import os, os.path,sys
from xml.etree import ElementTree as et

def select_files_in_folder(dir, ext):
  for file in os.listdir(dir):
    if file.endswith('.%s' % ext):
      if file.startswith(sys.argv[2]): continue
      yield os.path.join(dir, file)

def combine_xml(files):
  first = None
  for filename in files:
    data = et.parse(filename).getroot()
    if first is None:
      first = data
    else:
      first.extend(data)
  if first is not None:
    return et.ElementTree(first).write(sys.argv[2])

def run(files):
  content = None
  fileNum = 0
  content = combine_xml(files)
  if content is not None:
    with open(sys.argv[2], "w") as text_file:
      text_file.write(str(content))

if __name__ == "__main__":
  if (len(sys.argv) != 3):
    print("""
USAGE: XMLmerrge <dir> <merged_xml_file>
<dir> is the directory, where the source xml files are
<merged_xml_file> is the path and name of the merged xml file.
Example XMLmerrge trafficSrc trafficSrc\trafficSrc.xml
""")
    sys.exit(1)
  else:
    print ("Start XML merging in '{dir}' folder ...".format(dir=sys.argv[1]))
    fileNum = run(select_files_in_folder(sys.argv[1], 'xml'))
    print ("Done")