# Copyright 2013 VMware, 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.

from oslo_log import log as logging
from oslo_utils import excutils

from vmware_nsx._i18n import _
from vmware_nsx.common import exceptions as nsx_exc
from vmware_nsx.db import nsxv_db
from vmware_nsx.plugins.nsx_v.vshield.common import (
    exceptions as vcns_exc)

LOG = logging.getLogger(__name__)

VSE_FWAAS_ALLOW = "accept"
VSE_FWAAS_DENY = "deny"
VSE_FWAAS_REJECT = "reject"

FWAAS_ALLOW = "allow"
FWAAS_DENY = "deny"
FWAAS_REJECT = "reject"
FWAAS_ALLOW_EXT_RULE_NAME = 'Allow To External'


class EdgeFirewallDriver(object):
    """Implementation of driver APIs for
       Edge Firewall feature configuration
    """
    def __init__(self):
        super(EdgeFirewallDriver, self).__init__()
        self._icmp_echo_application_ids = None
        self._icmpv6_multicast_application_ids = None

    def _convert_firewall_action(self, action):
        if action == FWAAS_ALLOW:
            return VSE_FWAAS_ALLOW
        if action == FWAAS_DENY:
            return VSE_FWAAS_DENY
        if action == FWAAS_REJECT:
            return VSE_FWAAS_REJECT
        msg = _("Invalid action value %s in a firewall rule") % action
        raise vcns_exc.VcnsBadRequest(resource='firewall_rule', msg=msg)

    def _restore_firewall_action(self, action):
        if action == VSE_FWAAS_ALLOW:
            return FWAAS_ALLOW
        if action == VSE_FWAAS_DENY:
            return FWAAS_DENY
        if action == VSE_FWAAS_REJECT:
            return FWAAS_REJECT
        msg = (_("Invalid action value %s in "
                 "a vshield firewall rule") % action)
        raise vcns_exc.VcnsBadRequest(resource='firewall_rule', msg=msg)

    def _get_port_range(self, min_port, max_port):
        if not min_port or min_port == 'any':
            return None
        if min_port == max_port:
            return str(min_port)

        return '%d:%d' % (min_port, max_port)

    def _get_ports_list_from_string(self, port_str):
        """Receives a string representation of the service ports,
        and return a list of integers
        Supported formats:
        Empty string - no ports
        "number" - a single port
        "num1:num2" - a range
        "num1,num2,num3" - a list
        """
        if not port_str or port_str == 'any':
            return []
        if ':' in port_str:
            min_port, sep, max_port = port_str.partition(":")
            return ["%s-%s" % (int(min_port.strip()),
                               int(max_port.strip()))]
        if ',' in port_str:
            # remove duplications (using set) and empty/non numeric entries
            ports_set = set()
            for orig_port in port_str.split(','):
                port = orig_port.strip()
                if port and port.isdigit():
                    ports_set.add(int(port))
            return sorted(list(ports_set))
        return [int(port_str.strip())]

    def _convert_firewall_rule(self, rule, index=None):
        vcns_rule = {
            "action": self._convert_firewall_action(rule['action']),
            "enabled": rule.get('enabled', True)}
        if rule.get('name'):
            vcns_rule['name'] = rule['name']
        if rule.get('description'):
            vcns_rule['description'] = rule['description']
        if rule.get('source_ip_address'):
            vcns_rule['source'] = {
                "ipAddress": rule['source_ip_address']
            }
        if rule.get('source_vnic_groups'):
            vcns_rule['source'] = {
                "vnicGroupId": rule['source_vnic_groups']
            }
        if rule.get('destination_ip_address'):
            vcns_rule['destination'] = {
                "ipAddress": rule['destination_ip_address']
            }
        if rule.get('destination_vnic_groups'):
            vcns_rule['destination'] = {
                "vnicGroupId": rule['destination_vnic_groups']
            }
        if rule.get('application'):
            vcns_rule['application'] = rule['application']
        service = {}
        if rule.get('source_port'):
            service['sourcePort'] = self._get_ports_list_from_string(
                rule['source_port'])
        if rule.get('destination_port'):
            service['port'] = self._get_ports_list_from_string(
                rule['destination_port'])
        if rule.get('protocol'):
            service['protocol'] = rule['protocol']
            if rule['protocol'] == 'icmp':
                if rule.get('icmp_type'):
                    service['icmpType'] = rule['icmp_type']
                else:
                    service['icmpType'] = 'any'
        if rule.get('ruleId'):
            vcns_rule['ruleId'] = rule.get('ruleId')
        if service:
            vcns_rule['application'] = {
                'service': [service]
            }
        if rule.get('logged'):
            vcns_rule['loggingEnabled'] = rule['logged']

        if index:
            vcns_rule['ruleTag'] = index
        return vcns_rule

    def _restore_firewall_rule(self, context, edge_id, rule):
        fw_rule = {}
        rule_binding = nsxv_db.get_nsxv_edge_firewallrule_binding_by_vseid(
            context.session, edge_id, rule['ruleId'])
        if rule_binding:
            fw_rule['id'] = rule_binding['rule_id']

        fw_rule['ruleId'] = rule['ruleId']
        if rule.get('source'):
            src = rule['source']
            fw_rule['source_ip_address'] = src['ipAddress']
            fw_rule['source_vnic_groups'] = src['vnicGroupId']

        if rule.get('destination'):
            dest = rule['destination']
            fw_rule['destination_ip_address'] = dest['ipAddress']
            fw_rule['destination_vnic_groups'] = dest['vnicGroupId']

        if 'application' in rule and 'service' in rule['application']:
            service = rule['application']['service'][0]
            fw_rule['protocol'] = service['protocol']
            if service.get('sourcePort'):
                fw_rule['source_port'] = self._get_port_range(
                    service['sourcePort'][0], service['sourcePort'][-1])
            if service.get('destination_port'):
                fw_rule['destination_port'] = self._get_port_range(
                    service['port'][0], service['port'][-1])

        fw_rule['action'] = self._restore_firewall_action(rule['action'])
        fw_rule['enabled'] = rule['enabled']
        if rule.get('name'):
            fw_rule['name'] = rule['name']
        if rule.get('description'):
            fw_rule['description'] = rule['description']
        if rule.get('loggingEnabled'):
            fw_rule['logged'] = rule['loggingEnabled']

        return fw_rule

    def _convert_firewall(self, firewall, allow_external=False):
        ruleTag = 1
        vcns_rules = []
        for rule in firewall['firewall_rule_list']:
            tag = rule.get('ruleTag', ruleTag)
            vcns_rule = self._convert_firewall_rule(rule, tag)
            vcns_rules.append(vcns_rule)
            if not rule.get('ruleTag'):
                ruleTag += 1
        if allow_external:
            # Add the allow-external rule with the latest tag
            vcns_rules.append({'name': FWAAS_ALLOW_EXT_RULE_NAME,
                               'action': "accept",
                               'enabled': True,
                               'destination': {'vnicGroupId': ["external"]},
                               'ruleTag': ruleTag})
        return {
            'featureType': "firewall_4.0",
            'globalConfig': {'tcpTimeoutEstablished': 7200},
            'firewallRules': {
                'firewallRules': vcns_rules}}

    def _restore_firewall(self, context, edge_id, response):
        res = {}
        res['firewall_rule_list'] = []
        for rule in response['firewallRules']['firewallRules']:
            if rule.get('ruleType') == 'default_policy':
                continue
            firewall_rule = self._restore_firewall_rule(context, edge_id, rule)
            res['firewall_rule_list'].append({'firewall_rule': firewall_rule})
        return res

    def _get_firewall(self, edge_id):
        try:
            return self.vcns.get_firewall(edge_id)[1]
        except vcns_exc.VcnsApiException as e:
            LOG.exception("Failed to get firewall with edge "
                          "id: %s", edge_id)
            raise e

    def _get_firewall_rule_next(self, context, edge_id, rule_vseid):
        # Return the firewall rule below 'rule_vseid'
        fw_cfg = self._get_firewall(edge_id)
        for i in range(len(fw_cfg['firewallRules']['firewallRules'])):
            rule_cur = fw_cfg['firewallRules']['firewallRules'][i]
            if str(rule_cur['ruleId']) == rule_vseid:
                if (i + 1) == len(fw_cfg['firewallRules']['firewallRules']):
                    return None
                return fw_cfg['firewallRules']['firewallRules'][i + 1]

    def get_firewall_rule(self, context, id, edge_id):
        rule_map = nsxv_db.get_nsxv_edge_firewallrule_binding(
            context.session, id, edge_id)
        if rule_map is None:
            msg = _("No rule id:%s found in the edge_firewall_binding") % id
            LOG.error(msg)
            raise vcns_exc.VcnsNotFound(
                resource='vcns_firewall_rule_bindings', msg=msg)
        vcns_rule_id = rule_map.rule_vseid
        try:
            response = self.vcns.get_firewall_rule(
                edge_id, vcns_rule_id)[1]
        except vcns_exc.VcnsApiException as e:
            LOG.exception("Failed to get firewall rule: %(rule_id)s "
                          "with edge_id: %(edge_id)s", {
                                'rule_id': id,
                                'edge_id': edge_id})
            raise e
        return self._restore_firewall_rule(context, edge_id, response)

    def get_firewall(self, context, edge_id):
        response = self._get_firewall(edge_id)
        return self._restore_firewall(context, edge_id, response)

    def delete_firewall(self, context, edge_id):
        try:
            self.vcns.delete_firewall(edge_id)
        except vcns_exc.VcnsApiException as e:
            LOG.exception("Failed to delete firewall "
                          "with edge_id:%s", edge_id)
            raise e
        nsxv_db.cleanup_nsxv_edge_firewallrule_binding(
            context.session, edge_id)

    def update_firewall_rule(self, context, id, edge_id, firewall_rule):
        rule_map = nsxv_db.get_nsxv_edge_firewallrule_binding(
            context.session, id, edge_id)
        vcns_rule_id = rule_map.rule_vseid
        fwr_req = self._convert_firewall_rule(firewall_rule)
        try:
            self.vcns.update_firewall_rule(edge_id, vcns_rule_id, fwr_req)
        except vcns_exc.VcnsApiException:
            with excutils.save_and_reraise_exception():
                LOG.exception("Failed to update firewall rule: "
                              "%(rule_id)s "
                              "with edge_id: %(edge_id)s",
                              {'rule_id': id,
                               'edge_id': edge_id})

    def delete_firewall_rule(self, context, id, edge_id):
        rule_map = nsxv_db.get_nsxv_edge_firewallrule_binding(
            context.session, id, edge_id)
        vcns_rule_id = rule_map.rule_vseid
        try:
            self.vcns.delete_firewall_rule(edge_id, vcns_rule_id)
        except vcns_exc.VcnsApiException:
            with excutils.save_and_reraise_exception():
                LOG.exception("Failed to delete firewall rule: "
                              "%(rule_id)s "
                              "with edge_id: %(edge_id)s",
                              {'rule_id': id,
                               'edge_id': edge_id})
        nsxv_db.delete_nsxv_edge_firewallrule_binding(
            context.session, id)

    def _add_rule_above(self, context, ref_rule_id, edge_id, firewall_rule):
        rule_map = nsxv_db.get_nsxv_edge_firewallrule_binding(
            context.session, ref_rule_id, edge_id)
        ref_vcns_rule_id = rule_map.rule_vseid
        fwr_req = self._convert_firewall_rule(firewall_rule)
        try:
            header = self.vcns.add_firewall_rule_above(
                edge_id, ref_vcns_rule_id, fwr_req)[0]
        except vcns_exc.VcnsApiException:
            with excutils.save_and_reraise_exception():
                LOG.exception("Failed to add firewall rule above: "
                              "%(rule_id)s with edge_id: %(edge_id)s",
                              {'rule_id': ref_vcns_rule_id,
                               'edge_id': edge_id})

        objuri = header['location']
        fwr_vseid = objuri[objuri.rfind("/") + 1:]
        map_info = {
            'rule_id': firewall_rule['id'],
            'rule_vseid': fwr_vseid,
            'edge_id': edge_id}
        nsxv_db.add_nsxv_edge_firewallrule_binding(
            context.session, map_info)

    def _add_rule_below(self, context, ref_rule_id, edge_id, firewall_rule):
        rule_map = nsxv_db.get_nsxv_edge_firewallrule_binding(
            context.session, ref_rule_id, edge_id)
        ref_vcns_rule_id = rule_map.rule_vseid
        fwr_vse_next = self._get_firewall_rule_next(
            context, edge_id, ref_vcns_rule_id)
        fwr_req = self._convert_firewall_rule(firewall_rule)
        if fwr_vse_next:
            ref_vcns_rule_id = fwr_vse_next['ruleId']
            try:
                header = self.vcns.add_firewall_rule_above(
                    edge_id, int(ref_vcns_rule_id), fwr_req)[0]
            except vcns_exc.VcnsApiException:
                with excutils.save_and_reraise_exception():
                    LOG.exception("Failed to add firewall rule above: "
                                  "%(rule_id)s with edge_id: %(edge_id)s",
                                  {'rule_id': ref_vcns_rule_id,
                                   'edge_id': edge_id})
        else:
            # append the rule at the bottom
            try:
                header = self.vcns.add_firewall_rule(
                    edge_id, fwr_req)[0]
            except vcns_exc.VcnsApiException:
                with excutils.save_and_reraise_exception():
                    LOG.exception("Failed to append a firewall rule"
                                  "with edge_id: %s", edge_id)

        objuri = header['location']
        fwr_vseid = objuri[objuri.rfind("/") + 1:]
        map_info = {
            'rule_id': firewall_rule['id'],
            'rule_vseid': fwr_vseid,
            'edge_id': edge_id
        }
        nsxv_db.add_nsxv_edge_firewallrule_binding(
            context.session, map_info)

    def insert_rule(self, context, rule_info, edge_id, fwr):
        if rule_info.get('insert_before'):
            self._add_rule_above(
                context, rule_info['insert_before'], edge_id, fwr)
        elif rule_info.get('insert_after'):
            self._add_rule_below(
                context, rule_info['insert_after'], edge_id, fwr)
        else:
            msg = _("Can't execute insert rule operation "
                    "without reference rule_id")
            raise vcns_exc.VcnsBadRequest(resource='firewall_rule', msg=msg)

    def update_firewall(self, edge_id, firewall, context, allow_external=True):
        config = self._convert_firewall(firewall,
                                        allow_external=allow_external)

        try:
            self.vcns.update_firewall(edge_id, config)
        except vcns_exc.VcnsApiException:
            with excutils.save_and_reraise_exception():
                LOG.exception("Failed to update firewall "
                              "with edge_id: %s", edge_id)
        vcns_fw_config = self._get_firewall(edge_id)
        nsxv_db.cleanup_nsxv_edge_firewallrule_binding(
            context.session, edge_id)

        self._create_rule_id_mapping(
            context, edge_id, firewall, vcns_fw_config)

    def _create_rule_id_mapping(
            self, context, edge_id, firewall, vcns_fw):
        for rule in vcns_fw['firewallRules']['firewallRules']:
            if rule.get('ruleTag'):
                index = rule['ruleTag'] - 1
                # TODO(linb):a simple filter of the retrieved rules which may
                # be created by other operations unintentionally
                if index < len(firewall['firewall_rule_list']):
                    rule_vseid = rule['ruleId']
                    rule_id = firewall['firewall_rule_list'][index].get('id')
                    if rule_id:
                        map_info = {
                            'rule_id': rule_id,
                            'rule_vseid': rule_vseid,
                            'edge_id': edge_id
                        }
                        nsxv_db.add_nsxv_edge_firewallrule_binding(
                            context.session, map_info)

    def get_icmp_echo_application_ids(self):
        # check cached list first
        # (if backend version changes, neutron should be restarted)
        if self._icmp_echo_application_ids:
            return self._icmp_echo_application_ids

        self._icmp_echo_application_ids = self.get_application_ids(
                ['ICMP Echo', 'IPv6-ICMP Echo'])
        if not self._icmp_echo_application_ids:
            raise nsx_exc.NsxResourceNotFound(
                        res_name='ICMP Echo', res_id='')
        return self._icmp_echo_application_ids

    def get_icmpv6_multicast_application_ids(self):
        # check cached list first
        # (if backend version changes, neutron should be restarted)
        if self._icmpv6_multicast_application_ids:
            return self._icmpv6_multicast_application_ids

        self._icmpv6_multicast_application_ids = self.get_application_ids(
                ['IPv6-ICMP Version 2 Multicast Listener',
                 'IPv6-ICMP Multicast Listener Query'])
        if not self._icmpv6_multicast_application_ids:
            raise nsx_exc.NsxResourceNotFound(
                        res_name='ICMPv6 Multicast', res_id='')
        return self._icmpv6_multicast_application_ids

    def get_application_ids(self, application_names):
        results = self.vcns.list_applications()
        application_ids = []
        for result in results:
            for name in application_names:
                if result['name'] == name:
                    application_ids.append(result['objectId'])

        return application_ids
