# coding=utf-8
"""
Base Flask application class, used by tests or to be extended
in real applications.
"""
from __future__ import absolute_import

import os
import errno
import yaml
import logging
import logging.config
import importlib

from itertools import chain, count
from functools import partial
from pkg_resources import resource_filename
from pathlib import Path

import sqlalchemy as sa
from sqlalchemy.orm.attributes import NO_VALUE, NEVER_SET
import celery

from werkzeug.datastructures import ImmutableDict
from werkzeug.utils import import_string
import jinja2
from flask import (
  Flask, g, request, current_app, render_template,
  request_started, Blueprint, abort, appcontext_pushed,
  _request_ctx_stack
  )
from flask.config import ConfigAttribute
from flask.helpers import locked_cached_property
from flask.ext.assets import Bundle, Environment as AssetsEnv
from flask.ext.babel import get_locale as babel_get_locale
from flask.ext.migrate import Migrate
from flask.ext.script import Manager as ScriptManager

import abilian.i18n
from abilian.core import extensions, signals, redis
from abilian.core.celery import FlaskCelery
import abilian.core.util
from abilian.plugin.loader import AppLoader
from abilian.services import (
    audit_service, index_service, activity_service, auth_service,
    settings_service, security_service, preferences_service,
    repository_service, session_repository_service,
    converter as conversion_service, vocabularies_service, antivirus
)
from abilian.services.security import Anonymous

from abilian.web.action import actions
from abilian.web.views import Registry as ViewRegistry
from abilian.web.views.images import user_photo_url
from abilian.web.nav import BreadcrumbItem, Endpoint
from abilian.web.filters import init_filters
from abilian.web.assets.filters import ClosureJS
from abilian.web.util import send_file_from_directory, url_for
from abilian.web.admin import Admin
from abilian.web import csrf
from abilian.web.blueprints import allow_access_for_roles

logger = logging.getLogger(__name__)
db = extensions.db
__all__ = ['create_app', 'Application', 'ServiceManager']


class ServiceManager(object):
  """
  Mixin that provides lifecycle (register/start/stop) support for services.
  """
  def __init__(self):
    self.services = {}

  def start_services(self):
    for svc in self.services.values():
      svc.start()

  def stop_services(self):
    for svc in self.services.values():
      svc.stop()


class PluginManager(object):
  """
  Mixin that provides support for loading plugins.
  """
  def load_plugins(self):
    """
    Discovers and loads plugins.

    At this point, prefer explicit loading using the :method:~`register_plugin`
    method.
    """
    loader = AppLoader()
    loader.load(__name__.split('.')[0])
    loader.register(self)

  def register_plugin(self, name):
    """
    Loads and registers a plugin given its package name.
    """
    logger.info("Registering plugin: " + name)
    module = importlib.import_module(name)
    module.register_plugin(self)


default_config = dict(Flask.default_config)
default_config.update(
    PRIVATE_SITE=False,
    TEMPLATE_DEBUG=False,
    CSRF_ENABLED=True,
    BABEL_ACCEPT_LANGUAGES=None,
    DEFAULT_COUNTRY=None,
    PLUGINS=(),
    ADMIN_PANELS=(
        'abilian.web.admin.panels.dashboard.DashboardPanel',
        'abilian.web.admin.panels.audit.AuditPanel',
        'abilian.web.admin.panels.login_sessions.LoginSessionsPanel',
        'abilian.web.admin.panels.settings.SettingsPanel',
        'abilian.web.admin.panels.users.UsersPanel',
        'abilian.web.admin.panels.groups.GroupsPanel',
        'abilian.web.admin.panels.sysinfo.SysinfoPanel',
        'abilian.services.vocabularies.admin.VocabularyPanel',
    ),
    CELERY_ACCEPT_CONTENT = ['pickle', 'json', 'msgpack', 'yaml'],
    SENTRY_USER_ATTRS=('email', 'first_name', 'last_name',),
    SENTRY_INSTALL_CLIENT_JS=True, # also install client JS
    SENTRY_JS_VERSION='1.1.18',
    SENTRY_JS_PLUGINS=('jquery', 'native', 'require'),
    SESSION_COOKIE_NAME=None,
    SQLALCHEMY_POOL_RECYCLE=1800, # 30min. default value in flask_sa is None
    SQLALCHEMY_TRACK_MODIFICATIONS=False,
    LOGO_URL=Endpoint('abilian_static', filename='img/logo-abilian-32x32.png'),
    ABILIAN_UPSTREAM_INFO_ENABLED=False, # upstream info extension
    TRACKING_CODE_SNIPPET=u'', # tracking code to insert before </body>
    MAIL_ADDRESS_TAG_CHAR=None,
)
default_config = ImmutableDict(default_config)


class Application(Flask, ServiceManager, PluginManager):
  """
  Base application class. Extend it in your own app.
  """
  default_config = default_config

  #: Custom apps may want to always load some plugins: list them here.
  APP_PLUGINS = ('abilian.web.search',)

  #: Environment variable used to locate a config file to load last (after
  #: instance config file). Use this if you want to override some settings on a
  #: configured instance.
  CONFIG_ENVVAR = 'ABILIAN_CONFIG'

  #: True if application has a config file and can be considered configured for
  #: site.
  configured = ConfigAttribute('CONFIGURED')

  #: instance of :class:`.web.views.registry.Registry`.
  default_view = None

  #: json serializable dict to land in Javascript under Abilian.api
  js_api = None

  #: :class:`flask.ext.script.Manager` instance for shell commands of this app.
  #: defaults to `.commands.manager`, relative to app name.
  script_manager = '.commands.manager'

  #: celery app class
  celery_app_cls = FlaskCelery


  def __init__(self, name=None, config=None, *args, **kwargs):
    kwargs.setdefault('instance_relative_config', True)
    name = name or __name__

    # used by make_config to determine if we try to load config from instance /
    # environment variable /...
    self._ABILIAN_INIT_TESTING_FLAG = (getattr(config, 'TESTING', False)
                                       if config else False)
    Flask.__init__(self, name, *args, **kwargs)
    del self._ABILIAN_INIT_TESTING_FLAG

    self._setup_script_manager()
    appcontext_pushed.connect(self._install_id_generator)
    ServiceManager.__init__(self)
    PluginManager.__init__(self)
    self.default_view = ViewRegistry()
    self.js_api = dict()

    if config:
      self.config.from_object(config)

    # at this point we have loaded all external config files:
    # SQLALCHEMY_DATABASE_URI is definitively fixed (it cannot be defined in
    # database AFAICT), and LOGGING_FILE cannot be set in DB settings.
    self.setup_logging()

    configured = bool(self.config.get('SQLALCHEMY_DATABASE_URI'))
    self.config['CONFIGURED'] = configured

    if not self.testing:
      self.init_sentry()

    if not configured:
      # set fixed secret_key so that any unconfigured worker will use, so that
      # session can be used during setup even if multiple processes are
      # processing requests.
      self.config['SECRET_KEY'] = 'abilian_setup_key'

    # time to load config bits from database: 'settings'
    # First init required stuff: db to make queries, and settings service
    extensions.db.init_app(self)
    settings_service.init_app(self)

    if configured:
      with self.app_context():
        try:
          settings = self.services['settings'].namespace('config').as_dict()
        except sa.exc.DatabaseError as exc:
          # we may get here if DB is not initialized and "settings" table is
          # missing. Command "initdb" must be run to initialize db, but first we
          # must pass app init
          if not self.testing:
            # durint tests this message will show up on every test, since db is
            # always recreated
            logging.error(exc.message)
          self.db.session.rollback()
        else:
          self.config.update(settings)

    if not self.config.get('FAVICO_URL'):
      self.config['FAVICO_URL'] = self.config.get('LOGO_URL')

    languages = self.config.get('BABEL_ACCEPT_LANGUAGES')
    if languages is None:
      languages = abilian.i18n.VALID_LANGUAGES_CODE
    else:
      languages = tuple(lang for lang in languages
                        if lang in abilian.i18n.VALID_LANGUAGES_CODE)
    self.config['BABEL_ACCEPT_LANGUAGES'] = languages

    self._jinja_loaders = list()
    self.register_jinja_loaders(
      jinja2.PackageLoader('abilian.web', 'templates'))

    js_filters = (('closure_js',)
                  if self.config.get('PRODUCTION', False)
                  else None)

    self._assets_bundles = {
        'css': {'options': dict(filters=('less', 'cssmin'),
                                output='style-%(version)s.min.css',)},
        'js-top': {'options': dict(output='top-%(version)s.min.js',
                                   filters=js_filters,)},
        'js': {'options': dict(output='app-%(version)s.min.js',
                               filters=js_filters)},
    }

    # bundles for JS translations
    for lang in languages:
      code = 'js-i18n-' + lang
      filename = 'lang-' + lang + '-%(version)s.min.js'
      self._assets_bundles[code] = {
          'options': dict(output=filename, filters=js_filters),
      }

    for http_error_code in (403, 404, 500):
      self.install_default_handler(http_error_code)

    with self.app_context():
      self.init_extensions()
      self.register_plugins()
      self.add_access_controller('static', allow_access_for_roles(Anonymous),
                                 endpoint=True)

    self.maybe_register_setup_wizard()
    self._finalize_assets_setup()
    # At this point all models should have been imported: time to configure
    # mappers. Normally Sqlalchemy does it when needed but mappers may be
    # configured inside sa.orm.class_mapper() which hides a misconfiguration: if
    # a mapper is misconfigured its exception is swallowed by
    # class_mapper(model) results in this laconic (and misleading) message:
    # "model is not mapped"
    sa.orm.configure_mappers()

    signals.components_registered.send(self)
    self.before_first_request(self._set_current_celery_app)
    self.before_first_request(
        lambda: signals.register_js_api.send(self)
    )

    request_started.connect(self._setup_nav_and_breadcrumbs)

    # Initialize Abilian core services.
    # Must come after all entity classes have been declared.
    # Inherited from ServiceManager. Will need some configuration love later.
    if not self.config.get('TESTING', False):
      with self.app_context():
        self.start_services()

  def _setup_script_manager(self):
    manager = self.script_manager

    if manager is None or isinstance(manager, ScriptManager):
      return

    if isinstance(manager, (bytes, unicode)):
      manager = str(manager)
      if manager.startswith('.'):
        manager = self.import_name + manager

      manager = import_string(manager, silent=True)
      if manager is None:
        # fallback on abilian-core's
        from abilian.core.commands import setup_abilian_commands
        manager = ScriptManager()
        setup_abilian_commands(manager)

      self.script_manager = manager

  def _install_id_generator(self, sender, **kwargs):
    g.id_generator = count(start=1)

  def _set_current_celery_app(self):
    """
    Listener for `before_first_request`. Set our celery app as current, so that
    task use the correct config. Without that tasks may use their default set
    app.
    """
    self.extensions['celery'].set_current()

  def _setup_nav_and_breadcrumbs(self, app=None):
    """
    Listener for `request_started` event.

    If you want to customize first items of breadcrumbs, override
    :meth:`init_breadcrumbs`
    """
    g.nav = {'active': None} # active section
    g.breadcrumb = []
    self.init_breadcrumbs()

  def init_breadcrumbs(self):
    """
    Inserts the first element in breadcrumbs.

    This happens during `request_started` event, which is triggered before any
    url_value_preprocessor and `before_request` handlers.
    """
    g.breadcrumb.append(BreadcrumbItem(icon=u'home',
                                       url=u'/' + request.script_root))

  def check_instance_folder(self, create=False):
    """
    Verifies instance folder exists, is a directory, and has necessary permissions.

    :param:create: if `True`, creates directory hierarchy

    :raises: OSError with relevant errno
    """
    path = Path(self.instance_path)
    err = None
    eno = 0

    if not path.exists():
      if create:
        logger.info('Create instance folder: %s', unicode(path).encode('utf-8'))
        path.mkdir(0775, parents=True)
      else:
        err = 'Instance folder does not exists'
        eno = errno.ENOENT
    elif not path.is_dir():
      err = 'Instance folder is not a directory'
      eno = errno.ENOTDIR
    elif not os.access(str(path), os.R_OK | os.W_OK | os.X_OK):
      err = 'Require "rwx" access rights, please verify permissions'
      eno = errno.EPERM

    if err:
      raise OSError(eno, err, str(path))

    if not self.DATA_DIR.exists():
      self.DATA_DIR.mkdir(0775, parents=True)

  def make_config(self, instance_relative=False):
    config = Flask.make_config(self, instance_relative)
    if not config.get('SESSION_COOKIE_NAME'):
      config['SESSION_COOKIE_NAME'] = self.name + '-session'

    # during testing DATA_DIR is not created by instance app, but we still need
    # this attribute to be set
    self.DATA_DIR = Path(self.instance_path, 'data')

    if self._ABILIAN_INIT_TESTING_FLAG:
      # testing: don't load any config file!
      return config

    if instance_relative:
      self.check_instance_folder(create=True)

    cfg_path = os.path.join(config.root_path, 'config.py')
    logger.info('Try to load config: "%s"', cfg_path)
    try:
      config.from_pyfile(cfg_path, silent=False)
    except IOError:
      return config

    config.from_envvar(self.CONFIG_ENVVAR, silent=True)

    if 'WTF_CSRF_ENABLED' not in config:
      config['WTF_CSRF_ENABLED'] = config.get('CSRF_ENABLED', True)

    return config

  def setup_logging(self):
    self.logger  # force flask to create application logger before logging
                 # configuration; else, flask will overwrite our settings

    log_level = self.config.get("LOG_LEVEL")
    if log_level:
      self.logger.setLevel(log_level)

    logging_file = self.config.get('LOGGING_CONFIG_FILE')
    if logging_file:
      logging_file = os.path.abspath(os.path.join(self.instance_path,
                                                  logging_file))
    else:
      logging_file = resource_filename(__name__, 'default_logging.yml')

    if logging_file.endswith('.conf'):
      # old standard 'ini' file config
      logging.config.fileConfig(logging_file, disable_existing_loggers=False)
    elif logging_file.endswith('.yml'):
      # yml config file
      logging_cfg = yaml.load(open(logging_file, 'r'))
      logging_cfg.setdefault('version', 1)
      logging_cfg.setdefault('disable_existing_loggers', False)
      logging.config.dictConfig(logging_cfg)

  def init_debug_toolbar(self):
    if (not self.testing
        and self.config.get('DEBUG_TB_ENABLED')
        and 'debugtoolbar' not in self.blueprints):
      try:
        from flask.ext.debugtoolbar import DebugToolbarExtension, DebugToolbar
      except ImportError:
        logger.warning('DEBUG_TB_ENABLED is on but flask.ext.debugtoolbar '
                       'is not installed.')
      else:
        try:
          default_config = DebugToolbar.config
          init_dbt = DebugToolbarExtension
        except AttributeError:
          # debugtoolbar > 0.8.0
          dbt = DebugToolbarExtension()
          default_config = dbt._default_config(self)
          init_dbt = dbt.init_app

        if not 'DEBUG_TB_PANELS' in self.config:
          # add our panels to default ones
          self.config['DEBUG_TB_PANELS'] = list(default_config['DEBUG_TB_PANELS'])
          self.config['DEBUG_TB_PANELS'].append(
            'abilian.services.indexing.debug_toolbar.IndexedTermsDebugPanel'
          )
        init_dbt(self)
        for view_name in self.view_functions:
          if view_name.startswith('debugtoolbar.'):
            extensions.csrf.exempt(self.view_functions[view_name])

  def init_extensions(self):
    """
    Initializes flask extensions, helpers and services.
    """
    self.init_debug_toolbar()
    redis.Extension(self)
    extensions.mail.init_app(self)
    extensions.upstream_info.extension.init_app(self)
    actions.init_app(self)

    from abilian.core.jinjaext import DeferredJS
    DeferredJS(self)

    # auth_service installs a `before_request` handler (actually it's
    # flask-login). We want to authenticate user ASAP, so that sentry and logs
    # can report which user encountered any error happening later, in particular
    # in a before_request handler (like csrf validator)
    auth_service.init_app(self)

    # webassets
    self._setup_asset_extension()
    self._register_base_assets()

    # Babel (for i18n)
    abilian.i18n.babel.init_app(self)
    abilian.i18n.babel.add_translations('wtforms',
                                        translations_dir='locale',
                                        domain='wtforms')
    abilian.i18n.babel.add_translations('abilian')
    abilian.i18n.babel.localeselector(abilian.i18n.localeselector)
    abilian.i18n.babel.timezoneselector(abilian.i18n.timezoneselector)

    # Flask-Migrate
    Migrate(self, self.db)

    # CSRF by default
    if self.config.get('CSRF_ENABLED'):
      extensions.csrf.init_app(self)
      self.extensions['csrf'] = extensions.csrf
      extensions.abilian_csrf.init_app(self)

    self.register_blueprint(csrf.blueprint)

    # images blueprint
    from .web.views.images import blueprint as images_bp
    self.register_blueprint(images_bp)

    # Abilian Core services
    security_service.init_app(self)
    repository_service.init_app(self)
    session_repository_service.init_app(self)
    audit_service.init_app(self)
    index_service.init_app(self)
    activity_service.init_app(self)
    preferences_service.init_app(self)
    conversion_service.init_app(self)
    vocabularies_service.init_app(self)
    antivirus.init_app(self)

    from .web.preferences.user import UserPreferencesPanel
    preferences_service.register_panel(UserPreferencesPanel(), self)

    from .web.coreviews import users
    self.register_blueprint(users.bp)

    # Admin interface
    Admin().init_app(self)

    # Celery async service
    # this allows all shared tasks to use this celery app
    celery_app = self.extensions['celery'] = self.celery_app_cls()
    celery_app.set_default()

    # dev helper
    if self.debug:
      # during dev, one can go to /http_error/403 to see rendering of 403
      http_error_pages = Blueprint('http_error_pages', __name__)

      @http_error_pages.route('/<int:code>')
      def error_page(code):
        """ Helper for development to show 403, 404, 500..."""
        abort(code)

      self.register_blueprint(http_error_pages, url_prefix='/http_error')

  def register_plugins(self):
    """
    Loads plugins listed in config variable 'PLUGINS'.
    """
    registered = set()
    for plugin_fqdn in chain(self.APP_PLUGINS, self.config['PLUGINS']):
      if plugin_fqdn not in registered:
        self.register_plugin(plugin_fqdn)
        registered.add(plugin_fqdn)

  def maybe_register_setup_wizard(self):
    if self.configured:
      return

    logger.info('Application is not configured, installing setup wizard')
    from abilian.web import setupwizard

    self.register_blueprint(setupwizard.setup, url_prefix='/setup')

  def add_url_rule(self, rule, endpoint=None, view_func=None, **options):
    """
    See :meth:`Flask.add_url_rule`.

    If `roles` parameter is present, it must be a
    :class:`abilian.service.security.models.Role` instance, or a list of
    Role instances.
    """
    roles = options.pop('roles', None)
    super(Application, self).add_url_rule(rule, endpoint, view_func, **options)

    if roles:
      self.add_access_controller(endpoint, allow_access_for_roles(roles),
                                 endpoint=True)

  def add_access_controller(self, name, func, endpoint=False):
    """
    Add an access controller.

    If `name` is None it is added at application level, else if is
    considered as a blueprint name. If `endpoint` is True then it is
    considered as an endpoint.
    """
    auth_state = self.extensions[auth_service.name]
    adder = auth_state.add_bp_access_controller

    if endpoint:
      adder = auth_state.add_endpoint_access_controller
      if not isinstance(name, (str, unicode)):
        raise ValueError('{} is not a valid endpoint name', repr(name))

    adder(name, func)

  def add_static_url(self, url_path, directory, endpoint=None,
                     roles=None):
    """
    Adds a new url rule for static files.

    :param endpoint: flask endpoint name for this url rule.
    :param url: subpath from application static url path. No heading or trailing
                slash.
    :param directory: directory to serve content from.

    Example::

       app.add_static_url('myplugin',
                          '/path/to/myplugin/resources',
                          endpoint='myplugin_static')

    With default setup it will serve content from directory
    `/path/to/myplugin/resources` from url `http://.../static/myplugin`
    """
    url_path = self.static_url_path + '/' + url_path + '/<path:filename>'
    self.add_url_rule(url_path,
                      endpoint=endpoint,
                      view_func=partial(send_file_from_directory,
                                        directory=directory),
                      roles=roles)

  #
  # Templating and context injection setup
  #
  def create_jinja_environment(self):
    env = Flask.create_jinja_environment(self)
    env.globals.update(
        app=current_app,
        csrf=csrf,
        get_locale=babel_get_locale,
        local_dt=abilian.core.util.local_dt,
        url_for=url_for,
        user_photo_url=user_photo_url,
        NO_VALUE=NO_VALUE,
        NEVER_SET=NEVER_SET,
    )
    init_filters(env)
    return env

  @property
  def jinja_options(self):
    options = dict(Flask.jinja_options)

    extensions = options.setdefault('extensions', [])
    ext = 'abilian.core.jinjaext.DeferredJSExtension'
    if ext not in extensions:
      extensions.append(ext)

    if 'bytecode_cache' not in options:
      cache_dir = Path(self.instance_path, 'cache', 'jinja')
      if not cache_dir.exists():
        cache_dir.mkdir(0775, parents=True)

      options['bytecode_cache'] = jinja2.FileSystemBytecodeCache(str(cache_dir),
                                                                 '%s.cache')

    if (self.config.get('DEBUG', False)
        and self.config.get('TEMPLATE_DEBUG', False)):
      options['undefined'] = jinja2.StrictUndefined
    return options

  def register_jinja_loaders(self, *loaders):
    """
    Registers one or many `jinja2.Loader` instances for templates lookup.

    During application initialization plugins can register a loader so that
    their templates are available to jinja2 renderer.

    Order of registration matters: last registered is first looked up (after
    standard Flask lookup in app template folder). This allows a plugin to
    override templates provided by others, or by base application. The
    application can override any template from any plugins from its template
    folder (See `Flask.Application.template_folder`).

    :raise: `ValueError` if a template has already been rendered
    """
    if not hasattr(self, '_jinja_loaders'):
      raise ValueError(
        'Cannot register new jinja loaders after first template rendered'
      )

    self._jinja_loaders.extend(loaders)

  @locked_cached_property
  def jinja_loader(self):
    """
    Searches templates in custom app templates dir (default flask behaviour),
    fallback on abilian templates.
    """
    loaders = self._jinja_loaders
    del self._jinja_loaders
    loaders.append(Flask.jinja_loader.func(self))
    loaders.reverse()
    return jinja2.ChoiceLoader(loaders)

  # Error handling
  def handle_user_exception(self, e):
    # If session.transaction._parent is None, then exception has occured in
    # after_commit(): doing a rollback() raises an error and would hide actual
    # error
    session = db.session()
    if session.is_active and session.transaction._parent is not None:
      # inconditionally forget all DB changes, and ensure clean session during
      # exception handling
      session.rollback()
    else:
      self._remove_session_save_objects()

    return Flask.handle_user_exception(self, e)

  def handle_exception(self, e):
    session = db.session()
    if not session.is_active:
      # something happened in error handlers and session is not usable anymore.
      #
      self._remove_session_save_objects()

    return Flask.handle_exception(self, e)

  def _remove_session_save_objects(self):
    """
    Used during exception handling in case we need to remove() session: keep
    instances and merge them in the new session.
    """
    if self.testing:
      return
    # Before destroying the session, get all instances to be attached to the
    # new session. Without this, we get DetachedInstance errors, like when
    # tryin to get user's attribute in the error page...
    old_session = db.session()
    g_objs = []
    for key in iter(g):
      obj = getattr(g, key)
      if (isinstance(obj, db.Model) and
          sa.orm.object_session(obj) in (None, old_session)):
        g_objs.append((key, obj, obj in old_session.dirty))

    db.session.remove()
    session = db.session()

    for key, obj, load in g_objs:
      # replace obj instance in bad session by new instance in fresh session
      setattr(g, key, session.merge(obj, load=load))

    # refresh `current_user`
    user = getattr(_request_ctx_stack.top, 'user', None)
    if user is not None and isinstance(user, db.Model):
      _request_ctx_stack.top.user = session.merge(user, load=load)

  def log_exception(self, exc_info):
    """
    Log exception only if sentry is not installed (this avoids getting error
    twice in sentry).
    """
    if 'sentry' not in self.extensions:
      super(Application, self).log_exception(exc_info)

  def init_sentry(self):
    """
    Installs Sentry handler if config defines 'SENTRY_DSN'.
    """
    if self.config.get('SENTRY_DSN', None):
      try:
        from abilian.core.sentry import Sentry
      except ImportError:
        logger.error(
          'SENTRY_DSN is defined in config but package "raven" is not '
          'installed.')
        return

      ext = Sentry(self, logging=True, level=logging.ERROR)
      ext.client.tags['app_name'] = self.name
      ext.client.tags['process_type'] = 'web'
      server_name = str(self.config.get('SERVER_NAME', None))
      ext.client.tags['configured_server_name'] = server_name


  @property
  def db(self):
    return self.extensions['sqlalchemy'].db

  @property
  def redis(self):
    return self.extensions['redis'].client

  def create_db(self):
    from abilian.core.models.subjects import User

    db.create_all()
    if User.query.get(0) is None:
      root = User(id=0, last_name=u'SYSTEM', email=u'system@example.com',
                  can_login=False)
      db.session.add(root)
      db.session.commit()

  def _setup_asset_extension(self):
    assets = self.extensions['webassets'] = AssetsEnv(self)
    assets.debug = not self.config.get('PRODUCTION', False)

    assets_base_dir = Path(self.instance_path, 'webassets')
    assets_dir = assets_base_dir / 'compiled'
    assets_cache_dir = assets_base_dir / 'cache'
    for path in (assets_base_dir, assets_dir, assets_cache_dir):
      if not path.exists():
        path.mkdir()

    assets.directory = str(assets_dir)
    assets.cache = str(assets_cache_dir)
    manifest_file = assets_base_dir / 'manifest.json'
    assets.manifest = 'json:{}'.format(str(manifest_file))

    # set up load_path for application static dir. This is required since we are
    # setting Environment.load_path for other assets (like core_bundle below),
    # in this case Flask-Assets uses webasssets resolvers instead of Flask's one
    assets.append_path(self.static_folder, self.static_url_path)

    # filters options
    less_args = ['-ru']
    assets.config['less_extra_args'] = less_args
    assets.config['less_as_output'] = True
    if assets.debug:
      assets.config['less_source_map_file'] = 'style.map'

    # setup static url for our assets
    from abilian.web import assets as core_bundles

    assets.append_path(core_bundles.RESOURCES_DIR, '/static/abilian')
    self.add_static_url('abilian', core_bundles.RESOURCES_DIR,
                        endpoint='abilian_static',
                        roles=Anonymous)

    # static minified are here
    assets.url = self.static_url_path + '/min'
    assets.append_path(str(assets_dir), assets.url)
    self.add_static_url('min', str(assets_dir), endpoint='webassets_static',
                        roles=Anonymous,)

  def _finalize_assets_setup(self):
    assets = self.extensions['webassets']
    assets_dir = Path(assets.directory)
    closure_base_args = [
        '--jscomp_warning', 'internetExplorerChecks',
        '--source_map_format', 'V3',
        '--create_source_map',
    ]

    for name, data in self._assets_bundles.items():
      bundles = data.get('bundles', [])
      options = data.get('options', {})
      filters = options.get('filters', None) or []
      options['filters'] = []
      for f in filters:
        if f == 'closure_js':
           js_map_file = str(assets_dir / '{}.map'.format(name))
           f = ClosureJS(extra_args=closure_base_args + [js_map_file])
        options['filters'].append(f)

      if not options['filters']:
        options['filters'] = None

      if bundles:
        assets.register(name, Bundle(*bundles, **options))

  def register_asset(self, type_, *assets):
    """
    Registers webassets bundle to be served on all pages.

    :param type_: `"css"`, `"js-top"` or `"js""`.

    :param \*asset:
        a path to file, a :ref:`webassets.Bundle <webassets:bundles>` instance
        or a callable that returns a :ref:`webassets.Bundle <webassets:bundles>`
        instance.

    :raises KeyError: if `type_` is not supported.
    """
    supported = self._assets_bundles.keys()
    if type_ not in supported:
      raise KeyError("Invalid type: %s. Valid types: ",
                     repr(type_), ', '.join(sorted(supported)))

    for asset in assets:
      if not isinstance(asset, Bundle) and callable(asset):
        asset = asset()

      self._assets_bundles[type_].setdefault('bundles', []).append(asset)

  def register_i18n_js(self, *paths):
    """
    register templates path translations files, like
    `select2/select2_locale_{lang}.js`.

    Only existing files are registered.
    """
    languages = self.config['BABEL_ACCEPT_LANGUAGES']
    assets = self.extensions['webassets']

    for path in paths:
      for lang in languages:
        filename = path.format(lang=lang)
        try:
          assets.resolver.search_for_source(assets, filename)
        except IOError:
          logger.debug('i18n JS not found, skipped: "%s"', filename)
        else:
          self.register_asset('js-i18n-'+lang, filename)

  def _register_base_assets(self):
    """
    Registers assets needed by Abilian. This is done in a separate method in
    order to allow applications to redefine it at will.
    """
    from abilian.web import assets as bundles

    self.register_asset('css', bundles.LESS)
    self.register_asset('js-top', bundles.TOP_JS)
    self.register_asset('js', bundles.JS)
    self.register_i18n_js(*bundles.JS_I18N)

  def install_default_handler(self, http_error_code):
    """
    Installs a default error handler for `http_error_code`.

    The default error handler renders a template named error404.html for
    http_error_code 404.
    """
    logger.debug('Set Default HTTP error handler for status code %d',
                 http_error_code)
    handler = partial(self.handle_http_error, http_error_code)
    self.errorhandler(http_error_code)(handler)

  def handle_http_error(self, code, error):
    """
    Helper that renders `error{code}.html`.

    Convenient way to use it::

       from functools import partial
       handler = partial(app.handle_http_error, code)
       app.errorhandler(code)(handler)
    """
    if (code / 100) == 5:
      # 5xx code: error on server side
      db.session.rollback()  # ensure rollback if needed, else error page may
                             # have an error, too, resulting in raw 500 page :-(
    template = 'error{:d}.html'.format(code)
    return render_template(template, error=error), code


def create_app(config=None):
  return Application(config)
