"""Helper functions

Consists of functions to typically be used within templates, but also

available to Controllers. This module is available to both as 'h'.

"""

import random

import hashlib

import StringIO

import urllib

import math

import logging

import re

import urlparse

import textwrap

from datetime import datetime

from pygments.formatters.html import HtmlFormatter

from pygments import highlight as code_highlight

from pylons import url, request, config

from pylons.i18n.translation import _, ungettext

from hashlib import md5

from webhelpers.html import literal, HTML, escape

from webhelpers.html.tools import *

from webhelpers.html.builder import make_tag

from webhelpers.html.tags import auto_discovery_link, checkbox, css_classes, \

    end_form, file, form, hidden, image, javascript_link, link_to, \

    link_to_if, link_to_unless, ol, required_legend, select, stylesheet_link, \

    submit, text, password, textarea, title, ul, xml_declaration, radio

from webhelpers.html.tools import auto_link, button_to, highlight, \

    js_obfuscate, mail_to, strip_links, strip_tags, tag_re

from webhelpers.number import format_byte_size, format_bit_size

from webhelpers.pylonslib import Flash as _Flash

from webhelpers.pylonslib.secure_form import secure_form

from webhelpers.text import chop_at, collapse, convert_accented_entities, \

    convert_misc_entities, lchop, plural, rchop, remove_formatting, \

    replace_whitespace, urlify, truncate, wrap_paragraphs

from webhelpers.date import time_ago_in_words

from webhelpers.paginate import Page

from webhelpers.html.tags import _set_input_attrs, _set_id_attr, \

    convert_boolean_attrs, NotGiven, _make_safe_id_component

from rhodecode.lib.annotate import annotate_highlight

from rhodecode.lib.utils import repo_name_slug

from rhodecode.lib.utils2 import str2bool, safe_unicode, safe_str, \

    get_changeset_safe, datetime_to_time, time_to_datetime, AttributeDict

from rhodecode.lib.markup_renderer import MarkupRenderer

from rhodecode.lib.vcs.exceptions import ChangesetDoesNotExistError

from rhodecode.lib.vcs.backends.base import BaseChangeset, EmptyChangeset

from rhodecode.config.conf import DATE_FORMAT, DATETIME_FORMAT

from rhodecode.model.changeset_status import ChangesetStatusModel

from rhodecode.model.db import URL_SEP, Permission

log = logging.getLogger(__name__)

html_escape_table = {

    "&": "&",

    '"': """,

    "'": "'",

    ">": ">",

    "<": "&lt;",

}

def html_escape(text):

    """Produce entities within text."""

    return "".join(html_escape_table.get(c, c) for c in text)

def shorter(text, size=20):

    postfix = '...'

    if len(text) > size:

        return text[:size - len(postfix)] + postfix

    return text

def _reset(name, value=None, id=NotGiven, type="reset", **attrs):

    """

    Reset button

    """

    _set_input_attrs(attrs, type, name, value)

    _set_id_attr(attrs, id, name)

    convert_boolean_attrs(attrs, ["disabled"])

    return HTML.input(**attrs)

reset = _reset

safeid = _make_safe_id_component

def FID(raw_id, path):

    """

    Creates a uniqe ID for filenode based on it's hash of path and revision

    it's safe to use in urls

    :param raw_id:

    :param path:

    """

    return 'C-%s-%s' % (short_id(raw_id), md5(safe_str(path)).hexdigest()[:12])

def get_token():

    """Return the current authentication token, creating one if one doesn't

    already exist.

    """

    token_key = "_authentication_token"

    from pylons import session

    if not token_key in session:

        try:

            token = hashlib.sha1(str(random.getrandbits(128))).hexdigest()

        except AttributeError:  # Python < 2.4

            token = hashlib.sha1(str(random.randrange(2 ** 128))).hexdigest()

        session[token_key] = token

        if hasattr(session, 'save'):

            session.save()

    return session[token_key]

class _GetError(object):

    """Get error from form_errors, and represent it as span wrapped error

    message

    :param field_name: field to fetch errors for

    :param form_errors: form errors dict

    """

    def __call__(self, field_name, form_errors):

        tmpl = """<span class="error_msg">%s</span>"""

        if form_errors and field_name in form_errors:

            return literal(tmpl % form_errors.get(field_name))

get_error = _GetError()

class _ToolTip(object):

    def __call__(self, tooltip_title, trim_at=50):

        """

        Special function just to wrap our text into nice formatted

        autowrapped text

        :param tooltip_title:

        """

        tooltip_title = escape(tooltip_title)

        tooltip_title = tooltip_title.replace('<', '&lt;').replace('>', '&gt;')

        return tooltip_title

tooltip = _ToolTip()

class _FilesBreadCrumbs(object):

    def __call__(self, repo_name, rev, paths):

        if isinstance(paths, str):

            paths = safe_unicode(paths)

        url_l = [link_to(repo_name, url('files_home',

                                        repo_name=repo_name,

                                        revision=rev, f_path=''),

                         class_='ypjax-link')]

        paths_l = paths.split('/')

        for cnt, p in enumerate(paths_l):

            if p != '':

                url_l.append(link_to(p,

                                     url('files_home',

                                         repo_name=repo_name,

                                         revision=rev,

                                         f_path='/'.join(paths_l[:cnt + 1])

                                         ),

                                     class_='ypjax-link'

                                     )

                             )

        return literal('/'.join(url_l))

files_breadcrumbs = _FilesBreadCrumbs()

class CodeHtmlFormatter(HtmlFormatter):

    """

    My code Html Formatter for source codes

    """

    def wrap(self, source, outfile):

        return self._wrap_div(self._wrap_pre(self._wrap_code(source)))

    def _wrap_code(self, source):

        for cnt, it in enumerate(source):

            i, t = it

            t = '<div id="L%s">%s</div>' % (cnt + 1, t)

            yield i, t

    def _wrap_tablelinenos(self, inner):

        dummyoutfile = StringIO.StringIO()

        lncount = 0

        for t, line in inner:

            if t:

                lncount += 1

            dummyoutfile.write(line)

        fl = self.linenostart

        mw = len(str(lncount + fl - 1))

        sp = self.linenospecial

        st = self.linenostep

        la = self.lineanchors

        aln = self.anchorlinenos

        nocls = self.noclasses

        if sp:

            lines = []

            for i in range(fl, fl + lncount):

                if i % st == 0:

                    if i % sp == 0:

                        if aln:

                            lines.append('<a href="#%s%d" class="special">%*d</a>' %

                                         (la, i, mw, i))

                        else:

                            lines.append('<span class="special">%*d</span>' % (mw, i))

                    else:

                        if aln:

                            lines.append('<a href="#%s%d">%*d</a>' % (la, i, mw, i))

                        else:

                            lines.append('%*d' % (mw, i))

                else:

                    lines.append('')

            ls = '\n'.join(lines)

        else:

            lines = []

            for i in range(fl, fl + lncount):

                if i % st == 0:

                    if aln:

                        lines.append('<a href="#%s%d">%*d</a>' % (la, i, mw, i))

                    else:

                        lines.append('%*d' % (mw, i))

                else:

                    lines.append('')

            ls = '\n'.join(lines)

        # in case you wonder about the seemingly redundant <div> here: since the

        # content in the other cell also is wrapped in a div, some browsers in

        # some configurations seem to mess up the formatting...

        if nocls:

            yield 0, ('<table class="%stable">' % self.cssclass +

                      '<tr><td><div class="linenodiv" '

                      'style="background-color: #f0f0f0; padding-right: 10px">'

                      '<pre style="line-height: 125%">' +

                      ls + '</pre></div></td><td id="hlcode" class="code">')

        else:

            yield 0, ('<table class="%stable">' % self.cssclass +

                      '<tr><td class="linenos"><div class="linenodiv"><pre>' +

                      ls + '</pre></div></td><td id="hlcode" class="code">')

        yield 0, dummyoutfile.getvalue()

        yield 0, '</td></tr></table>'

def pygmentize(filenode, **kwargs):

    """pygmentize function using pygments

    :param filenode:

    """

    return literal(code_highlight(filenode.content,

                                  filenode.lexer, CodeHtmlFormatter(**kwargs)))

def pygmentize_annotation(repo_name, filenode, **kwargs):

    """

    pygmentize function for annotation

    :param filenode:

    """

    color_dict = {}

    def gen_color(n=10000):

        """generator for getting n of evenly distributed colors using

        hsv color and golden ratio. It always return same order of colors

        :returns: RGB tuple

        """

        def hsv_to_rgb(h, s, v):

            if s == 0.0:

                return v, v, v

            i = int(h * 6.0)  # XXX assume int() truncates!

            f = (h * 6.0) - i

            p = v * (1.0 - s)

            q = v * (1.0 - s * f)

            t = v * (1.0 - s * (1.0 - f))

            i = i % 6

            if i == 0:

                return v, t, p

            if i == 1:

                return q, v, p

            if i == 2:

                return p, v, t

            if i == 3:

                return p, q, v

            if i == 4:

                return t, p, v

            if i == 5:

                return v, p, q

        golden_ratio = 0.618033988749895

        h = 0.22717784590367374

        for _ in xrange(n):

            h += golden_ratio

            h %= 1

            HSV_tuple = [h, 0.95, 0.95]

            RGB_tuple = hsv_to_rgb(*HSV_tuple)

            yield map(lambda x: str(int(x * 256)), RGB_tuple)

    cgenerator = gen_color()

    def get_color_string(cs):

        if cs in color_dict:

            col = color_dict[cs]

        else:

            col = color_dict[cs] = cgenerator.next()

        return "color: rgb(%s)! important;" % (', '.join(col))

    def url_func(repo_name):

        def _url_func(changeset):

            author = changeset.author

            date = changeset.date

            message = tooltip(changeset.message)

            tooltip_html = ("<div style='font-size:0.8em'><b>Author:</b>"

                            " %s<br/><b>Date:</b> %s</b><br/><b>Message:"

                            "</b> %s<br/></div>")

            tooltip_html = tooltip_html % (author, date, message)

            lnk_format = '%5s:%s' % ('r%s' % changeset.revision,

                                     short_id(changeset.raw_id))

            uri = link_to(

                    lnk_format,

                    url('changeset_home', repo_name=repo_name,

                        revision=changeset.raw_id),

                    style=get_color_string(changeset.raw_id),

                    class_='tooltip',

                    title=tooltip_html

                  )

            uri += '\n'

            return uri

        return _url_func

    return literal(annotate_highlight(filenode, url_func(repo_name), **kwargs))

def is_following_repo(repo_name, user_id):

    from rhodecode.model.scm import ScmModel

    return ScmModel().is_following_repo(repo_name, user_id)

flash = _Flash()

#==============================================================================

# SCM FILTERS available via h.

#==============================================================================

from rhodecode.lib.vcs.utils import author_name, author_email

from rhodecode.lib.utils2 import credentials_filter, age as _age

from rhodecode.model.db import User, ChangesetStatus

age = lambda  x: _age(x)

capitalize = lambda x: x.capitalize()

email = author_email

short_id = lambda x: x[:12]

hide_credentials = lambda x: ''.join(credentials_filter(x))

def fmt_date(date):

    if date:

        _fmt = _(u"%a, %d %b %Y %H:%M:%S").encode('utf8')

        return date.strftime(_fmt).decode('utf8')

    return ""

def is_git(repository):

    if hasattr(repository, 'alias'):

        _type = repository.alias

    elif hasattr(repository, 'repo_type'):

        _type = repository.repo_type

    else:

        _type = repository

    return _type == 'git'

def is_hg(repository):

    if hasattr(repository, 'alias'):

        _type = repository.alias

    elif hasattr(repository, 'repo_type'):

        _type = repository.repo_type

    else:

        _type = repository

    return _type == 'hg'

def email_or_none(author):

    # extract email from the commit string

    _email = email(author)

    if _email != '':

        # check it against RhodeCode database, and use the MAIN email for this

        # user

        user = User.get_by_email(_email, case_insensitive=True, cache=True)

        if user is not None:

            return user.email

        return _email

    # See if it contains a username we can get an email from

    user = User.get_by_username(author_name(author), case_insensitive=True,

                                cache=True)

    if user is not None:

        return user.email

    # No valid email, not a valid user in the system, none!

    return None

def person(author, show_attr="username_and_name"):

    # attr to return from fetched user

    person_getter = lambda usr: getattr(usr, show_attr)

    # Valid email in the attribute passed, see if they're in the system

    _email = email(author)

    if _email != '':

        user = User.get_by_email(_email, case_insensitive=True, cache=True)

        if user is not None:

            return person_getter(user)

        return _email

    # Maybe it's a username?

    _author = author_name(author)

    user = User.get_by_username(_author, case_insensitive=True,

                                cache=True)

    if user is not None:

        return person_getter(user)

    # Still nothing?  Just pass back the author name then

    return _author

def person_by_id(id_, show_attr="username_and_name"):

    # attr to return from fetched user

    person_getter = lambda usr: getattr(usr, show_attr)

    #maybe it's an ID ?

    if str(id_).isdigit() or isinstance(id_, int):

        id_ = int(id_)

        user = User.get(id_)

        if user is not None:

            return person_getter(user)

    return id_

def desc_stylize(value):

    """

    converts tags from value into html equivalent

    :param value:

    """

    value = re.sub(r'\[see\ \=\>\ *([a-zA-Z0-9\/\=\?\&\ \:\/\.\-]*)\]',

                   '<div class="metatag" tag="see">see =&gt; \\1 </div>', value)

    value = re.sub(r'\[license\ \=\>\ *([a-zA-Z0-9\/\=\?\&\ \:\/\.\-]*)\]',

                   '<div class="metatag" tag="license"><a href="http:\/\/www.opensource.org/licenses/\\1">\\1</a></div>', value)

                   '<div class="metatag" tag="\\1">\\1 =&gt; <a href="/\\2">\\2</a></div>', value)

    value = re.sub(r'\[(lang|language)\ \=\>\ *([a-zA-Z\-\/\#\+]*)\]',

                   '<div class="metatag" tag="lang">\\2</div>', value)

    value = re.sub(r'\[([a-z]+)\]',

                  '<div class="metatag" tag="\\1">\\1</div>', value)

    return value

def bool2icon(value):

    """Returns True/False values represented as small html image of true/false

    icons

    :param value: bool value

    """

    if value is True:

        return HTML.tag('img', src=url("/images/icons/accept.png"),

                        alt=_('True'))

    if value is False:

        return HTML.tag('img', src=url("/images/icons/cancel.png"),

                        alt=_('False'))

    return value

def action_parser(user_log, feed=False, parse_cs=False):

    """

    This helper will action_map the specified string action into translated

    fancy names with icons and links

    :param user_log: user log instance

    :param feed: use output for feeds (no html and fancy icons)

    :param parse_cs: parse Changesets into VCS instances

    """

    action = user_log.action

    action_params = ' '

    x = action.split(':')

    if len(x) > 1:

        action, action_params = x

    def get_cs_links():

        revs_limit = 3  # display this amount always

        revs_top_limit = 50  # show upto this amount of changesets hidden

        revs_ids = action_params.split(',')

        deleted = user_log.repository is None

        if deleted:

            return ','.join(revs_ids)

        repo_name = user_log.repository.repo_name

        def lnk(rev, repo_name):

            if isinstance(rev, BaseChangeset) or isinstance(rev, AttributeDict):

                lazy_cs = True

                if getattr(rev, 'op', None) and getattr(rev, 'ref_name', None):

                    lazy_cs = False

                    lbl = '?'

                    if rev.op == 'delete_branch':

                        lbl = '%s' % _('Deleted branch: %s') % rev.ref_name

                        title = ''

                    elif rev.op == 'tag':

                        lbl = '%s' % _('Created tag: %s') % rev.ref_name

                        title = ''

                    _url = '#'

                else:

                    lbl = '%s' % (rev.short_id[:8])

                    _url = url('changeset_home', repo_name=repo_name,

                               revision=rev.raw_id)

                    title = tooltip(rev.message)

            else:

                ## changeset cannot be found/striped/removed etc.

                lbl = ('%s' % rev)[:12]

                _url = '#'

                title = _('Changeset not found')

            if parse_cs:

                return link_to(lbl, _url, title=title, class_='tooltip')

            return link_to(lbl, _url, raw_id=rev.raw_id, repo_name=repo_name,

                           class_='lazy-cs' if lazy_cs else '')

        revs = []

        if len(filter(lambda v: v != '', revs_ids)) > 0:

            repo = None

            for rev in revs_ids[:revs_top_limit]:

                _op = _name = None

                if len(rev.split('=>')) == 2:

                    _op, _name = rev.split('=>')

                # we want parsed changesets, or new log store format is bad

                if parse_cs:

                    try:

                        if repo is None:

                            repo = user_log.repository.scm_instance

                        _rev = repo.get_changeset(rev)

                        revs.append(_rev)

                    except ChangesetDoesNotExistError:

                        log.error('cannot find revision %s in this repo' % rev)

                        revs.append(rev)

                        continue

                else:

                    _rev = AttributeDict({

                        'short_id': rev[:12],

                        'raw_id': rev,

                        'message': '',

                        'op': _op,

                        'ref_name': _name

                    })

                    revs.append(_rev)

        cs_links = []

        cs_links.append(" " + ', '.join(

            [lnk(rev, repo_name) for rev in revs[:revs_limit]]

            )

        )

        compare_view = (

            ' <div class="compare_view tooltip" title="%s">'

            '<a href="%s">%s</a> </div>' % (

                _('Show all combined changesets %s->%s') % (

                    revs_ids[0][:12], revs_ids[-1][:12]

                ),

                url('changeset_home', repo_name=repo_name,

                    revision='%s...%s' % (revs_ids[0], revs_ids[-1])

                ),

                _('compare view')

            )

        )

        # if we have exactly one more than normally displayed

        # just display it, takes less space than displaying

        # "and 1 more revisions"

        if len(revs_ids) == revs_limit + 1:

            rev = revs[revs_limit]

            cs_links.append(", " + lnk(rev, repo_name))

        # hidden-by-default ones

        if len(revs_ids) > revs_limit + 1:

            uniq_id = revs_ids[0]

            html_tmpl = (

                '<span> %s <a class="show_more" id="_%s" '

                'href="#more">%s</a> %s</span>'

            )

            if not feed:

                cs_links.append(html_tmpl % (

                      _('and'),

                      uniq_id, _('%s more') % (len(revs_ids) - revs_limit),

                      _('revisions')

                    )

                )

            if not feed:

                html_tmpl = '<span id="%s" style="display:none">, %s </span>'

            else:

                html_tmpl = '<span id="%s"> %s </span>'

            morelinks = ', '.join(

              [lnk(rev, repo_name) for rev in revs[revs_limit:]]

            )

            if len(revs_ids) > revs_top_limit:

                morelinks += ', ...'

            cs_links.append(html_tmpl % (uniq_id, morelinks))

        if len(revs) > 1:

            cs_links.append(compare_view)

        return ''.join(cs_links)

    def get_fork_name():

        repo_name = action_params

        _url = url('summary_home', repo_name=repo_name)

        return _('fork name %s') % link_to(action_params, _url)

    def get_user_name():

        user_name = action_params

        return user_name

    def get_users_group():

        group_name = action_params

        return group_name

    def get_pull_request():

        pull_request_id = action_params

        deleted = user_log.repository is None

        if deleted:

            repo_name = user_log.repository_name

        else:

            repo_name = user_log.repository.repo_name

        return link_to(_('Pull request #%s') % pull_request_id,

                    url('pullrequest_show', repo_name=repo_name,

                    pull_request_id=pull_request_id))

    # action : translated str, callback(extractor), icon

    action_map = {

    'user_deleted_repo':           (_('[deleted] repository'),

                                    None, 'database_delete.png'),

    'user_created_repo':           (_('[created] repository'),

                                    None, 'database_add.png'),

    'user_created_fork':           (_('[created] repository as fork'),

                                    None, 'arrow_divide.png'),

    'user_forked_repo':            (_('[forked] repository'),

                                    get_fork_name, 'arrow_divide.png'),

    'user_updated_repo':           (_('[updated] repository'),

                                    None, 'database_edit.png'),

    'admin_deleted_repo':          (_('[delete] repository'),

                                    None, 'database_delete.png'),

    'admin_created_repo':          (_('[created] repository'),

                                    None, 'database_add.png'),

    'admin_forked_repo':           (_('[forked] repository'),

                                    None, 'arrow_divide.png'),

    'admin_updated_repo':          (_('[updated] repository'),

                                    None, 'database_edit.png'),

    'admin_created_user':          (_('[created] user'),

                                    get_user_name, 'user_add.png'),

    'admin_updated_user':          (_('[updated] user'),

                                    get_user_name, 'user_edit.png'),

    'admin_created_users_group':   (_('[created] users group'),

                                    get_users_group, 'group_add.png'),

    'admin_updated_users_group':   (_('[updated] users group'),

                                    get_users_group, 'group_edit.png'),

    'user_commented_revision':     (_('[commented] on revision in repository'),

                                    get_cs_links, 'comment_add.png'),

    'user_commented_pull_request': (_('[commented] on pull request for'),

                                    get_pull_request, 'comment_add.png'),

    'user_closed_pull_request':    (_('[closed] pull request for'),

                                    get_pull_request, 'tick.png'),

    'push':                        (_('[pushed] into'),

                                    get_cs_links, 'script_add.png'),

    'push_local':                  (_('[committed via RhodeCode] into repository'),

                                    get_cs_links, 'script_edit.png'),

    'push_remote':                 (_('[pulled from remote] into repository'),

                                    get_cs_links, 'connect.png'),

    'pull':                        (_('[pulled] from'),

                                    None, 'down_16.png'),

    'started_following_repo':      (_('[started following] repository'),

                                    None, 'heart_add.png'),

    'stopped_following_repo':      (_('[stopped following] repository'),

                                    None, 'heart_delete.png'),

    }

    action_str = action_map.get(action, action)

    if feed:

        action = action_str[0].replace('[', '').replace(']', '')

    else:

        action = action_str[0]\

            .replace('[', '<span class="journal_highlight">')\

            .replace(']', '</span>')

    action_params_func = lambda: ""

    if callable(action_str[1]):

        action_params_func = action_str[1]

    def action_parser_icon():

        action = user_log.action

        action_params = None

        x = action.split(':')

        if len(x) > 1:

            action, action_params = x

        tmpl = """<img src="%s%s" alt="%s"/>"""

        ico = action_map.get(action, ['', '', ''])[2]

        return literal(tmpl % ((url('/images/icons/')), ico, action))

    # returned callbacks we need to call to get

    return [lambda: literal(action), action_params_func, action_parser_icon]

#==============================================================================

# PERMS

#==============================================================================

from rhodecode.lib.auth import HasPermissionAny, HasPermissionAll, \

HasRepoPermissionAny, HasRepoPermissionAll

#==============================================================================

# GRAVATAR URL

#==============================================================================

def gravatar_url(email_address, size=30):

    from pylons import url  # doh, we need to re-import url to mock it later

    if (not str2bool(config['app_conf'].get('use_gravatar')) or

        not email_address or email_address == 'anonymous@rhodecode.org'):

        f = lambda a, l: min(l, key=lambda x: abs(x - a))

        return url("/images/user%s.png" % f(size, [14, 16, 20, 24, 30]))

    if(str2bool(config['app_conf'].get('use_gravatar')) and

       config['app_conf'].get('alternative_gravatar_url')):

        tmpl = config['app_conf'].get('alternative_gravatar_url', '')

        parsed_url = urlparse.urlparse(url.current(qualified=True))

        tmpl = tmpl.replace('{email}', email_address)\

                   .replace('{md5email}', hashlib.md5(email_address.lower()).hexdigest()) \

                   .replace('{netloc}', parsed_url.netloc)\

                   .replace('{scheme}', parsed_url.scheme)\

                   .replace('{size}', str(size))

        return tmpl

    ssl_enabled = 'https' == request.environ.get('wsgi.url_scheme')

    default = 'identicon'

    baseurl_nossl = "http://www.gravatar.com/avatar/"

    baseurl_ssl = "https://secure.gravatar.com/avatar/"

    baseurl = baseurl_ssl if ssl_enabled else baseurl_nossl

    if isinstance(email_address, unicode):

        #hashlib crashes on unicode items

        email_address = safe_str(email_address)

    # construct the url

    gravatar_url = baseurl + hashlib.md5(email_address.lower()).hexdigest() + "?"

    gravatar_url += urllib.urlencode({'d': default, 's': str(size)})

    return gravatar_url

#==============================================================================

# REPO PAGER, PAGER FOR REPOSITORY

#==============================================================================

class RepoPage(Page):

    def __init__(self, collection, page=1, items_per_page=20,

                 item_count=None, url=None, **kwargs):

        """Create a "RepoPage" instance. special pager for paging

        repository

        """

        self._url_generator = url

        # Safe the kwargs class-wide so they can be used in the pager() method

        self.kwargs = kwargs

        # Save a reference to the collection

        self.original_collection = collection

        self.collection = collection

        # The self.page is the number of the current page.

        # The first page has the number 1!

        try:

            self.page = int(page)  # make it int() if we get it as a string

        except (ValueError, TypeError):

            self.page = 1

        self.items_per_page = items_per_page

        # Unless the user tells us how many items the collections has

        # we calculate that ourselves.

        if item_count is not None:

            self.item_count = item_count

        else:

            self.item_count = len(self.collection)

        # Compute the number of the first and last available page

        if self.item_count > 0:

            self.first_page = 1

            self.page_count = int(math.ceil(float(self.item_count) /

                                            self.items_per_page))

            self.last_page = self.first_page + self.page_count - 1

            # Make sure that the requested page number is the range of

            # valid pages

            if self.page > self.last_page:

                self.page = self.last_page

            elif self.page < self.first_page:

                self.page = self.first_page

            # Note: the number of items on this page can be less than

            #       items_per_page if the last page is not full

            self.first_item = max(0, (self.item_count) - (self.page *

                                                          items_per_page))

            self.last_item = ((self.item_count - 1) - items_per_page *

                              (self.page - 1))

            self.items = list(self.collection[self.first_item:self.last_item + 1])

            # Links to previous and next page

            if self.page > self.first_page:

                self.previous_page = self.page - 1

            else:

                self.previous_page = None

            if self.page < self.last_page:

                self.next_page = self.page + 1

            else:

                self.next_page = None

        # No items available

        else:

            self.first_page = None

            self.page_count = 0

            self.last_page = None

            self.first_item = None

            self.last_item = None

            self.previous_page = None

            self.next_page = None

            self.items = []

        # This is a subclass of the 'list' type. Initialise the list now.

        list.__init__(self, reversed(self.items))

def changed_tooltip(nodes):

    """

    Generates a html string for changed nodes in changeset page.

    It limits the output to 30 entries

    :param nodes: LazyNodesGenerator