"""Source to query another RQL repository using pyro

:organization: Logilab

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

"""

__docformat__ = "restructuredtext en"

import threading

from os.path import join

from Pyro.errors import PyroError, ConnectionClosedError

from logilab.common.configuration import REQUIRED

from rql.nodes import Constant

from rql.utils import rqlvar_maker

from cubicweb import dbapi, server

from cubicweb import BadConnectionId, UnknownEid, ConnectionError

from cubicweb.cwconfig import register_persistent_options

from cubicweb.server.sources import AbstractSource, ConnectionWrapper

class ReplaceByInOperator:

    def __init__(self, eids):

        self.eids = eids

class PyroRQLSource(AbstractSource):

    """External repository source, using Pyro connection"""

    # boolean telling if modification hooks should be called when something is

    # modified in this source

    should_call_hooks = False

    # boolean telling if the repository should connect to this source during

    # migration

    connect_for_migration = False

    support_entities = None

    options = (

        # XXX pyro-ns host/port

        ('pyro-ns-id',

         {'type' : 'string',

          'default': REQUIRED,

          'help': 'identifier of the repository in the pyro name server',

          'group': 'pyro-source', 'inputlevel': 0,

          }),

        ('mapping-file',

         {'type' : 'string',

          'default': REQUIRED,

          'help': 'path to a python file with the schema mapping definition',

          'group': 'pyro-source', 'inputlevel': 1,

          }),

        ('cubicweb-user',

         {'type' : 'string',

          'default': REQUIRED,

          'help': 'user to use for connection on the distant repository',

          'group': 'pyro-source', 'inputlevel': 0,

          }),

        ('cubicweb-password',

         {'type' : 'password',

          'default': '',

          'help': 'user to use for connection on the distant repository',

          'group': 'pyro-source', 'inputlevel': 0,

          }),

        ('base-url',

         {'type' : 'string',

          'default': '',

          'help': 'url of the web site for the distant repository, if you want '

          'to generate external link to entities from this repository',

          'group': 'pyro-source', 'inputlevel': 1,

          }),

        ('pyro-ns-host',

         {'type' : 'string',

          'default': None,

          'help': 'Pyro name server\'s host. If not set, default to the value \

from all_in_one.conf.',

          'group': 'pyro-source', 'inputlevel': 1,

          }),

        ('pyro-ns-port',

         {'type' : 'int',

          'default': None,

          'help': 'Pyro name server\'s listening port. If not set, default to \

the value from all_in_one.conf.',

          'group': 'pyro-source', 'inputlevel': 1,

          }),

        ('pyro-ns-group',

         {'type' : 'string',

          'default': None,

          'help': 'Pyro name server\'s group where the repository will be \

registered. If not set, default to the value from all_in_one.conf.',

          'group': 'pyro-source', 'inputlevel': 1,

          }),

        ('synchronization-interval',

         {'type' : 'int',

          'default': 5*60,

          'help': 'interval between synchronization with the external \

repository (default to 5 minutes).',

          'group': 'pyro-source', 'inputlevel': 2,

          }),

    )

    PUBLIC_KEYS = AbstractSource.PUBLIC_KEYS + ('base-url',)

    _conn = None

    def __init__(self, repo, appschema, source_config, *args, **kwargs):

        AbstractSource.__init__(self, repo, appschema, source_config,

                                *args, **kwargs)

        mappingfile = source_config['mapping-file']

        if not mappingfile[0] == '/':

            mappingfile = join(repo.config.apphome, mappingfile)

        mapping = {}

        execfile(mappingfile, mapping)

        self.support_entities = mapping['support_entities']

        self.support_relations = mapping.get('support_relations', {})

        self.dont_cross_relations = mapping.get('dont_cross_relations', ())

        self.cross_relations = mapping.get('cross_relations', ())

        baseurl = source_config.get('base-url')

        if baseurl and not baseurl.endswith('/'):

            source_config['base-url'] += '/'

        self.config = source_config

        myoptions = (('%s.latest-update-time' % self.uri,

                      {'type' : 'int', 'sitewide': True,

                       'default': 0,

                       'help': _('timestamp of the latest source synchronization.'),

                       'group': 'sources', 

                       }),)

        register_persistent_options(myoptions)

    def last_update_time(self):

        pkey = u'sources.%s.latest-update-time' % self.uri

        rql = 'Any V WHERE X is EProperty, X value V, X pkey %(k)s'

        session = self.repo.internal_session()

        try:

            rset = session.execute(rql, {'k': pkey})

            if not rset:

                # insert it

                session.execute('INSERT EProperty X: X pkey %(k)s, X value %(v)s',

                                {'k': pkey, 'v': u'0'})

                session.commit()

                timestamp = 0

            else:

                assert len(rset) == 1

                timestamp = int(rset[0][0])

        finally:

            session.close()

    def init(self):

        """method called by the repository once ready to handle request"""

        interval = int(self.config.get('synchronization-interval', 5*60))

        self.repo.looping_task(interval, self.synchronize) 

    def synchronize(self, mtime=None):

        """synchronize content known by this repository with content in the

        external repository

        """

        self.info('synchronizing pyro source %s', self.uri)

        cnx = self.get_connection()

        extrepo = cnx._repo

        etypes = self.support_entities.keys()

        if mtime is None:

            mtime = self.last_update_time()

        updatetime, modified, deleted = extrepo.entities_modified_since(etypes,

                                                                        mtime)

        repo = self.repo

        session = repo.internal_session()

        try:

            for etype, extid in modified:

                try:

                    exturi = cnx.describe(extid)[1]

                    if exturi == 'system' or not exturi in repo.sources_by_uri:

                        eid = self.extid2eid(extid, etype, session)

                        rset = session.eid_rset(eid, etype)

                        entity = rset.get_entity(0, 0)

                        entity.complete(entity.e_schema.indexable_attributes())

                        repo.index_entity(session, entity)

                except:

                    self.exception('while updating %s with external id %s of source %s',

                                   etype, extid, self.uri)

                    continue

            for etype, extid in deleted:

                try:

                    eid = self.extid2eid(extid, etype, session, insert=False)

                    # entity has been deleted from external repository but is not known here

                    if eid is not None:

                        repo.delete_info(session, eid)

                except:

                    self.exception('while updating %s with external id %s of source %s',

                                   etype, extid, self.uri)

                    continue

            session.execute('SET X value %(v)s WHERE X pkey %(k)s',

                            {'k': u'sources.%s.latest-update-time' % self.uri,

            session.commit()

        finally:

            session.close()

    def _get_connection(self):

        """open and return a connection to the source"""

        nshost = self.config.get('pyro-ns-host') or self.repo.config['pyro-ns-host']

        nsport = self.config.get('pyro-ns-port') or self.repo.config['pyro-ns-port']

        nsgroup = self.config.get('pyro-ns-group') or self.repo.config['pyro-ns-group']

        #cnxprops = ConnectionProperties(cnxtype=self.config['cnx-type'])

        return dbapi.connect(database=self.config['pyro-ns-id'],

                             user=self.config['cubicweb-user'],

                             password=self.config['cubicweb-password'],

                             host=nshost, port=nsport, group=nsgroup,

                             setvreg=False) #cnxprops=cnxprops)

    def get_connection(self):

        try:

            return self._get_connection()

        except (ConnectionError, PyroError):

            self.critical("can't get connection to source %s", self.uri,

                          exc_info=1)

            return ConnectionWrapper()

    def check_connection(self, cnx):

        """check connection validity, return None if the connection is still valid

        else a new connection

        """

        # we have to transfer manually thread ownership. This can be done safely

        # since the pool to which belong the connection is affected to one

        # session/thread and can't be called simultaneously

        try:

            cnx._repo._transferThread(threading.currentThread())

        except AttributeError:

            # inmemory connection

            pass

        if not isinstance(cnx, ConnectionWrapper):

            try:

                cnx.check()

                return # ok

            except (BadConnectionId, ConnectionClosedError):

                pass

        # try to reconnect

        return self.get_connection()

    def syntax_tree_search(self, session, union, args=None, cachekey=None,

                           varmap=None):

        """return result from this source for a rql query (actually from a rql 

        syntax tree and a solution dictionary mapping each used variable to a 

        possible type). If cachekey is given, the query necessary to fetch the

        results (but not the results themselves) may be cached using this key.

        """

        if not args is None:

            args = args.copy()

        if server.DEBUG:

            print 'RQL FOR PYRO SOURCE', self.uri

            print union.as_string()

            if args: print 'ARGS', args

            print 'SOLUTIONS', ','.join(str(s.solutions) for s in union.children)

        # get cached cursor anyway

        cu = session.pool[self.uri]

        if cu is None:

            # this is a ConnectionWrapper instance

            msg = session._("can't connect to source %s, some data may be missing")

            session.set_shared_data('sources_error', msg % self.uri)

            return []

        try:

            rql, cachekey = RQL2RQL(self).generate(session, union, args)

        except UnknownEid, ex:

            if server.DEBUG:

                print 'unknown eid', ex, 'no results'

            return []

        if server.DEBUG:

            print 'TRANSLATED RQL', rql

        try:

            rset = cu.execute(rql, args, cachekey)

        except Exception, ex:

            self.exception(str(ex))

            msg = session._("error while querying source %s, some data may be missing")

            session.set_shared_data('sources_error', msg % self.uri)

            return []

        descr = rset.description

        if rset:

            needtranslation = []

            rows = rset.rows

            for i, etype in enumerate(descr[0]):

                if (etype is None or not self.schema.eschema(etype).is_final() or

                    getattr(union.locate_subquery(i, etype, args).selection[i], 'uidtype', None)):

                    needtranslation.append(i)

            if needtranslation:

                cnx = session.pool.connection(self.uri)

                for rowindex in xrange(rset.rowcount - 1, -1, -1):

                    row = rows[rowindex]

                    for colindex in needtranslation:

                        if row[colindex] is not None: # optional variable

                            etype = descr[rowindex][colindex]

                            exttype, exturi, extid = cnx.describe(row[colindex])

                            if exturi == 'system' or not exturi in self.repo.sources_by_uri:

                                eid = self.extid2eid(row[colindex], etype, session)

                                row[colindex] = eid

                            else:

                                # skip this row

                                del rows[rowindex]

                                del descr[rowindex]

                                break

            results = rows

        else:

            results = []

        if server.DEBUG:

            if len(results)>10:

                print '--------------->', results[:10], '...', len(results)

            else:

                print '--------------->', results

        return results

    def _entity_relations_and_kwargs(self, session, entity):

        relations = []

        kwargs = {'x': self.eid2extid(entity.eid, session)}

        for key, val in entity.iteritems():

            relations.append('X %s %%(%s)s' % (key, key))

            kwargs[key] = val

        return relations, kwargs

    def add_entity(self, session, entity):

        """add a new entity to the source"""

        raise NotImplementedError()

    def update_entity(self, session, entity):

        """update an entity in the source"""

        relations, kwargs = self._entity_relations_and_kwargs(session, entity)

        cu = session.pool[self.uri]

        cu.execute('SET %s WHERE X eid %%(x)s' % ','.join(relations),

                   kwargs, 'x')

    def delete_entity(self, session, etype, eid):

        """delete an entity from the source"""

        cu = session.pool[self.uri]

        cu.execute('DELETE %s X WHERE X eid %%(x)s' % etype,

                   {'x': self.eid2extid(eid, session)}, 'x')

    def add_relation(self, session, subject, rtype, object):

        """add a relation to the source"""

        cu = session.pool[self.uri]

        cu.execute('SET X %s Y WHERE X eid %%(x)s, Y eid %%(y)s' % rtype,

                   {'x': self.eid2extid(subject, session),

                    'y': self.eid2extid(object, session)}, ('x', 'y'))

    def delete_relation(self, session, subject, rtype, object):

        """delete a relation from the source"""

        cu = session.pool[self.uri]

        cu.execute('DELETE X %s Y WHERE X eid %%(x)s, Y eid %%(y)s' % rtype,

                   {'x': self.eid2extid(subject, session),

                    'y': self.eid2extid(object, session)}, ('x', 'y'))

class RQL2RQL(object):

    """translate a local rql query to be executed on a distant repository"""

    def __init__(self, source):

        self.source = source

        self.current_operator = None

    def _accept_children(self, node):

        res = []

        for child in node.children:

            rql = child.accept(self)

            if rql is not None:

                res.append(rql)

        return res

    def generate(self, session, rqlst, args):

        self._session = session 

        self.kwargs = args

        self.cachekey = []

        self.need_translation = False

        return self.visit_union(rqlst), self.cachekey

    def visit_union(self, node):

        s = self._accept_children(node)

        if len(s) > 1:

            return ' UNION '.join('(%s)' % q for q in s)

        return s[0]

    def visit_select(self, node):

        """return the tree as an encoded rql string"""

        self._varmaker = rqlvar_maker(defined=node.defined_vars.copy())