#!/usr/bin/python2 -E
#
# Authors:
#   Rob Crittenden <rcritten@redhat.com>
#
# Copyright (C) 2014  Red Hat
# 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/>.

import sys
import os
import cherrypy
import json
import syslog
import pwd
from optparse import OptionParser
from functools import wraps
from cherrypy import response
from cherrypy.process import plugins
from ipalib import api
from ipalib import errors
from ipalib import util
from ipaserver.rpcserver import json_encode_binary
from ipapython.version import VERSION


def jsonout(func):
    '''JSON output decorator'''
    @wraps(func)
    def wrapper(*args, **kw):
        value = func(*args, **kw)
        response.headers["Content-Type"] = "application/json;charset=utf-8"
        data = json_encode_binary(value)
        return json.dumps(data, sort_keys=True, indent=2)

    return wrapper


def handle_error(status, message, traceback, version):
    """
    Return basic messages to user and log backtrace in case of 500
    error.
    """
    if status.startswith('500'):
        cherrypy.log(msg=message + '\n', context='IPA', traceback=True)

    resp = cherrypy.response
    resp.headers['Content-Type'] = 'application/json'
    return json.dumps({'status': status, 'message': message})


def convert_unicode(value):
    """
    IPA requires all incoming values to be unicode. Recursively
    convert the values.
    """
    if not isinstance(value, basestring):
        return value

    if value is not None:
        return unicode(value)
    else:
        return None


def Command(command, *args, **options):
    if (cherrypy.request.config.get('local_only', False) and
       cherrypy.request.remote.ip not in ['::1', '127.0.0.1']):
        raise IPAError(
            status=401,
            message="Not a local request"
        )

    if not api.Backend.rpcclient.isconnected():
        api.Backend.rpcclient.connect()
    try:
        if not api.Backend.rpcclient.isconnected():
            api.Backend.rpcclient.connect()
    except errors.CCacheError, e:
        raise IPAError(
            status=401,
            message=e
        )

    # IPA wants all its strings as unicode
    args = map(lambda v: convert_unicode(v), args)
    options = dict(zip(options, map(convert_unicode, options.values())))

    params = api.Command[command].args_options_2_params(*args, **options)
    cherrypy.log(context='IPA', msg='%s(%s)' %
        (command, ', '.join(api.Command[command]._repr_iter(**params))))
    try:
        return api.Command[command](*args, **options)['result']
    except (errors.DuplicateEntry, errors.DNSNotARecordError,
            errors.ValidationError, errors.ConversionError,) as e:
        raise IPAError(
            status=400,
            message=e
        )
    except errors.ACIError, e:
        raise IPAError(
            status=401,
            message=e
        )
    except errors.NotFound, e:
        raise IPAError(
            status=404,
            message=e
        )
    except Exception, e:
        raise IPAError(
            status=500,
            message=e
        )


@jsonout
def GET(command, *args, **options):
    return Command(command, *args, **options)


@jsonout
def POST(command, *args, **options):
    cherrypy.response.status = 201
    return Command(command, *args, **options)


@jsonout
def DELETE(command, *args, **options):
    return Command(command, *args, **options)


class IPAError(cherrypy.HTTPError):
    """
    Return errors in IPA-style json.

    Local errors are treated as strings so do not include the code and
    name attributes within the error dict.

    This is not padded for IE.
    """

    def set_response(self):
        response = cherrypy.serving.response

        cherrypy._cperror.clean_headers(self.code)

        # In all cases, finalize will be called after this method,
        # so don't bother cleaning up response values here.
        response.status = self.status

        if isinstance(self._message, Exception):
            error = {'code': self._message.errno,
                     'message': self._message.message,
                     'name': self._message.__class__.__name__}
        elif isinstance(self._message, basestring):
            error = {'message': self._message}
        else:
            error = {'message':
                     'Unable to handle error message type %s' % type(self._message)}

        response.body = json.dumps({'error': error,
                                    'id': 0,
                                    'principal': util.get_current_principal(),
                                    'result': None,
                                    'version': VERSION},
                                    sort_keys=True, indent=2)


class Host(object):

    exposed = True

    def GET(self, fqdn=None):

        if fqdn is None:
            command = 'host_find'
        else:
            command = 'host_show'

        return GET(command, fqdn)

    def POST(self, hostname, description=None, random=False,
             macaddress=None, userclass=None, ip_address=None,
             password=None):
        return POST('host_add', hostname,
                    description=description, random=random,
                    force=True, macaddress=macaddress,
                    userclass=userclass, ip_address=ip_address,
                    userpassword=password)

    def DELETE(self, fqdn):
        return DELETE('host_del', fqdn)


class Hostgroup(object):

    exposed = True

    def GET(self, name=None):

        if name is None:
            command = 'hostgroup_find'
        else:
            command = 'hostgroup_show'

        return GET(command, name)

    def POST(self, name=None, description=None):
        cherrypy.response.status = 201
        return POST('hostgroup_add', name,
                    description=description,)

    def DELETE(self, name):
        return DELETE('hostgroup_del', name)

class Features(object):
    exposed = True

    def GET(self):
        return '["realm"]'


def start(config=None, daemonize=False, pidfile=None):
    # Set the umask so only the owner can read the log files
    old_umask = os.umask(077)

    cherrypy.tree.mount(
        Features(), '/features',
        {'/':
            {'request.dispatch': cherrypy.dispatch.MethodDispatcher()}
        }
    )
    cherrypy.tree.mount(
        Host(), '/ipa/smartproxy/host',
        {'/':
            {'request.dispatch': cherrypy.dispatch.MethodDispatcher()}
        }
    )
    cherrypy.tree.mount(
        Hostgroup(), '/ipa/smartproxy/hostgroup',
        {'/':
            {'request.dispatch': cherrypy.dispatch.MethodDispatcher()}
        }
    )

    api.bootstrap(context='ipasmartproxy')
    api.finalize()

    # Register the domain for requests from Foreman
    cherrypy.tree.mount(
        Host(), '/realm/%s' % api.env.domain,
        {'/':
            {'request.dispatch': cherrypy.dispatch.MethodDispatcher()}
        }
    )

    for c in config or []:
        try:
            cherrypy.config.update(c)
        except (IOError, OSError), e:
            cherrypy.log(msg="Exception trying to load %s: %s" % (c, e),
                context='IPA', traceback=False)
            return 1

    # Log files are created, reset umask
    os.umask(old_umask)

    user = cherrypy.config.get('user', None)
    if user is None:
        cherrypy.log(msg="User is required", context='IPA', traceback=False)
        return 1
    pent = pwd.getpwnam(user)

    if daemonize:
        cherrypy.config.update({'log.screen': False})
        plugins.Daemonizer(cherrypy.engine).subscribe()

    if pidfile:
        plugins.PIDFile(cherrypy.engine, pidfile).subscribe()

    cherrypy.engine.signal_handler.subscribe()

    cherrypy.config.update({'error_page.500': handle_error})

    # If you don't use GSS-Proxy you're on your own in ensuring that
    # there is always a valid ticket for the smartproxy to use.
    if cherrypy.config.get('use_gssproxy', False):
        cherrypy.log(msg="Enabling GSS-Proxy", context='IPA')
        os.environ['GSS_USE_PROXY'] = '1'

    if os.geteuid() == 0:
        cherrypy.log(msg="Dropping root privileges to %s" % user,
                     context='IPA')
        plugins.DropPrivileges(cherrypy.engine,
                               uid=pent.pw_uid,
                               gid=pent.pw_gid).subscribe()

    try:
        cherrypy.engine.start()
    except Exception:
        return 1
    else:
        cherrypy.engine.block()

    return 0

if __name__ == '__main__':
    p = OptionParser()
    p.add_option('-c', '--config', action="append", dest='config',
                 help="specify config file(s)")
    p.add_option('-d', action="store_true", dest='daemonize',
                 help="run the server as a daemon")
    p.add_option('-p', '--pidfile', dest='pidfile', default=None,
                 help="store the process id in the given file")
    options, args = p.parse_args()

    try:
        sys.exit(start(options.config, options.daemonize, options.pidfile))
    except Exception, e:
        cherrypy.log(msg="Exception trying to start: %s" % e,
                     context='IPA',
                     traceback=True)
        syslog.syslog(syslog.LOG_ERR, "Exception trying to start: %s" % e)