# copyright 2003-2012 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
#
# (disable pylint msg for client obj access to protected member as in obj._cw)
# pylint: disable=W0212
"""The ``ajaxcontroller`` module defines the :class:`AjaxController`
controller and the ``ajax-func`` cubicweb registry.

.. autoclass:: cubicweb.web.views.ajaxcontroller.AjaxController
   :members:

``ajax-funcs`` registry hosts exposed remote functions, that is
functions that can be called from the javascript world.

To register a new remote function, either decorate your function
with the :func:`~cubicweb.web.views.ajaxcontroller.ajaxfunc` decorator:

.. sourcecode:: python

    from cubicweb.predicates import mactch_user_groups
    from cubicweb.web.views.ajaxcontroller import ajaxfunc

    @ajaxfunc(output_type='json', selector=match_user_groups('managers'))
    def list_users(self):
        return [u for (u,) in self._cw.execute('Any L WHERE U login L')]

or inherit from :class:`~cubicweb.web.views.ajaxcontroller.AjaxFunction` and
implement the ``__call__`` method:

.. sourcecode:: python

    from cubicweb.web.views.ajaxcontroller import AjaxFunction
    class ListUser(AjaxFunction):
        __regid__ = 'list_users' # __regid__ is the name of the exposed function
        __select__ = match_user_groups('managers')
        output_type = 'json'

        def __call__(self):
            return [u for (u, ) in self._cw.execute('Any L WHERE U login L')]


.. autoclass:: cubicweb.web.views.ajaxcontroller.AjaxFunction
   :members:

.. autofunction:: cubicweb.web.views.ajaxcontroller.ajaxfunc

"""

__docformat__ = "restructuredtext en"

from warnings import warn
from functools import partial

from logilab.common.date import strptime
from logilab.common.registry import yes
from logilab.common.deprecation import deprecated

from cubicweb import ObjectNotFound, NoSelectableObject
from cubicweb.appobject import AppObject
from cubicweb.utils import json, json_dumps, UStringIO
from cubicweb.uilib import exc_message
from cubicweb.web import RemoteCallFailed, DirectResponse
from cubicweb.web.controller import Controller
from cubicweb.web.views import vid_from_rset
from cubicweb.web.views import basecontrollers


def optional_kwargs(extraargs):
    if extraargs is None:
        return {}
    # we receive unicode keys which is not supported by the **syntax
    return dict((str(key), value) for key, value in extraargs.iteritems())


class AjaxController(Controller):
    """AjaxController handles ajax remote calls from javascript

    The following javascript function call:

    .. sourcecode:: javascript

      var d = asyncRemoteExec('foo', 12, "hello");
      d.addCallback(function(result) {
          alert('server response is: ' + result);
      });

    will generate an ajax HTTP GET on the following url::

        BASE_URL/ajax?fname=foo&arg=12&arg="hello"

    The AjaxController controller will therefore be selected to handle those URLs
    and will itself select the :class:`cubicweb.web.views.ajaxcontroller.AjaxFunction`
    matching the *fname* parameter.
    """
    __regid__ = 'ajax'

    def publish(self, rset=None):
        self._cw.ajax_request = True
        try:
            fname = self._cw.form['fname']
        except KeyError:
            raise RemoteCallFailed('no method specified')
        # 1/ check first for old-style (JSonController) ajax func for bw compat
        try:
            func = getattr(basecontrollers.JSonController, 'js_%s' % fname).im_func
            func = partial(func, self)
        except AttributeError:
            # 2/ check for new-style (AjaxController) ajax func
            try:
                func = self._cw.vreg['ajax-func'].select(fname, self._cw)
            except ObjectNotFound:
                raise RemoteCallFailed('no %s method' % fname)
        else:
            warn('[3.15] remote function %s found on JSonController, '
                 'use AjaxFunction / @ajaxfunc instead' % fname,
                 DeprecationWarning, stacklevel=2)
        # no <arg> attribute means the callback takes no argument
        args = self._cw.form.get('arg', ())
        if not isinstance(args, (list, tuple)):
            args = (args,)
        try:
            args = [json.loads(arg) for arg in args]
        except ValueError as exc:
            self.exception('error while decoding json arguments for '
                           'js_%s: %s (err: %s)', fname, args, exc)
            raise RemoteCallFailed(exc_message(exc, self._cw.encoding))
        try:
            result = func(*args)
        except (RemoteCallFailed, DirectResponse):
            raise
        except Exception as exc:
            self.exception('an exception occurred while calling js_%s(%s): %s',
                           fname, args, exc)
            raise RemoteCallFailed(exc_message(exc, self._cw.encoding))
        if result is None:
            return ''
        # get unicode on @htmlize methods, encoded string on @jsonize methods
        elif isinstance(result, unicode):
            return result.encode(self._cw.encoding)
        return result

class AjaxFunction(AppObject):
    """
    Attributes on this base class are:

    :attr: `check_pageid`: make sure the pageid received is valid before proceeding
    :attr: `output_type`:

           - *None*: no processing, no change on content-type

           - *json*: serialize with `json_dumps` and set *application/json*
                     content-type

           - *xhtml*: wrap result in an XML node and forces HTML / XHTML
                      content-type (use ``_cw.html_content_type()``)

    """
    __registry__ = 'ajax-func'
    __select__ = yes()
    __abstract__ = True

    check_pageid = False
    output_type = None

    @staticmethod
    def _rebuild_posted_form(names, values, action=None):
        form = {}
        for name, value in zip(names, values):
            # remove possible __action_xxx inputs
            if name.startswith('__action'):
                if action is None:
                    # strip '__action_' to get the actual action name
                    action = name[9:]
                continue
            # form.setdefault(name, []).append(value)
            if name in form:
                curvalue = form[name]
                if isinstance(curvalue, list):
                    curvalue.append(value)
                else:
                    form[name] = [curvalue, value]
            else:
                form[name] = value
        # simulate click on __action_%s button to help the controller
        if action:
            form['__action_%s' % action] = u'whatever'
        return form

    def validate_form(self, action, names, values):
        self._cw.form = self._rebuild_posted_form(names, values, action)
        return basecontrollers._validate_form(self._cw, self._cw.vreg)

    def _exec(self, rql, args=None, rocheck=True):
        """json mode: execute RQL and return resultset as json"""
        rql = rql.strip()
        if rql.startswith('rql:'):
            rql = rql[4:]
        if rocheck:
            self._cw.ensure_ro_rql(rql)
        try:
            return self._cw.execute(rql, args)
        except Exception as ex:
            self.exception("error in _exec(rql=%s): %s", rql, ex)
            return None
        return None

    def _call_view(self, view, paginate=False, **kwargs):
        divid = self._cw.form.get('divid')
        # we need to call pagination before with the stream set
        try:
            stream = view.set_stream()
        except AttributeError:
            stream = UStringIO()
            kwargs['w'] = stream.write
            assert not paginate
        if divid == 'pageContent':
            # ensure divid isn't reused by the view (e.g. table view)
            del self._cw.form['divid']
            # mimick main template behaviour
            stream.write(u'<div id="pageContent">')
            vtitle = self._cw.form.get('vtitle')
            if vtitle:
                stream.write(u'<h1 class="vtitle">%s</h1>\n' % vtitle)
            paginate = True
        nav_html = UStringIO()
        if paginate and not view.handle_pagination:
            view.paginate(w=nav_html.write)
        stream.write(nav_html.getvalue())
        if divid == 'pageContent':
            stream.write(u'<div id="contentmain">')
        view.render(**kwargs)
        extresources = self._cw.html_headers.getvalue(skiphead=True)
        if extresources:
            stream.write(u'<div class="ajaxHtmlHead">\n') # XXX use a widget ?
            stream.write(extresources)
            stream.write(u'</div>\n')
        if divid == 'pageContent':
            stream.write(u'</div>%s</div>' % nav_html.getvalue())
        return stream.getvalue()


def _ajaxfunc_factory(implementation, selector=yes(), _output_type=None,
                      _check_pageid=False, regid=None):
    """converts a standard python function into an AjaxFunction appobject"""
    class AnAjaxFunc(AjaxFunction):
        __regid__ = regid or implementation.__name__
        __select__ = selector
        output_type = _output_type
        check_pageid = _check_pageid

        def serialize(self, content):
            if self.output_type is None:
                return content
            elif self.output_type == 'xhtml':
                self._cw.set_content_type(self._cw.html_content_type())
                return ''.join((u'<div>',
                                content.strip(), u'</div>'))
            elif self.output_type == 'json':
                self._cw.set_content_type('application/json')
                return json_dumps(content)
            raise RemoteCallFailed('no serializer found for output type %s'
                                   % self.output_type)

        def __call__(self, *args, **kwargs):
            if self.check_pageid:
                data = self._cw.session.data.get(self._cw.pageid)
                if data is None:
                    raise RemoteCallFailed(self._cw._('pageid-not-found'))
            return self.serialize(implementation(self, *args, **kwargs))

    AnAjaxFunc.__name__ = implementation.__name__
    # make sure __module__ refers to the original module otherwise
    # vreg.register(obj) will ignore ``obj``.
    AnAjaxFunc.__module__ = implementation.__module__
    # relate the ``implementation`` object to its wrapper appobject
    # will be used by e.g.:
    #   import base_module
    #   @ajaxfunc
    #   def foo(self):
    #       return 42
    #   assert foo(object) == 42
    #   vreg.register_and_replace(foo, base_module.older_foo)
    implementation.__appobject__ = AnAjaxFunc
    return implementation


def ajaxfunc(implementation=None, selector=yes(), output_type=None,
             check_pageid=False, regid=None):
    """promote a standard function to an ``AjaxFunction`` appobject.

    All parameters are optional:

    :param selector: a custom selector object if needed, default is ``yes()``

    :param output_type: either None, 'json' or 'xhtml' to customize output
                        content-type. Default is None

    :param check_pageid: whether the function requires a valid `pageid` or not
                         to proceed. Default is False.

    :param regid: a custom __regid__ for the created ``AjaxFunction`` object. Default
                  is to keep the wrapped function name.

    ``ajaxfunc`` can be used both as a standalone decorator:

    .. sourcecode:: python

        @ajaxfunc
        def my_function(self):
            return 42

    or as a parametrizable decorator:

    .. sourcecode:: python

        @ajaxfunc(output_type='json')
        def my_function(self):
            return 42

    """
    # if used as a parametrized decorator (e.g. @ajaxfunc(output_type='json'))
    if implementation is None:
        def _decorator(func):
            return _ajaxfunc_factory(func, selector=selector,
                                     _output_type=output_type,
                                     _check_pageid=check_pageid,
                                     regid=regid)
        return _decorator
    # else, used as a standalone decorator (i.e. @ajaxfunc)
    return _ajaxfunc_factory(implementation, selector=selector,
                             _output_type=output_type,
                             _check_pageid=check_pageid, regid=regid)



###############################################################################
#  Cubicweb remote functions for :                                            #
#  - appobject rendering                                                      #
#  - user / page session data management                                      #
###############################################################################
@ajaxfunc(output_type='xhtml')
def view(self):
    # XXX try to use the page-content template
    req = self._cw
    rql = req.form.get('rql')
    if rql:
        rset = self._exec(rql)
    elif 'eid' in req.form:
        rset = self._cw.eid_rset(req.form['eid'])
    else:
        rset = None
    vid = req.form.get('vid') or vid_from_rset(req, rset, self._cw.vreg.schema)
    try:
        viewobj = self._cw.vreg['views'].select(vid, req, rset=rset)
    except NoSelectableObject:
        vid = req.form.get('fallbackvid', 'noresult')
        viewobj = self._cw.vreg['views'].select(vid, req, rset=rset)
    viewobj.set_http_cache_headers()
    req.validate_cache()
    return self._call_view(viewobj, paginate=req.form.pop('paginate', False))


@ajaxfunc(output_type='xhtml')
def component(self, compid, rql, registry='components', extraargs=None):
    if rql:
        rset = self._exec(rql)
    else:
        rset = None
    # XXX while it sounds good, addition of the try/except below cause pb:
    # when filtering using facets return an empty rset, the edition box
    # isn't anymore selectable, as expected. The pb is that with the
    # try/except below, we see a "an error occurred" message in the ui, while
    # we don't see it without it. Proper fix would probably be to deal with
    # this by allowing facet handling code to tell to js_component that such
    # error is expected and should'nt be reported.
    #try:
    comp = self._cw.vreg[registry].select(compid, self._cw, rset=rset,
                                          **optional_kwargs(extraargs))
    #except NoSelectableObject:
    #    raise RemoteCallFailed('unselectable')
    return self._call_view(comp, **optional_kwargs(extraargs))

@ajaxfunc(output_type='xhtml')
def render(self, registry, oid, eid=None,
              selectargs=None, renderargs=None):
    if eid is not None:
        rset = self._cw.eid_rset(eid)
        # XXX set row=0
    elif self._cw.form.get('rql'):
        rset = self._cw.execute(self._cw.form['rql'])
    else:
        rset = None
    viewobj = self._cw.vreg[registry].select(oid, self._cw, rset=rset,
                                             **optional_kwargs(selectargs))
    return self._call_view(viewobj, **optional_kwargs(renderargs))


@ajaxfunc(output_type='json')
def i18n(self, msgids):
    """returns the translation of `msgid`"""
    return [self._cw._(msgid) for msgid in msgids]

@ajaxfunc(output_type='json')
def format_date(self, strdate):
    """returns the formatted date for `msgid`"""
    date = strptime(strdate, '%Y-%m-%d %H:%M:%S')
    return self._cw.format_date(date)

@ajaxfunc(output_type='json')
def external_resource(self, resource):
    """returns the URL of the external resource named `resource`"""
    return self._cw.uiprops[resource]

@ajaxfunc(output_type='json', check_pageid=True)
def user_callback(self, cbname):
    """execute the previously registered user callback `cbname`.

    If matching callback is not found, return None
    """
    page_data = self._cw.session.data.get(self._cw.pageid, {})
    try:
        cb = page_data[cbname]
    except KeyError:
        self.warning('unable to find user callback %s', cbname)
        return None
    return cb(self._cw)


@ajaxfunc
def unregister_user_callback(self, cbname):
    """unregister user callback `cbname`"""
    self._cw.unregister_callback(self._cw.pageid, cbname)

@ajaxfunc
def unload_page_data(self):
    """remove user's session data associated to current pageid"""
    self._cw.session.data.pop(self._cw.pageid, None)

@ajaxfunc(output_type='json')
@deprecated("[3.13] use jQuery.cookie(cookiename, cookievalue, {path: '/'}) in js land instead")
def set_cookie(self, cookiename, cookievalue):
    """generates the Set-Cookie HTTP reponse header corresponding
    to `cookiename` / `cookievalue`.
    """
    cookiename, cookievalue = str(cookiename), str(cookievalue)
    self._cw.set_cookie(cookiename, cookievalue)