#
# Copyright (c) 2014 ThoughtWorks, Inc.
#
# Pixelated is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Pixelated 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with Pixelated. If not, see <http://www.gnu.org/licenses/>.
import os
import requests
import json
from leap.common import ca_bundle

from .config import AUTO_DETECT_CA_BUNDLE

LEAP_CERT = None
LEAP_FINGERPRINT = None


def which_api_CA_bundle(provider):
    return str(LeapCertificate(provider).api_ca_bundle())


def which_bootstrap_cert_fingerprint():
    return LEAP_FINGERPRINT


def which_bootstrap_CA_bundle(provider):
    if LEAP_CERT is not None:
        return LEAP_CERT
    return str(LeapCertificate(provider).auto_detect_bootstrap_ca_bundle())


def refresh_ca_bundle(provider):
    LeapCertificate(provider).refresh_ca_bundle()


class LeapCertificate(object):
    def __init__(self, provider):
        self._config = provider.config
        self._server_name = provider.server_name
        self._certs_home = self._config.certs_home
        self._provider = provider

    def auto_detect_bootstrap_ca_bundle(self):
        if self._config.bootstrap_ca_cert_bundle == AUTO_DETECT_CA_BUNDLE:
            local_cert = self._local_bootstrap_server_cert()
            if local_cert:
                return local_cert
            else:
                return ca_bundle.where()
        else:
            return self._config.bootstrap_ca_cert_bundle

    def api_ca_bundle(self):
        if self._provider.config.ca_cert_bundle:
            return self._provider.config.ca_cert_bundle

        cert_file = self._api_cert_file()

        if not os.path.isfile(cert_file):
            self._download_server_cert(cert_file)

        return cert_file

    def refresh_ca_bundle(self):
        cert_file = self._api_cert_file()
        self._download_server_cert(cert_file)

    def _api_cert_file(self):
        certs_root = self._api_certs_root_path()
        return os.path.join(certs_root, 'api.pem')

    def _api_certs_root_path(self):
        path = os.path.join(self._provider.config.leap_home, 'providers', self._server_name, 'keys', 'client')
        if not os.path.isdir(path):
            os.makedirs(path, 0700)
        return path

    def _local_bootstrap_server_cert(self):
        cert_file = os.path.join(self._certs_home, '%s.ca.crt' % self._server_name)
        if not os.path.isfile(cert_file):
            response = requests.get('https://%s/provider.json' % self._server_name)
            provider_data = json.loads(response.content)
            ca_cert_uri = str(provider_data['ca_cert_uri'])

            response = requests.get(ca_cert_uri)
            with open(cert_file, 'w') as file:
                file.write(response.content)

        return cert_file

    def _download_server_cert(self, cert_file_name):
        cert = self._provider.fetch_valid_certificate()

        with open(cert_file_name, 'w') as file:
            file.write(cert)