"""abstract class for http request

:organization: Logilab

:copyright: 2001-2010 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses

"""

__docformat__ = "restructuredtext en"

import Cookie

import sha

import time

import random

import base64

from datetime import date

from urlparse import urlsplit

from itertools import count

from simplejson import dumps

from rql.utils import rqlvar_maker

from logilab.common.decorators import cached

from logilab.common.deprecation import deprecated

from logilab.mtconverter import xml_escape

from cubicweb.dbapi import DBAPIRequest

from cubicweb.mail import header

from cubicweb.uilib import remove_html_tags

from cubicweb.utils import SizeConstrainedList, HTMLHead, make_uid

from cubicweb.view import STRICT_DOCTYPE, TRANSITIONAL_DOCTYPE_NOEXT

from cubicweb.web import (INTERNAL_FIELD_VALUE, LOGGER, NothingToEdit,

                          RequestError, StatusResponse)

_MARKER = object()

def list_form_param(form, param, pop=False):

    """get param from form parameters and return its value as a list,

    skipping internal markers if any

    * if the parameter isn't defined, return an empty list

    * if the parameter is a single (unicode) value, return a list

      containing that value

    * if the parameter is already a list or tuple, just skip internal

      markers

    if pop is True, the parameter is removed from the form dictionnary

    """

    if pop:

        try:

            value = form.pop(param)

        except KeyError:

            return []

    else:

        value = form.get(param, ())

    if value is None:

        value = ()

    elif not isinstance(value, (list, tuple)):

        value = [value]

    return [v for v in value if v != INTERNAL_FIELD_VALUE]

class CubicWebRequestBase(DBAPIRequest):

    """abstract HTTP request, should be extended according to the HTTP backend"""

    json_request = False # to be set to True by json controllers

    def __init__(self, vreg, https, form=None):

        super(CubicWebRequestBase, self).__init__(vreg)

        self.message = None

        self.authmode = vreg.config['auth-mode']

        self.https = https

        # raw html headers that can be added from any view

        self.html_headers = HTMLHead()

        # form parameters

        self.setup_params(form)

        # dictionnary that may be used to store request data that has to be

        # shared among various components used to publish the request (views,

        # controller, application...)

        self.data = {}

        # search state: 'normal' or 'linksearch' (eg searching for an object

        # to create a relation with another)

        self.search_state = ('normal',)

        # tabindex generator

        self.tabindexgen = count(1)

        self.next_tabindex = self.tabindexgen.next

        # page id, set by htmlheader template

        self.pageid = None

        self.datadir_url = self._datadir_url()

        self._set_pageid()

    def _set_pageid(self):

        """initialize self.pageid

        if req.form provides a specific pageid, use it, otherwise build a

        new one.

        """

        pid = self.form.get('pageid')

        if pid is None:

            pid = make_uid(id(self))

        self.pageid = pid

        self.html_headers.define_var('pageid', pid, override=False)

    @property

    def varmaker(self):

        varmaker = self.get_page_data('rql_varmaker')

        if varmaker is None:

            varmaker = rqlvar_maker()

            self.set_page_data('rql_varmaker', varmaker)

        return varmaker

    def set_connection(self, cnx, user=None):

        """method called by the session handler when the user is authenticated

        or an anonymous connection is open

        """

        super(CubicWebRequestBase, self).set_connection(cnx, user)

        # set request language

        vreg = self.vreg

        if self.user:

            try:

                # 1. user specified language

                lang = vreg.typed_value('ui.language',

                                        self.user.properties['ui.language'])

                self.set_language(lang)

                return

            except KeyError, ex:

                pass

        if vreg.config['language-negociation']:

            # 2. http negociated language

            for lang in self.header_accept_language():

                if lang in self.translations:

                    self.set_language(lang)

                    return

        # 3. default language

        self.set_default_language(vreg)

        # XXX code smell

        # have to be done here because language is not yet set in setup_params

        #

        # special key for created entity, added in controller's reset method

        # if no message set, we don't want this neither

        if '__createdpath' in self.form and self.message:

            self.message += ' (<a href="%s">%s</a>)' % (

                self.build_url(self.form.pop('__createdpath')),

                self._('click here to see created entity'))

    def set_language(self, lang):

        gettext, self.pgettext = self.translations[lang]

        self._ = self.__ = gettext

        self.lang = lang

        self.cnx.set_session_props(lang=lang)

        self.debug('request language: %s', lang)

    # input form parameters management ########################################

    # common form parameters which should be protected against html values

    # XXX can't add 'eid' for instance since it may be multivalued

    # dont put rql as well, if query contains < and > it will be corrupted!

    no_script_form_params = set(('vid',

                                 'etype',

                                 'vtitle', 'title',

                                 '__message',

                                 '__redirectvid', '__redirectrql'))

    def setup_params(self, params):

        """WARNING: we're intentionaly leaving INTERNAL_FIELD_VALUE here

        subclasses should overrides to

        """

        if params is None:

            params = {}

        self.form = params

        encoding = self.encoding

        for k, v in params.items():

            if isinstance(v, (tuple, list)):

                v = [unicode(x, encoding) for x in v]

                if len(v) == 1:

                    v = v[0]

            if k in self.no_script_form_params:

                v = self.no_script_form_param(k, value=v)

            if isinstance(v, str):

                v = unicode(v, encoding)

            if k == '__message':

                self.set_message(v)

                del self.form[k]

            else:

                self.form[k] = v

    def no_script_form_param(self, param, default=None, value=None):

        """ensure there is no script in a user form param

        by default return a cleaned string instead of raising a security

        exception

        this method should be called on every user input (form at least) fields

        that are at some point inserted in a generated html page to protect

        against script kiddies

        """

        if value is None:

            value = self.form.get(param, default)

        if not value is default and value:

            # safety belt for strange urls like http://...?vtitle=yo&vtitle=yo

            if isinstance(value, (list, tuple)):

                self.error('no_script_form_param got a list (%s). Who generated the URL ?',

                           repr(value))

                value = value[0]

            return remove_html_tags(value)

        return value

    def list_form_param(self, param, form=None, pop=False):

        """get param from form parameters and return its value as a list,

        skipping internal markers if any

        * if the parameter isn't defined, return an empty list

        * if the parameter is a single (unicode) value, return a list

          containing that value

        * if the parameter is already a list or tuple, just skip internal

          markers

        if pop is True, the parameter is removed from the form dictionnary

        """

        if form is None:

            form = self.form

        return list_form_param(form, param, pop)

    def reset_headers(self):

        """used by AutomaticWebTest to clear html headers between tests on

        the same resultset

        """

        self.html_headers = HTMLHead()

        return self

    # web state helpers #######################################################

    def set_message(self, msg):

        assert isinstance(msg, unicode)

        self.message = msg

    def update_search_state(self):

        """update the current search state"""

        searchstate = self.form.get('__mode')

        if not searchstate and self.cnx is not None:

            searchstate = self.get_session_data('search_state', 'normal')

        self.set_search_state(searchstate)

    def set_search_state(self, searchstate):

        """set a new search state"""

        if searchstate is None or searchstate == 'normal':

            self.search_state = (searchstate or 'normal',)

        else:

            self.search_state = ('linksearch', searchstate.split(':'))

            assert len(self.search_state[-1]) == 4

        if self.cnx is not None:

            self.set_session_data('search_state', searchstate)

    def match_search_state(self, rset):

        """when searching an entity to create a relation, return True if entities in

        the given rset may be used as relation end

        """

        try:

            searchedtype = self.search_state[1][-1]

        except IndexError:

            return False # no searching for association

        for etype in rset.column_types(0):

            if etype != searchedtype:

                return False

        return True

    def update_breadcrumbs(self):

        """stores the last visisted page in session data"""

        searchstate = self.get_session_data('search_state')

        if searchstate == 'normal':

            breadcrumbs = self.get_session_data('breadcrumbs', None)

            if breadcrumbs is None:

                breadcrumbs = SizeConstrainedList(10)

                self.set_session_data('breadcrumbs', breadcrumbs)

            breadcrumbs.append(self.url())

    def last_visited_page(self):

        breadcrumbs = self.get_session_data('breadcrumbs', None)

        if breadcrumbs:

            return breadcrumbs.pop()

        return self.base_url()

    def user_rql_callback(self, args, msg=None):

        """register a user callback to execute some rql query and return an url

        to call it ready to be inserted in html

        """

        def rqlexec(req, rql, args=None, key=None):

            req.execute(rql, args, key)

        return self.user_callback(rqlexec, args, msg)

    def user_callback(self, cb, args, msg=None, nonify=False):

        """register the given user callback and return an url to call it ready to be

        inserted in html

        """

        self.add_js('cubicweb.ajax.js')

        cbname = self.register_onetime_callback(cb, *args)

        msg = dumps(msg or '')

        return "javascript:userCallbackThenReloadPage('%s', %s)" % (

            cbname, msg)

    def register_onetime_callback(self, func, *args):

        cbname = 'cb_%s' % (

            sha.sha('%s%s%s%s' % (time.time(), func.__name__,

                                  random.random(),

                                  self.user.login)).hexdigest())

        def _cb(req):

            try:

                ret = func(req, *args)

            except TypeError:

                from warnings import warn

                warn('user callback should now take request as argument')

                ret = func(*args)

            self.unregister_callback(self.pageid, cbname)

            return ret

        self.set_page_data(cbname, _cb)

        return cbname

    def unregister_callback(self, pageid, cbname):

        assert pageid is not None

        assert cbname.startswith('cb_')

        self.info('unregistering callback %s for pageid %s', cbname, pageid)

        self.del_page_data(cbname)

    def clear_user_callbacks(self):

        if self.cnx is not None:

            sessdata = self.session_data()

            callbacks = [key for key in sessdata if key.startswith('cb_')]

            for callback in callbacks:

                self.del_session_data(callback)

    # web edition helpers #####################################################

    @cached # so it's writed only once

    def fckeditor_config(self):

        self.add_js('fckeditor/fckeditor.js')

        self.html_headers.define_var('fcklang', self.lang)

        self.html_headers.define_var('fckconfigpath',

                                     self.build_url('data/cubicweb.fckcwconfig.js'))

    def use_fckeditor(self):

        return self.vreg.config.fckeditor_installed() and self.property_value('ui.fckeditor')

    def edited_eids(self, withtype=False):

        """return a list of edited eids"""

        yielded = False

        # warning: use .keys since the caller may change `form`

        form = self.form

        try:

            eids = form['eid']

        except KeyError:

            raise NothingToEdit(self._('no selected entities'))

        if isinstance(eids, basestring):

            eids = (eids,)

        for peid in eids:

            if withtype:

                typekey = '__type:%s' % peid

                assert typekey in form, 'no entity type specified'

                yield peid, form[typekey]

            else:

                yield peid

            yielded = True

        if not yielded:

            raise NothingToEdit(self._('no selected entities'))

    # minparams=3 by default: at least eid, __type, and some params to change

    def extract_entity_params(self, eid, minparams=3):

        """extract form parameters relative to the given eid"""

        params = {}

        eid = str(eid)

        form = self.form

        for param in form:

            try:

                name, peid = param.split(':', 1)

            except ValueError:

                if not param.startswith('__') and param != "eid":

                    self.warning('param %s mis-formatted', param)

                continue

            if peid == eid:

                value = form[param]

                if value == INTERNAL_FIELD_VALUE:

                    value = None

                params[name] = value

        params['eid'] = eid

        if len(params) < minparams:

            raise RequestError(self._('missing parameters for entity %s') % eid)

        return params

    def remove_pending_operations(self):

        """shortcut to clear req's pending_{delete,insert} entries

        This is needed when the edition is completed (whether it's validated

        or cancelled)

        """

        self.del_session_data('pending_insert')