#!/usr/bin/python
#
# Copyright (C) 2014  Simo Sorce <simo@redhat.com>
#
# see file 'COPYING' for use and warranty information
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# 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 General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from ipsilon.tools.saml2metadata import Metadata
from ipsilon.tools.saml2metadata import SAML2_NAMEID_MAP
from ipsilon.tools.saml2metadata import SAML2_SERVICE_MAP
from ipsilon.tools.certs import Certificate
from ipsilon.tools import files
from urllib import urlencode
import argparse
import ConfigParser
import getpass
import json
import logging
import os
import pwd
import requests
import shutil
import socket
import sys


HTTPDCONFD = '/etc/httpd/conf.d'
SAML2_TEMPLATE = '/usr/share/ipsilon/templates/install/saml2/sp.conf'
SAML2_CONFFILE = '/etc/httpd/conf.d/ipsilon-saml.conf'
SAML2_HTTPDIR = '/etc/httpd/saml2'
SAML2_PROTECTED = '/saml2protected'

#Installation arguments
args = dict()

# Regular logging
logger = logging.getLogger()


def openlogs():
    global logger  # pylint: disable=W0603
    logger = logging.getLogger()
    lh = logging.StreamHandler(sys.stderr)
    logger.addHandler(lh)


def saml2():
    logger.info('Installing SAML2 Service Provider')

    if args['saml_idp_metadata'] is None:
        #TODO: detect via SRV records ?
        if args['saml_idp_url']:
            args['saml_idp_metadata'] = ('%s/saml2/metadata' %
                                         args['saml_idp_url'].rstrip('/'))
        else:
            raise ValueError('An IDP URL or metadata file/URL is required.')

    idpmeta = None

    try:
        if os.path.exists(args['saml_idp_metadata']):
            with open(args['saml_idp_metadata']) as f:
                idpmeta = f.read()
        elif args['saml_idp_metadata'].startswith('file://'):
            with open(args['saml_idp_metadata'][7:]) as f:
                idpmeta = f.read()
        else:
            r = requests.get(args['saml_idp_metadata'])
            r.raise_for_status()
            idpmeta = r.content
    except Exception, e:  # pylint: disable=broad-except
        logger.error("Failed to retrieve IDP Metadata file!\n" +
                     "Error: [%s]" % repr(e))
        raise

    path = None
    if not args['saml_no_httpd']:
        path = os.path.join(SAML2_HTTPDIR, args['hostname'])
        os.makedirs(path, 0750)
    else:
        path = os.getcwd()

    proto = 'https'
    if not args['saml_secure_setup']:
        proto = 'http'

    port_str = ''
    if args['port']:
        port_str = ':%s' % args['port']

    url = '%s://%s%s' % (proto, args['hostname'], port_str)
    url_sp = url + args['saml_sp']
    url_logout = url + args['saml_sp_logout']
    url_post = url + args['saml_sp_post']

    # Generate metadata
    m = Metadata('sp')
    c = Certificate(path)
    c.generate('certificate', args['hostname'])
    m.set_entity_id(url_sp)
    m.add_certs(c)
    m.add_service(SAML2_SERVICE_MAP['logout-redirect'], url_logout)
    m.add_service(SAML2_SERVICE_MAP['response-post'], url_post, index="0")
    m.add_allowed_name_format(SAML2_NAMEID_MAP[args['saml_nameid']])
    sp_metafile = os.path.join(path, 'metadata.xml')
    m.output(sp_metafile)

    # Register with the IDP if the IDP URL was provided
    if args['saml_idp_url']:
        if args['admin_password']:
            if args['admin_password'] == '-':
                admin_password = sys.stdin.readline().rstrip('\n')
            else:
                try:
                    with open(args['admin_password']) as f:
                        admin_password = f.read().rstrip('\n')
                except Exception as e:  # pylint: disable=broad-except
                    logger.error("Failed to read password file!\n" +
                                 "Error: [%s]" % e)
                    raise
        else:
            admin_password = getpass.getpass('%s password: ' %
                                             args['admin_user'])

        # Read our metadata
        sp_metadata = ''
        try:
            with open(sp_metafile) as f:
                for line in f:
                    sp_metadata += line.strip()
        except Exception as e:  # pylint: disable=broad-except
            logger.error("Failed to read SP Metadata file!\n" +
                         "Error: [%s]" % e)
            raise

        # Register the SP
        try:
            saml2_register_sp(args['saml_idp_url'], args['admin_user'],
                              admin_password, args['saml_sp_name'],
                              sp_metadata)
        except Exception as e:  # pylint: disable=broad-except
            logger.error("Failed to register SP with IDP!\n" +
                         "Error: [%s]" % e)
            raise

    if not args['saml_no_httpd']:
        idp_metafile = os.path.join(path, 'idp-metadata.xml')
        with open(idp_metafile, 'w+') as f:
            f.write(idpmeta)

        saml_protect = 'auth'
        saml_auth=''
        if args['saml_base'] != args['saml_auth']:
            saml_protect = 'info'
            saml_auth = '<Location %s>\n' \
                        '    MellonEnable "auth"\n' \
                        '    Header append Cache-Control "no-cache"\n' \
                        '</Location>\n' % args['saml_auth']

        psp = '# '
        if args['saml_auth'] == SAML2_PROTECTED:
            # default location, enable the default page
            psp = ''

        saml_secure = 'Off'
        ssl_require = '#'
        ssl_rewrite = '#'
        if args['port']:
            ssl_port = args['port']
        else:
            ssl_port = '443'

        if args['saml_secure_setup']:
            saml_secure = 'On'
            ssl_require = ''
            ssl_rewrite = ''

        samlopts = {'saml_base': args['saml_base'],
                    'saml_protect': saml_protect,
                    'saml_sp_key': c.key,
                    'saml_sp_cert': c.cert,
                    'saml_sp_meta': sp_metafile,
                    'saml_idp_meta': idp_metafile,
                    'saml_sp': args['saml_sp'],
                    'saml_secure_on': saml_secure,
                    'saml_auth': saml_auth,
                    'ssl_require': ssl_require,
                    'ssl_rewrite': ssl_rewrite,
                    'ssl_port': ssl_port,
                    'sp_hostname': args['hostname'],
                    'sp_port': port_str,
                    'sp': psp}
        files.write_from_template(SAML2_CONFFILE, SAML2_TEMPLATE, samlopts)

        files.fix_user_dirs(SAML2_HTTPDIR, args['httpd_user'])

        logger.info('SAML Service Provider configured.')
        logger.info('You should be able to restart the HTTPD server and' +
                    ' then access it at %s%s' % (url, args['saml_auth']))
    else:
        logger.info('SAML Service Provider configuration ready.')
        logger.info('Use the certificate, key and metadata.xml files to' +
                    ' configure your Service Provider')


def saml2_register_sp(url, user, password, sp_name, sp_metadata):
    s = requests.Session()

    # Authenticate to the IdP
    form_auth_url = '%s/login/form' % url.rstrip('/')
    test_auth_url = '%s/login/testauth' % url.rstrip('/')
    auth_data = {'login_name': user,
                 'login_password': password}

    r = s.post(form_auth_url, data=auth_data)
    if r.status_code == 404:
        r = s.post(test_auth_url, data=auth_data)

    if r.status_code != 200:
        raise Exception('Unable to authenticate to IdP (%d)' % r.status_code)

    # Add the SP
    sp_url = '%s/rest/providers/saml2/SPS/%s' % (url.rstrip('/'), sp_name)
    sp_headers = {'Content-type': 'application/x-www-form-urlencoded',
                  'Referer': sp_url}
    sp_data = urlencode({'metadata': sp_metadata})

    r = s.post(sp_url, headers=sp_headers, data=sp_data)
    if r.status_code != 201:
        message = json.loads(r.text)['message']
        raise Exception('%s' % message)


def install():
    if args['saml']:
        saml2()


def saml2_uninstall():
    try:
        shutil.rmtree(os.path.join(SAML2_HTTPDIR, args['hostname']))
    except Exception, e:  # pylint: disable=broad-except
        log_exception(e)
    try:
        os.remove(SAML2_CONFFILE)
    except Exception, e:  # pylint: disable=broad-except
        log_exception(e)


def uninstall():
    logger.info('Uninstalling Service Provider')
    #FXIME: ask confirmation
    saml2_uninstall()
    logger.info('Uninstalled SAML2 data')


def log_exception(e):
    if 'debug' in args and args['debug']:
        logger.exception(e)
    else:
        logger.error(e)


def parse_config_profile(args):
    config = ConfigParser.ConfigParser()
    files = config.read(args['config_profile'])
    if len(files) == 0:
        raise ConfigurationError('Config Profile file %s not found!' %
                                 args['config_profile'])

    if 'globals' in config.sections():
        G = config.options('globals')
        for g in G:
            val = config.get('globals', g)
            if val == 'False':
                val = False
            elif val == 'True':
                val = True
            if g in globals():
                globals()[g] = val
            else:
                for k in globals().keys():
                    if k.lower() == g.lower():
                        globals()[k] = val
                        break

    if 'arguments' in config.sections():
        A = config.options('arguments')
        for a in A:
            val = config.get('arguments', a)
            if val == 'False':
                val = False
            elif val == 'True':
                val = True
            args[a] = val

    return args


def parse_args():
    global args

    fc = argparse.ArgumentDefaultsHelpFormatter
    parser = argparse.ArgumentParser(description='Client Install Options',
                                     formatter_class=fc)
    parser.add_argument('--version',
                        action='version', version='%(prog)s 0.1')
    parser.add_argument('--hostname', default=socket.getfqdn(),
                        help="Machine's fully qualified host name")
    parser.add_argument('--port', default=None,
                        help="Port number that SP listens on")
    parser.add_argument('--admin-user', default='admin',
                        help="Account allowed to create a SP")
    parser.add_argument('--admin-password', default=None,
                        help="File containing the password for the account " +
                             "used to create a SP (- to read from stdin)")
    parser.add_argument('--httpd-user', default='apache',
                        help="Web server account used to read certs")
    parser.add_argument('--saml', action='store_true', default=True,
                        help="Whether to install a saml2 SP")
    parser.add_argument('--saml-idp-url', default=None,
                        help="A URL of the IDP to register the SP with")
    parser.add_argument('--saml-idp-metadata', default=None,
                        help="A URL pointing at the IDP Metadata (FILE or HTTP)")
    parser.add_argument('--saml-no-httpd', action='store_true', default=False,
                        help="Do not configure httpd")
    parser.add_argument('--saml-base', default='/',
                        help="Where saml2 authdata is available")
    parser.add_argument('--saml-auth', default=SAML2_PROTECTED,
                        help="Where saml2 authentication is enforced")
    parser.add_argument('--saml-sp', default='/saml2',
                        help="Where saml communication happens")
    parser.add_argument('--saml-sp-logout', default='/saml2/logout',
                        help="Single Logout URL")
    parser.add_argument('--saml-sp-post', default='/saml2/postResponse',
                        help="Post response URL")
    parser.add_argument('--saml-secure-setup', action='store_true',
                        default=True, help="Turn on all security checks")
    parser.add_argument('--saml-nameid', default='unspecified',
                        choices=SAML2_NAMEID_MAP.keys(),
                        help="SAML NameID format to use")
    parser.add_argument('--saml-sp-name', default=None,
                        help="The SP name to register with the IdP")
    parser.add_argument('--debug', action='store_true', default=False,
                        help="Turn on script debugging")
    parser.add_argument('--config-profile', default=None,
                        help=argparse.SUPPRESS)
    parser.add_argument('--uninstall', action='store_true',
                        help="Uninstall the server and all data")

    args = vars(parser.parse_args())

    if args['config_profile']:
        args = parse_config_profile(args)

    if len(args['hostname'].split('.')) < 2:
        raise ValueError('Hostname: %s is not a FQDN.' % args['hostname'])

    if args['port'] and not args['port'].isdigit():
        raise ValueError('Port number: %s is not an integer.' % args['port'])

    # Validate that all path options begin with '/'
    path_args = ['saml_base', 'saml_auth', 'saml_sp', 'saml_sp_logout',
                 'saml_sp_post']
    for path_arg in path_args:
        if not args[path_arg].startswith('/'):
            raise ValueError('--%s must begin with a / character.' %
                             path_arg.replace('_', '-'))

    # The saml_sp setting must be a subpath of saml_base since it is
    # used as the MellonEndpointPath.
    if not args['saml_sp'].startswith(args['saml_base']):
        raise ValueError('--saml-sp must be a subpath of --saml-base.')

    # The saml_sp_logout and saml_sp_post settings must be subpaths
    # of saml_sp (the mellon endpoint).
    path_args = ['saml_sp_logout', 'saml_sp_post']
    for path_arg in path_args:
        if not args[path_arg].startswith(args['saml_sp']):
            raise ValueError('--%s must be a subpath of --saml-sp' %
                             path_arg.replace('_', '-'))

    # If saml_idp_url if being used, we require saml_sp_name to
    # use when registering the SP.
    if args['saml_idp_url'] and not args['saml_sp_name']:
        raise ValueError('--saml-sp-name must be specified when using' +
                         '--saml-idp-url')

    # At least one on this list needs to be specified or we do nothing
    sp_list = ['saml']
    present = False
    for sp in sp_list:
        if args[sp]:
            present = True
    if not present and not args['uninstall']:
        raise ValueError('Nothing to install, please select a Service type.')


if __name__ == '__main__':
    out = 0
    openlogs()
    try:
        parse_args()

        if 'uninstall' in args and args['uninstall'] is True:
            uninstall()
        else:
            install()
    except Exception, e:  # pylint: disable=broad-except
        log_exception(e)
        if 'uninstall' in args and args['uninstall'] is True:
            logging.info('Uninstallation aborted.')
        else:
            logging.info('Installation aborted.')
        out = 1
    finally:
        if out == 0:
            if 'uninstall' in args and args['uninstall'] is True:
                logging.info('Uninstallation complete.')
            else:
                logging.info('Installation complete.')
    sys.exit(out)