#!/usr/bin/env python3

import os
import sys
import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text      import MIMEText

def check_env (member_id):
    """ 
    Checks if wireguard is correctly installed, the script is run as 
    root and the member id is correct. 
    """
    wgInstalled = os.system("wg")
    if os.geteuid() != 0:
        print("On a besoin des droits root pour créer un accès VPN.")
        print("Relancez la commande préfixée d'un sudo.")
        raise Exception("Got root?")
    if wgInstalled != 0:
        print("Wireguard ne semble pas être installé sur votre système.")
        print("Il faudrait installer wireguard-tools et wireguard-dkms avant\
               d'utiliser ce script")
        raise Exception("Install wg")
    if member_id == 0 and member_id < 255:
        print("On est parti du principe que les IDs des membres commencent à 1.")
        print("Ah, aussi, pour le moment, on est aussi partis du principe que ça \
               s'arrête à 254.")
        print("Si on a plus de 254 membres, premièrement, FÉLICITATIONS venant\
               du Félix du passé. Par contre, il faut repenser l'adressage des \
               IPs du VPN maintenant :( Ranson du succès j'immagine.")
        raise Exception("Wrong member_id")

def gen_wg_keys (member_id, key_dir):
    """
    Generates both the private and the public wireguard key of the new member.
    """
    privkey_path = os.path.join(key_dir,"{0}.key".format(member_id))
    pubkey_path  = os.path.join(key_dir,"{0}.public".format(member_id))
    gen_key_cmd  = "wg genkey | tee {0} | wg pubkey > {1}".format(privkey_path, pubkey_path)
    if os.system(gen_key_cmd) != 0:
        print("Erreur lors de la génération des clés wireguard.")
        print("Contactez un administrateur technique en lui envoyant le message d'erreur ci-dessus.")
        sys.exit(1)
    return (privkey_path, pubkey_path)

def create_wg_config (member_id, config_dir, wg_server_privkey, pubkey_path):
    """
    Generate the wireguard configuration for this new member.
    """
    wg_filename = os.path.join (config_dir, "wg{0}.conf".format(member_id))
    with open(pubkey_path, "r") as pub_file:
        wg_peer_pubkey = pub_file.read()
        wg_config     = '''
        [Interface]
        PrivateKey = {0} 
        ListenPort = 51820

        [Peer]
        PublicKey  = {1}
        AllowedIPs = 0.0.0.0/24
        '''.format(wg_server_privkey, wg_peer_pubkey)
        with open(wgFileName, "w") as wg_file:
            wg_file.write(wg_config)

def create_if_file (member_id, config_dir):
    """
    Create and configure the new network interface for this new member.
    """
    iface_name     = "wg{0}".format(member_id)
    iface_addrv4   = "10.0.0.{0}".format(member_id)
    iface_filename = os.path.join (config_dir, "{}.conf".format(iface_name))
    iface_config   = '''
    auto {0} 
    iface {0} inet static
            address {1}
            netmask 255.255.255.0
            pre-up ip link add $IFACE type wireguard
            pre-up wg setconf $IFACE /etc/wireguard/$IFACE.conf
            post-down ip link del $IFACE
    '''.format(iface_name, iface_addrv4)
    with open(iface_filename, "w") as iface_file:
        iface_file.write(iface_config)

class Email:
    """
    Not really necessary, but I keep on forgetting most of an email arguments
    and I'm tired of debugging this class of error... Too bad we don't have any
    record type in this language.

    PS: I hate python.
    """
    def __init__(self, username, passwd, from_addr, to_addr, server):
        self.username  = username
        self.passwd    = passwd
        self.from_addr = from_addr
        self.to_addr   = to_addr
        self.server    = server

def send_mail(email, wgconfig):
    """
    Send the private key by email. 

    email:
        - username
        - passwd
        - from_addr
        - to_addr
        - server
    """
    from_addr      = 'bureau@baionet.fr'
    password       = email.passwd
    msg            = MIMEMultipart()
    msg['Subject'] = "Votre acces VPN Baionet"
    msg['From']    = email.from_addr
    msg['To']      = [email.to_addr]
    body           = '''
    blahblah, cf le wiki blahblahblah
    '''
    mail_static_text = random.choice(messages)
    msg.attach([MIMEText(body), MIMEText(config)])
    username = email.username
    server   = smtplib.SMTP(email.server)
    server.ehlo()
    server.starttls()
    server.login(email.username, email.passwd)
    server.sendmail(email.from_addr, email.to_addr, msg.as_string())
    server.quit()

# Main Function
# =============
# *************
# =============
# 1- Parse email/member id.
# 2- Génère les clés wireguard.
# 3- Crée/déploie la configuration wireguard.
# 4- Crée/déploie la nouvelle interface réseau.
# 5- Envoie la clé à l'utilisateur (email/manuellement)
if __name__ == '__main__':
    key_dir    = "/etc/wireguard/keys"
    wg_config_dir = "/etc/wireguard"
    if_config_dir = "/etc/interfaces"

    # On récupère le numéro d'adhérant et l'email d'un nouveau membre.
    member_email = input("EMail du nouveau membre: ")
    try:
        member_id = int(input("Numéro d'adhérant du nouveau membre: "))
    except Exception as e:
        print("ERREUR: Le numéro d'adhérant est en théorie un entier entre 1 et 254.")
    try:
        check_env(member_id)
    except Exception as e:
        print("ERREUR: problème d'environnement: {}".format(e))
        sys.exit(1)
    print("[+] Génération des clés wireguard")
    (privkey_path,pubkey_path) = gen_wg_keys(member_id, tmp_key_dir)
    print("[+] Création de la configuration wireguard")
    create_wg_config(member_id, wg_config_dir, privkey_path, pubkey_path)
    print("[+] Création de la nouvelle interface réseau")
    create_if_file(member_id, if_config_dir)
    print("[+] Chargement de la nouvelle interface réseau")
    os.system("systemctl restart networking") 
    print("[+] Envoi de la clé privée au nouveau membre")
    try:
        username = os.environ['SMTP_USERNAME']
        passwd   = os.environ['SMTP_PASSWD']
        server   = os.environ['SMTP_SERVER']
        email    = Email(username, passwd, "bureau@baionet.fr", member_email, "smtp://server")
        send_email(email, privkey_path, "")
    except Exception as e:
        print("ERREUR: erreur lors de l'envoi de l'email: {}".format(e))
        print("Veuillez envoyer tout ce message d'erreur à la liste bayonetek@framalistes.org")
        sys.exit(1)
    print("[+] Nettoyage")
    print("[+] DONE")