import json
import uuid
from django.utils.translation import gettext as _
from django.conf import settings


CA_CERT = settings.OPENVPN_CA

CONFIG_OS = (
    ("windows", _("Windows")),
    ("android", _("Android")),
    ("ubuntu", _("Ubuntu")),
    ("osx", _("OS X")),
    ("ios", _("iOS")),
    ("chromeos", _("Chrome OS")),
    ("freebox", _("Freebox")),
    ("other", _("Other / GNU/Linux")),
)

PROTOCOLS = (
    ("udp", _("UDP (default)")),
    ("tcp", _("TCP")),
    ("udpl", _("UDP (low MTU)")),
)


def _make_onc(username, name, hostname, port, protocol, http_proxy=None, ipv6=True):
    cert_id = "{%s}" % uuid.uuid4()
    vpn_id = "{%s}" % uuid.uuid4()

    openvpn_config = {
        "ServerCARef": cert_id,
        "ClientCertType": "None",
        "CompLZO": "true",
        "Port": port,
        "Proto": protocol,
        "ServerPollTimeout": 10,
        "NsCertType": "server",
        "Username": username,
    }
    cert = {
        "GUID": cert_id,
        "Type": "Authority",
        "X509": CA_CERT.strip(),
    }
    vpn = {
        "GUID": vpn_id,
        "Name": name,
        "Type": "VPN",
        "VPN": {
            "Type": "OpenVPN",
            "Host": hostname,
            "OpenVPN": openvpn_config,
        },
    }

    return json.dumps(
        {
            "type": "UnencryptedConfiguration",
            "Certificates": [cert],
            "NetworkConfigurations": [vpn],
        },
        indent=2,
    )


def make_config(username, gw_name, os, protocol, http_proxy=None, ipv6=True):

    use_frag = protocol == "udpl" and os != "ios"
    ipv6 = ipv6 and (os != "freebox")
    http_proxy = http_proxy if protocol == "tcp" else None
    resolvconf = os in ("ubuntu", "other")

    openvpn_proto = {"udp": "udp", "udpl": "udp", "tcp": "tcp"}
    openvpn_ports = {"udp": 1196, "udpl": 1194, "tcp": 443}

    hostname = "gw.%s.204vpn.net" % gw_name
    port = openvpn_ports[protocol]
    proto = openvpn_proto[protocol]

    if os == "chromeos":
        name = "CCrypto VPN"
        if gw_name != "random":
            name += " " + gw_name.upper()
        return _make_onc(username, name, hostname, port, proto, http_proxy, ipv6)

    remote = str(hostname)
    remote += " " + str(port)
    remote += " " + proto

    config = """\
# +----------------------------+
# | Cognitive Cryptography VPN |
# |  https://vpn.ccrypto.org/  |
# +----------------------------+

verb 4
client
tls-client
script-security 2
remote-cert-tls server
dev tun
nobind
persist-key
persist-tun
comp-lzo yes

remote {remote}

auth-user-pass

""".format(
        remote=remote
    )

    if os == "ios":
        # i'd like to note here how much i hate OpenVPN
        config += "redirect-gateway ipv6\n"
        config += 'push "route 0.0.0.0 128.0.0.0"\n'
        config += 'push "route 128.0.0.0 128.0.0.0"\n'
    else:
        config += "redirect-gateway def1\n"
        if ipv6:
            config += "tun-ipv6\n"
            config += "route-ipv6 2000::/3\n"
            config += "\n"

    if use_frag:
        config += "fragment 1300\n"
        config += "mssfix 1300\n"
        config += "\n"

    if http_proxy:
        config += "http-proxy %s\n\n" % http_proxy

    if resolvconf:
        config += "up /etc/openvpn/update-resolv-conf\n"
        config += "down /etc/openvpn/update-resolv-conf\n"
        config += "\n"

    if os == "windows":
        config += "register-dns\n"
        config += "\n"

    config += "<ca>\n%s\n</ca>" % CA_CERT

    if os == "windows":
        config = config.replace("\n", "\r\n")

    return config