sent, False if invalid reservoir provided
        """

        if reservoir not in [0, 1]:
            return False

        payload = integer_to_bytearray(reservoir)

        message = DenaliMessage.build_message(channel_id=DenaliChannels.dialin_to_dg_ch_id,
                                              message_id=MsgIds.MSG_ID_DG_SWITCH_RESERVOIR_CMD.value,
                                              payload=payload)

        self.logger.debug("Sending command to switch DG reservoir to {0}".format(reservoir))

        self.can_interface.send(message, 0)

        return True

    @_publish([
        "active_reservoir",
        "fill_to_vol_ml",
        "drain_to_vol_ml"
        ])
    def _handler_reservoirs_sync(self, message):
        """
        Handles published reservoir data messages.  Reservoir data are captured
        for reference.

        @param message:  published reservoir data message
        @return: none
        """

        res = struct.unpack('i', bytearray(
            message['message'][MsgFieldPositions.START_POS_FIELD_1:MsgFieldPositions.END_POS_FIELD_1]))
        fil = struct.unpack('i', bytearray(
            message['message'][MsgFieldPositions.START_POS_FIELD_2:MsgFieldPositions.END_POS_FIELD_2]))
        dra = struct.unpack('i', bytearray(
            message['message'][MsgFieldPositions.START_POS_FIELD_3:MsgFieldPositions.END_POS_FIELD_3]))

        self.active_reservoir = res[0]
        self.fill_to_vol_ml = fil[0]
        self.drain_to_vol_ml = dra[0]