def get_width_height( fname, orig_modtime=None ):
    """get (possibly cached) width and height of .svg file with inkscape"""
    # compute filename of cached width/height
    wh_cache_path, wh_cache_fname = os.path.split(fname)
    wh_cache_fname = CACHE_PREFIX+os.path.splitext(wh_cache_fname)[0]+'.txt'
    wh_cache_fname = os.path.join( wh_cache_path, wh_cache_fname )

    # read cache if it exists
    if os.path.exists( wh_cache_fname ):
        modtime = os.stat(wh_cache_fname)[stat.ST_MTIME]
        if orig_modtime is None:
            orig_modtime = os.stat(fname)[stat.ST_MTIME]
        if modtime > orig_modtime:
            width,height = open( wh_cache_fname ).read().strip().split()
            return width,height

    # no cache, query inkscape for information
    tmpf = tempfile.NamedTemporaryFile(suffix='.png')
    tmpf.close()
    cmd = [INKSCAPE,'-C',fname,'-e',tmpf.name]
    get_stdout(cmd)
    import Image
    # XXX TODO: convert to reading XML file instead of using PIL
    im = Image.open(tmpf.name)
    (width, height) = im.size
    os.unlink(tmpf.name)

    fd = open (wh_cache_fname,mode="w")
    fd.write("%s %s\n"%(width,height))
    fd.close()
    return width, height

def p2p_set_nego(mac):
    print 'p2p_set_nego:'
    print 'mac: %s' % mac
    get_stdout('iwpriv eth0 p2p_set nego=%s' % mac)

    # Enter negotiation loop
    while 1:

        # Wait for result
        time.sleep(0.5)

        # Poll status
        peer_status = p2p_status_get()
        print 'peer_status: %d' % peer_status

        # For Windows 8.1 support, we consider 19 as negotiation completed
        if peer_status in [10, 19]:
            print 'Negotiation suceeded!'
            break

    # Get role
    role = p2p_role_get()
    print 'Role: %s' % role

    # TODO: doesn't seem to return anything
    #p2p_opch_get()

    # Get peer interface address
    peer_mac_get()

    p2p_go_mode_set()

def wfd_connection_wait():
    get_stdout(cmd_killall_wpa_spplicant)
    get_stdout(cmd_killall_hostapd)

    # Disable p2p
    p2p_disable()

    time.sleep(0.5)

    # Enable p2p
    p2p_enable()

    #p2p_peer_scan()

    print 'Waiting for incoming connection...'

    while 1:

        peer_status = p2p_status_get()

        print 'peer_status: %d' % peer_status

        if peer_status == 0:
            print 'p2p disabled! Re-enable p2p...'
            p2p_enable()

        if peer_status in [8, 19, 22]:
            # Discovery request or gonego fail
            print 'Discovery request received!'
            peer_found = p2p_peer_scan()

            if peer_found:
                break

            p2p_disable()

        time.sleep(1)

    print 'Getting peer device address...'

    # Get peer device address
    mac = p2p_peer_devaddr_get()
    print 'peer_devaddr: %s' % mac

    # Notify received wps info
    p2p_wpsinfo()

    print 'Getting peer authentication type...'

    # Get request configuration
    p2p_req_cm_get()

    print 'Confirming peer authentication...'

    # Set negotiation
    p2p_set_nego(mac)

def p2p_go_mode_set():

    # Start hostAPd and wait for it to daemonize; ignore stdout
    get_stdout(["./hostapd", "-B", "p2p_hostapd.conf"])

    # Wait for initialization
    time.sleep(1)

    do_wps()

    # Wait for host apd interval
    time.sleep(1)

def p2p_peer_port_get():
    print 'p2p_peer_port_get:'
    output = get_stdout('iwpriv wlan0 p2p_get peer_port')
    print output
    match = re.search(r'^Port=(\d+)$', output, re.M)
    print match.group(1)
    return int(match.group(1))

def p2p_peer_devaddr_get():
    print 'p2p_peer_devaddr_get:'
    output = get_stdout(["iwpriv", "wlan0", "p2p_get", "peer_deva"])
    match = re.search(r'\n(.*)$', output)
    mac = ':'.join(re.findall('..', match.group(1)))

    return mac

def p2p_enable():

    # Enable p2p
    get_stdout('iwpriv eth0 p2p_set enable=1')

    # Set intent
    get_stdout('iwpriv eth0 p2p_set intent=15')

    # Set operation channel
    get_stdout('iwpriv eth0 p2p_set op_ch=%d' % 11)

    # Sleep for 50ms
    time.sleep(0.05)

    # Set ssid
    get_stdout('iwpriv eth0 p2p_set ssid=DIRECT-RT')

    # Set DN
    get_stdout('iwpriv eth0 p2p_set setDN=Piracast')

def p2p_go_mode_set():

    # Start hostAPd and wait for it to daemonize; ignore stdout
    get_stdout(["./hostapd", "-B", "p2p_hostapd.conf"])

    # Wait for initialization
    time.sleep(1)

    do_wps()

    # Wait for host apd interval
    time.sleep(1)

    while 1:
        status = read_all_sta()

        if status:
            print 'Wireless display negotiation completed!'
            break

        time.sleep(1)

def p2p_peer_devaddr_get():
    print 'p2p_peer_devaddr_get:'
    output = get_stdout(["iwpriv", "wlan0", "p2p_get", "peer_deva"])
    match = re.search(r'\n(.*)$', output)
    mac = '%s%s:%s%s:%s%s:%s%s:%s%s:%s%s' % match.group(1)[0:11]
    #mac = match.group(1)[0] + match.group(1)[1] + ':' \
    #    + match.group(1)[2] + match.group(1)[3] + ':' \
    #    + match.group(1)[4] + match.group(1)[5] + ':' \
    #    + match.group(1)[6] + match.group(1)[7] + ':' \
    #    + match.group(1)[8] + match.group(1)[9] + ':' \
    #    + match.group(1)[10] + match.group(1)[11]

    return mac

def do_wps():

    while 1:
        print 'do_wps:'
        output = get_stdout(["./hostapd_cli", "wps_pbc", "any"])

        print output

        if 'OK' in output:
            print 'wps passed!'
            return

        time.sleep(1)

def p2p_peer_scan():
    count = 0

    while 1:
        output = get_stdout(cmd_iwlist_eth0_scan)

        print output

        if 'No scan results' not in output:
            return True

        if count > 3:
            return False

        count += 1

def p2p_peer_devaddr_get():
    print 'p2p_peer_devaddr_get:'
    output = get_stdout('iwpriv wlan0 p2p_get peer_deva')
    print output
    match = re.search(r'^([0-9A-Fa-f]{12})$', output, re.M)
    print match.group(1)
    mac = '%s:%s:%s:%s:%s:%s' % tuple(re.findall('[0-9A-Fa-f]{2}',match.group(1)))
    print mac
    #mac = match.group(1)[0] + match.group(1)[1] + ':' \
    #    + match.group(1)[2] + match.group(1)[3] + ':' \
    #    + match.group(1)[4] + match.group(1)[5] + ':' \
    #    + match.group(1)[6] + match.group(1)[7] + ':' \
    #    + match.group(1)[8] + match.group(1)[9] + ':' \
    #    + match.group(1)[10] + match.group(1)[11]

    return mac

def p2p_status_get():
    #print 'p2p_status_get:'
    output = get_stdout('iwpriv eth0 p2p_get status')
    match = re.search(r'Status=(\d*)', output)
    return int(match.group(1))

def p2p_wpsinfo():
    print 'p2p_wpsinfo:'
    get_stdout('iwpriv eth0 p2p_set got_wpsinfo=3')

def wps_status_get():
    print 'wps_status_get:'
    output = get_stdout(["./wpa_cli", "status"])
    print output

def wps_auth():
    print 'wps_auth:'
    output = get_stdout(["./hostapd_cli", "wps_pbc", "any"])
    print output
    time.sleep(1)

def wpa_supplicant_start():
    print 'wpa_supplicant_start:'
    get_stdout(["./wpa_supplicant", "-i", "eth0", "-c", "./wpa_0_8.conf", "-B"])
    time.sleep(1)

def p2p_role_get():
    print 'p2p_role_get:'
    output = get_stdout('iwpriv eth0 p2p_get role')
    match = re.search(r'Role=(\d*)', output)
    role = int(match.group(1))
    return role

lease_file = '/var/lib/dhcp/dhcpd.leases'

def lease_file_timestamp_get():
    return get_stdout('ls -l "%s"' % lease_file)

# get the leased IP address
def leased_ip_get():
    contents = open(lease_file).read()
    ip_list = re.findall(r'lease (\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})', contents)

    # return the most recently leased IP address
    return ip_list[-1]

print 'Bring up eth0 just in case...'
get_stdout(cmd_eth0_up)

print 'Increase rmem_default...'
get_stdout(cmd_inc_rmem_default)

# Don't kill running application as
# it is started explicitly
#print 'Kill running application...'
#core_channel.end()
#print get_stdout(cmd_kill_core_app)

while 1:

    # Don't launch application, because it stuck
    # the execution
    # get_stdout(cmd_launch_core_app)

def p2p_disable():
    get_stdout('iwpriv eth0 p2p_set enable=0')