#!/usr/bin/env python3
import ldap
import ldap.modlist
import string
from random import SystemRandom

# LDAP Server Configuration
LDAP_URI = "ldap://ldap1.dmz.lilik.it"
LDAP_STARTTLS = True
LDAP_BASEDN = "dc=lilik,dc=it"
MAIL_DOMAIN = "lilik.it"
NEW_PW_LEN = 10

# Manager Account
# Required privileges:
#  - New user creation in `ou=People`
#  - User search in `ou=People`
# All other action are performed as the logged-in user, and must be
# allowed by LDAP ACLs
LDAPMANAGER_BINDDN = "cn=,ou=Server,dc=lilik,dc=it"
LDAPMANAGER_BINDPW = ""


def ldapmanager_check_uid_exists(uid):
    conn = ldap.initialize(LDAP_URI)
    if(LDAP_STARTTLS):
        conn.start_tls_s()
    conn.simple_bind_s(LDAPMANAGER_BINDDN, LDAPMANAGER_BINDPW)
    results = conn.search_s('ou=People,{}'.format(LDAP_BASEDN),
                            ldap.SCOPE_SUBTREE,
                            'uid={}'.format(uid),
                            ['uid'])
    conn.unbind_s()
    return len(results) > 0

def ldapmanager_create_uid(uid, group_cn, req_attrs):
    dn="uid={},ou=People,{}".format(uid, LDAP_BASEDN)

    # New user template
    attrs = {
        'objectClass': [b'top', b'inetOrgPerson', b'authorizedServiceObject'],
        'uid': uid.encode('utf-8'),
        'mail': "{}@{}".format(uid, MAIL_DOMAIN).encode('utf-8'),
        'manager': "cn={},ou=Group,{}".format(group_cn, LDAP_BASEDN).encode('utf-8'),
        'cn': req_attrs['cn'].encode('utf-8'),
        'sn': req_attrs['sn'].encode('utf-8'),
        'authorizedService': [b'nextcloud', b'matrix', b'gitea']
    }

    conn = ldap.initialize(LDAP_URI)
    if(LDAP_STARTTLS):
        conn.start_tls_s()
    conn.simple_bind_s(LDAPMANAGER_BINDDN, LDAPMANAGER_BINDPW)
    conn.add_s(dn, ldap.modlist.addModlist(attrs))
    conn.unbind_s()

    return

class Group(object):

    def __init__(self, admin_uid, admin_pass):
        self.admin_uid = admin_uid
        self.conn = self.bind(admin_uid, admin_pass)

    def bind(self, admin_uid, admin_pass):
        conn = ldap.initialize(LDAP_URI)
        if(LDAP_STARTTLS):
            conn.start_tls_s()
        conn.simple_bind_s("uid={},ou=People,{}".format(admin_uid, LDAP_BASEDN), admin_pass)
        return conn

    def group_list(self):
        results = self.conn.search_s('ou=Group,{}'.format(LDAP_BASEDN),
                                ldap.SCOPE_SUBTREE,
                                'owner=uid={},ou=People,{}'.format(self.admin_uid, LDAP_BASEDN),
                                ['cn', 'description'])
        return [ (group["cn"][0].decode('utf-8'),
                  group["description"][0].decode('utf-8')) for key, group in results ]

    def member_list(self, group_cn):
        results = self.conn.search_s('cn={},ou=Group,{}'.format(group_cn, LDAP_BASEDN),
                                         ldap.SCOPE_BASE,
                                         'owner=uid={},ou=People,{}'.format(self.admin_uid, LDAP_BASEDN),
                                         ['member'])

        return [ ldap.dn.str2dn(member)[0][0][1] for member in results[0][1]["member"] ]

    def add_member(self, group_cn, uid):
        self.conn.modify_s('cn={},ou=Group,{}'.format(group_cn, LDAP_BASEDN),
                           [ (ldap.MOD_ADD, 'member', ["uid={},ou=People,{}".format(uid, LDAP_BASEDN).encode('utf-8')]) ])
        return
    def reset_password(self, uid):
        valid_chars = (string.ascii_uppercase
                       + string.ascii_lowercase
                       + string.digits)
        rng = SystemRandom()
        passwd = "".join([rng.choice(valid_chars) for _ in range(NEW_PW_LEN)])

        result = self.conn.passwd_s('uid={},ou=People,{}'.format(uid, LDAP_BASEDN),
                                    None,
                                    passwd)

        return passwd

from flask import Flask
from flask import request, jsonify
app = Flask(__name__)

@app.route('/get_list', methods=['POST'])
def display_list():
    try:
        g = Group(request.form['username'], request.form['password'])
        result = [
            { "cn": group[0],
              "description": group[1],
              "members": g.member_list(group[0])
            }
            for group in g.group_list()
        ]
    except Exception as e:
        return jsonify({"failed": True, "reason": str(e)})
    return jsonify(result)



@app.route('/group/<group_cn>/create/<new_uid>', methods=['POST'])
def new_user(group_cn, new_uid):
    try:
        g = Group(request.json['username'], request.json['password'])
        if group_cn not in [ group[0] for group in g.group_list() ]:
            result = { "failed": True,
                       "reason": "User {} is not an administrator for group {}".format(request.json['username'], group_cn) }
        elif ldapmanager_check_uid_exists(new_uid):
            result = { "failed": True,
                       "reason": "User {} already exists, choose another name.".format(new_uid) }
        else:
            ldapmanager_create_uid(new_uid, group_cn, request.json['newEntry'])
            g.add_member(group_cn, new_uid)
            if 'memberOf' in request.json['newEntry']:
                for extra_group in request.json['newEntry']['memberOf']:
                    g.add_member(extra_group, new_uid)
            new_passwd = g.reset_password(new_uid)
            result = { "failed": False,
                       "newPasswd": new_passwd }
    except Exception as e:
        return jsonify({ "failed": True, "reason": str(e) })

    return jsonify(result)

@app.route('/groups', methods=['POST'])
def group_list():
    try:
        g = Group(request.json['username'], request.json['password'])
        result = {
            "failed": False,
            "groups": { group[0]: group[1] for group in g.group_list() }
        }
    except Exception as e:
        return jsonify({"failed": True, "reason": str(e)})
    return jsonify(result)

@app.route('/reset_password/<target_user>', methods=['POST'])
def reset_password(target_user):
    try:
        g = Group(request.form['username'], request.form['password'])
        newpasswd = g.reset_password(target_user)
    except Exception as e:
        return jsonify({"failed": True, "reason": str(e)})
    return jsonify({"failed": False, "passwd": newpasswd})

if __name__ == "__main__":
    app.run(host='127.0.0.1')