# nxt.usbsock module -- USB 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 usb
from nxt.brick import Brick

ID_VENDOR_LEGO = 0x0694
ID_PRODUCT_NXT = 0x0002

class USBSock(object):
        'Object for USB connection to NXT'

	bsize = 60	# USB socket block size

	def __init__(self, device):
		self.device = device
		self.handle = None
		self.debug = False

	def __str__(self):
		return 'USB (%s)' % (self.device.filename)

	def connect(self):
                'Use to connect to NXT.'
                if self.debug:
                        print 'Connecting via USB...'
		config = self.device.configurations[0]
		iface = config.interfaces[0][0]
		self.blk_out, self.blk_in = iface.endpoints
		self.handle = self.device.open()
		self.handle.setConfiguration(1)
		self.handle.claimInterface(0)
		if self.debug:
                        print 'Connected.'
		return Brick(self)

	def close(self):
                'Use to close the connection.'
                if self.debug:
                        print 'Closing USB connection...'
		self.device = None
		self.handle = None
		self.blk_out = None
		self.blk_in = None
		if self.debug:
                        print 'USB connection closed.'

	def send(self, data):
                'Use to send raw data over USB connection ***ADVANCED USERS ONLY***'
		if self.debug:
			print 'Send:',
			print ':'.join('%02x' % ord(c) for c in data)
		self.handle.bulkWrite(self.blk_out.address, data)

	def recv(self):
                'Use to recieve raw data over USB connection ***ADVANCED USERS ONLY***'
		data = self.handle.bulkRead(self.blk_in.address, 64)
		if self.debug:
			print 'Recv:',
			print ':'.join('%02x' % (c & 0xFF) for c in data)
		# NOTE: bulkRead returns a tuple of ints ... make it sane
		return ''.join(chr(d & 0xFF) for d in data)

def find_bricks(host=None, name=None):
        'Use to look for NXTs connected by USB only. ***ADVANCED USERS ONLY***'
	# FIXME: probably should check host and name
	for bus in usb.busses():
		for device in bus.devices:
			if device.idVendor == ID_VENDOR_LEGO and \
			   device.idProduct == ID_PRODUCT_NXT:
				yield USBSock(device)
