# copyright 2010-2011 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/>.
"""datafeed parser for xml generated by cubicweb

Example of mapping for CWEntityXMLParser::

  {u'CWUser': {                                        # EntityType
      (u'in_group', u'subject', u'link'): [            # (rtype, role, action)
          (u'CWGroup', {u'linkattr': u'name'})],       #   -> rules = [(EntityType, options), ...]
      (u'tags', u'object', u'link-or-create'): [       # (...)
          (u'Tag', {u'linkattr': u'name'})],           #   -> ...
      (u'use_email', u'subject', u'copy'): [           # (...)
          (u'EmailAddress', {})]                       #   -> ...
      }
   }

"""

import urllib2
import StringIO
import os.path as osp
from cookielib import CookieJar
from datetime import datetime, timedelta

from lxml import etree

from logilab.common.date import todate, totime
from logilab.common.textutils import splitstrip, text_to_dict

from yams.constraints import BASE_CONVERTERS
from yams.schema import role_name as rn

from cubicweb import ValidationError, typed_eid
from cubicweb.server.sources import datafeed

def ensure_str_keys(dic):
    for key in dic:
        dic[str(key)] = dic.pop(key)

# XXX see cubicweb.cwvreg.YAMS_TO_PY
# XXX see cubicweb.web.views.xmlrss.SERIALIZERS
DEFAULT_CONVERTERS = BASE_CONVERTERS.copy()
DEFAULT_CONVERTERS['String'] = unicode
DEFAULT_CONVERTERS['Password'] = lambda x: x.encode('utf8')
def convert_date(ustr):
    return todate(datetime.strptime(ustr, '%Y-%m-%d'))
DEFAULT_CONVERTERS['Date'] = convert_date
def convert_datetime(ustr):
    if '.' in ustr: # assume %Y-%m-%d %H:%M:%S.mmmmmm
        ustr = ustr.split('.',1)[0]
    return datetime.strptime(ustr, '%Y-%m-%d %H:%M:%S')
DEFAULT_CONVERTERS['Datetime'] = convert_datetime
def convert_time(ustr):
    return totime(datetime.strptime(ustr, '%H:%M:%S'))
DEFAULT_CONVERTERS['Time'] = convert_time
def convert_interval(ustr):
    return time(seconds=int(ustr))
DEFAULT_CONVERTERS['Interval'] = convert_interval

# use a cookie enabled opener to use session cookie if any
_OPENER = urllib2.build_opener()
try:
    from logilab.common import urllib2ext
    _OPENER.add_handler(urllib2ext.HTTPGssapiAuthHandler())
except ImportError: # python-kerberos not available
    pass
_OPENER.add_handler(urllib2.HTTPCookieProcessor(CookieJar()))

def extract_typed_attrs(eschema, stringdict, converters=DEFAULT_CONVERTERS):
    typeddict = {}
    for rschema in eschema.subject_relations():
        if rschema.final and rschema in stringdict:
            if rschema == 'eid':
                continue
            attrtype = eschema.destination(rschema)
            typeddict[rschema.type] = converters[attrtype](stringdict[rschema])
    return typeddict

def _parse_entity_etree(parent):
    for node in list(parent):
        try:
            item = {'cwtype': unicode(node.tag),
                    'cwuri': node.attrib['cwuri'],
                    'eid': typed_eid(node.attrib['eid']),
                    }
        except KeyError:
            # cw < 3.11 compat mode XXX
            item = {'cwtype': unicode(node.tag),
                    'cwuri': node.find('cwuri').text,
                    'eid': typed_eid(node.find('eid').text),
                    }
        rels = {}
        for child in node:
            role = child.get('role')
            if role:
                # relation
                related = rels.setdefault(role, {}).setdefault(child.tag, [])
                related += [ritem for ritem, _ in _parse_entity_etree(child)]
            else:
                # attribute
                item[child.tag] = unicode(child.text)
        yield item, rels

def build_search_rql(etype, attrs):
    restrictions = ['X %(attr)s %%(%(attr)s)s'%{'attr': attr} for attr in attrs]
    return 'Any X WHERE X is %s, %s' % (etype, ', '.join(restrictions))

def rtype_role_rql(rtype, role):
    if role == 'object':
        return 'Y %s X WHERE X eid %%(x)s' % rtype
    else:
        return 'X %s Y WHERE X eid %%(x)s' % rtype


def _check_no_option(action, options, eid, _):
    if options:
        msg = _("'%s' action doesn't take any options") % action
        raise ValidationError(eid, {rn('options', 'subject'): msg})

def _check_linkattr_option(action, options, eid, _):
    if not 'linkattr' in options:
        msg = _("'%s' action requires 'linkattr' option") % action
        raise ValidationError(eid, {rn('options', 'subject'): msg})


class CWEntityXMLParser(datafeed.DataFeedParser):
    """datafeed parser for the 'xml' entity view"""
    __regid__ = 'cw.entityxml'

    action_options = {
        'copy': _check_no_option,
        'link-or-create': _check_linkattr_option,
        'link': _check_linkattr_option,
        }

    def __init__(self, *args, **kwargs):
        super(CWEntityXMLParser, self).__init__(*args, **kwargs)
        self.action_methods = {
            'copy': self.related_copy,
            'link-or-create': self.related_link_or_create,
            'link': self.related_link,
            }

    # mapping handling #########################################################

    def add_schema_config(self, schemacfg, checkonly=False):
        """added CWSourceSchemaConfig, modify mapping accordingly"""
        _ = self._cw._
        try:
            rtype = schemacfg.schema.rtype.name
        except AttributeError:
            msg = _("entity and relation types can't be mapped, only attributes "
                    "or relations")
            raise ValidationError(schemacfg.eid, {rn('cw_for_schema', 'subject'): msg})
        if schemacfg.options:
            options = text_to_dict(schemacfg.options)
        else:
            options = {}
        try:
            role = options.pop('role')
            if role not in ('subject', 'object'):
                raise KeyError
        except KeyError:
            msg = _('"role=subject" or "role=object" must be specified in options')
            raise ValidationError(schemacfg.eid, {rn('options', 'subject'): msg})
        try:
            action = options.pop('action')
            self.action_options[action](action, options, schemacfg.eid, _)
        except KeyError:
            msg = _('"action" must be specified in options; allowed values are '
                    '%s') % ', '.join(self.action_methods)
            raise ValidationError(schemacfg.eid, {rn('options', 'subject'): msg})
        if not checkonly:
            if role == 'subject':
                etype = schemacfg.schema.stype.name
                ttype = schemacfg.schema.otype.name
            else:
                etype = schemacfg.schema.otype.name
                ttype = schemacfg.schema.stype.name
            etyperules = self.source.mapping.setdefault(etype, {})
            etyperules.setdefault((rtype, role, action), []).append(
                (ttype, options) )
            self.source.mapping_idx[schemacfg.eid] = (
                etype, rtype, role, action, ttype)

    def del_schema_config(self, schemacfg, checkonly=False):
        """deleted CWSourceSchemaConfig, modify mapping accordingly"""
        etype, rtype, role, action, ttype = self.source.mapping_idx[schemacfg.eid]
        rules = self.source.mapping[etype][(rtype, role, action)]
        rules = [x for x in rules if not x[0] == ttype]
        if not rules:
            del self.source.mapping[etype][(rtype, role, action)]

    # import handling ##########################################################

    def process(self, url, partialcommit=True):
        """IDataFeedParser main entry point"""
        # XXX suppression support according to source configuration. If set, get
        # all cwuri of entities from this source, and compare with newly
        # imported ones
        error = False
        for item, rels in self.parse(url):
            cwuri = item['cwuri']
            try:
                self.process_item(item, rels)
                if partialcommit:
                    # commit+set_pool instead of commit(reset_pool=False) to let
                    # other a chance to get our pool
                    self._cw.commit()
                    self._cw.set_pool()
            except ValidationError, exc:
                if partialcommit:
                    self.source.error('Skipping %s because of validation error %s' % (cwuri, exc))
                    self._cw.rollback()
                    self._cw.set_pool()
                    error = True
                else:
                    raise
        return error

    def parse(self, url):
        if not url.startswith('http'):
            stream = StringIO.StringIO(url)
        else:
            for mappedurl in HOST_MAPPING:
                if url.startswith(mappedurl):
                    url = url.replace(mappedurl, HOST_MAPPING[mappedurl], 1)
                    break
            self.source.info('GET %s', url)
            stream = _OPENER.open(url)
        return _parse_entity_etree(etree.parse(stream).getroot())

    def process_item(self, item, rels):
        entity = self.extid2entity(str(item.pop('cwuri')),  item.pop('cwtype'),
                                   item=item)
        if not (self.created_during_pull(entity) or self.updated_during_pull(entity)):
            self.notify_updated(entity)
            item.pop('eid')
            # XXX check modification date
            attrs = extract_typed_attrs(entity.e_schema, item)
            entity.set_attributes(**attrs)
        for (rtype, role, action), rules in self.source.mapping.get(entity.__regid__, {}).iteritems():
            try:
                related_items = rels[role][rtype]
            except KeyError:
                self.source.error('relation %s-%s not found in xml export of %s',
                                  rtype, role, entity.__regid__)
                continue
            try:
                actionmethod = self.action_methods[action]
            except KeyError:
                raise Exception('Unknown action %s' % action)
            actionmethod(entity, rtype, role, related_items, rules)
        return entity

    def before_entity_copy(self, entity, sourceparams):
        """IDataFeedParser callback"""
        attrs = extract_typed_attrs(entity.e_schema, sourceparams['item'])
        entity.cw_edited.update(attrs)

    def related_copy(self, entity, rtype, role, others, rules):
        """implementation of 'copy' action

        Takes no option.
        """
        assert not any(x[1] for x in rules), "'copy' action takes no option"
        ttypes = set([x[0] for x in rules])
        others = [item for item in others if item['cwtype'] in ttypes]
        eids = [] # local eids
        if not others:
            self._clear_relation(entity, rtype, role, ttypes)
            return
        for item in others:
            item, _rels = self._complete_item(item)
            other_entity = self.process_item(item, [])
            eids.append(other_entity.eid)
        self._set_relation(entity, rtype, role, eids)

    def related_link(self, entity, rtype, role, others, rules):
        """implementation of 'link' action

        requires an options to control search of the linked entity.
        """
        for ttype, options in rules:
            assert 'linkattr' in options, (
                "'link' action requires a list of attributes used to "
                "search if the entity already exists")
            self._related_link(entity, rtype, role, ttype, others, [options['linkattr']],
                               create_when_not_found=False)

    def related_link_or_create(self, entity, rtype, role, others, rules):
        """implementation of 'link-or-create' action

        requires an options to control search of the linked entity.
        """
        for ttype, options in rules:
            assert 'linkattr' in options, (
                "'link-or-create' action requires a list of attributes used to "
                "search if the entity already exists")
            self._related_link(entity, rtype, role, ttype, others, [options['linkattr']],
                               create_when_not_found=True)

    def _related_link(self, entity, rtype, role, ttype, others, searchattrs,
                      create_when_not_found):
        def issubset(x,y):
            return all(z in y for z in x)
        eids = [] # local eids
        for item in others:
            if item['cwtype'] != ttype:
                continue
            if not issubset(searchattrs, item):
                item, _rels = self._complete_item(item, False)
                if not issubset(searchattrs, item):
                    self.source.error('missing attribute, got %s expected keys %s'
                                      % item, searchattrs)
                    continue
            kwargs = dict((attr, item[attr]) for attr in searchattrs)
            rql = build_search_rql(item['cwtype'], kwargs)
            rset = self._cw.execute(rql, kwargs)
            if len(rset) > 1:
                self.source.error('ambiguous link: found %s entity %s with attributes %s',
                                  len(rset), item['cwtype'], kwargs)
            elif len(rset) == 1:
                eids.append(rset[0][0])
            elif create_when_not_found:
                ensure_str_keys(kwargs) # XXX necessary with python < 2.6
                eids.append(self._cw.create_entity(item['cwtype'], **kwargs).eid)
            else:
                self.source.error('can not find %s entity with attributes %s',
                                  item['cwtype'], kwargs)
        if not eids:
            self._clear_relation(entity, rtype, role, (ttype,))
        else:
            self._set_relation(entity, rtype, role, eids)

    def _complete_item(self, item, add_relations=True):
        itemurl = item['cwuri'] + '?vid=xml'
        if add_relations:
            for rtype, role, _ in self.source.mapping.get(item['cwtype'], ()):
                itemurl += '&relation=%s_%s' % (rtype, role)
        item_rels = list(self.parse(itemurl))
        assert len(item_rels) == 1
        return item_rels[0]

    def _clear_relation(self, entity, rtype, role, ttypes):
        if entity.eid not in self.stats['created']:
            if len(ttypes) > 1:
                typerestr = ', Y is IN(%s)' % ','.join(ttypes)
            else:
                typerestr = ', Y is %s' % ','.join(ttypes)
            self._cw.execute('DELETE ' + rtype_role_rql(rtype, role) + typerestr,
                             {'x': entity.eid})

    def _set_relation(self, entity, rtype, role, eids):
        rqlbase = rtype_role_rql(rtype, role)
        rql = 'DELETE %s' % rqlbase
        if eids:
            eidstr = ','.join(str(eid) for eid in eids)
            rql += ', NOT Y eid IN (%s)' % eidstr
        self._cw.execute(rql, {'x': entity.eid})
        if eids:
            if role == 'object':
                rql = 'SET %s, Y eid IN (%s), NOT Y %s X' % (rqlbase, eidstr, rtype)
            else:
                rql = 'SET %s, Y eid IN (%s), NOT X %s Y' % (rqlbase, eidstr, rtype)
            self._cw.execute(rql, {'x': entity.eid})

def registration_callback(vreg):
    vreg.register_all(globals().values(), __name__)
    global HOST_MAPPING
    HOST_MAPPING = {}
    if vreg.config.apphome:
        host_mapping_file = osp.join(vreg.config.apphome, 'hostmapping.py')
        if osp.exists(host_mapping_file):
            HOST_MAPPING = eval(file(host_mapping_file).read())
            vreg.info('using host mapping %s from %s', HOST_MAPPING, host_mapping_file)