#!/usr/bin/python
#-*- coding: UTF-8 -*-
import os, time
import usb.core
import usb.util
from sys import exit

#DYMO M25
VENDOR_ID = 0x0922
PRODUCT_ID = 0x8004

def connect():
    # find the USB device
    dev = usb.core.find(idVendor=VENDOR_ID, idProduct=PRODUCT_ID)
    if dev is None:
        print("device not found")
    else:
        devmanufacturer = usb.util.get_string(dev, dev.iManufacturer)
        devname = usb.util.get_string(dev,  dev.iProduct)
        serialno = usb.util.get_string(dev, dev.iSerialNumber)
        print("device found: ", devmanufacturer, devname, serialno)

        interface = 0
        try:
            dev.detach_kernel_driver(interface)
        except usb.core.USBError as e:
            exit("Kernel driver won't give up control over device: %s" % str(e))
        try:
            # use the first/default configuration
            dev.set_configuration()
            dev.reset()
            usb.util.claim_interface(dev, interface)
            print("claiming device")
        except:
            exit("Cannot set configuration the device: %s" % str(e))
    return dev

def disconnect(dev):
    interface = 0
    print('release claimed interface')
    usb.util.release_interface(dev, interface)
    print('now attaching the kernel driver again')
    dev.attach_kernel_driver(0)
    print('device disconnected')

def analyzeData(data):
    DATA_MODE_GRAMS = 2
    DATA_MODE_OUNCES = 11

    weight = 0

    if data != None:
        raw_weight = data[4] + data[5] * 256

    if raw_weight > 0 and data[1] == 4:
        if data[2] == DATA_MODE_OUNCES:
            ounces = raw_weight * 0.1
            weight = "%s oz" % ounces
        elif data[2] == DATA_MODE_GRAMS:
            grams = raw_weight
            #convert to ounces
            grams = round(grams / 28.3495, 2)
            weight = "%s oz" % grams

        print("stable weight: " + weight)

    if raw_weight == 0:
        print('All zeros')


def grabData(dev):
    try:
        # first endpoint
        endpoint = dev[0][(0,0)][0] #get the first endpoint for the first interface and alt setting for the first configuration
        # read a data packet
        attempts = 5
        data = []
        while (data is None or len(data) < 6) and attempts > 0:
            try:
                data = dev.read(endpoint.bEndpointAddress,
                                endpoint.wMaxPacketSize,
                                timeout=2000)
                print(data, len(data), type(data))
            except usb.core.USBError as e:
                data = None
                print(str(e.args))
                if e.args[0] == 110: #timeout
                    attempts -= 1
                    print("timed out... trying again")
                    continue
                elif e.args[0] is None:
                    print("Error: ", e.args[1])
                    continue
                #if e.args[0] == libusb._libusb_errno[libusb.LIBUSB_ERROR_PIPE]:
                #    print("broken pipe" )
                #if e.args[0] == libusb._libusb_errno[libusb.LIBUSB_ERROR_TIMEOUT]:
                #    attempts -= 1
                #    print("timed out... trying again")
                #    continue

        return data
    except usb.core.USBError as e:
        print("USBError: " + str(e.args))
    except IndexError as e:
        print("IndexError: " + str(e.args))

#############main################
while True:
    dev = connect()
    if dev is not None:
        print('Connected')
        data = grabData(dev)
        print('Got data: ' + str(data))
        analyzeData(data)
        print('Data Analyzed')
        print(str(grabData(dev)))
        print('data cleared')
        disconnect(dev)