#!/usr/bin/python
#
# Verify the <indexterm> ranges of a docbook document, ensuring
# endofrange come after startofrange, and the IDs used by startofrange
# are unique.

from  lxml import etree
import subprocess

def main():
    filename = 'freeculture.xml'

    # make sure entities are looked up / available
    # Based on idea from
    # http://stackoverflow.com/questions/14731633/how-to-resolve-external-entities-with-xml-etree-like-lxml-etree
    proc = subprocess.Popen(['xmllint','--noent',filename],stdout=subprocess.PIPE)
    output = proc.communicate()[0]
    doc = ElementTree.parse(StringIO.StringIO(output))

    ids = {}
    order = 0
    for it in doc.getroot().xpath('//indexterm'):
        order = order + 1
        indextermclass = None
        id = None
        if 'class' in it.attrib:
            indextermclass = it.attrib['class']
            if 'startofrange' == indextermclass:
                id=it.attrib['id']
                if id in ids:
                    print "error: non-unique indexterm id: %s" % id
                ids[id] = order
            if  'endofrange' == indextermclass:
                id = it.attrib['startref']
                if id not in ids:
                    print "error: indexterm id=\"%s\" not listed before endofrange" % id
            print indextermclass, id

if __name__ == "main":
    main()