#!/usr/bin/env python
"""
validate.py - Validate a File or URI
Author: Sean B. Palmer, inamidst.com
"""

import sys, urllib
import xml.dom.minidom
from optparse import OptionParser

def validator(uri): 
   return ("http://validator.w3.org/check?uri=%s" + 
           "&charset=%%28detect+automatically%%29" + 
           "&doctype=Inline&verbose=1&output=xml") % urllib.quote(uri)

def single(seq): 
   if not hasattr(seq, 'next'): 
      seq = (item for item in seq)
   first = seq.next()

   try: seq.next()
   except StopIteration: pass
   else: raise ValueError("Sequence had more than one member")
   return first

def text(element): 
   result = []
   for node in element.childNodes: 
      if node.nodeType == node.TEXT_NODE: 
         result.append(node.data)
   return ''.join(result)

def validate(uri, verbosity=1): 
   u = urllib.urlopen(validator(uri))
   bytes = u.read()
   u.close()

   doc = xml.dom.minidom.parseString(bytes)

   doctype = single(doc.getElementsByTagName("doctype"))
   doctype = text(doctype)

   if doctype.startswith('-//W3C//DTD ') and doctype.endswith('//EN'): 
      doctype = doctype[12:-4]

   errors = single(doc.getElementsByTagName("errors"))
   errors = int(text(errors))

   if not errors: 
      if verbosity > 0: 
         print "Valid %s" % doctype
      sys.exit(0)
   else: 
      if verbosity > 0: 
         print "Invalid %s (%s errors)" % (doctype or 'HTML', errors)
      if verbosity > 1: 
         print bytes # @@
      sys.exit(1)

def main(): 
   parser = OptionParser(usage="%prog [options] <input>")
   parser.add_option("-q", "--quiet", dest="quiet", action="store_true", 
                     default=False, help="produce no output")
   parser.add_option("-v", "--verbose", dest="verbose", action="store_true", 
                     default=False, help="produce much output")
   options, args = parser.parse_args()

   if options.quiet and options.verbose: 
      parser.error("-q and -v are mutally exclusive")

   if options.quiet: 
      verbosity = 0
   elif options.verbose: 
      verbosity = 2
   else: verbosity = 1

   if len(args) != 1: 
      parser.print_help()
   else: uri = args[0]

   validate(uri, verbosity=verbosity)

if __name__=="__main__": 
   main()