#!/usr/bin/python
# -*- coding: utf-8 -*-

import os, sys, re, time, subprocess

    # Pen button to switch
wacBtn = 'Button2'

    # X buttons to choose from
xBtns = ['2', '3']


## If a local xsetwacom is installed, it should probably take precedent (?)
if os.path.isfile('/usr/local/bin/xsetwacom'):
    xsetwacom = '/usr/local/bin/xsetwacom'
elif os.path.isfile('/usr/bin/xsetwacom'):
    xsetwacom = '/usr/bin/xsetwacom'
else:
    ## If it's not one of those two, just hope it's in the path somewhere.
    xsetwacom = 'xsetwacom'

xinput = '/usr/bin/xinput'

def main():
    if len(sys.argv) < 2:     # No button specified, just go to the next one in the preferred list
        cb = getCurrentButton()
        if cb in xBtns:
            cInd = (xBtns.index(cb)+1) % len(xBtns)
            next = xBtns[cInd]
        else:
            next = xBtns[0]
    else:
        next = sys.argv[1]
        if not next in xBtns:
            sys.stderr.write("Button %s not allowed.\n" % next)
            sys.exit(-1)
    print "Setting %s to %s" % (wacBtn, next)
    setButton(next)



def runCmd(cmd):
    c = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
    rval = c.wait()
    stdout = c.stdout.read()
    stderr = c.stderr.read()
    if rval != 0:
        sys.stderr.write("WARNING--Command failed (returned %d):\n  %s\n" % (rval, cmd))
        sys.stderr.write(stdout)
        sys.stderr.write(stderr)
    return (rval, stdout.split('\n'), stderr.split('\n'))

#def runCmd(cmd):
    #f = os.popen(cmd)
    #l = f.readlines()
    #f.close()
    #return l

def getCurrentButton():
    setEnv()
    b = runCmd("xsetwacom get %s %s" % (listDevices()[0], wacBtn))[1][0].strip()
    #print "current:", b
    return b

def setButton(b):
    setEnv()
    #print "devices:", listDevices()
    for d in listDevices():
        runCmd("xsetwacom set %s %s %s" % (d, wacBtn, b))
            ## workaround for xsetwacom bug
        runCmd("xsetwacom set %s Button1 1" % d)
    for i in range(0, int(b)):
        setLed(0, "off")
        time.sleep(0.1)
        setLed(0, "on")
        time.sleep(0.1)

def setEnv():
    if os.system('pidof kdm') == 0:
        kdmsts = '/var/lib/kdm/kdmsts'
        if os.access(kdmsts, os.R_OK):
            kdmdata = open(kdmsts).readlines()
            userline = filter(lambda s: re.match(r':0=', s), kdmdata)[0]
            user = re.sub(r':0=', '', userline).strip()
            os.environ['DISPLAY'] = ':0.0'
            os.environ['XAUTHORITY'] = '/home/%s/.Xauthority' % user
    elif os.system('pidof gdm') == 0:
        os.environ['DISPLAY'] = ':0.0'
        os.environ['XAUTHORITY'] = '/var/lib/gdm/:0.Xauth'
    
def setLed(n, mode):
    fd = open('/proc/acpi/ibm/led', 'w')
    fd.write("%d  %s" % (n, mode))
    fd.close()

def listDevices():
    cmd = runCmd("%s --list" % xinput)[1]                                                                                                                                    
    dev = []                                                                                                                                                                 
    for s in cmd:                                                                                                                                                            
        m = re.search(r'Serial Wacom Table.*id=\d*', s)                                                                                                                      
        if m != None:                                                                                                                                                        
            dev.append(re.sub(r'[\WA-Za-z]', '', m.group(0)))                                                                                                                 
    return dev     


main()