import re

from django.conf import settings

# Capitalizes the first letter of a string.

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

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.

    """

    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 "".join(_generator())

def truncate_words(s, num):

    "Truncates a string after a certain number of words."

    length = int(num)

    words = s.split()

    if len(words) > length:

        words = words[:length]

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

            words.append('...')

    return ' '.join(words)

def truncate_html_words(s, num):

    """

    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.

    """

    length = int(num)

    if length <= 0:

        return ''

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

    # Set up regular expressions

    re_words = re.compile(r'&.*?;|<.*?>|([A-Za-z0-9][\w-]*)')

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

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

    pos = 0

    ellipsis_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:

                ellipsis_pos = pos

            continue

        # Check for tag

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

        if not tag or ellipsis_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[:ellipsis_pos] + ' ...'

    # Close any tags still open

    for tag in open_tags:

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

    # Return string

    return out

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 all non-filename-safe characters

    are removed.

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

    'johns_portrait_in_2004.jpg'

    """

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

    return re.sub(r'[^-A-Za-z0-9_.]', '', s)

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

    """

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

    'a, b, c or d'

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

    'a, b and c'

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

    'a and b'

    >>> get_text_list(['a'])

    'a'

    >>> get_text_list([])

    ''

    """

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

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

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

def normalize_newlines(text):

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

def recapitalize(text):

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

#     capwords = ()

    text = text.lower()

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

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

#     for capword in capwords:

#         capwordRE = re.compile(r'\b%s\b' % capword, re.I)

#         text = capwordRE.sub(capword, text)

    return text

def phone2numeric(phone):

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

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

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

         'd': '3', 'g': '4', 'f': '3', 'i': '4', 'h': '4', 'k': '5',

         'j': '5', 'm': '6', 'l': '5', 'o': '6', 'n': '6', 'p': '7',

         's': '7', 'r': '7', 'u': '8', 't': '8', 'w': '9', 'v': '8',

         'y': '9', 'x': '9'}.get(m.group(0).lower())

    return letters.sub(char2number, phone)

# 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(settings.DEFAULT_CHARSET)

    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))

smart_split_re = re.compile('("(?:[^"\\\\]*(?:\\\\.[^"\\\\]*)*)"|\'(?:[^\'\\\\]*(?:\\\\.[^\'\\\\]*)*)\'|[^\\s]+)')

def smart_split(text):

    """

    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.

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

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

    """

    for bit in smart_split_re.finditer(text):

        bit = bit.group(0)

        if bit[0] == '"':

            yield '"' + bit[1:-1].replace('\\"', '"').replace('\\\\', '\\') + '"'

        elif bit[0] == "'":

            yield "'" + bit[1:-1].replace("\\'", "'").replace("\\\\", "\\") + "'"

        else:

            yield bit