"""cssutils helper
"""
__docformat__ = 'restructuredtext'
__version__ = '$Id: errorhandler.py 1234 2008-05-22 20:26:12Z cthedot $'

import os
import re
import sys
import urllib

class Deprecated(object):
    """This is a decorator which can be used to mark functions
    as deprecated. It will result in a warning being emitted
    when the function is used.

    It accepts a single paramter ``msg`` which is shown with the warning.
    It should contain information which function or method to use instead.
    """
    def __init__(self, msg):
        self.msg = msg

    def __call__(self, func):
        def newFunc(*args, **kwargs):
            import warnings
            warnings.warn("Call to deprecated method %r. %s" %
                            (func.__name__, self.msg),
                            category=DeprecationWarning,
                            stacklevel=2)
            return func(*args, **kwargs)
        newFunc.__name__ = func.__name__
        newFunc.__doc__ = func.__doc__
        newFunc.__dict__.update(func.__dict__)
        return newFunc

# simple escapes, all non unicodes
_simpleescapes = re.compile(ur'(\\[^0-9a-fA-F])').sub    
def normalize(x):
    """
    normalizes x, namely:

    - remove any \ before non unicode sequences (0-9a-zA-Z) so for
      x=="c\olor\" return "color" (unicode escape sequences should have
      been resolved by the tokenizer already)
    - lowercase
    """
    if x:
        def removeescape(matchobj):
            return matchobj.group(0)[1:]
        x = _simpleescapes(removeescape, x)
        return x.lower()
    else:
        return x

def path2url(path):
    """Return file URL of `path`"""
    return u'file:' + urllib.pathname2url(os.path.abspath(path))    

def pushtoken(token, tokens):
    """Return new generator starting with token followed by all tokens in 
    ``tokens``"""
    # TODO: may use itertools.chain?
    yield token
    for t in tokens:
        yield t
                  
def string(value):
    """
    Serialize value with quotes e.g.::
    
        ``a \'string`` => ``'a \'string'``
    """
    # \n = 0xa, \r = 0xd, \f = 0xc
    value = value.replace(u'\n', u'\\a ').replace(
                          u'\r', u'\\d ').replace(
                          u'\f', u'\\c ').replace(
                          u'"', u'\\"')
    
    if value.endswith(u'\\'):
        value = value[:-1] + u'\\\\'

    return u'"%s"' % value

def stringvalue(string):
    """
    Retrieve actual value of string without quotes. Escaped 
    quotes inside the value are resolved, e.g.::
    
        ``'a \'string'`` => ``a 'string``
    """
    return string.replace(u'\\'+string[0], string[0])[1:-1]

_match_forbidden_in_uri = re.compile(ur'''.*?[\(\)\s\;,'"]''', re.U).match
def uri(value):
    """
    Serialize value by adding ``url()`` and with quotes if needed e.g.::
    
        ``"`` => ``url("\"")`` 
    """
    if _match_forbidden_in_uri(value):
        value = string(value)
    return u'url(%s)' % value

def urivalue(uri):
    """
    Return actual content without surrounding "url(" and ")"
    and removed surrounding quotes too including contained 
    escapes of quotes, e.g.::
    
         ``url("\"")`` => ``"``
    """
    uri = uri[uri.find('(')+1:-1].strip()
    if uri and (uri[0] in '\'"') and (uri[0] == uri[-1]):
        return stringvalue(uri)
    else:
        return uri

#def normalnumber(num):
#    """
#    Return normalized number as string.
#    """
#    sign = ''
#    if num.startswith('-'):
#        sign = '-'
#        num = num[1:]
#    elif num.startswith('+'):
#        num = num[1:]
#
#    if float(num) == 0.0:
#        return '0'
#    else:        
#        if num.find('.') == -1:
#            return sign + str(int(num)) 
#        else: 
#            a, b = num.split('.')
#            if not a:
#                a = '0'
#            return '%s%s.%s' % (sign, int(a), b)