# copyright 2003-2016 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/>.

"""cubicweb server sources support"""

from time import time

from logging import getLogger

from logilab.common import configuration

from logilab.common.textutils import unormalize

from yams.schema import role_name

from cubicweb import ValidationError, set_log_methods, server, _

from cubicweb.server import SOURCE_TYPES

def dbg_st_search(uri, union, args, cachekey=None, prefix='rql for'):

    if server.DEBUG & server.DBG_RQL:

        global t

        print('  %s %s source: %s' % (prefix, uri, repr(union.as_string())))

        t = time()

        if server.DEBUG & server.DBG_MORE:

            print('    args', repr(args))

            print('    cache key', cachekey)

            print('    solutions', ','.join(str(s.solutions)

                                            for s in union.children))

    # return true so it can be used as assertion (and so be killed by python -O)

    return True

def dbg_results(results):

    if server.DEBUG & server.DBG_RQL:

        if len(results) > 10:

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

        else:

            print('  -->', results, end=' ')

        print('time: ', time() - t)

    # return true so it can be used as assertion (and so be killed by python -O)

    return True

class AbstractSource(object):

    """an abstract class for sources"""

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

    # migration

    connect_for_migration = True

    # a global identifier for this source, which has to be set by the source

    # instance

    uri = None

    # a reference to the system information helper

    repo = None

    # a reference to the instance'schema (may differs from the source'schema)

    schema = None

    # force deactivation (configuration error for instance)

    disabled = False

    # boolean telling if cwuri of entities from this source is the url that

    # should be used as entity's absolute url

    use_cwuri_as_url = False

    # source configuration options

    options = ()

    # these are overridden by set_log_methods below

    # only defining here to prevent pylint from complaining

    info = warning = error = critical = exception = debug = lambda msg, *a, **kw: None

    def __init__(self, repo, source_config, eid=None):

        self.repo = repo

        self.set_schema(repo.schema)

        self.eid = eid

        self.public_config = source_config.copy()

        self.public_config['use-cwuri-as-url'] = self.use_cwuri_as_url

        self.remove_sensitive_information(self.public_config)

        self.uri = source_config.pop('uri')

        # unormalize to avoid non-ascii characters in logger's name, this will cause decoding error

        # on logging

        source_config.pop('type')

        self.config = self._check_config_dict(

            eid, source_config, raise_on_error=False)

    def __repr__(self):

        return '<%s %s source %s @%#x>' % (self.uri, self.__class__.__name__,

                                           self.eid, id(self))

    def __lt__(self, other):

        """simple comparison function to get predictable source order, with the

        system source at last

        """

        if self.uri == other.uri:

            return False

        if self.uri == 'system':

            return False

        if other.uri == 'system':

            return True

        return self.uri < other.uri

    def __eq__(self, other):

        return self.uri == other.uri

    def __ne__(self, other):

        return not (self == other)

    def backup(self, backupfile, confirm, format='native'):

        """method called to create a backup of source's data"""

        pass

    def restore(self, backupfile, confirm, drop, format='native'):

        """method called to restore a backup of source's data"""

        pass

    def _check_config_dict(self, eid, confdict, raise_on_error=True):

        """Check configuration of source entity and return config dict properly

        typed with defaults set.

        If `raise_on_error` is True (the default), a ValidationError will be

        raised if some error is encountered, else the problem will be ignored.

        """

        processed = {}

        for optname, optdict in self.options:

            value = confdict.pop(optname, optdict.get('default'))

            if value is configuration.REQUIRED:

                if not raise_on_error:

                    continue

                msg = _('specifying %s is mandatory')

                msgargs = optname

                raise ValidationError(eid, {role_name('config', 'subject'): msg}, msgargs)

            elif value is not None:

                # type check

                try:

                    value = configuration._validate(value, optdict, optname)

                except Exception as ex:

                    if not raise_on_error:

                        continue

                    raise ValidationError(eid, {role_name('config', 'subject'): msg})

            processed[optname] = value

        # cw < 3.10 bw compat

        try:

            processed['adapter'] = confdict['adapter']

        except KeyError:

            pass

        # check for unknown options

        if confdict and tuple(confdict) != ('adapter',):

            if raise_on_error:

                msg = _('unknown options %s')

                msgargs = ', '.join(confdict)

                raise ValidationError(eid, {role_name('config', 'subject'): msg}, msgargs)

            else:

                self.warning('unknown options %s', ', '.join(confdict))

                # add options to processed, they may be necessary during migration

                processed.update(confdict)

        return processed

    def check_config(self, source_entity):

        """Check configuration of source entity, raise ValidationError if some

        errors are detected.

        """

        return self._check_config_dict(source_entity.eid, source_entity.dictconfig)

    def check_urls(self, source_entity):

        """Check URL of source entity: `urls` is a string that may contain one

        URL per line), and return a list of at least one validated URL.

        """

        urls = source_entity.url if source_entity.url else ''

        urls = [url.strip() for url in urls.splitlines() if url.strip()]

        if not urls:

            msg = _('specifying an URL is mandatory')

            raise ValidationError(source_entity.eid, {role_name('url', 'subject'): msg})

        return urls

    # source initialization / finalization #####################################

    def set_schema(self, schema):

        """set the instance'schema"""

        self.schema = schema

    def init_creating(self):

        """method called by the repository once ready to create a new instance"""

        pass

    def init(self, source_entity):

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

        `activated` is a boolean flag telling if the source is activated or not.

        """

        source_entity.complete()

        if source_entity.url:

            self.urls = self.check_urls(source_entity)

        else:

            self.urls = []

    PUBLIC_KEYS = ('type', 'uri', 'use-cwuri-as-url')

    def remove_sensitive_information(self, sourcedef):

        """remove sensitive information such as login / password from source

        definition

        """

        for key in list(sourcedef):

            if key not in self.PUBLIC_KEYS:

                sourcedef.pop(key)

    # connections handling #####################################################

    def get_connection(self):

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

        raise NotImplementedError(self)

    def close_source_connections(self):

        for cnxset in self.repo.cnxsets:

            cnxset.cu = None

            cnxset.cnx.close()

    def open_source_connections(self):

        for cnxset in self.repo.cnxsets:

            cnxset.cnx = self.get_connection()

            cnxset.cu = cnxset.cnx.cursor()

    # user authentication api ##################################################

    def authenticate(self, cnx, login, **kwargs):

        """if the source support CWUser entity type, it should implement

        this method which should return CWUser eid for the given login/password

        if this account is defined in this source and valid login / password is

        given. Else raise `AuthenticationError`

        """

        raise NotImplementedError(self)

    # RQL query api ############################################################

    def syntax_tree_search(self, cnx, union,

                           args=None, cachekey=None, debug=0):

        """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.

        """

        raise NotImplementedError(self)

    # write modification api ###################################################

    # read-only sources don't have to implement methods below

    def add_entity(self, cnx, entity):

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

        raise NotImplementedError(self)

    def update_entity(self, cnx, entity):

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

        raise NotImplementedError(self)

    def delete_entities(self, cnx, entities):

        """delete several entities from the source"""

        for entity in entities:

            self.delete_entity(cnx, entity)

    def delete_entity(self, cnx, entity):

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

        raise NotImplementedError(self)

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

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

        raise NotImplementedError(self)

    def add_relations(self, cnx, rtype, subj_obj_list):

        """add a relations to the source"""

        # override in derived classes if you feel you can

        # optimize

        for subject, object in subj_obj_list:

            self.add_relation(cnx, subject, rtype, object)

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

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

        raise NotImplementedError(self)

    # system source interface #################################################

    def eid_type(self, cnx, eid):

        """Return the type of entity `eid`."""

        raise NotImplementedError(self)

    def create_eid(self, cnx):

        raise NotImplementedError(self)

    def add_info(self, cnx, entity, source):

        """add type and source info for an eid into the system table"""

        raise NotImplementedError(self)

    def update_info(self, cnx, entity, need_fti_update):

        """mark entity as being modified, fulltext reindex if needed"""

        raise NotImplementedError(self)

    def index_entity(self, cnx, entity):

        """create an operation to [re]index textual content of the given entity

        on commit

        """

        raise NotImplementedError(self)

    def fti_unindex_entities(self, cnx, entities):

        """remove text content for entities from the full text index

        """

        raise NotImplementedError(self)

    def fti_index_entities(self, cnx, entities):

        """add text content of created/modified entities to the full text index

        """

        raise NotImplementedError(self)

    # sql system source interface #############################################

    def sqlexec(self, cnx, sql, args=None):

        """execute the query and return its result"""

        raise NotImplementedError(self)

    def create_index(self, cnx, table, column, unique=False):

        raise NotImplementedError(self)

    def drop_index(self, cnx, table, column, unique=False):

        raise NotImplementedError(self)

def source_adapter(source_type):

    try:

        return SOURCE_TYPES[source_type]

    except KeyError:

        raise RuntimeError('Unknown source type %r' % source_type)

def get_source(type, source_config, repo, eid):

    """return a source adapter according to the adapter field in the source's

    configuration

    """

    return source_adapter(type)(repo, source_config, eid)