import xml.etree.ElementTree as ElementTree
import sys

FILE_IN = sys.argv[1]
FILE_OUT = sys.argv[2]

with open(FILE_IN, "r") as fp:
    xml_tree = ElementTree.XML(fp.read())

SEARCH_FOR = ["u1"]
ID = "ozbo_id" # should be the same in all files!

out_xml = ElementTree.Element('top')

ctr = 0
def add_ctr(el, previous=False):
    global ctr
    if previous:
        el.attrib[ID] = str(ctr - 1)
    else:
        el.attrib[ID] = str(ctr)
        ctr += 1

empty = ElementTree.Element('')
last_w1 = empty
last_w2 = empty

for idx, el in enumerate(xml_tree.findall(".//*")):
    if el.tag == "w3":
        add_ctr(el)
        
    elif el.tag == "w2":
        add_ctr(el, el.text == last_w2.text)
        last_w2 = el
    
    elif el.tag == "w1":
        add_ctr(el, el.text == last_w1.text)
        last_w1 = el
        
    # reset last_w1 lastw2
    elif el.tag == "S":
        last_w1 = empty
        last_w2 = empty


with open(FILE_OUT, "wb") as fp:
    fp.write(ElementTree.tostring(xml_tree, encoding='utf8', method='xml'))