# -*- coding: utf-8 -*-
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
"""
rhodecode.model.__init__
~~~~~~~~~~~~~~~~~~~~~~~~

The application's model objects

:created_on: Nov 25, 2010
:author: marcink
:copyright: (c) 2013 RhodeCode GmbH.
:license: GPLv3, see LICENSE for more details.


:example:

    .. code-block:: python

       from paste.deploy import appconfig
       from pylons import config
       from sqlalchemy import engine_from_config
       from rhodecode.config.environment import load_environment

       conf = appconfig('config:development.ini', relative_to = './../../')
       load_environment(conf.global_conf, conf.local_conf)

       engine = engine_from_config(config, 'sqlalchemy.')
       init_model(engine)
       # RUN YOUR CODE HERE

"""


import logging
from rhodecode.model import meta
from rhodecode.lib.utils2 import safe_str, obfuscate_url_pw

log = logging.getLogger(__name__)


def init_model(engine):
    """
    Initializes db session, bind the engine with the metadata,
    Call this before using any of the tables or classes in the model,
    preferably once in application start

    :param engine: engine to bind to
    """
    engine_str = obfuscate_url_pw(str(engine.url))
    log.info("initializing db for %s" % engine_str)
    meta.Base.metadata.bind = engine


class BaseModel(object):
    """
    Base Model for all RhodeCode models, it adds sql alchemy session
    into instance of model

    :param sa: If passed it reuses this session instead of creating a new one
    """

    cls = None  # override in child class

    def __init__(self, sa=None):
        if sa is not None:
            self.sa = sa
        else:
            self.sa = meta.Session()

    def _get_instance(self, cls, instance, callback=None):
        """
        Gets instance of given cls using some simple lookup mechanism.

        :param cls: class to fetch
        :param instance: int or Instance
        :param callback: callback to call if all lookups failed
        """

        if isinstance(instance, cls):
            return instance
        elif isinstance(instance, (int, long)) or safe_str(instance).isdigit():
            return cls.get(instance)
        else:
            if instance:
                if callback is None:
                    raise Exception(
                        'given object must be int, long or Instance of %s '
                        'got %s, no callback provided' % (cls, type(instance))
                    )
                else:
                    return callback(instance)

    def _get_user(self, user):
        """
        Helper method to get user by ID, or username fallback

        :param user: UserID, username, or User instance
        """
        from rhodecode.model.db import User
        return self._get_instance(User, user,
                                  callback=User.get_by_username)

    def _get_repo(self, repository):
        """
        Helper method to get repository by ID, or repository name

        :param repository: RepoID, repository name or Repository Instance
        """
        from rhodecode.model.db import Repository
        return self._get_instance(Repository, repository,
                                  callback=Repository.get_by_repo_name)

    def _get_perm(self, permission):
        """
        Helper method to get permission by ID, or permission name

        :param permission: PermissionID, permission_name or Permission instance
        """
        from rhodecode.model.db import Permission
        return self._get_instance(Permission, permission,
                                  callback=Permission.get_by_key)

    @classmethod
    def get_all(cls):
        """
        Returns all instances of what is defined in `cls` class variable
        """
        return cls.cls.getAll()