from .packet import Packet


class DFrame:
    PACKET_COMMAND_DATA = 0x01
    PACKET_COMMAND_RELIABLE = 0x02
    PACKET_COMMAND_SEQUENTIAL = 0x04
    PACKET_COMMAND_POLL = 0x08
    PACKET_COMMAND_NEW_MSG = 0x10
    PACKET_COMMAND_END_MSG = 0x20
    PACKET_COMMAND_USER_1 = 0x40
    PACKET_COMMAND_USER_2 = 0x80

    PACKET_CONTROL_RETRY = 0x01
    PACKET_CONTROL_KEEPALIVE_OR_CORRELATE = 0x02
    PACKET_CONTROL_COALESCE = 0x04
    PACKET_CONTROL_END_STREAM = 0x08
    PACKET_CONTROL_SACK1 = 0x10
    PACKET_CONTROL_SACK2 = 0x20
    PACKET_CONTROL_SEND1 = 0x40
    PACKET_CONTROL_SEND2 = 0x80

    def __init__(self, packet=None):
        self.Command = DFrame.PACKET_COMMAND_DATA
        self.Control = 0x00
        self.Seq = 0
        self.NRcv = 0
        self.SACKMask1 = b''
        self.SACKMask2 = b''
        self.SendMask1 = b''
        self.SendMask2 = b''
        self.Signature = b''
        self.SessID = b''
        self.Payload = b''

        if packet:
            self.parse(packet)

    def parse(self, packet):
        packet.seek(0)
        self.Command = packet.getByte()
        self.Control = packet.getByte()
        self.Seq = packet.getByte()
        self.NRcv = packet.getByte()
        if self.Control & DFrame.PACKET_CONTROL_SACK1:
            self.SACKMask1 = packet.getLong()
        if self.Control & DFrame.PACKET_CONTROL_SACK2:
            self.SACKMask2 = packet.getLong()
        if self.Control & DFrame.PACKET_CONTROL_SEND1:
            self.SendMask1 = packet.getLong()
        if self.Control & DFrame.PACKET_CONTROL_SEND2:
            self.SendMask2 = packet.getLong()

        # TODO: handle signature

        if self.Control & DFrame.PACKET_CONTROL_KEEPALIVE_OR_CORRELATE:
            self.SessID = packet.getLong()
        self.Payload = packet.read()

    def to_packet(self):
        packet = Packet()
        packet.putByte(self.Command)
        packet.putByte(self.Control)
        packet.putByte(self.Seq)
        packet.putByte(self.NRcv)
        if self.Control & DFrame.PACKET_CONTROL_SACK1:
            packet.putLong(self.SACKMask1)
        if self.Control & DFrame.PACKET_CONTROL_SACK2:
            packet.putLong(self.SACKMask2)
        if self.Control & DFrame.PACKET_CONTROL_SEND1:
            packet.putLong(self.SendMask1)
        if self.Control & DFrame.PACKET_CONTROL_SEND2:
            packet.putLong(self.SendMask2)
        if self.Signature:
            packet.putLongLong(self.Signature)
        if self.Control & DFrame.PACKET_CONTROL_KEEPALIVE_OR_CORRELATE:
            packet.putLong(self.SessID)
        packet.putBytes(self.Payload)

        return packet