from django.db.models import Q

from .choices import FHRPGroupProtocolChoices, IPAddressRoleChoices

# BGP ASN bounds
BGP_ASN_MIN = 1
BGP_ASN_MAX = 2**32 - 1


#
# VRFs
#

# Per RFC 4364 section 4.2, a route distinguisher may be encoded as one of the following:
#   * Type 0 (16-bit AS number : 32-bit integer)
#   * Type 1 (32-bit IPv4 address : 16-bit integer)
#   * Type 2 (32-bit AS number : 16-bit integer)
# 21 characters are sufficient to convey the longest possible string value (255.255.255.255:65535)
# Also used for RouteTargets
VRF_RD_MAX_LENGTH = 21


#
# Prefixes
#

PREFIX_LENGTH_MIN = 1
PREFIX_LENGTH_MAX = 127  # IPv6


#
# IPAddresses
#

IPADDRESS_ASSIGNMENT_MODELS = Q(
    Q(app_label='dcim', model='interface') |
    Q(app_label='ipam', model='fhrpgroup') |
    Q(app_label='virtualization', model='vminterface')
)

IPADDRESS_MASK_LENGTH_MIN = 1
IPADDRESS_MASK_LENGTH_MAX = 128  # IPv6

IPADDRESS_ROLES_NONUNIQUE = (
    # IPAddress roles which are exempt from unique address enforcement
    IPAddressRoleChoices.ROLE_ANYCAST,
    IPAddressRoleChoices.ROLE_VIP,
    IPAddressRoleChoices.ROLE_VRRP,
    IPAddressRoleChoices.ROLE_HSRP,
    IPAddressRoleChoices.ROLE_GLBP,
    IPAddressRoleChoices.ROLE_CARP,
)


#
# FHRP groups
#

FHRPGROUPASSIGNMENT_PRIORITY_MIN = 0
FHRPGROUPASSIGNMENT_PRIORITY_MAX = 255

FHRP_PROTOCOL_ROLE_MAPPINGS = {
    FHRPGroupProtocolChoices.PROTOCOL_VRRP2: IPAddressRoleChoices.ROLE_VRRP,
    FHRPGroupProtocolChoices.PROTOCOL_VRRP3: IPAddressRoleChoices.ROLE_VRRP,
    FHRPGroupProtocolChoices.PROTOCOL_HSRP: IPAddressRoleChoices.ROLE_HSRP,
    FHRPGroupProtocolChoices.PROTOCOL_GLBP: IPAddressRoleChoices.ROLE_GLBP,
    FHRPGroupProtocolChoices.PROTOCOL_CARP: IPAddressRoleChoices.ROLE_CARP,
}


#
# VLANs
#

# 12-bit VLAN ID (values 0 and 4095 are reserved)
VLAN_VID_MIN = 1
VLAN_VID_MAX = 4094

# models values for ContentTypes which may be VLANGroup scope types
VLANGROUP_SCOPE_TYPES = (
    'region', 'sitegroup', 'site', 'location', 'rack', 'clustergroup', 'cluster',
)


#
# Services
#

# 16-bit port number
SERVICE_PORT_MIN = 1
SERVICE_PORT_MAX = 65535