##################################################
# SPYCE - Python-based HTML Scripting
# Copyright (c) 2002 Rimon Barr.
#
# Refer to spyce.py
# CVS: $Id: transform.py 598 2005-04-20 22:18:20Z jbe $
##################################################

from spyceModule import spyceModule
import types, re, string

__doc__ = '''Transform module intercepts different kinds of Spyce ouput, and
can install functions to perform processing. It also includes some standard
Spyce transformation functions.'''

OUTPUT_POSITON = 20

class transform(spyceModule):
  def start(self):
    self.ident = lambda x, **kwargs: x
    self._filter = FilterFn(self.ident, self.ident, self.ident)
    # install filter functions into response module
    self._prevfilter = self._api.getModule('response').addFilter(OUTPUT_POSITON, self._filter)
  def finish(self, theError=None):
    self._prevfilter = self._api.getModule('response').addFilter(OUTPUT_POSITON, self._prevfilter)
  # set filters
  def dynamic(self, fn=None):
    if not fn: fn = self.ident
    self._filter.dynamicFilter = self.create(fn)
  def static(self, fn=None):
    if not fn: fn = self.ident
    self._filter.staticFilter = self.create(fn)
  def expr(self, fn=None):
    if not fn: fn = self.ident
    self._filter.exprFilter = self.create(fn)
  # create filter
  def create(self, fn):
    '''Create filter function.'''
    if fn==None or fn==() or fn==[]:
      # identity
      return self.ident
    elif type(fn) == types.FunctionType:
      # function type
      return fn
    elif type(fn) == type(''):
      # string
      file_name = string.split(fn, ':')
      if len(file_name)==1: file, name = None, file_name[0]
      else: file, name = file_name[:2]
      if file: fn = loadModule(name, file, self._api.getFilename())
      else: fn = eval(name)
      return fn
    elif type(fn) == type(()) or type(fn) == type([]):
      # tuple or array
      fn0 = self.create(fn[0])
      fn1 = self.create(fn[1:])
      def filterfn(x, _fn0=fn0, _fn1=fn1, **kwargs):
        x = apply(_fn0, (x,), kwargs)
        return apply(_fn1, (x,), kwargs)
      return filterfn
  # commonly used transformations
  def html_encode(self, s, also='', **kwargs):
    '''Return HTML-encoded string.'''
    return html_encode(s, also)
  def url_encode(self, s, **kwargs):
    '''Return url-encoded string.'''
    return url_encode(s)
  def __repr__(self):
    return 'static: %s, expr: %s, dynamic: %s' % (
      str(self._filter.staticFilter!=self.ident),
      str(self._filter.exprFilter!=self.ident),
      str(self._filter.dynamicFilter!=self.ident),
    )

try:
  eval('Filter')
except NameError:
  from response import Filter
class FilterFn(Filter):
  def __init__(self, dynamicFilter=None, staticFilter=None, exprFilter=None):
    ident = lambda x: x
    if not dynamicFilter: dynamicFilter = ident
    if not staticFilter: staticFilter = ident
    if not exprFilter: exprFilter = ident
    self.dynamicFilter = dynamicFilter
    self.staticFilter = staticFilter
    self.exprFilter = exprFilter
  def dynamicImpl(self, s, *args, **kwargs):
    return apply(self.dynamicFilter, (s,)+args, kwargs)
  def staticImpl(self, s, *args, **kwargs):
    return apply(self.staticFilter, (s,)+args, kwargs)
  def exprImpl(self, s, *args, **kwargs):
    return apply(self.exprFilter, (s,)+args, kwargs)
  def flushImpl(self):
    pass
  def clearImpl(self):
    pass

# standard transformation functions
def ignore_none(o, **kwargs):
  '''Does not print None.'''
  if o==None: return ''
  else: return o

def silence(o, **kwargs):
  '''Gobbles anything.'''
  return ''

def truncate(o, maxlen=None, **kwargs):
  '''Limits output to a maximum string length.'''
  if maxlen!=None: return str(o)[:maxlen]
  else: return o

_html_enc = { 
  chr(34): '"', chr(38): '&', chr(60): '<', chr(62): '>',
  chr(160): ' ', chr(161): '¡', chr(162): '¢', chr(163): '£',
  chr(164): '¤', chr(165): '¥', chr(166): '¦', chr(167): '§',
  chr(168): '¨', chr(169): '©', chr(170): 'ª', chr(171): '«',
  chr(172): '¬', chr(173): '­', chr(174): '®', chr(175): '¯',
  chr(176): '°', chr(177): '±', chr(178): '²', chr(179): '³',
  chr(180): '´', chr(181): 'µ', chr(182): '¶', chr(183): '·',
  chr(184): '¸', chr(185): '¹', chr(186): 'º', chr(187): '»',
  chr(188): '¼', chr(189): '½', chr(190): '¾', chr(191): '¿',
  chr(192): 'À', chr(193): 'Á', chr(194): 'Â', chr(195): 'Ã',
  chr(196): 'Ä', chr(197): 'Å', chr(198): 'Æ', chr(199): 'Ç',
  chr(200): 'È', chr(201): 'É', chr(202): 'Ê', chr(203): 'Ë',
  chr(204): 'Ì', chr(205): 'Í', chr(206): 'Î', chr(207): 'Ï',
  chr(208): 'Ð', chr(209): 'Ñ', chr(210): 'Ò', chr(211): 'Ó',
  chr(212): 'Ô', chr(213): 'Õ', chr(214): 'Ö', chr(215): '×',
  chr(216): 'Ø', chr(217): 'Ù', chr(218): 'Ú', chr(219): 'Û',
  chr(220): 'Ü', chr(221): 'Ý', chr(222): 'Þ', chr(223): 'ß',
  chr(224): 'à', chr(225): 'á', chr(226): 'â', chr(227): 'ã',
  chr(228): 'ä', chr(229): 'å', chr(230): 'æ', chr(231): 'ç',
  chr(232): 'è', chr(233): 'é', chr(234): 'ê', chr(235): 'ë',
  chr(236): 'ì', chr(237): 'í', chr(238): 'î', chr(239): 'ï',
  chr(240): 'ð', chr(241): 'ñ', chr(242): 'ò', chr(243): 'ó',
  chr(244): 'ô', chr(245): 'õ', chr(246): 'ö', chr(247): '÷',
  chr(248): 'ø', chr(249): 'ù', chr(250): 'ú', chr(251): 'û',
  chr(252): 'ü', chr(253): 'ý', chr(254): 'þ', chr(255): 'ÿ',
}
_html_ch = re.compile(r'['+reduce(lambda n, i: n+i, _html_enc.keys())+']')
def html_encode(o, also='', **kwargs):
  '''Return HTML-encoded string.'''
  o = _html_ch.sub(lambda match: _html_enc[match.group(0)], str(o))
  for c in also:
    try: r=_html_enc[c]
    except: r='&#%d;' % ord(c)
    o=o.replace(c, r)
  return o

_url_ch = re.compile(r'[^A-Za-z0-9_.!~*()-]') # RFC 2396 section 2.3
def url_encode(o, **kwargs):
  '''Return URL-encoded string.'''
  return _url_ch.sub(lambda match: "%%%02X" % ord(match.group(0)), str(o))

_nb_space_ch = re.compile(' ')
def nb_space(o, **kwargs):
  '''Return string with spaces converted to be non-breaking.'''
  return _nb_space_ch.sub(lambda match: ' ', str(o))