# -*- coding: utf-8 -*-

# Copyright (C) 2010-2016  RhodeCode GmbH
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License, version 3
# (only), as published by the Free Software Foundation.
#
# 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 Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# This program is dual-licensed. If you wish to learn more about the
# RhodeCode Enterprise Edition, including its added features, Support services,
# and proprietary license terms, please see https://rhodecode.com/licenses/

"""
Pylons middleware initialization
"""
import logging

from paste.registry import RegistryManager
from paste.gzipper import make_gzip_middleware
from pylons.wsgiapp import PylonsApp
from pyramid.authorization import ACLAuthorizationPolicy
from pyramid.config import Configurator
from pyramid.static import static_view
from pyramid.settings import asbool, aslist
from pyramid.wsgi import wsgiapp
from pyramid.httpexceptions import HTTPError, HTTPInternalServerError
from pylons.controllers.util import abort, redirect
import pyramid.httpexceptions as httpexceptions
from pyramid.renderers import render_to_response, render
from routes.middleware import RoutesMiddleware
import routes.util

import rhodecode
import rhodecode.integrations # do not remove this as it registers celery tasks
from rhodecode.config import patches
from rhodecode.config.routing import STATIC_FILE_PREFIX
from rhodecode.config.environment import (
    load_environment, load_pyramid_environment)
from rhodecode.lib.middleware import csrf
from rhodecode.lib.middleware.appenlight import wrap_in_appenlight_if_enabled
from rhodecode.lib.middleware.disable_vcs import DisableVCSPagesWrapper
from rhodecode.lib.middleware.https_fixup import HttpsFixup
from rhodecode.lib.middleware.vcs import VCSMiddleware
from rhodecode.lib.plugins.utils import register_rhodecode_plugin


log = logging.getLogger(__name__)


# this is used to avoid avoid the route lookup overhead in routesmiddleware
# for certain routes which won't go to pylons to - eg. static files, debugger
# it is only needed for the pylons migration and can be removed once complete
class SkippableRoutesMiddleware(RoutesMiddleware):
    """ Routes middleware that allows you to skip prefixes """

    def __init__(self, *args, **kw):
        self.skip_prefixes = kw.pop('skip_prefixes', [])
        super(SkippableRoutesMiddleware, self).__init__(*args, **kw)

    def __call__(self, environ, start_response):
        for prefix in self.skip_prefixes:
            if environ['PATH_INFO'].startswith(prefix):
                return self.app(environ, start_response)

        return super(SkippableRoutesMiddleware, self).__call__(
            environ, start_response)


def make_app(global_conf, full_stack=True, static_files=True, **app_conf):
    """Create a Pylons WSGI application and return it

    ``global_conf``
        The inherited configuration for this application. Normally from
        the [DEFAULT] section of the Paste ini file.

    ``full_stack``
        Whether or not this application provides a full WSGI stack (by
        default, meaning it handles its own exceptions and errors).
        Disable full_stack when this application is "managed" by
        another WSGI middleware.

    ``app_conf``
        The application's local configuration. Normally specified in
        the [app:<name>] section of the Paste ini file (where <name>
        defaults to main).

    """
    # Apply compatibility patches
    patches.kombu_1_5_1_python_2_7_11()
    patches.inspect_getargspec()

    # Configure the Pylons environment
    config = load_environment(global_conf, app_conf)

    # The Pylons WSGI app
    app = PylonsApp(config=config)
    if rhodecode.is_test:
        app = csrf.CSRFDetector(app)

    expected_origin = config.get('expected_origin')
    if expected_origin:
        # The API can be accessed from other Origins.
        app = csrf.OriginChecker(app, expected_origin,
                                 skip_urls=[routes.util.url_for('api')])


    if asbool(full_stack):

        # Appenlight monitoring and error handler
        app, appenlight_client = wrap_in_appenlight_if_enabled(app, config)

        # we want our low level middleware to get to the request ASAP. We don't
        # need any pylons stack middleware in them
        app = VCSMiddleware(app, config, appenlight_client)

    # Establish the Registry for this application
    app = RegistryManager(app)

    app.config = config

    return app


def make_pyramid_app(global_config, **settings):
    """
    Constructs the WSGI application based on Pyramid and wraps the Pylons based
    application.

    Specials:

    * We migrate from Pylons to Pyramid. While doing this, we keep both
      frameworks functional. This involves moving some WSGI middlewares around
      and providing access to some data internals, so that the old code is
      still functional.

    * The application can also be integrated like a plugin via the call to
      `includeme`. This is accompanied with the other utility functions which
      are called. Changing this should be done with great care to not break
      cases when these fragments are assembled from another place.

    """
    # The edition string should be available in pylons too, so we add it here
    # before copying the settings.
    settings.setdefault('rhodecode.edition', 'Community Edition')

    # As long as our Pylons application does expect "unprepared" settings, make
    # sure that we keep an unmodified copy. This avoids unintentional change of
    # behavior in the old application.
    settings_pylons = settings.copy()

    sanitize_settings_and_apply_defaults(settings)
    config = Configurator(settings=settings)
    add_pylons_compat_data(config.registry, global_config, settings_pylons)

    load_pyramid_environment(global_config, settings)

    includeme_first(config)
    includeme(config)
    pyramid_app = config.make_wsgi_app()
    pyramid_app = wrap_app_in_wsgi_middlewares(pyramid_app, config)
    return pyramid_app


def add_pylons_compat_data(registry, global_config, settings):
    """
    Attach data to the registry to support the Pylons integration.
    """
    registry._pylons_compat_global_config = global_config
    registry._pylons_compat_settings = settings


def webob_to_pyramid_http_response(webob_response):
    ResponseClass = httpexceptions.status_map[webob_response.status_int]
    pyramid_response = ResponseClass(webob_response.status)
    pyramid_response.status = webob_response.status
    pyramid_response.headers.update(webob_response.headers)
    if pyramid_response.headers['content-type'] == 'text/html':
        pyramid_response.headers['content-type'] = 'text/html; charset=UTF-8'
    return pyramid_response


def error_handler(exception, request):
    # TODO: dan: replace the old pylons error controller with this
    from rhodecode.model.settings import SettingsModel
    from rhodecode.lib.utils2 import AttributeDict

    try:
        rc_config = SettingsModel().get_all_settings()
    except Exception:
        log.exception('failed to fetch settings')
        rc_config = {}

    base_response = HTTPInternalServerError()
    # prefer original exception for the response since it may have headers set
    if isinstance(exception, HTTPError):
        base_response = exception

    c = AttributeDict()
    c.error_message = base_response.status
    c.error_explanation = base_response.explanation or str(base_response)
    c.visual = AttributeDict()

    c.visual.rhodecode_support_url = (
        request.registry.settings.get('rhodecode_support_url') or
        request.route_url('rhodecode_support')
    )
    c.redirect_time = 0
    c.rhodecode_name = rc_config.get('rhodecode_title', '')
    if not c.rhodecode_name:
        c.rhodecode_name = 'Rhodecode'

    response = render_to_response(
        '/errors/error_document.html', {'c': c}, request=request,
        response=base_response)

    return response


def includeme(config):
    settings = config.registry.settings

    # plugin information
    config.registry.rhodecode_plugins = {}

    config.add_directive(
        'register_rhodecode_plugin', register_rhodecode_plugin)

    if asbool(settings.get('appenlight', 'false')):
        config.include('appenlight_client.ext.pyramid_tween')

    # Includes which are required. The application would fail without them.
    config.include('pyramid_mako')
    config.include('pyramid_beaker')
    config.include('rhodecode.admin')
    config.include('rhodecode.authentication')
    config.include('rhodecode.integrations')
    config.include('rhodecode.login')
    config.include('rhodecode.tweens')
    config.include('rhodecode.api')
    config.add_route(
        'rhodecode_support', 'https://rhodecode.com/help/', static=True)

    # Set the authorization policy.
    authz_policy = ACLAuthorizationPolicy()
    config.set_authorization_policy(authz_policy)

    # Set the default renderer for HTML templates to mako.
    config.add_mako_renderer('.html')

    # include RhodeCode plugins
    includes = aslist(settings.get('rhodecode.includes', []))
    for inc in includes:
        config.include(inc)

    pylons_app = make_app(
        config.registry._pylons_compat_global_config,
        **config.registry._pylons_compat_settings)
    config.registry._pylons_compat_config = pylons_app.config

    pylons_app_as_view = wsgiapp(pylons_app)

    # Protect from VCS Server error related pages when server is not available
    vcs_server_enabled = asbool(settings.get('vcs.server.enable', 'true'))
    if not vcs_server_enabled:
        pylons_app_as_view = DisableVCSPagesWrapper(pylons_app_as_view)


    def pylons_app_with_error_handler(context, request):
        """
        Handle exceptions from rc pylons app:

        - old webob type exceptions get converted to pyramid exceptions
        - pyramid exceptions are passed to the error handler view
        """
        try:
            response = pylons_app_as_view(context, request)
            if 400 <= response.status_int <= 599: # webob type error responses
                return error_handler(
                    webob_to_pyramid_http_response(response), request)
        except HTTPError as e: # pyramid type exceptions
            return error_handler(e, request)
        except Exception:
            if settings.get('debugtoolbar.enabled', False):
                raise
            return error_handler(HTTPInternalServerError(), request)
        return response

    # This is the glue which allows us to migrate in chunks. By registering the
    # pylons based application as the "Not Found" view in Pyramid, we will
    # fallback to the old application each time the new one does not yet know
    # how to handle a request.
    config.add_notfound_view(pylons_app_with_error_handler)

    if not settings.get('debugtoolbar.enabled', False):
        # if no toolbar, then any exception gets caught and rendered
        config.add_view(error_handler, context=Exception)

    config.add_view(error_handler, context=HTTPError)


def includeme_first(config):
    # redirect automatic browser favicon.ico requests to correct place
    def favicon_redirect(context, request):
        return redirect(
            request.static_url('rhodecode:public/images/favicon.ico'))

    config.add_view(favicon_redirect, route_name='favicon')
    config.add_route('favicon', '/favicon.ico')

    config.add_static_view(
        '_static', path='rhodecode:public', cache_max_age=3600 * 24)


def wrap_app_in_wsgi_middlewares(pyramid_app, config):
    """
    Apply outer WSGI middlewares around the application.

    Part of this has been moved up from the Pylons layer, so that the
    data is also available if old Pylons code is hit through an already ported
    view.
    """
    settings = config.registry.settings

    # enable https redirects based on HTTP_X_URL_SCHEME set by proxy
    pyramid_app = HttpsFixup(pyramid_app, settings)

    # Add RoutesMiddleware to support the pylons compatibility tween during
    # migration to pyramid.
    pyramid_app = SkippableRoutesMiddleware(
        pyramid_app, config.registry._pylons_compat_config['routes.map'],
        skip_prefixes=(STATIC_FILE_PREFIX, '/_debug_toolbar'))

    if asbool(settings.get('appenlight', 'false')):
        pyramid_app, _ = wrap_in_appenlight_if_enabled(
            pyramid_app, config.registry._pylons_compat_config)

    if asbool(settings.get('gzip_responses', 'true')):
        pyramid_app = make_gzip_middleware(
            pyramid_app, settings, compress_level=1)

    return pyramid_app


def sanitize_settings_and_apply_defaults(settings):
    """
    Applies settings defaults and does all type conversion.

    We would move all settings parsing and preparation into this place, so that
    we have only one place left which deals with this part. The remaining parts
    of the application would start to rely fully on well prepared settings.

    This piece would later be split up per topic to avoid a big fat monster
    function.
    """

    # Pyramid's mako renderer has to search in the templates folder so that the
    # old templates still work. Ported and new templates are expected to use
    # real asset specifications for the includes.
    mako_directories = settings.setdefault('mako.directories', [
        # Base templates of the original Pylons application
        'rhodecode:templates',
    ])
    log.debug(
        "Using the following Mako template directories: %s",
        mako_directories)

    # Default includes, possible to change as a user
    pyramid_includes = settings.setdefault('pyramid.includes', [
        'rhodecode.lib.middleware.request_wrapper',
    ])
    log.debug(
        "Using the following pyramid.includes: %s",
        pyramid_includes)

    # TODO: johbo: Re-think this, usually the call to config.include
    # should allow to pass in a prefix.
    settings.setdefault('rhodecode.api.url', '/_admin/api')

    _bool_setting(settings, 'vcs.server.enable', 'true')
    _bool_setting(settings, 'is_test', 'false')

    return settings


def _bool_setting(settings, name, default):
    settings[name] = asbool(settings.get(name, default))