#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright 2016 Deutsches Klimarechenzentrum GmbH

# 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 datetime import datetime, timedelta
import getpass
import os
import os.path
import requests
import stat
import sys
import time

SWIFT_BASE = 'https://swift.dkrz.de/'


def is_sh_family():
    return os.environ.get("SHELL", '').split('/')[-1] in ["bash", "sh", "ksh"]


def get_env_content(sh, token, storage_url):
    if sh:
        return "OS_AUTH_TOKEN={}\nOS_STORAGE_URL={}\n"\
               "export OS_AUTH_TOKEN\nexport OS_STORAGE_URL\n"\
               "unset OS_AUTH_URL\n"\
               "unset OS_USERNAME\n"\
               "unset OS_PASSWORD\n".format(token, storage_url)
    else:
        return "setenv OS_AUTH_TOKEN {}\n"\
               "setenv OS_STORAGE_URL {}\n"\
               "setenv OS_AUTH_URL \" \"\n"\
               "setenv OS_USERNAME \" \"\n"\
               "setenv OS_PASSWORD \" \"\n".format(token, storage_url)


def create_token():
    account = raw_input("Account: ")
    username = raw_input("Username: ")
    password = getpass.getpass()

    timezone = time.tzname[-1]
    expires = token = storage_url = None

    try:
        resp = requests.get(SWIFT_BASE + 'auth/v1.0',
                            headers={'X-Auth-User': "{}:{}".format(account,
                                                                   username),
                                     'X-Auth-Key': password})
        resp.raise_for_status()

        token = resp.headers["x-auth-token"]
        storage_url = resp.headers["x-storage-url"]
        expires_in = int(resp.headers["x-auth-token-expires"])
        expires_at = datetime.fromtimestamp(time.time() + expires_in)
        expires = expires_at.strftime('%a %d. %b %H:%M:%S {tz} %Y'.format(
                                      tz=timezone))

        if expires and token and storage_url:
            with open(os.path.expanduser("~/.swiftenv"), "w") as f:
                content = get_env_content(is_sh_family(), token, storage_url)
                f.write("#token expires on: {}\n{}".format(expires, content))
                os.chmod(os.path.expanduser("~/.swiftenv"),
                         stat.S_IREAD | stat.S_IWRITE)
    except requests.RequestException:
        print "Login failed."
        sys.exit(-1)


def info_token():
    try:
        with open(os.path.expanduser("~/.swiftenv"), "r") as f:
            line = f.readline()[:-1]
            expire_s = ' '.join(line.split(' ')[3:])
            expire_d = datetime.strptime(expire_s, '%a %d. %b %H:%M:%S %Z %Y')
            now = datetime.now()
            soon = now + timedelta(hours=8)

            if now > expire_d:
                print ("Your swift token is expired. "
                       "Please create a new one with swift-token. ")
                sys.exit(0)

            print "Your swift token will expire on {}".format(expire_s)

            if soon > expire_d:
                print ('Your swift token will expire soon. '
                       'You might create a new one with swift-token new. ')

            if opt == "new":
                print ("Please type {} ~/.swiftenv".format(
                       "." if is_sh_family() else "source"))

    except IOError:
        print ("Error while reading environment variables in "
               "{}".format(os.path.expanduser("~/.swiftenv")))


if __name__ == '__main__':
    opt = sys.argv[1] if len(sys.argv) > 1 else None
    if opt == "new":
        create_token()
        info_token()
    elif opt == "info":
        info_token()
    else:
        print "Usage: python swift-token.py <new|info>"