#! /usr/bin/python
# Copyright (C) 2015 Nicira, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import argparse
import atexit
import getpass
import json
import os
import re
import shlex
import subprocess
import sys
import time
import uuid

import ovs.dirs
import ovs.util
import ovs.daemon
import ovs.unixctl.server
import ovs.vlog

from neutronclient.v2_0 import client
from flask import Flask, jsonify
from flask import request, abort

app = Flask(__name__)
vlog = ovs.vlog.Vlog("ovn-docker-underlay-driver")

AUTH_STRATEGY = ""
AUTH_URL = ""
ENDPOINT_URL = ""
OVN_BRIDGE = ""
PASSWORD = ""
PLUGIN_DIR = "/etc/docker/plugins"
PLUGIN_FILE = "/etc/docker/plugins/openvswitch.spec"
TENANT_ID = ""
USERNAME = ""
VIF_ID = ""


def call_popen(cmd):
    child = subprocess.Popen(cmd, stdout=subprocess.PIPE)
    output = child.communicate()
    if child.returncode:
        raise RuntimeError("Fatal error executing %s" % (cmd))
    if len(output) == 0 or output[0] == None:
        output = ""
    else:
        output = output[0].strip()
    return output


def call_prog(prog, args_list):
    cmd = [prog, "--timeout=5", "-vconsole:off"] + args_list
    return call_popen(cmd)


def ovs_vsctl(*args):
    return call_prog("ovs-vsctl", list(args))


def cleanup():
    if os.path.isfile(PLUGIN_FILE):
        os.remove(PLUGIN_FILE)


def ovn_init_underlay(args):
    global USERNAME, PASSWORD, TENANT_ID, AUTH_URL, AUTH_STRATEGY, VIF_ID
    global OVN_BRIDGE

    if not args.bridge:
        sys.exit("OVS bridge name not provided")
    OVN_BRIDGE = args.bridge

    VIF_ID = os.environ.get('OS_VIF_ID', '')
    if not VIF_ID:
        sys.exit("env OS_VIF_ID not set")
    USERNAME = os.environ.get('OS_USERNAME', '')
    if not USERNAME:
        sys.exit("env OS_USERNAME not set")
    TENANT_ID = os.environ.get('OS_TENANT_ID', '')
    if not TENANT_ID:
        sys.exit("env OS_TENANT_ID not set")
    AUTH_URL = os.environ.get('OS_AUTH_URL', '')
    if not AUTH_URL:
        sys.exit("env OS_AUTH_URL not set")
    AUTH_STRATEGY = "keystone"

    PASSWORD = os.environ.get('OS_PASSWORD', '')
    if not PASSWORD:
        PASSWORD = getpass.getpass()


def prepare():
    parser = argparse.ArgumentParser()
    parser.add_argument('--bridge', help="The Bridge to which containers "
                        "interfaces connect to.")

    ovs.vlog.add_args(parser)
    ovs.daemon.add_args(parser)
    args = parser.parse_args()
    ovs.vlog.handle_args(args)
    ovs.daemon.handle_args(args)
    ovn_init_underlay(args)

    if not os.path.isdir(PLUGIN_DIR):
        os.makedirs(PLUGIN_DIR)

    ovs.daemon.daemonize()
    try:
        fo = open(PLUGIN_FILE, "w")
        fo.write("tcp://127.0.0.1:5000")
        fo.close()
    except Exception as e:
        ovs.util.ovs_fatal(0, "Failed to write to spec file (%s)" % str(e),
                           vlog)

    atexit.register(cleanup)


@app.route('/Plugin.Activate', methods=['POST'])
def plugin_activate():
    return jsonify({"Implements": ["NetworkDriver"]})


@app.route('/NetworkDriver.GetCapabilities', methods=['POST'])
def get_capability():
    return jsonify({"Scope": "global"})


@app.route('/NetworkDriver.DiscoverNew', methods=['POST'])
def new_discovery():
    return jsonify({})


@app.route('/NetworkDriver.DiscoverDelete', methods=['POST'])
def delete_discovery():
    return jsonify({})


def neutron_login():
    try:
        neutron = client.Client(username=USERNAME,
                                password=PASSWORD,
                                tenant_id=TENANT_ID,
                                auth_url=AUTH_URL,
                                endpoint_url=ENDPOINT_URL,
                                auth_strategy=AUTH_STRATEGY)
    except Exception as e:
        raise RuntimeError("Failed to login into Neutron(%s)" % str(e))
    return neutron


def get_networkuuid_by_name(neutron, name):
    param = {'fields': 'id', 'name': name}
    ret = neutron.list_networks(**param)
    if len(ret['networks']) > 1:
        raise RuntimeError("More than one network for the given name")
    elif len(ret['networks']) == 0:
        network = None
    else:
        network = ret['networks'][0]['id']
    return network


def get_subnetuuid_by_name(neutron, name):
    param = {'fields': 'id', 'name': name}
    ret = neutron.list_subnets(**param)
    if len(ret['subnets']) > 1:
        raise RuntimeError("More than one subnet for the given name")
    elif len(ret['subnets']) == 0:
        subnet = None
    else:
        subnet = ret['subnets'][0]['id']
    return subnet


@app.route('/NetworkDriver.CreateNetwork', methods=['POST'])
def create_network():
    if not request.data:
        abort(400)

    data = json.loads(request.data)

    # NetworkID will have docker generated network uuid and it
    # becomes 'name' in a neutron network record.
    network = data.get("NetworkID", "")
    if not network:
        abort(400)

    # Limit subnet handling to ipv4 till ipv6 usecase is clear.
    ipv4_data = data.get("IPv4Data", "")
    if not ipv4_data:
        error = "create_network: No ipv4 subnet provided"
        return jsonify({'Err': error})

    subnet = ipv4_data[0].get("Pool", "")
    if not subnet:
        error = "create_network: no subnet in ipv4 data from libnetwork"
        return jsonify({'Err': error})

    gateway_ip = ipv4_data[0].get("Gateway", "").rsplit('/', 1)[0]
    if not gateway_ip:
        error = "create_network: no gateway in ipv4 data from libnetwork"
        return jsonify({'Err': error})

    try:
        neutron = neutron_login()
    except Exception as e:
        error = "create_network: neutron login. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        if get_networkuuid_by_name(neutron, network):
            error = "create_network: network has already been created"
            return jsonify({'Err': error})
    except Exception as e:
        error = "create_network: neutron network uuid by name. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        body = {'network': {'name': network, 'admin_state_up': True}}
        ret = neutron.create_network(body)
        network_id = ret['network']['id']
    except Exception as e:
        error = "create_network: neutron net-create call. (%s)" % str(e)
        return jsonify({'Err': error})

    subnet_name = "docker-%s" % (network)

    try:
        body = {'subnet': {'network_id': network_id,
                           'ip_version': 4,
                           'cidr': subnet,
                           'gateway_ip': gateway_ip,
                           'name': subnet_name}}
        created_subnet = neutron.create_subnet(body)
    except Exception as e:
        error = "create_network: neutron subnet-create call. (%s)" % str(e)
        return jsonify({'Err': error})

    return jsonify({})


@app.route('/NetworkDriver.DeleteNetwork', methods=['POST'])
def delete_network():
    if not request.data:
        abort(400)

    data = json.loads(request.data)

    nid = data.get("NetworkID", "")
    if not nid:
        abort(400)

    try:
        neutron = neutron_login()
    except Exception as e:
        error = "delete_network: neutron login. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        network = get_networkuuid_by_name(neutron, nid)
        if not network:
            error = "delete_network: failed in network by name. (%s)" % (nid)
            return jsonify({'Err': error})
    except Exception as e:
        error = "delete_network: network uuid by name. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        neutron.delete_network(network)
    except Exception as e:
        error = "delete_network: neutron net-delete. (%s)" % str(e)
        return jsonify({'Err': error})

    return jsonify({})


def reserve_vlan():
    reserved_vlan = 0
    vlans = ovs_vsctl("--if-exists", "get", "Open_vSwitch", ".",
                      "external_ids:vlans").strip('"')
    if not vlans:
        reserved_vlan = 1
        ovs_vsctl("set", "Open_vSwitch", ".",
                  "external_ids:vlans=" + str(reserved_vlan))
        return reserved_vlan

    vlan_set = str(vlans).split(',')

    for vlan in range(1, 4095):
        if str(vlan) not in vlan_set:
            vlan_set.append(str(vlan))
            reserved_vlan = vlan
            vlans = re.sub(r'[ \[\]\']', '', str(vlan_set))
            ovs_vsctl("set", "Open_vSwitch", ".",
                      "external_ids:vlans=" + vlans)
            return reserved_vlan

    if not reserved_vlan:
        raise RuntimeError("No more vlans available on this host")


def unreserve_vlan(reserved_vlan):
    vlans = ovs_vsctl("--if-exists", "get", "Open_vSwitch", ".",
                      "external_ids:vlans").strip('"')
    if not vlans:
        return

    vlan_set = str(vlans).split(',')
    if str(reserved_vlan) not in vlan_set:
        return

    vlan_set.remove(str(reserved_vlan))
    vlans = re.sub(r'[ \[\]\']', '', str(vlan_set))
    if vlans:
        ovs_vsctl("set", "Open_vSwitch", ".", "external_ids:vlans=" + vlans)
    else:
        ovs_vsctl("remove", "Open_vSwitch", ".", "external_ids", "vlans")


def create_port_underlay(neutron, network, eid, ip_address, mac_address):
    reserved_vlan = reserve_vlan()
    if mac_address:
        body = {'port': {'network_id': network,
                         'binding:profile': {'parent_name': VIF_ID,
                                             'tag': int(reserved_vlan)},
                         'mac_address': mac_address,
                         'fixed_ips': [{'ip_address': ip_address}],
                         'name': eid,
                         'admin_state_up': True}}
    else:
        body = {'port': {'network_id': network,
                         'binding:profile': {'parent_name': VIF_ID,
                                             'tag': int(reserved_vlan)},
                         'fixed_ips': [{'ip_address': ip_address}],
                         'name': eid,
                         'admin_state_up': True}}

    try:
        ret = neutron.create_port(body)
        mac_address = ret['port']['mac_address']
    except Exception as e:
        unreserve_vlan(reserved_vlan)
        raise RuntimeError("Failed in creation of neutron port (%s)." % str(e))

    ovs_vsctl("set", "Open_vSwitch", ".",
              "external_ids:" + eid + "_vlan=" + str(reserved_vlan))

    return mac_address


def get_endpointuuid_by_name(neutron, name):
    param = {'fields': 'id', 'name': name}
    ret = neutron.list_ports(**param)
    if len(ret['ports']) > 1:
        raise RuntimeError("More than one endpoint for the given name")
    elif len(ret['ports']) == 0:
        endpoint = None
    else:
        endpoint = ret['ports'][0]['id']
    return endpoint


@app.route('/NetworkDriver.CreateEndpoint', methods=['POST'])
def create_endpoint():
    if not request.data:
        abort(400)

    data = json.loads(request.data)

    nid = data.get("NetworkID", "")
    if not nid:
        abort(400)

    eid = data.get("EndpointID", "")
    if not eid:
        abort(400)

    interface = data.get("Interface", "")
    if not interface:
        error = "create_endpoint: no interfaces supplied by libnetwork"
        return jsonify({'Err': error})

    ip_address_and_mask = interface.get("Address", "")
    if not ip_address_and_mask:
        error = "create_endpoint: ip address not provided by libnetwork"
        return jsonify({'Err': error})

    ip_address = ip_address_and_mask.rsplit('/', 1)[0]
    mac_address_input = interface.get("MacAddress", "")
    mac_address_output = ""

    try:
        neutron = neutron_login()
    except Exception as e:
        error = "create_endpoint: neutron login. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        endpoint = get_endpointuuid_by_name(neutron, eid)
        if endpoint:
            error = "create_endpoint: Endpoint has already been created"
            return jsonify({'Err': error})
    except Exception as e:
        error = "create_endpoint: endpoint uuid by name. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        network = get_networkuuid_by_name(neutron, nid)
        if not network:
            error = "Failed to get neutron network record for (%s)" % (nid)
            return jsonify({'Err': error})
    except Exception as e:
        error = "create_endpoint: network uuid by name. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        mac_address = create_port_underlay(neutron, network, eid, ip_address,
                                           mac_address_input)
    except Exception as e:
        error = "create_endpoint: neutron port-create (%s)" % (str(e))
        return jsonify({'Err': error})

    if not mac_address_input:
        mac_address_output = mac_address

    return jsonify({"Interface": {
                                    "Address": "",
                                    "AddressIPv6": "",
                                    "MacAddress": mac_address_output
                                    }})


@app.route('/NetworkDriver.EndpointOperInfo', methods=['POST'])
def show_endpoint():
    if not request.data:
        abort(400)

    data = json.loads(request.data)

    nid = data.get("NetworkID", "")
    if not nid:
        abort(400)

    eid = data.get("EndpointID", "")
    if not eid:
        abort(400)

    try:
        neutron = neutron_login()
    except Exception as e:
        error = "%s" % (str(e))
        return jsonify({'Err': error})

    try:
        endpoint = get_endpointuuid_by_name(neutron, eid)
        if not endpoint:
            error = "show_endpoint: Failed to get endpoint by name"
            return jsonify({'Err': error})
    except Exception as e:
        error = "show_endpoint: get endpoint by name. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        ret = neutron.show_port(endpoint)
        mac_address = ret['port']['mac_address']
        ip_address = ret['port']['fixed_ips'][0]['ip_address']
    except Exception as e:
        error = "show_endpoint: show port (%s)" % (str(e))
        return jsonify({'Err': error})

    veth_outside = eid[0:15]
    return jsonify({"Value": {"ip_address": ip_address,
                              "mac_address": mac_address,
                              "veth_outside": veth_outside
                              }})


@app.route('/NetworkDriver.DeleteEndpoint', methods=['POST'])
def delete_endpoint():
    if not request.data:
        abort(400)

    data = json.loads(request.data)

    nid = data.get("NetworkID", "")
    if not nid:
        abort(400)

    eid = data.get("EndpointID", "")
    if not eid:
        abort(400)

    try:
        neutron = neutron_login()
    except Exception as e:
        error = "delete_endpoint: neutron login (%s)" % (str(e))
        return jsonify({'Err': error})

    endpoint = get_endpointuuid_by_name(neutron, eid)
    if not endpoint:
        return jsonify({})

    reserved_vlan = ovs_vsctl("--if-exists", "get", "Open_vSwitch", ".",
                              "external_ids:" + eid + "_vlan").strip('"')
    if reserved_vlan:
        unreserve_vlan(reserved_vlan)
        ovs_vsctl("remove", "Open_vSwitch", ".", "external_ids",
                  eid + "_vlan")

    try:
        neutron.delete_port(endpoint)
    except Exception as e:
        error = "delete_endpoint: neutron port-delete. (%s)" % (str(e))
        return jsonify({'Err': error})

    return jsonify({})


@app.route('/NetworkDriver.Join', methods=['POST'])
def network_join():
    if not request.data:
        abort(400)

    data = json.loads(request.data)

    nid = data.get("NetworkID", "")
    if not nid:
        abort(400)

    eid = data.get("EndpointID", "")
    if not eid:
        abort(400)

    sboxkey = data.get("SandboxKey", "")
    if not sboxkey:
        abort(400)

    # sboxkey is of the form: /var/run/docker/netns/CONTAINER_ID
    vm_id = sboxkey.rsplit('/')[-1]

    try:
        neutron = neutron_login()
    except Exception as e:
        error = "network_join: neutron login. (%s)" % (str(e))
        return jsonify({'Err': error})

    subnet_name = "docker-%s" % (nid)
    try:
        subnet = get_subnetuuid_by_name(neutron, subnet_name)
        if not subnet:
            error = "network_join: can't find subnet in neutron"
            return jsonify({'Err': error})
    except Exception as e:
        error = "network_join: subnet uuid by name. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        ret = neutron.show_subnet(subnet)
        gateway_ip = ret['subnet']['gateway_ip']
        if not gateway_ip:
            error = "network_join: no gateway_ip for the subnet"
            return jsonify({'Err': error})
    except Exception as e:
        error = "network_join: neutron show subnet. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        endpoint = get_endpointuuid_by_name(neutron, eid)
        if not endpoint:
            error = "network_join: Failed to get endpoint by name"
            return jsonify({'Err': error})
    except Exception as e:
        error = "network_join: neutron endpoint by name. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        ret = neutron.show_port(endpoint)
        mac_address = ret['port']['mac_address']
    except Exception as e:
        error = "network_join: neutron show port. (%s)" % (str(e))
        return jsonify({'Err': error})

    veth_outside = eid[0:15]
    veth_inside = eid[0:13] + "_c"
    command = "ip link add %s type veth peer name %s" \
              % (veth_inside, veth_outside)
    try:
        call_popen(shlex.split(command))
    except Exception as e:
        error = "network_join: failed to create veth pair. (%s)" % (str(e))
        return jsonify({'Err': error})

    command = "ip link set dev %s address %s" \
              % (veth_inside, mac_address)

    try:
        call_popen(shlex.split(command))
    except Exception as e:
        error = "network_join: failed to set veth mac address. (%s)" % (str(e))
        return jsonify({'Err': error})

    command = "ip link set %s up" % (veth_outside)

    try:
        call_popen(shlex.split(command))
    except Exception as e:
        error = "network_join: failed to up the veth iface. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        reserved_vlan = ovs_vsctl("--if-exists", "get", "Open_vSwitch", ".",
                                  "external_ids:" + eid + "_vlan").strip('"')
        if not reserved_vlan:
            error = "network_join: no reserved vlan for this endpoint"
            return jsonify({'Err': error})
        ovs_vsctl("add-port", OVN_BRIDGE, veth_outside, "tag=" + reserved_vlan)
    except Exception as e:
        error = "network_join: failed to create a OVS port. (%s)" % (str(e))
        return jsonify({'Err': error})

    return jsonify({"InterfaceName": {
                                        "SrcName": veth_inside,
                                        "DstPrefix": "eth"
                                     },
                    "Gateway": gateway_ip,
                    "GatewayIPv6": ""})


@app.route('/NetworkDriver.Leave', methods=['POST'])
def network_leave():
    if not request.data:
        abort(400)

    data = json.loads(request.data)

    nid = data.get("NetworkID", "")
    if not nid:
        abort(400)

    eid = data.get("EndpointID", "")
    if not eid:
        abort(400)

    veth_outside = eid[0:15]
    command = "ip link delete %s" % (veth_outside)
    try:
        call_popen(shlex.split(command))
    except Exception as e:
        error = "network_leave: failed to delete veth pair. (%s)" % (str(e))
        return jsonify({'Err': error})

    try:
        ovs_vsctl("--if-exists", "del-port", veth_outside)
    except Exception as e:
        error = "network_leave: Failed to delete port (%s)" % (str(e))
        return jsonify({'Err': error})

    return jsonify({})

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