# Copyright (C) 2015 Nippon Telegraph and Telephone Corporation.
#
# 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.

from __future__ import absolute_import

import os
import time
import itertools

from fabric.api import local, lcd
from fabric import colors
from fabric.state import env, output
try:
    from docker import Client
except ImportError:
    from docker import APIClient as Client
import netaddr

DEFAULT_TEST_PREFIX = ''
DEFAULT_TEST_BASE_DIR = '/tmp/gobgp'
TEST_PREFIX = DEFAULT_TEST_PREFIX
TEST_BASE_DIR = DEFAULT_TEST_BASE_DIR

BGP_FSM_IDLE = 'idle'
BGP_FSM_ACTIVE = 'active'
BGP_FSM_ESTABLISHED = 'established'

BGP_ATTR_TYPE_ORIGIN = 1
BGP_ATTR_TYPE_AS_PATH = 2
BGP_ATTR_TYPE_NEXT_HOP = 3
BGP_ATTR_TYPE_MULTI_EXIT_DISC = 4
BGP_ATTR_TYPE_LOCAL_PREF = 5
BGP_ATTR_TYPE_COMMUNITIES = 8
BGP_ATTR_TYPE_ORIGINATOR_ID = 9
BGP_ATTR_TYPE_CLUSTER_LIST = 10
BGP_ATTR_TYPE_MP_REACH_NLRI = 14
BGP_ATTR_TYPE_EXTENDED_COMMUNITIES = 16

env.abort_exception = RuntimeError
output.stderr = False


def wait_for_completion(f, timeout=120):
    interval = 1
    count = 0
    while True:
        if f():
            return

        time.sleep(interval)
        count += interval
        if count >= timeout:
            raise Exception('timeout')


def try_several_times(f, t=3, s=1):
    e = Exception
    for _ in range(t):
        try:
            r = f()
        except RuntimeError as e:
            time.sleep(s)
        else:
            return r
    raise e


def get_bridges():
    return try_several_times(lambda: local("docker network ls | awk 'NR > 1{print $2}'", capture=True)).split('\n')


def get_containers():
    return try_several_times(lambda: local("docker ps -a | awk 'NR > 1 {print $NF}'", capture=True)).split('\n')


class CmdBuffer(list):
    def __init__(self, delim='\n'):
        super(CmdBuffer, self).__init__()
        self.delim = delim

    def __lshift__(self, value):
        self.append(value)

    def __str__(self):
        return self.delim.join(self)


def make_gobgp_ctn(tag='gobgp', local_gobgp_path='', from_image='osrg/quagga'):
    if local_gobgp_path == '':
        local_gobgp_path = os.getcwd()

    c = CmdBuffer()
    c << 'FROM {0}'.format(from_image)
    c << 'ADD gobgp /go/src/github.com/osrg/gobgp/'
    c << 'RUN go get github.com/osrg/gobgp/gobgpd'
    c << 'RUN go install github.com/osrg/gobgp/gobgpd'
    c << 'RUN go get github.com/osrg/gobgp/gobgp'
    c << 'RUN go install github.com/osrg/gobgp/gobgp'

    rindex = local_gobgp_path.rindex('gobgp')
    if rindex < 0:
        raise Exception('{0} seems not gobgp dir'.format(local_gobgp_path))

    workdir = local_gobgp_path[:rindex]
    with lcd(workdir):
        local('echo \'{0}\' > Dockerfile'.format(str(c)))
        local('docker build -t {0} .'.format(tag))
        local('rm Dockerfile')


class Bridge(object):
    def __init__(self, name, subnet='', with_ip=True, self_ip=False):
        self.name = name
        if TEST_PREFIX != '':
            self.name = '{0}_{1}'.format(TEST_PREFIX, name)
        self.with_ip = with_ip
        if with_ip:
            self.subnet = netaddr.IPNetwork(subnet)

            def _f():
                for host in self.subnet:
                    yield host
            self._ip_generator = _f()
            # throw away first network address
            self.next_ip_address()

        def f():
            if self.name in get_bridges():
                self.delete()
            v6 = ''
            if self.subnet.version == 6:
                v6 = '--ipv6'
            self.id = local('docker network create --driver bridge {0} --subnet {1} {2}'.format(v6, subnet, self.name), capture=True)
        try_several_times(f)

        self.self_ip = self_ip
        if self_ip:
            self.ip_addr = self.next_ip_address()
            try_several_times(lambda: local("ip addr add {0} dev {1}".format(self.ip_addr, self.name)))
        self.ctns = []

    def next_ip_address(self):
        return "{0}/{1}".format(self._ip_generator.next(),
                                self.subnet.prefixlen)

    def addif(self, ctn):
        _name = ctn.next_if_name()
        self.ctns.append(ctn)
        local("docker network connect {0} {1}".format(self.name, ctn.docker_name()))
        i = [x for x in Client(timeout=60, version='auto').inspect_network(self.id)['Containers'].values() if x['Name'] == ctn.docker_name()][0]
        if self.subnet.version == 4:
            addr = i['IPv4Address']
        else:
            addr = i['IPv6Address']
        ctn.ip_addrs.append(('eth1', addr, self.name))

    def delete(self):
        try_several_times(lambda: local("docker network rm {0}".format(self.name)))


class Container(object):
    def __init__(self, name, image):
        self.name = name
        self.image = image
        self.shared_volumes = []
        self.ip_addrs = []
        self.ip6_addrs = []
        self.is_running = False
        self.eths = []
        self.tcpdump_running = False

        if self.docker_name() in get_containers():
            self.remove()

    def docker_name(self):
        if TEST_PREFIX == DEFAULT_TEST_PREFIX:
            return self.name
        return '{0}_{1}'.format(TEST_PREFIX, self.name)

    def next_if_name(self):
        name = 'eth{0}'.format(len(self.eths) + 1)
        self.eths.append(name)
        return name

    def run(self):
        c = CmdBuffer(' ')
        c << "docker run --privileged=true"
        for sv in self.shared_volumes:
            c << "-v {0}:{1}".format(sv[0], sv[1])
        c << "--name {0} -id {1}".format(self.docker_name(), self.image)
        self.id = try_several_times(lambda: local(str(c), capture=True))
        self.is_running = True
        self.local("ip li set up dev lo")
        for line in self.local("ip a show dev eth0", capture=True).split('\n'):
            if line.strip().startswith("inet "):
                elems = [e.strip() for e in line.strip().split(' ')]
                self.ip_addrs.append(('eth0', elems[1], 'docker0'))
            elif line.strip().startswith("inet6 "):
                elems = [e.strip() for e in line.strip().split(' ')]
                self.ip6_addrs.append(('eth0', elems[1], 'docker0'))
        return 0

    def stop(self):
        ret = try_several_times(lambda: local("docker stop -t 0 " + self.docker_name(), capture=True))
        self.is_running = False
        return ret

    def remove(self):
        ret = try_several_times(lambda: local("docker rm -f " + self.docker_name(), capture=True))
        self.is_running = False
        return ret

    def pipework(self, bridge, ip_addr, intf_name=""):
        if not self.is_running:
            print colors.yellow('call run() before pipeworking')
            return
        c = CmdBuffer(' ')
        c << "pipework {0}".format(bridge.name)

        if intf_name != "":
            c << "-i {0}".format(intf_name)
        else:
            intf_name = "eth1"
        c << "{0} {1}".format(self.docker_name(), ip_addr)
        self.ip_addrs.append((intf_name, ip_addr, bridge.name))
        try_several_times(lambda: local(str(c)))

    def local(self, cmd, capture=False, stream=False, detach=False, tty=True):
        if stream:
            dckr = Client(timeout=120, version='auto')
            i = dckr.exec_create(container=self.docker_name(), cmd=cmd)
            return dckr.exec_start(i['Id'], tty=tty, stream=stream, detach=detach)
        else:
            flag = '-d' if detach else ''
            return local('docker exec {0} {1} {2}'.format(flag, self.docker_name(), cmd), capture)

    def get_pid(self):
        if self.is_running:
            cmd = "docker inspect -f '{{.State.Pid}}' " + self.docker_name()
            return int(local(cmd, capture=True))
        return -1

    def start_tcpdump(self, interface=None, filename=None, expr='tcp port 179'):
        if self.tcpdump_running:
            raise Exception('tcpdump already running')
        self.tcpdump_running = True
        if not interface:
            interface = "eth0"
        if not filename:
            filename = '{0}.dump'.format(interface)
        self.local("tcpdump -U -i {0} -w {1}/{2} {3}".format(interface, self.shared_volumes[0][1], filename, expr), detach=True)
        return '{0}/{1}'.format(self.shared_volumes[0][0], filename)

    def stop_tcpdump(self):
        self.local("pkill tcpdump")
        self.tcpdump_running = False


class BGPContainer(Container):

    WAIT_FOR_BOOT = 1
    RETRY_INTERVAL = 5

    def __init__(self, name, asn, router_id, ctn_image_name):
        self.config_dir = '/'.join((TEST_BASE_DIR, TEST_PREFIX, name))
        local('if [ -e {0} ]; then rm -rf {0}; fi'.format(self.config_dir))
        local('mkdir -p {0}'.format(self.config_dir))
        local('chmod 777 {0}'.format(self.config_dir))
        self.asn = asn
        self.router_id = router_id
        self.peers = {}
        self.routes = {}
        self.policies = {}
        super(BGPContainer, self).__init__(name, ctn_image_name)

    def __repr__(self):
        return str({'name': self.name, 'asn': self.asn, 'router_id': self.router_id})

    def run(self):
        self.create_config()
        super(BGPContainer, self).run()
        return self.WAIT_FOR_BOOT

    def peer_name(self, peer):
        if peer not in self.peers:
            raise Exception('not found peer {0}'.format(peer.router_id))
        name = self.peers[peer]['interface']
        if name == '':
            name = self.peers[peer]['neigh_addr'].split('/')[0]
        return name

    def add_peer(self, peer, passwd=None, vpn=False, is_rs_client=False,
                 policies=None, passive=False,
                 is_rr_client=False, cluster_id=None,
                 flowspec=False, bridge='', reload_config=True, as2=False,
                 graceful_restart=None, local_as=None, prefix_limit=None,
                 v6=False, llgr=None, vrf='', interface=''):
        neigh_addr = ''
        local_addr = ''
        it = itertools.product(self.ip_addrs, peer.ip_addrs)
        if v6:
            it = itertools.product(self.ip6_addrs, peer.ip6_addrs)

        if interface == '':
            for me, you in it:
                if bridge != '' and bridge != me[2]:
                    continue
                if me[2] == you[2]:
                    neigh_addr = you[1]
                    local_addr = me[1]
                    if v6:
                        addr, mask = local_addr.split('/')
                        local_addr = "{0}%{1}/{2}".format(addr, me[0], mask)
                    break

            if neigh_addr == '':
                raise Exception('peer {0} seems not ip reachable'.format(peer))

        if not policies:
            policies = {}

        self.peers[peer] = {'neigh_addr': neigh_addr,
                            'interface': interface,
                            'passwd': passwd,
                            'vpn': vpn,
                            'flowspec': flowspec,
                            'is_rs_client': is_rs_client,
                            'is_rr_client': is_rr_client,
                            'cluster_id': cluster_id,
                            'policies': policies,
                            'passive': passive,
                            'local_addr': local_addr,
                            'as2': as2,
                            'graceful_restart': graceful_restart,
                            'local_as': local_as,
                            'prefix_limit': prefix_limit,
                            'llgr': llgr,
                            'vrf': vrf}
        if self.is_running and reload_config:
            self.create_config()
            self.reload_config()

    def del_peer(self, peer, reload_config=True):
        del self.peers[peer]
        if self.is_running and reload_config:
            self.create_config()
            self.reload_config()

    def disable_peer(self, peer):
        raise Exception('implement disable_peer() method')

    def enable_peer(self, peer):
        raise Exception('implement enable_peer() method')

    def log(self):
        return local('cat {0}/*.log'.format(self.config_dir), capture=True)

    def add_route(self, route, rf='ipv4', attribute=None, aspath=None,
                  community=None, med=None, extendedcommunity=None,
                  nexthop=None, matchs=None, thens=None,
                  local_pref=None, reload_config=True):
        self.routes[route] = {'prefix': route,
                              'rf': rf,
                              'attr': attribute,
                              'next-hop': nexthop,
                              'as-path': aspath,
                              'community': community,
                              'med': med,
                              'local-pref': local_pref,
                              'extended-community': extendedcommunity,
                              'matchs': matchs,
                              'thens': thens}
        if self.is_running and reload_config:
            self.create_config()
            self.reload_config()

    def add_policy(self, policy, peer, typ, default='accept', reload_config=True):
        self.set_default_policy(peer, typ, default)
        self.define_policy(policy)
        self.assign_policy(peer, policy, typ)
        if self.is_running and reload_config:
            self.create_config()
            self.reload_config()

    def set_default_policy(self, peer, typ, default):
        if typ in ['in', 'out', 'import', 'export'] and default in ['reject', 'accept']:
            if 'default-policy' not in self.peers[peer]:
                self.peers[peer]['default-policy'] = {}
            self.peers[peer]['default-policy'][typ] = default
        else:
            raise Exception('wrong type or default')

    def define_policy(self, policy):
        self.policies[policy['name']] = policy

    def assign_policy(self, peer, policy, typ):
        if peer not in self.peers:
            raise Exception('peer {0} not found'.format(peer.name))
        name = policy['name']
        if name not in self.policies:
            raise Exception('policy {0} not found'.format(name))
        self.peers[peer]['policies'][typ] = policy

    def get_local_rib(self, peer, rf):
        raise Exception('implement get_local_rib() method')

    def get_global_rib(self, rf):
        raise Exception('implement get_global_rib() method')

    def get_neighbor_state(self, peer_id):
        raise Exception('implement get_neighbor() method')

    def get_reachablily(self, prefix, timeout=20):
        version = netaddr.IPNetwork(prefix).version
        addr = prefix.split('/')[0]
        if version == 4:
            ping_cmd = 'ping'
        elif version == 6:
            ping_cmd = 'ping6'
        else:
            raise Exception('unsupported route family: {0}'.format(version))
        cmd = '/bin/bash -c "/bin/{0} -c 1 -w 1 {1} | xargs echo"'.format(ping_cmd, addr)
        interval = 1
        count = 0
        while True:
            res = self.local(cmd, capture=True)
            print colors.yellow(res)
            if '1 packets received' in res and '0% packet loss':
                break
            time.sleep(interval)
            count += interval
            if count >= timeout:
                raise Exception('timeout')
        return True

    def wait_for(self, expected_state, peer, timeout=120):
        interval = 1
        count = 0
        while True:
            state = self.get_neighbor_state(peer)
            y = colors.yellow
            print y("{0}'s peer {1} state: {2}".format(self.router_id,
                                                       peer.router_id,
                                                       state))
            if state == expected_state:
                return

            time.sleep(interval)
            count += interval
            if count >= timeout:
                raise Exception('timeout')

    def add_static_route(self, network, next_hop):
        cmd = '/sbin/ip route add {0} via {1}'.format(network, next_hop)
        self.local(cmd)

    def set_ipv6_forward(self):
        cmd = 'sysctl -w net.ipv6.conf.all.forwarding=1'
        self.local(cmd)

    def create_config(self):
        raise Exception('implement create_config() method')

    def reload_config(self):
        raise Exception('implement reload_config() method')


class OSPFContainer(Container):
    WAIT_FOR_BOOT = 1

    def __init__(self, name, ctn_image_name):
        self.config_dir = '/'.join((TEST_BASE_DIR, TEST_PREFIX, name))
        local('if [ -e {0} ]; then rm -rf {0}; fi'.format(self.config_dir))
        local('mkdir -p {0}'.format(self.config_dir))
        local('chmod 777 {0}'.format(self.config_dir))

        # Example:
        # networks = {
        #     '192.168.1.0/24': '0.0.0.0',  # <network>: <area>
        # }
        self.networks = {}
        super(OSPFContainer, self).__init__(name, ctn_image_name)

    def __repr__(self):
        return str({'name': self.name, 'networks': self.networks})

    def run(self):
        self.create_config()
        super(OSPFContainer, self).run()
        return self.WAIT_FOR_BOOT

    def create_config(self):
        raise NotImplementedError