# Copyright (c) 2010-2011 OpenStack, LLC.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from webob import Request
from webob.exc import HTTPBadRequest


class DomainRemapMiddleware(object):
    """
    Middleware that translates container and account parts of a domain to
    path parameters that the proxy server understands.

    container.account.storageurl/object gets translated to
    container.account.storageurl/path_root/account/container/object

    account.storageurl/path_root/container/object gets translated to
    account.storageurl/path_root/account/container/object

    Browsers can convert a url to lowercase, so check that reseller_prefix
    is the correct case and fix if necessary

    """

    def __init__(self, app, conf):
        self.app = app
        self.storage_domain = conf.get('storage_domain', 'example.com')
        if self.storage_domain and self.storage_domain[0] != '.':
            self.storage_domain = '.' + self.storage_domain
        self.path_root = conf.get('path_root', 'v1').strip('/')
        self.reseller_prefix = conf.get('reseller_prefix','AUTH');

    def __call__(self, env, start_response):
        if not self.storage_domain:
            return self.app(env, start_response)
        given_domain = env['HTTP_HOST']
        port = ''
        if ':' in given_domain:
            given_domain, port = given_domain.rsplit(':', 1)
        if given_domain.endswith(self.storage_domain):
            parts_to_parse = given_domain[:-len(self.storage_domain)]
            parts_to_parse = parts_to_parse.strip('.').split('.')
            len_parts_to_parse = len(parts_to_parse)
            if len_parts_to_parse == 2:
                container, account = parts_to_parse
            elif len_parts_to_parse == 1:
                container, account = None, parts_to_parse[0]
            else:
                resp = HTTPBadRequest(request=Request(env),
                                      body='Bad domain in host header',
                                      content_type='text/plain')
                return resp(env, start_response)
            if '_' not in account and '-' in account:
                account = account.replace('-', '_', 1)
            if account.lower().startswith(self.reseller_prefix.lower()) and not account.startswith(self.reseller_prefix):
                account_suffix = account[len(self.reseller_prefix):]
                account = self.reseller_prefix + account_suffix
            path = env['PATH_INFO'].strip('/')
            new_path_parts = ['', self.path_root, account]
            if container:
                new_path_parts.append(container)
            if path.startswith(self.path_root):
                path = path[len(self.path_root):].lstrip('/')
            if path:
                new_path_parts.append(path)
            new_path = '/'.join(new_path_parts)
            env['PATH_INFO'] = new_path
        return self.app(env, start_response)


def filter_factory(global_conf, **local_conf):
    conf = global_conf.copy()
    conf.update(local_conf)

    def domain_filter(app):
        return DomainRemapMiddleware(app, conf)
    return domain_filter