# 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 fabric.api import local, lcd
from fabric import colors
from fabric.utils import indent
from fabric.state import env

import netaddr
import os
import time
import itertools

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

BGP_FSM_IDLE = 'BGP_FSM_IDLE'
BGP_FSM_ACTIVE = 'BGP_FSM_ACTIVE'
BGP_FSM_ESTABLISHED = 'BGP_FSM_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_MP_REACH_NLRI = 14
BGP_ATTR_TYPE_EXTENDED_COMMUNITIES = 16

env.abort_exception = RuntimeError

def try_several_times(f, t=3, s=1):
    e = None
    for i 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("brctl show | awk 'NR > 1{print $1}'", 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()
            local("ip link add {0} type bridge".format(self.name))
        try_several_times(f)
        try_several_times(lambda : local("ip link set up dev {0}".format(self.name)))

        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)
        if self.with_ip:

            ctn.pipework(self, self.next_ip_address(), name)
        else:
            ctn.pipework(self, '0/0', name)

    def delete(self):
        try_several_times(lambda : local("ip link set down dev {0}".format(self.name)))
        try_several_times(lambda : local("ip link delete {0} type bridge".format(self.name)))


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

        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'))
        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, flag=''):
        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


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 -r {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 add_peer(self, peer, passwd=None, evpn=False, is_rs_client=False,
                 policies=None, passive=False,
                 is_rr_client=False, cluster_id=None,
                 flowspec=False, bridge='', reload_config=True):
        neigh_addr = ''
        local_addr = ''
        for me, you in itertools.product(self.ip_addrs, peer.ip_addrs):
            if bridge != '' and bridge != me[2]:
                continue
            if me[2] == you[2]:
                neigh_addr = you[1]
                local_addr = me[1]
                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,
                            'passwd': passwd,
                            'evpn': evpn,
                            '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}
        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=None, reload_config=True):
        self.policies[policy['name']] = policy
        if peer in self.peers:
            self.peers[peer]['policies'][policy['name']] = policy
        if self.is_running and reload_config:
            self.create_config()
            self.reload_config()

    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')