import warnings
from django.core.exceptions import FieldError
from django.db.models import Lookup, Transform, IntegerField
from django.db.models.lookups import EndsWith, IEndsWith, StartsWith, IStartsWith, Regex, IRegex
import ipaddress
from netfields.fields import InetAddressField, CidrAddressField


class InvalidLookup(Lookup):
    """
    Emulate Django 1.9 error for unsupported lookups
    """
    def as_sql(self, qn, connection):
        raise FieldError("Unsupported lookup '%s'" % self.lookup_name)


class InvalidSearchLookup(Lookup):
    """
    Emulate Django 1.9 error for unsupported search lookup
    """
    lookup_name = 'search'

    def as_sql(self, qn, connection):
        raise NotImplementedError("Full-text search is not implemented for this database backend")


class NetFieldDecoratorMixin(object):
    def process_lhs(self, qn, connection, lhs=None):
        lhs = lhs or self.lhs
        lhs_string, lhs_params = qn.compile(lhs)
        if isinstance(lhs.source if hasattr(lhs, 'source') else lhs.output_field, InetAddressField):
            lhs_string = 'HOST(%s)' % lhs_string
        elif isinstance(lhs.source if hasattr(lhs, 'source') else lhs.output_field, CidrAddressField):
            lhs_string = 'TEXT(%s)' % lhs_string
        return lhs_string, lhs_params


class EndsWith(NetFieldDecoratorMixin, EndsWith):
    pass


class IEndsWith(NetFieldDecoratorMixin, IEndsWith):
    pass


class StartsWith(NetFieldDecoratorMixin, StartsWith):
    pass


class IStartsWith(NetFieldDecoratorMixin, IStartsWith):
    pass


class Regex(NetFieldDecoratorMixin, Regex):
    pass


class IRegex(NetFieldDecoratorMixin, IRegex):
    pass


class NetworkLookup(object):
    def get_prep_lookup(self):
        if hasattr(self.rhs, 'resolve_expression'):
            return self.rhs
        if isinstance(self.rhs, ipaddress._BaseNetwork):
            return str(self.rhs)
        return str(ipaddress.ip_network(self.rhs))


class AddressLookup(object):
    def get_prep_lookup(self):
        if hasattr(self.rhs, 'resolve_expression'):
            return self.rhs
        if isinstance(self.rhs, ipaddress._BaseAddress):
            return str(self.rhs)
        return str(ipaddress.ip_interface(self.rhs))


class NetContains(AddressLookup, Lookup):
    lookup_name = 'net_contains'

    def as_sql(self, qn, connection):
        lhs, lhs_params = self.process_lhs(qn, connection)
        rhs, rhs_params = self.process_rhs(qn, connection)
        params = lhs_params + rhs_params
        return '%s >> %s' % (lhs, rhs), params


class NetContained(NetworkLookup, Lookup):
    lookup_name = 'net_contained'

    def as_sql(self, qn, connection):
        lhs, lhs_params = self.process_lhs(qn, connection)
        rhs, rhs_params = self.process_rhs(qn, connection)
        params = lhs_params + rhs_params
        return '%s << %s' % (lhs, rhs), params


class NetContainsOrEquals(AddressLookup, Lookup):
    lookup_name = 'net_contains_or_equals'

    def as_sql(self, qn, connection):
        lhs, lhs_params = self.process_lhs(qn, connection)
        rhs, rhs_params = self.process_rhs(qn, connection)
        params = lhs_params + rhs_params
        return '%s >>= %s' % (lhs, rhs), params


class NetContainedOrEqual(NetworkLookup, Lookup):
    lookup_name = 'net_contained_or_equal'

    def as_sql(self, qn, connection):
        lhs, lhs_params = self.process_lhs(qn, connection)
        rhs, rhs_params = self.process_rhs(qn, connection)
        params = lhs_params + rhs_params
        return '%s <<= %s' % (lhs, rhs), params


class NetOverlaps(NetworkLookup, Lookup):
    lookup_name = 'net_overlaps'

    def as_sql(self, qn, connection):
        lhs, lhs_params = self.process_lhs(qn, connection)
        rhs, rhs_params = self.process_rhs(qn, connection)
        params = lhs_params + rhs_params
        return '%s && %s' % (lhs, rhs), params


class HostMatches(AddressLookup, Lookup):
    lookup_name = 'host'

    def as_sql(self, qn, connection):
        lhs, lhs_params = self.process_lhs(qn, connection)
        rhs, rhs_params = self.process_rhs(qn, connection)
        params = lhs_params + rhs_params
        return 'HOST(%s) = HOST(%s)' % (lhs, rhs), params


class Family(Transform):
    lookup_name = 'family'

    def as_sql(self, compiler, connection):
        lhs, params = compiler.compile(self.lhs)
        return "family(%s)" % lhs, params

    @property
    def output_field(self):
        return IntegerField()


class _PrefixlenMixin(object):
    format_string = None

    def as_sql(self, qn, connection):
        warnings.warn(
            'min_prefixlen and max_prefixlen will be depreciated in the future; '
            'use prefixlen__gte and prefixlen__lte respectively',
            DeprecationWarning
        )
        assert self.format_string is not None, "Prefixlen lookups must specify a format_string"
        lhs, lhs_params = self.process_lhs(qn, connection)
        rhs, rhs_params = self.process_rhs(qn, connection)
        params = lhs_params + rhs_params
        return self.format_string % (lhs, rhs), params

    def process_lhs(self, qn, connection, lhs=None):
        lhs = lhs or self.lhs
        lhs_string, lhs_params = qn.compile(lhs)
        lhs_string = 'MASKLEN(%s)' % lhs_string
        return lhs_string, lhs_params

    def get_prep_lookup(self):
        return str(int(self.rhs))


class MaxPrefixlen(_PrefixlenMixin, Lookup):
    lookup_name = 'max_prefixlen'
    format_string = '%s <= %s'


class MinPrefixlen(_PrefixlenMixin, Lookup):
    lookup_name = 'min_prefixlen'
    format_string = '%s >= %s'


class Prefixlen(Transform):
    lookup_name = 'prefixlen'

    def as_sql(self, compiler, connection):
        lhs, params = compiler.compile(self.lhs)
        return "masklen(%s)" % lhs, params

    @property
    def output_field(self):
        return IntegerField()