import re
import os
import sys
from sgmllib import SGMLParser

try:
    import win32api
    WIN32 = True
except ImportError:
    WIN32 = False

class MissingBinary(Exception): pass

envPath = os.environ['PATH']
bin_search_path = [path for path in envPath.split(os.pathsep)
                   if os.path.isdir(path)]

cygwin = 'c:/cygwin'

# cygwin support
if sys.platform == 'win32' and os.path.isdir(cygwin):
    for p in ['/bin', '/usr/bin', '/usr/local/bin' ]:
        p = os.path.join(cygwin, p)
        if os.path.isdir(p):
            bin_search_path.append(p)

if sys.platform == 'win32':
    extensions = ('.exe', '.com', '.bat', )
else:
    extensions = ()

def bin_search(binary):
    """search the bin_search_path  for a given binary
    returning its fullname or raises MissingBinary"""
    result = None
    mode   = os.R_OK | os.X_OK
    for path in bin_search_path:
        for ext in ('', ) + extensions:
            pathbin = os.path.join(path, binary) + ext
            if os.access(pathbin, mode) == 1:
                result = pathbin
                break
    if not result:
        raise MissingBinary('Unable to find binary "%s" in %s' % 
                             (binary, os.pathsep.join(bin_search_path)))
    else:
        return result

def getShortPathName(binary):
    if WIN32:
        try:
            binary = win32api.GetShortPathName(binary)
        except win32api.error:
            log("Failed to GetShortPathName for '%s'" % binary)
    return binary

def sansext(path):
    return os.path.splitext(os.path.basename(path))[0]


##########################################################################
# The code below is taken from CMFDefault.utils to remove
# dependencies for Python-only installations
##########################################################################

def bodyfinder(text):
    """ Return body or unchanged text if no body tags found.

    Always use html_headcheck() first.
    """
    lowertext = text.lower()
    bodystart = lowertext.find('<body')
    if bodystart == -1:
        return text
    bodystart = lowertext.find('>', bodystart) + 1
    if bodystart == 0:
        return text
    bodyend = lowertext.rfind('</body>', bodystart)
    if bodyend == -1:
        return text
    return text[bodystart:bodyend]


#
#   HTML cleaning code
#

# These are the HTML tags that we will leave intact
VALID_TAGS = { 'a'          : 1
             , 'b'          : 1
             , 'base'       : 0
             , 'blockquote' : 1
             , 'body'       : 1
             , 'br'         : 0
             , 'caption'    : 1
             , 'cite'       : 1
             , 'code'       : 1
             , 'div'        : 1
             , 'dl'         : 1
             , 'dt'         : 1
             , 'dd'         : 1
             , 'em'         : 1
             , 'h1'         : 1
             , 'h2'         : 1
             , 'h3'         : 1
             , 'h4'         : 1
             , 'h5'         : 1
             , 'h6'         : 1
             , 'head'       : 1
             , 'hr'         : 0
             , 'html'       : 1
             , 'i'          : 1
             , 'img'        : 0
             , 'kbd'        : 1
             , 'li'         : 1
           # , 'link'       : 1 type="script" hoses us
             , 'meta'       : 0
             , 'ol'         : 1
             , 'p'          : 1
             , 'pre'        : 1
             , 'span'       : 1
             , 'strong'     : 1
             , 'table'      : 1
             , 'tbody'      : 1
             , 'td'         : 1
             , 'th'         : 1
             , 'title'      : 1
             , 'tr'         : 1
             , 'tt'         : 1
             , 'u'          : 1
             , 'ul'         : 1
             }

NASTY_TAGS = { 'script'     : 1
             , 'object'     : 1
             , 'embed'      : 1
             , 'applet'     : 1
             }

class IllegalHTML( ValueError ):
    pass

class StrippingParser( SGMLParser ):
    """ Pass only allowed tags;  raise exception for known-bad.  """

    from htmlentitydefs import entitydefs # replace entitydefs from sgmllib

    def __init__( self ):

        SGMLParser.__init__( self )
        self.result = ""

    def handle_data( self, data ):

        if data:
            self.result = self.result + data

    def handle_charref( self, name ):

        self.result = "%s&#%s;" % ( self.result, name )

    def handle_entityref(self, name):

        if self.entitydefs.has_key(name):
            x = ';'
        else:
            # this breaks unstandard entities that end with ';'
            x = ''

        self.result = "%s&%s%s" % (self.result, name, x)

    def unknown_starttag(self, tag, attrs):

        """ Delete all tags except for legal ones.
        """
        if VALID_TAGS.has_key(tag):

            self.result = self.result + '<' + tag

            for k, v in attrs:

                if k.lower().startswith( 'on' ):
                    raise IllegalHTML, 'Javascipt event "%s" not allowed.' % k

                if v.lower().startswith( 'javascript:' ):
                    raise IllegalHTML, 'Javascipt URI "%s" not allowed.' % v

                self.result = '%s %s="%s"' % (self.result, k, v)

            endTag = '</%s>' % tag
            if VALID_TAGS.get(tag):
                self.result = self.result + '>'
            else:
                self.result = self.result + ' />'

        elif NASTY_TAGS.get( tag ):
            raise IllegalHTML, 'Dynamic tag "%s" not allowed.' % tag

        else:
            pass    # omit tag

    def unknown_endtag(self, tag):

        if VALID_TAGS.get( tag ):

            self.result = "%s</%s>" % (self.result, tag)
            remTag = '</%s>' % tag


def scrubHTML( html ):
    """ Strip illegal HTML tags from string text.  """
    parser = StrippingParser()
    parser.feed( html )
    parser.close()
    return parser.result
