# copyright 2017 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# copyright 2014-2016 UNLISH S.A.S. (Montpellier, 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/>.

"""Pyramid interface to CubicWeb"""

import atexit
import os

import wsgicors

from cubicweb.cwconfig import CubicWebConfiguration as cwcfg
from pyramid.config import Configurator
from pyramid.exceptions import ConfigurationError
from pyramid.settings import asbool, aslist

try:
    from configparser import SafeConfigParser
except ImportError:
    from ConfigParser import SafeConfigParser


def config_from_cwconfig(cwconfig, settings=None):
    """Return a Pyramid Configurator instance built from a CubicWeb config and
    Pyramid-specific configuration files (pyramid.ini).

    :param cwconfig: A CubicWeb configuration
    :returns: A Pyramid config object
    """
    settings = dict(settings) if settings else {}
    settings.update(settings_from_cwconfig(cwconfig))
    config = Configurator(settings=settings)
    config.registry['cubicweb.config'] = cwconfig
    config.include('cubicweb.pyramid')
    return config


def settings_from_cwconfig(cwconfig):
    '''
    Extract settings from pyramid.ini and pyramid-debug.ini (if in debug)

    Can be used to configure middleware WSGI with settings from pyramid.ini files

    :param cwconfig: A CubicWeb configuration
    :returns: A settings dictionnary
    '''
    settings_filenames = [os.path.join(cwconfig.apphome, 'pyramid.ini')]
    settings = {}
    if cwconfig.debugmode:
        settings_filenames.insert(
            0, os.path.join(cwconfig.apphome, 'pyramid-debug.ini'))

        settings.update({
            'pyramid.debug_authorization': True,
            'pyramid.debug_notfound': True,
            'pyramid.debug_routematch': True,
            'pyramid.reload_templates': True,
        })

    for fname in settings_filenames:
        if os.path.exists(fname):
            cp = SafeConfigParser()
            cp.read(fname)
            settings.update(cp.items('main'))
            break

    return settings


def wsgi_application_from_cwconfig(
        cwconfig,
        profile=False, profile_output=None, profile_dump_every=None):
    """ Build a WSGI application from a cubicweb configuration

    :param cwconfig: A CubicWeb configuration
    :param profile: Enable profiling. See :ref:`profiling`.
    :param profile_output: Profiling output filename. See :ref:`profiling`.
    :param profile_dump_every: Profiling number of requests before dumping the
                               stats. See :ref:`profiling`.

    :returns: A fully operationnal WSGI application
    """
    config = config_from_cwconfig(cwconfig)
    profile = profile or asbool(config.registry.settings.get(
        'cubicweb.profile.enable', False))
    if profile:
        config.add_route('profile_ping', '_profile/ping')
        config.add_route('profile_cnx', '_profile/cnx')
        config.scan('cubicweb.pyramid.profile')
    app = config.make_wsgi_app()
    # This replaces completely web/cors.py, which is not used by
    # cubicweb.pyramid anymore
    app = wsgicors.CORS(
        app,
        origin=' '.join(cwconfig['access-control-allow-origin']),
        headers=', '.join(cwconfig['access-control-allow-headers']),
        methods=', '.join(cwconfig['access-control-allow-methods']),
        credentials='true')

    if profile:
        from cubicweb.pyramid.profile import wsgi_profile
        filename = profile_output or config.registry.settings.get(
            'cubicweb.profile.output', 'program.prof')
        dump_every = profile_dump_every or config.registry.settings.get(
            'cubicweb.profile.dump_every', 100)
        app = wsgi_profile(app, filename=filename, dump_every=dump_every)
    return app


def wsgi_application(instance_name=None, debug=None):
    """ Build a WSGI application from a cubicweb instance name

    :param instance_name: Name of the cubicweb instance (optional). If not
                          provided, :envvar:`CW_INSTANCE` must exists.
    :param debug: Enable/disable the debug mode. If defined to True or False,
                  overrides :envvar:`CW_DEBUG`.

    The following environment variables are used if they exist:

    .. envvar:: CW_INSTANCE

        A CubicWeb instance name.

    .. envvar:: CW_DEBUG

        If defined, the debugmode is enabled.

    The function can be used as an entry-point for third-party wsgi containers.
    Below is a sample uswgi configuration file:

    .. code-block:: ini

        [uwsgi]
        http = 127.0.1.1:8080
        env = CW_INSTANCE=myinstance
        env = CW_DEBUG=1
        module = cubicweb.pyramid:wsgi_application()
        virtualenv = /home/user/.virtualenvs/myvirtualenv
        processes = 1
        threads = 8
        stats = 127.0.0.1:9191
        plugins = http,python

    """
    if instance_name is None:
        instance_name = os.environ['CW_INSTANCE']
    if debug is None:
        debug = 'CW_DEBUG' in os.environ

    cwconfig = cwcfg.config_for(instance_name, debugmode=debug)

    return wsgi_application_from_cwconfig(cwconfig)


def pyramid_app(global_config, **settings):
    """Return a Pyramid WSGI application bound to a CubicWeb repository."""
    config = Configurator(settings=settings)
    config.include('cubicweb.pyramid')
    return config.make_wsgi_app()


def includeme(config):
    """Set-up a CubicWeb instance.

    The CubicWeb instance can be set in several ways:

    -   Provide an already loaded CubicWeb repository in the registry:

        .. code-block:: python

            config.registry['cubicweb.repository'] = your_repo_instance

    -   Provide an already loaded CubicWeb config instance in the registry:

        .. code-block:: python

            config.registry['cubicweb.config'] = your_config_instance

    -   Provide an instance name in the pyramid settings with
        :confval:`cubicweb.instance`.

    A CubicWeb repository is instantiated and attached in
    'cubicweb.repository' registry key if not already present.

    The CubicWeb instance registry is attached in 'cubicweb.registry' registry
    key.
    """
    cwconfig = config.registry.get('cubicweb.config')
    repo = config.registry.get('cubicweb.repository')

    if repo is not None:
        if cwconfig is None:
            config.registry['cubicweb.config'] = cwconfig = repo.config
        elif cwconfig is not repo.config:
            raise ConfigurationError(
                'CubicWeb config instance (found in "cubicweb.config" '
                'registry key) mismatches with that of the repository '
                '(registry["cubicweb.repository"])'
            )

    if cwconfig is None:
        debugmode = asbool(
            config.registry.settings.get('cubicweb.debug', False))
        cwconfig = cwcfg.config_for(
            config.registry.settings['cubicweb.instance'], debugmode=debugmode)
        config.registry['cubicweb.config'] = cwconfig

    if repo is None:
        repo = config.registry['cubicweb.repository'] = cwconfig.repository()
    config.registry['cubicweb.registry'] = repo.vreg

    if cwconfig.mode != 'test':
        @atexit.register
        def shutdown_repo():
            if repo.shutting_down:
                return
            repo.shutdown

    if asbool(config.registry.settings.get('cubicweb.defaults', True)):
        config.include('cubicweb.pyramid.defaults')

    for name in aslist(config.registry.settings.get('cubicweb.includes', [])):
        config.include(name)

    config.include('cubicweb.pyramid.core')

    if asbool(config.registry.settings.get('cubicweb.bwcompat', True)):
        config.include('cubicweb.pyramid.bwcompat')
