from nameko.events import EventDispatcher, event_handler
from nameko.rpc import rpc
from configparser import ConfigParser
from ldap3 import Server, ServerPool, Connection, ObjectDef, AttrDef, Reader, Writer
from datetime import datetime

# For testing
from random import randint

# Read the config in the nameko.conf
config = ConfigParser()
config.read('nameko.conf')

# Sanity check for config
try:
    mult_server = int(config['LDAP']['SERVERMULTIPLE'])
# SERVERMULTIPLE is set to something not a number
except:
    exit("[LDAP] SERVERMULTIPLE has to be an integer >= 1")
# less than one server is not a sensible option
if mult_server < 1:
    exit("[LDAP] SERVERMULTIPLE has to be an integer >= 1")


# Function to setup the server or serverpool
def ldapservers():
    # Just one server, no need for a pool
    if mult_server == 1:
        ldapserver = Server(config['LDAP']['LDAPSERVER1'])
        return ldapserver
    # Multiple servers, set up a pool
    else:
        ldapserver = ServerPool(None)
        for x in range(1, (mult_server+1)):
            ins = Server(config['LDAP']['LDAPSERVER' + str(x)])
            ldapserver.add(ins)
        return ldapserver


# Since there's no reason why someone in ou=users shouldn't use the service,
# here's the helper function to check whether an uid is in ou=customers or
# ou=users
# returns the full dn
def user_or_customer(uid):
    server = ldapservers()
    conn = Connection(server)
    conn.bind()
    search_customers = conn.search('ou=customers,dc=ungleich,dc=ch', '(%s)' % uid)
    if search_customers:
        conn.unbind()
        return '%s,ou=customers,dc=ungleich,dc=ch' % uid
    search_users = conn.search('ou=customers,dc=ungleich,dc=ch', '(%s)' % uid)
    if search_users:
        conn.unbind()
        return '%s,ou=customers,dc=ungleich,dc=ch' % uid
    conn.unbind()
    return False


# checks if a user already exists in the LDAP
class UserLookUp(object):
    name = "userlookup"
    dispatch = EventDispatcher()

    @rpc
    def lookup(self, user):
        # Setup the search parameter and connect to LDAP
        LDAP_UID = 'uid=%s' % user
        server = ldapservers()
        conn = Connection(server)
        conn.bind()
        # Strange result. It keeps complaining LDAP_UID not set if I try to directly
        # substitute x and y to the if
        # Searches for user in ou=customers and ou=users
        x = conn.search('ou=customers,dc=ungleich,dc=ch', '(%s)' % LDAP_UID)
        y = conn.search('ou=users,dc=ungleich,dc=ch', '(%s)' % LDAP_UID)
        if x or y:
            # return conn.entries[0] for first search result since we can assume uid is unique
            self.dispatch('ldap', '%s [Info: UserLookUp] Searched for %s and found it\n' % (datetime.now(), LDAP_UID) )
            conn.unbind()
            # return True since the user is already in LDAP
            return True
        # User not in LDAP, so just close it down, write the log and return False
        else:
            conn.unbind()
            self.dispatch('ldap', '%s [Info: UserLookUp] Searched for %s and not found it.\n' % (datetime.now(), LDAP_UID) )
            return False


# Create a user in the LDAP. Assumes the checks are already in place for existing users
class CreateUser(object):
    name = "createuser"
    dispatch = EventDispatcher()

    @rpc
    def create_user(self, user, password, firstname, lastname, email):
        # Creates a user with some basic data
        server = ldapservers()
        conn = Connection(server, config['LDAP']['LDAPMANAGER'], config['LDAP']['LDAPMANAGERPASSWORD'])
        if not conn.bind():
            self.dispatch('ldap', '%s [Error CreateUser] Could not connect to LDAPserver\n' % datetime.now() )
            return "Could not connect to LDAP Server."
        # set objectClasses for the new user
        obj_new_user = ObjectDef(['inetOrgPerson', 'posixAccount', 'shadowAccount'], conn)
        w = Writer(conn, obj_new_user)
        # newly created users get put into ou=customers
        dn = 'uid=%s,ou=customers,dc=ungleich,dc=ch' % user
        w.new(dn)
        # Filling in some of the data
        # required attributes are sn, cn, homeDirectory, uid (already handled by dn), uidNumber, gidNumber
        w[0].givenName = firstname
        w[0].sn = lastname
        w[0].cn = firstname + " " + lastname
        w[0].mail = email
        w[0].userPassword = password
        w[0].homeDirectory = '/home/%s' % user
        # TODO: Learn how to get the last uidNumber and what gidNumber to use
        w[0].uidNumber = randint(1200,50000)
        w[0].gidNumber = randint(1200,50000)
        if not w.commit():
            conn.unbind()
            self.dispatch('ldap', '%s [Error CreateUser] Could not write new user %s to LDAP DB\n' % (datetime.now(), dn) )
            return "Couldn't write data to the LDAP Server."
        conn.unbind()
        self.dispatch('ldap', '%s [Info CreateUser] %s created.\n' % (datetime.now(), dn) )
        return True

# Returns some basic data from an user
class GetUserData(object):
    name = "getuserdata"
    dispatch = EventDispatcher()

    @rpc
    def get_data(self, user):
        # Setup the search parameter and connect to LDAP
        LDAP_UID = 'uid=%s' % user
        server = ldapservers()
        conn = Connection(server)
        conn.bind()
        if not conn.bound:
            self.dispatch('ldap', '%s [Error GetUserData] Could not connect to LDAP server.\n' % datetime.now() )
            return ("error", "Could not connect to LDAP server.", "", "")
        rdn = user_or_customer(LDAP_UID)
        if rdn == False:
            conn.unbind()
            self.dispatch('ldap', '%s [Info GetUserData] Could not find user %s\n' % (datetime.now(), LDAP_UID) )
            return ("error", "Could not find the user.", "", "")
        obj = ObjectDef(['inetOrgPerson', 'posixAccount', 'shadowAccount'], conn)
        # The Reader gets the data for the user
        r = Reader(conn, obj, rdn)
        r.search()
        # Since the DN is basically confirmed by user_or_customer() it shouldn't throw an exception, but better check
        try:
            x = r[0].sn
        except:
            conn.unbind()
            self.dispatch('ldap', '%s [Error GetUserData] Could not open Reader for %s\n' % (datetime.now(), rdn) )
            return ("error", "Could not read data for user.", "", "")
        # Putting the results into strings and then clean it up a bit if some attribute is not set in LDAP
        (firstname, lastname, email) = (str(r[0].givenName), str(r[0].sn), str(r[0].mail))
        if firstname == '[]':
            firstname = 'No firstname given'
        if lastname == '[]':
            lastname = 'No lastname given'
        if email == '[]':
            email = 'No email given'
        conn.unbind()
        self.dispatch('ldap', '%s [Info GetUserData] Got data for %s  Firstname: %s  Lastname: %s  Email: %s\n' % (datetime.now(), rdn, firstname, lastname, email) )
        return ("OK", firstname, lastname, email)



# change some (firstname, lastname, email) data for the user
class ChangeUserData(object):
    name = "changeuserdata"
    dispatch = EventDispatcher()

    @rpc
    def change_data(self, user, firstname, lastname, email):
        LDAP_UID = 'uid=%s' % user
        server = ldapservers()
        # Establish connection with a user who can change the data
        conn = Connection(server, config['LDAP']['LDAPMANAGER'], config['LDAP']['LDAPMANAGERPASSWORD'])
        if not conn.bind():
            self.dispatch('ldap', '%s [Error ChangeUserData] Could not connect to LDAP server.\n' % datetime.now() )
            return "Could not connect to LDAP server."
        # get the DN of the user
        rdn = user_or_customer(LDAP_UID)
        if rdn == False:
            conn.unbind()
            self.dispatch('ldap', '%s [Info ChangeUserData] User with %s not found.\n' % (datetime.now(), LDAP_UID) )
            return "Could not find user."
        # Set up a reader for the user
        obj = ObjectDef(['inetOrgPerson', 'posixAccount', 'shadowAccount'], conn)
        r = Reader(conn, obj, rdn)
        r.search()
        # Again, user_or_customer() should prevent it from throwing an exception because it's a confirmed user
        try:
            x = r[0].sn
        except:
            conn.unbind()
            self.dispatch('ldap', '%s [Error ChangeUserData] Could not open Reader for %s\n' % (datetime.now(), rdn) )
            return "Could not open the data of user."
        # Opens a Writer instance prefilled with the old data
        # We could check if something has changed, but since the form takes the old data as standard values, let's
        # just update the relevant attributes
        w = Writer.from_cursor(r)
        w[0].sn = lastname
        w[0].cn = firstname + " " + lastname
        w[0].givenName = firstname
        w[0].mail = email
        # check if the data is written
        if not w.commit():
            conn.unbind()
            self.dispatch('ldap', '%s [Error ChangeUserData] Could not write changes for %s\n' % (datetime.now(), rdn) )
            return "Could not write changes for user."
        conn.unbind()
        self.dispatch('ldap', '%s [Info ChangeUserData] Changed data for %s  Firstname: %s  Lastname: %s  Email: %s\n' % (datetime.now(), rdn, firstname, lastname, email) )
        return True


# change the password for the user
class ChangePassword(object):
    name = "changepassword"
    dispatch = EventDispatcher()

    @rpc
    def change_password(self, user, newpassword):
        LDAP_UID = 'uid=%s' % user
        server = ldapservers()
        conn = Connection(server, config['LDAP']['LDAPMANAGER'], config['LDAP']['LDAPMANAGERPASSWORD'])
        if not conn.bind():
            self.dispatch('ldap', '%s [Error ChangePassword] Could not connect to LDAP server.\n' % datetime.now() )
            return "Could not connect to LDAP server."
        # check if uid=user is in either ou=customers or ou=users
        rdn = user_or_customer(LDAP_UID)
        if rdn == False:
            conn.unbind()
            self.dispatch('ldap', '%s [Error ChangePassword] Could not find user %s\n' % (datetime.now(), LDAP_UID) )
            return "Could not find the user."
        # Set up a Reader for the DN
        obj = ObjectDef(['inetOrgPerson', 'posixAccount', 'shadowAccount'], conn)
        r = Reader(conn, obj, rdn)
        r.search()
        # Shouldn't throw an exception, since the user is confirmed to be there
        try:
            x = r[0].sn
        except:
            conn.unbind()
            self.dispatch('ldap', '%s [Error ChangePassword] Could not open Reader for %s\n' % (datetime.now(), rdn) )
            return "Could not open the data for the user."
        # Set up the writer and overwrite the attribute with the new password
        w = Writer.from_cursor(r)
        w[0].userPassword = newpassword
        # Check to see if the change has gone through
        if not w.commit():
            conn.unbind()
            self.dispatch('ldap', '%s [Error ChangePassword] Could not write data for %s\n' % (datetime.now(), rdn) )
            return "Could not write data for the user."
        conn.unbind()
        self.dispatch('ldap', '%s [Info ChangePassword] Password changed for %s\n' % (datetime.now(), rdn) )
        return True


# Deletes a user from LDAP
class DeleteUser(object):
    name = "deleteuser"
    dispatch = EventDispatcher()

    @rpc
    def delete_user(self, user):
        LDAP_UID = 'uid=%s' % user
        server = ldapservers()
        conn = Connection(server, config['LDAP']['LDAPMANAGER'], config['LDAP']['LDAPMANAGERPASSWORD'])
        conn.bind()
        if not conn.bound:
            self.dispatch('ldap', '%s [Error DeleteUser] Could not connect to LDAP server.\n' % datetime.now() )
            return "Could not connect to LDAP server."
        # again, check whether the uid= is in ou=users or ou=customers
        dn = user_or_customer(LDAP_UID)
        if dn == False:
            conn.unbind()
            self.dispatch('ldap', '%s [Error DeleteUser] Could not find the user %s\n' % (datetime.now(), LDAP_UID) )
            return "Could not find the user."
        # Check if the delete was successfull
        deleted = conn.delete(dn)
        if not deleted:
            conn.unbind()
            self.dispatch('ldap', '%s [Error DeleteUser] Could not delete %s\n' % (datetime.now(), dn) )
            return "Could not delete the user."
        conn.unbind()
        self.dispatch('ldap', '%s [Info DeleteUser] Deleted %s\n' % (datetime.now(), dn) )
        return True


# the class to log all the dispatches
# for now everything gets logged into the same logfile, but 
# I don't forsee that much traffic plus with timestamps and the class name 
# in the log should be readable
class Log(object):
    name = "log"
    ldaplog = config['System']['LOGDIR'] + '/ldap.log'


    # Gets all the dispatches with 'ldap' and writes them into the ldap.log 
    @event_handler('userlookup', 'ldap')
    @event_handler('createuser', 'ldap')
    @event_handler('getuserdata', 'ldap')
    @event_handler('changeuserdata', 'ldap')
    @event_handler('passwordresetrequest', 'ldap')
    @event_handler('changepassword', 'ldap')
    @event_handler('deleteuser', 'ldap')
    def event_handler_ldap(self, payload):
        f = open(self.ldaplog, mode='a', encoding='utf-8')
        f.write(payload)
        f.close