import struct
from msg.container import MsgContainer
from msg.listener import MsgListener
from msg.talker import MsgTalker
from ubx.ubx import UBX_SYNC_WORD, frame_parse

UBX_PKT_DEBUG = False
def ubx_pkt_debug(s: str):
	if UBX_PKT_DEBUG:
		print(s)

class UbxPacketizer(MsgListener, MsgTalker):
	def __init__(self, sync_bytes: bytes = UBX_SYNC_WORD):
		MsgListener.__init__(self)
		MsgTalker.__init__(self)
		self.sync_bytes = sync_bytes
		self.packet = b''
		self.wait_sync = True
		self.sync_count = 0
		self.d_save = b''

	def reset(self):
		self.packet = b''
		self.wait_sync = True
		self.sync_count = 0

	def is_msg(self, msg: MsgContainer):
		return True

	def on_recv(self, msg: MsgContainer):
		for d in msg.data:
			if d == self.sync_bytes[self.sync_count]:
				self.d_save += struct.pack('B', d)
				self.sync_count += 1
				if self.sync_count == len(self.sync_bytes):
					ubx_pkt_debug(f"{msg.source.name}:UBX-sync")
					if len(self.packet) > 0:
						ubx_pkt_debug(f"{msg.source.name}:Remaining packet: {self.packet}")
					self.sync_count = 0
					self.d_save = b''
					self.packet = b''
					self.wait_sync = False
			else:
				if self.sync_count > 0:
					self.packet += self.d_save
					self.d_save = b''
					self.sync_count = 0
				if not self.wait_sync:
					self.packet += struct.pack('B', d)
					data, hdr = frame_parse(self.packet)
					if data is not None:
						if hdr.length == len(data):
							self.call_listener(MsgContainer(self.packet, msg.source))
							self.packet = b''
							self.wait_sync = True