import re

from django.utils.encoding import force_unicode

from django.utils.functional import allow_lazy

from django.utils.translation import ugettext_lazy

from htmlentitydefs import name2codepoint

# Capitalizes the first letter of a string.

capfirst = lambda x: x and force_unicode(x)[0].upper() + force_unicode(x)[1:]

capfirst = allow_lazy(capfirst, unicode)

def wrap(text, width):

    """

    A word-wrap function that preserves existing line breaks and most spaces in

    the text. Expects that existing line breaks are posix newlines.

    """

    text = force_unicode(text)

    def _generator():

        it = iter(text.split(' '))

        word = it.next()

        yield word

        pos = len(word) - word.rfind('\n') - 1

        for word in it:

            if "\n" in word:

                lines = word.split('\n')

            else:

                lines = (word,)

            pos += len(lines[0]) + 1

            if pos > width:

                yield '\n'

                pos = len(lines[-1])

            else:

                yield ' '

                if len(lines) > 1:

                    pos = len(lines[-1])

            yield word

    return u''.join(_generator())

wrap = allow_lazy(wrap, unicode)

def truncate_words(s, num, end_text='...'):

    """Truncates a string after a certain number of words. Takes an optional

    argument of what should be used to notify that the string has been

    truncated, defaults to ellipsis (...)"""

    s = force_unicode(s)

    length = int(num)

    words = s.split()

    if len(words) > length:

        words = words[:length]

        if not words[-1].endswith(end_text):

            words.append(end_text)

    return u' '.join(words)

truncate_words = allow_lazy(truncate_words, unicode)

def truncate_html_words(s, num, end_text='...'):

    """Truncates html to a certain number of words (not counting tags and

    comments). Closes opened tags if they were correctly closed in the given

    html. Takes an optional argument of what should be used to notify that the

    string has been truncated, defaults to ellipsis (...)."""

    s = force_unicode(s)

    length = int(num)

    if length <= 0:

        return u''

    html4_singlets = ('br', 'col', 'link', 'base', 'img', 'param', 'area', 'hr', 'input')

    # Set up regular expressions

    re_words = re.compile(r'&.*?;|<.*?>|(\w[\w-]*)', re.U)

    re_tag = re.compile(r'<(/)?([^ ]+?)(?: (/)| .*?)?>')

    # Count non-HTML words and keep note of open tags

    pos = 0

    end_text_pos = 0

    words = 0

    open_tags = []

    while words <= length:

        m = re_words.search(s, pos)

        if not m:

            # Checked through whole string

            break

        pos = m.end(0)

        if m.group(1):

            # It's an actual non-HTML word

            words += 1

            if words == length:

                end_text_pos = pos

            continue

        # Check for tag

        tag = re_tag.match(m.group(0))

        if not tag or end_text_pos:

            # Don't worry about non tags or tags after our truncate point

            continue

        closing_tag, tagname, self_closing = tag.groups()

        tagname = tagname.lower()  # Element names are always case-insensitive

        if self_closing or tagname in html4_singlets:

            pass

        elif closing_tag:

            # Check for match in open tags list

            try:

                i = open_tags.index(tagname)

            except ValueError:

                pass

            else:

                # SGML: An end tag closes, back to the matching start tag, all unclosed intervening start tags with omitted end tags

                open_tags = open_tags[i+1:]

        else:

            # Add it to the start of the open tags list

            open_tags.insert(0, tagname)

    if words <= length:

        # Don't try to close tags if we don't need to truncate

        return s

    out = s[:end_text_pos]

    if end_text:

        out += ' ' + end_text

    # Close any tags still open

    for tag in open_tags:

        out += '</%s>' % tag

    # Return string

    return out

truncate_html_words = allow_lazy(truncate_html_words, unicode)

def get_valid_filename(s):

    """

    Returns the given string converted to a string that can be used for a clean

    filename. Specifically, leading and trailing spaces are removed; other

    spaces are converted to underscores; and anything that is not a unicode

    alphanumeric, dash, underscore, or dot, is removed.

    >>> get_valid_filename("john's portrait in 2004.jpg")

    u'johns_portrait_in_2004.jpg'

    """

    s = force_unicode(s).strip().replace(' ', '_')

    return re.sub(r'(?u)[^-\w.]', '', s)

get_valid_filename = allow_lazy(get_valid_filename, unicode)

def get_text_list(list_, last_word=ugettext_lazy(u'or')):

    """

    >>> get_text_list(['a', 'b', 'c', 'd'])

    u'a, b, c or d'

    >>> get_text_list(['a', 'b', 'c'], 'and')

    u'a, b and c'

    >>> get_text_list(['a', 'b'], 'and')

    u'a and b'

    >>> get_text_list(['a'])

    u'a'

    >>> get_text_list([])

    u''

    """

    if len(list_) == 0: return u''

    if len(list_) == 1: return force_unicode(list_[0])

    return u'%s %s %s' % (', '.join([force_unicode(i) for i in list_][:-1]), force_unicode(last_word), force_unicode(list_[-1]))

get_text_list = allow_lazy(get_text_list, unicode)

def normalize_newlines(text):

    return force_unicode(re.sub(r'\r\n|\r|\n', '\n', text))

normalize_newlines = allow_lazy(normalize_newlines, unicode)

def recapitalize(text):

    "Recapitalizes text, placing caps after end-of-sentence punctuation."

    text = force_unicode(text).lower()

    capsRE = re.compile(r'(?:^|(?<=[\.\?\!] ))([a-z])')

    text = capsRE.sub(lambda x: x.group(1).upper(), text)

    return text

recapitalize = allow_lazy(recapitalize)

def phone2numeric(phone):

    "Converts a phone number with letters into its numeric equivalent."

    letters = re.compile(r'[A-Z]', re.I)

    char2number = lambda m: {'a': '2', 'b': '2', 'c': '2', 'd': '3', 'e': '3',

         'f': '3', 'g': '4', 'h': '4', 'i': '4', 'j': '5', 'k': '5', 'l': '5',

         'm': '6', 'n': '6', 'o': '6', 'p': '7', 'q': '7', 'r': '7', 's': '7',

         't': '8', 'u': '8', 'v': '8', 'w': '9', 'x': '9', 'y': '9', 'z': '9',

        }.get(m.group(0).lower())

    return letters.sub(char2number, phone)

phone2numeric = allow_lazy(phone2numeric)

# From http://www.xhaus.com/alan/python/httpcomp.html#gzip

# Used with permission.

def compress_string(s):

    import cStringIO, gzip

    zbuf = cStringIO.StringIO()

    zfile = gzip.GzipFile(mode='wb', compresslevel=6, fileobj=zbuf)

    zfile.write(s)

    zfile.close()

    return zbuf.getvalue()

ustring_re = re.compile(u"([\u0080-\uffff])")

def javascript_quote(s, quote_double_quotes=False):

    def fix(match):

        return r"\u%04x" % ord(match.group(1))

    if type(s) == str:

        s = s.decode('utf-8')

    elif type(s) != unicode:

        raise TypeError(s)

    s = s.replace('\\', '\\\\')

    s = s.replace('\r', '\\r')

    s = s.replace('\n', '\\n')

    s = s.replace('\t', '\\t')

    s = s.replace("'", "\\'")

    if quote_double_quotes:

        s = s.replace('"', '"')

    return str(ustring_re.sub(fix, s))

javascript_quote = allow_lazy(javascript_quote, unicode)

# Expression to match some_token and some_token="with spaces" (and similarly

# for single-quoted strings).

smart_split_re = re.compile(r"""

    ((?:

        [^\s'"]*

        (?:

            (?:"(?:[^"\\]|\\.)*" | '(?:[^'\\]|\\.)*')

            [^\s'"]*

        )+

    ) | \S+)

""", re.VERBOSE)

def smart_split(text):

    r"""

    Generator that splits a string by spaces, leaving quoted phrases together.

    Supports both single and double quotes, and supports escaping quotes with

    backslashes. In the output, strings will keep their initial and trailing

    quote marks and escaped quotes will remain escaped (the results can then

    be further processed with unescape_string_literal()).

    >>> list(smart_split(r'This is "a person\'s" test.'))

    [u'This', u'is', u'"a person\\\'s"', u'test.']

    >>> list(smart_split(r"Another 'person\'s' test."))

    [u'Another', u"'person\\'s'", u'test.']

    >>> list(smart_split(r'A "\"funky\" style" test.'))

    [u'A', u'"\\"funky\\" style"', u'test.']

    """

    text = force_unicode(text)

    for bit in smart_split_re.finditer(text):

        yield bit.group(0)

smart_split = allow_lazy(smart_split, unicode)

def _replace_entity(match):

    text = match.group(1)

    if text[0] == u'#':

        text = text[1:]

        try:

            if text[0] in u'xX':

                c = int(text[1:], 16)

            else:

                c = int(text)

            return unichr(c)

        except ValueError:

            return match.group(0)

    else:

        try:

            return unichr(name2codepoint[text])

        except (ValueError, KeyError):

            return match.group(0)

_entity_re = re.compile(r"&(#?[xX]?(?:[0-9a-fA-F]+|\w{1,8}));")

def unescape_entities(text):

    return _entity_re.sub(_replace_entity, text)

unescape_entities = allow_lazy(unescape_entities, unicode)

def unescape_string_literal(s):

    r"""

    Convert quoted string literals to unquoted strings with escaped quotes and

    backslashes unquoted::

        >>> unescape_string_literal('"abc"')

        'abc'

        >>> unescape_string_literal("'abc'")

        'abc'

        >>> unescape_string_literal('"a \"bc\""')

        'a "bc"'

        >>> unescape_string_literal("'\'ab\' c'")

        "'ab' c"

    """

    if s[0] not in "\"'" or s[-1] != s[0]:

        raise ValueError("Not a string literal: %r" % s)

    quote = s[0]

    return s[1:-1].replace(r'\%s' % quote, quote).replace(r'\\', '\\')

unescape_string_literal = allow_lazy(unescape_string_literal)