# babelizer.py - API for simple access to babelfish.altavista.com.
#                Requires python 2.0 or better.
#
# $Id: babeliser.py,v 1.1 2001/09/04 23:45:33 riaan Exp $
#
# Copyright 2001 by Jonathan Feinberg <jdf@pobox.com>
# http://MrFeinberg.com
#
#                All Rights Reserved
#
# Permission to use, copy, modify, and distribute this software and
# its documentation for any purpose and without fee is hereby granted,
# provided that the above copyright notice appear in all copies and
# that both that copyright notice and this permission notice appear in
# supporting documentation, and that the name of Jonathan Feinberg not
# be used in advertising or publicity pertaining to distribution of
# the software without specific, written prior permission.
#
# Jonathan Feinberg DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
# SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
# FITNESS, IN NO EVENT SHALL Jonathan Feinberg BE LIABLE FOR ANY
# SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
# RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
# CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#
# I feel goofy putting in a boilerplate disclaimer for such a
# frivolous piece of code, but this is a litigious society.
#
"""API for simple access to babelfish.altavista.com.

Summary:

    import babelizer

        print ' '.join(babelizer.available_languages)

    print babelizer.translate( 'How much is that doggie in the window?',
                                       'English', 'French' )

    def babel_callback(phrase):
                print phrase
                sys.stdout.flush()

        babelizer.babelize( 'I love a reigning knight.',
                                                'English', 'German',
                                                callback = babel_callback )

available_languages
    A list of languages available for use with babelfish.

translate( phrase, from_lang, to_lang )
    Uses babelfish to translate phrase from from_lang to to_lang.

babelize(phrase, from_lang, through_lang, limit = 12, callback = None)
    Uses babelfish to translate back and forth between from_lang and
    through_lang until either no more changes occur in translation or
    limit iterations have been reached, whichever comes first.  Takes
    an optional callback function which should receive a single
    parameter, being the next translation.  Without the callback
    returns a list of successive translations.

It's only guaranteed to work if 'english' is one of the two languages
given to either of the translation methods.

Both translation methods throw exceptions which are all subclasses of
BabelizerError.  They include

LanguageNotAvailableError
    Thrown on an attempt to use an unknown language.

BabelfishChangedError
    Thrown when babelfish.altavista.com changes some detail of their
    layout, and babelizer can no longer parse the results or submit
    the correct form (a not infrequent occurance).

BabelizerIOError
    Thrown for various networking and IO errors.

Version: $Id: babeliser.py,v 1.1 2001/09/04 23:45:33 riaan Exp $
Author: Jonathan Feinberg <jdf@pobox.com>
"""
import re, string, urllib

"""
Various patterns I have encountered in looking for the babelfish result.
We try each of them in turn, based on the relative number of times I've
seen each of these patterns.  $1.00 to anyone who can provide a heuristic
for knowing which one to use.   This includes AltaVista employees.
"""
__where = [ re.compile(r'name=\"q\">([^<]*)'),
            re.compile(r'td bgcolor=white>([^<]*)'),
            re.compile(r'<\/strong><br>([^<]*)')
          ]

__languages = { 'english'   : 'en',
                'french'    : 'fr',
                'spanish'   : 'es',
                'german'    : 'de',
                'italian'   : 'it',
                'portugese' : 'pt',
              }

"""
  All of the available language names.
"""
#available_languages = [ x.title() for x in __languages.keys() ]
available_languages = map(string.capitalize, __languages.keys())

"""
  Calling translate() or babelize() can raise a BabelizerError
"""
class BabelizerError(Exception):
    pass

class LanguageNotAvailableError(BabelizerError):
    pass
class BabelfishChangedError(BabelizerError):
    pass
class BabelizerIOError(BabelizerError):
    pass

def clean(text):
#    return ' '.join(string.replace(text.strip(), "\n", ' ').split())
    return string.join(string.split(string.replace(string.strip(text), "\n", ' ')))

def translate(phrase, from_lang, to_lang):
    phrase = clean(phrase)
    try:
##        from_code = __languages[from_lang.lower()]
##        to_code = __languages[to_lang.lower()]
        from_code = __languages[string.lower(from_lang)]
        to_code = __languages[string.lower(to_lang)]
    except KeyError, lang:
        raise LanguageNotAvailableError(lang)

    params = urllib.urlencode( { 'BabelFishFrontPage' : 'yes',
                                 'doit' : 'done',
                                 'urltext' : phrase,
                                 'lp' : from_code + '_' + to_code } )
    try:
        response = urllib.urlopen('http://babelfish.altavista.com/tr', params)
    except IOError, what:
        raise BabelizerIOError("Couldn't talk to server: %s" % what)
    except:
        print "Unexpected error:", sys.exc_info()[0]

    html = response.read()
    for regex in __where:
        match = regex.search(html)
        if match: break
    if not match: raise BabelfishChangedError("Can't recognize translated string.")
    return clean(match.group(1))

def babelize(phrase, from_language, through_language, limit = 12, callback = None):
    phrase = clean(phrase)
    seen = { phrase: 1 }
    if callback:
        callback(phrase)
    else:
        results = [ phrase ]
    flip = { from_language: through_language, through_language: from_language }
    next = from_language
    for i in range(limit):
        phrase = translate(phrase, next, flip[next])
        if seen.has_key(phrase): break
        seen[phrase] = 1
        if callback:
            callback(phrase)
        else:
            results.append(phrase)
        next = flip[next]
    if not callback: return results

if __name__ == '__main__':
    import sys
    def printer(x):
        print x
        sys.stdout.flush();


##    babelize("I won't take that sort of treatment from you, or from your doggie!",
##             'english', 'french', callback = printer)
    babelize("Für die Validierung der Ausgabedatei catalog.xml sollte ebenfalls ein Perl-Modul zur Anwendung kommen", 'German', 'English', callback = printer)

