# nxt.bluesock module -- Bluetooth socket communication with LEGO Minstorms NXT
# Copyright (C) 2006-2007  Douglas P Lau
# Copyright (C) 2009  Marcus Wanner
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

import bluetooth
import os
from nxt.brick import Brick

class BlueSock(object):

	bsize = 118	# Bluetooth socket block size
	PORT = 1	# Standard NXT rfcomm port

	def __init__(self, host):
		self.host = host
		self.sock = None
		self.debug = False

	def __str__(self):
		return 'Bluetooth (%s)' % self.host

	def connect(self):
                if self.debug:
                        print 'Connecting via Bluetooth...'
		sock = bluetooth.BluetoothSocket(bluetooth.RFCOMM)
		sock.connect((self.host, BlueSock.PORT))
		self.sock = sock
		if self.debug:
                        print 'Connected.'
		return Brick(self)

	def close(self):
                if self.debug:
                        print 'Closing Bluetooth connection...'
		self.sock.close()
		if self.debug:
                        print 'Bluetooth connection closed.'

	def send(self, data):
		if self.debug:
			print 'Send:',
			print ':'.join('%02x' % ord(c) for c in data)
		l0 = len(data) & 0xFF
		l1 = (len(data) >> 8) & 0xFF
		d = chr(l0) + chr(l1) + data
		self.sock.send(d)

	def recv(self):
		data = self.sock.recv(2)
		l0 = ord(data[0])
		l1 = ord(data[1])
		plen = l0 + (l1 << 8)
		data = self.sock.recv(plen)
		if self.debug:
			print 'Recv:',
			print ':'.join('%02x' % ord(c) for c in data)
		return data

def _check_brick(arg, value):
	return arg is None or arg == value

def find_bricks(host=None, name=None):
	for h, n in bluetooth.discover_devices(lookup_names=True):
		if _check_brick(host, h) and _check_brick(name, n):
			yield BlueSock(h)
