#!/usr/bin/python
import os,sys,re

import urllib, cgi

import cgitb
cgitb.enable()
form = cgi.FieldStorage()

# blacklist taken from wp-latex:
# http://wordpress.org/extend/plugins/wp-latex/
blacklist=['^^',\
    'afterassignment',\
    'aftergroup',\
    'batchmode',\
    'catcode',\
    'closein',\
    'closeout',\
    'command',\
    'csname',\
    'document',\
    'def',\
    'errhelp',\
    'errcontextlines',\
    'errorstopmode',\
    'every',\
    'expandafter',\
    'immediate',\
    'include',\
    'input',\
    'jobname',\
    'loop',\
    'lowercase',\
    'makeat',\
    'meaning',\
    'message',\
    'name',\
    'newhelp',\
    'noexpand',\
    'nonstopmode',\
    'open',\
    'output',\
    'pagestyle',\
    'package',\
    'pathname',\
    'read',\
    'relax',\
    'repeat',\
    'shipout',\
    'show',\
    'scrollmode',\
    'special',\
    'syscall',\
    'toks',\
    'tracing',\
    'typeout',\
    'typein',\
    'uppercase',\
    'write']

sys.stdout.write('Content-type: image/png\n\n')
badtex()
latex = "$$p_n=\\frac{\\pi}{n^2}$$"

def badtex():
    f=open('_img/badtex.png','rb')
    sys.stdout.write(f.read())
    f.close()
    sys.exit(0)

for word in blacklist:
    if word in latex:
        badtex()
        
if re.search("/(^|[^\\\\])\$/",latex):
    badtex()
    sys.exit(0)