"""Implement configuration file parsing."""

# Copyright (C) 2015 Brad Cowie, Christopher Lorier and Joe Stringer.
# Copyright (C) 2015 Research and Education Advanced Network New Zealand Ltd.
# Copyright (C) 2015--2017 The Contributors
#
# 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 collections
import re

from faucet import config_parser_util
from faucet.acl import ACL
from faucet.conf import InvalidConfigError
from faucet.dp import DP
from faucet.meter import Meter
from faucet.port import Port
from faucet.router import Router
from faucet.vlan import VLAN
from faucet.watcher_conf import WatcherConf


V2_TOP_CONFS = (
    'acls',
    'dps',
    'meters',
    'routers',
    'vlans')


def dp_parser(config_file, logname):
    conf = config_parser_util.read_config(config_file, logname)
    config_hashes = None
    dps = None

    try:
        assert conf is not None, 'Config file is empty'
        assert isinstance(conf, dict), 'Config file does not have valid syntax'
        version = conf.pop('version', 2)
        assert version == 2, 'Only config version 2 is supported'
        config_hashes, dps = _config_parser_v2(config_file, logname)
        assert dps is not None, 'no DPs are not defined'

    except AssertionError as err:
        raise InvalidConfigError(err)

    return config_hashes, dps


def _dp_parser_v2(acls_conf, dps_conf, meters_conf,
                  routers_conf, vlans_conf):
    dps = []
    vid_dp = collections.defaultdict(set)

    def _get_vlan_by_identifier(dp_id, vlan_ident, vlans):
        if vlan_ident in vlans:
            return vlans[vlan_ident]
        for vlan in list(vlans.values()):
            if vlan_ident == str(vlan.vid):
                return vlan
        # Create VLAN with VID, if not defined.
        return vlans.setdefault(vlan_ident, VLAN(vlan_ident, dp_id))

    def _dp_add_vlan(dp, vlan):
        if vlan not in dp.vlans:
            dp.add_vlan(vlan)
            vid_dp[vlan.vid].add(dp.name)

            if len(vid_dp[vlan.vid]) > 1:
                assert not vlan.bgp_routerid, (
                    'DPs %s sharing a BGP speaker VLAN is unsupported' % (
                        str.join(', ', vid_dp[vlan.vid])))

    def _dp_parse_port(dp_id, p_identifier, port_conf, vlans):
        port = Port(p_identifier, dp_id, port_conf)

        if port.native_vlan is not None:
            v_identifier = port.native_vlan
            vlan = _get_vlan_by_identifier(dp_id, v_identifier, vlans)
            port.native_vlan = vlan
            vlan.add_untagged(port)
        port_tagged_vlans = [
            _get_vlan_by_identifier(dp_id, v_identifier, vlans) for v_identifier in port.tagged_vlans]
        port.tagged_vlans = port_tagged_vlans
        for vlan in port.tagged_vlans:
            vlan.add_tagged(port)
        return port

    def _dp_add_ports(dp, dp_conf, dp_id, vlans):
        ports_conf = dp_conf.get('interfaces', {})
        port_ranges_conf = dp_conf.get('interface_ranges', {})
        # as users can config port vlan by using vlan name, we store vid in
        # Port instance instead of vlan name for data consistency
        assert isinstance(ports_conf, dict), 'Invalid syntax in interface config '
        assert isinstance(port_ranges_conf, dict), 'Invalid syntax in interface ranges config'
        port_num_to_port_conf = {}
        for port_ident, port_conf in list(ports_conf.items()):
            assert isinstance(port_conf, dict), 'Invalid syntax in port config'
            if 'number' in port_conf:
                port_num = port_conf['number']
            else:
                port_num = port_ident
            try:
                port_num_to_port_conf[port_num] = (port_ident, port_conf)
            except TypeError:
                assert False, 'Invalid syntax in port config'
        for port_range, port_conf in list(port_ranges_conf.items()):
            # port range format: 1-6 OR 1-6,8-9 OR 1-3,5,7-9
            assert isinstance(port_conf, dict), 'Invalid syntax in port conig'
            port_nums = set()
            if 'number' in port_conf:
                del port_conf['number']
            for range_ in re.findall(r'(\d+-\d+)', port_range):
                start_num, end_num = [int(num) for num in range_.split('-')]
                assert start_num < end_num, (
                    'Incorrect port range (%d - %d)' % (start_num, end_num))
                port_nums.update(list(range(start_num, end_num + 1)))
                port_range = re.sub(range_, '', port_range)
            other_nums = [int(p) for p in re.findall(r'\d+', port_range)]
            port_nums.update(other_nums)
            assert len(port_nums) > 0, 'interface-ranges contain invalid config'
            for port_num in port_nums:
                if port_num in port_num_to_port_conf:
                    # port range config has lower priority than individual port config
                    for attr, value in list(port_conf.items()):
                        port_num_to_port_conf[port_num][1].setdefault(attr, value)
                else:
                    port_num_to_port_conf[port_num] = (port_num, port_conf)
        for port_num, port_conf in list(port_num_to_port_conf.values()):
            port = _dp_parse_port(dp_id, port_num, port_conf, vlans)
            dp.add_port(port)
        for vlan in list(vlans.values()):
            if vlan.get_ports():
                _dp_add_vlan(dp, vlan)

    for identifier, dp_conf in list(dps_conf.items()):
        assert isinstance(dp_conf, dict)
        dp = DP(identifier, dp_conf.get('dp_id', None), dp_conf)
        dp_id = dp.dp_id

        vlans = {}
        for vlan_ident, vlan_conf in list(vlans_conf.items()):
            vlans[vlan_ident] = VLAN(vlan_ident, dp_id, vlan_conf)
        for acl_ident, acl_conf in list(acls_conf.items()):
            acl = ACL(acl_ident, dp_id, acl_conf)
            dp.add_acl(acl_ident, acl)
        for router_ident, router_conf in list(routers_conf.items()):
            router = Router(router_ident, dp_id, router_conf)
            dp.add_router(router_ident, router)
        for meter_ident, meter_conf in list(meters_conf.items()):
            dp.meters[meter_ident] = Meter(meter_ident, dp_id, meter_conf)
        _dp_add_ports(dp, dp_conf, dp_id, vlans)
        dps.append(dp)

    for dp in dps:
        dp.finalize_config(dps)
    for dp in dps:
        dp.resolve_stack_topology(dps)

    return dps


def _config_parser_v2(config_file, logname):
    config_path = config_parser_util.dp_config_path(config_file)
    top_confs = {}
    config_hashes = {}
    dps = None
    for top_conf in V2_TOP_CONFS:
        top_confs[top_conf] = {}

    if not config_parser_util.dp_include(
            config_hashes, config_path, logname, top_confs):
        assert False, 'Error found while loading config file: %s' % config_path
    elif not top_confs['dps']:
        assert False, 'DPs not configured in file: %s' % config_path
    else:
        dps = _dp_parser_v2(
            top_confs['acls'],
            top_confs['dps'],
            top_confs['meters'],
            top_confs['routers'],
            top_confs['vlans'])
    return (config_hashes, dps)


def get_config_for_api(valves):
    """Return config as dict for all DPs."""
    config = {}
    for i in V2_TOP_CONFS:
        config[i] = {}
    for valve in list(valves.values()):
        valve_conf = valve.get_config_dict()
        for i in V2_TOP_CONFS:
            if i in valve_conf:
                config[i].update(valve_conf[i])
    return config


def watcher_parser(config_file, logname, prom_client):
    """Return Watcher instances from config."""
    conf = config_parser_util.read_config(config_file, logname)
    return _watcher_parser_v2(conf, logname, prom_client)


def _watcher_parser_v2(conf, logname, prom_client):
    logger = config_parser_util.get_logger(logname)
    result = []

    dps = {}
    for faucet_file in conf['faucet_configs']:
        _, dp_list = dp_parser(faucet_file, logname)
        if dp_list:
            for dp in dp_list:
                dps[dp.name] = dp

    dbs = conf.pop('dbs')

    for watcher_name, watcher_conf in list(conf['watchers'].items()):
        if watcher_conf.get('all_dps', False):
            watcher_dps = list(dps.keys())
        else:
            watcher_dps = watcher_conf['dps']
        # Watcher config has a list of DPs, but actually a WatcherConf is
        # created for each DP.
        # TODO: refactor watcher_conf as a container.
        for dp_name in watcher_dps:
            if dp_name not in dps:
                logger.error('DP %s in Gauge but not configured in FAUCET', dp_name)
                continue
            dp = dps[dp_name]
            watcher = WatcherConf(watcher_name, dp.dp_id, watcher_conf, prom_client)
            watcher.add_db(dbs[watcher.db])
            watcher.add_dp(dp)
            result.append(watcher)

    return result
