// allocateAddress tries to pick an address out of the given subnet and
// allocates it to the container.
func (p *ProvisionerAPI) allocateAddress(
	environ environs.NetworkingEnviron,
	subnet *state.Subnet,
	host, container *state.Machine,
	instId instance.Id,
	macAddress string,
) (*state.IPAddress, error) {

	subnetId := network.Id(subnet.ProviderId())
	name := names.NewMachineTag(container.Id()).String()
	for {
		addr, err := subnet.PickNewAddress()
		if err != nil {
			return nil, err
		}
		logger.Tracef("picked new address %q on subnet %q", addr.String(), subnetId)
		// Attempt to allocate with environ.
		err = environ.AllocateAddress(instId, subnetId, addr.Address(), macAddress, name)
		if err != nil {
			logger.Warningf(
				"allocating address %q on instance %q and subnet %q failed: %v (retrying)",
				addr.String(), instId, subnetId, err,
			)
			// It's as good as unavailable for us, so mark it as
			// such.
			err = setAddrState(addr, state.AddressStateUnavailable)
			if err != nil {
				logger.Warningf(
					"cannot set address %q to %q: %v (ignoring and retrying)",
					addr.String(), state.AddressStateUnavailable, err,
				)
				continue
			}
			logger.Tracef(
				"setting address %q to %q and retrying",
				addr.String(), state.AddressStateUnavailable,
			)
			continue
		}
		logger.Infof(
			"allocated address %q on instance %q and subnet %q",
			addr.String(), instId, subnetId,
		)
		err = p.setAllocatedOrRelease(addr, environ, instId, container, subnetId, macAddress)
		if err != nil {
			// Something went wrong - retry.
			continue
		}
		return addr, nil
	}
}

// allocateAddress tries to pick an address out of the given subnet and
// allocates it to the container.
func (p *ProvisionerAPI) allocateAddress(
	environ environs.NetworkingEnviron,
	subnet *state.Subnet,
	host, container *state.Machine,
	instId instance.Id,
	macAddress string,
) (*state.IPAddress, error) {
	hostname := containerHostname(container.Tag())

	if !environs.AddressAllocationEnabled() {
		// Even if the address allocation feature flag is not enabled, we might
		// be running on MAAS 1.8+ with devices support, which we can use to
		// register containers getting IPs via DHCP. However, most of the usual
		// allocation code can be bypassed, we just need the parent instance ID
		// and a MAC address (no subnet or IP address).
		allocatedAddress := network.Address{}
		err := environ.AllocateAddress(instId, network.AnySubnet, &allocatedAddress, macAddress, hostname)
		if err != nil {
			// Not using MAAS 1.8+ or some other error.
			return nil, errors.Trace(err)
		}

		logger.Infof(
			"allocated address %q on instance %q for container %q",
			allocatedAddress.String(), instId, hostname,
		)

		// Add the address to state, so we can look it up later by MAC address.
		stateAddr, err := p.st.AddIPAddress(allocatedAddress, string(network.AnySubnet))
		if err != nil {
			return nil, errors.Annotatef(err, "failed to save address %q", allocatedAddress)
		}

		err = p.setAllocatedOrRelease(stateAddr, environ, instId, container, network.AnySubnet, macAddress)
		if err != nil {
			return nil, errors.Trace(err)
		}

		return stateAddr, nil
	}

	subnetId := network.Id(subnet.ProviderId())
	for {
		addr, err := subnet.PickNewAddress()
		if err != nil {
			return nil, err
		}
		netAddr := addr.Address()
		logger.Tracef("picked new address %q on subnet %q", addr.String(), subnetId)
		// Attempt to allocate with environ.
		err = environ.AllocateAddress(instId, subnetId, &netAddr, macAddress, hostname)
		if err != nil {
			logger.Warningf(
				"allocating address %q on instance %q and subnet %q failed: %v (retrying)",
				addr.String(), instId, subnetId, err,
			)
			// It's as good as unavailable for us, so mark it as
			// such.
			err = setAddrState(addr, state.AddressStateUnavailable)
			if err != nil {
				logger.Warningf(
					"cannot set address %q to %q: %v (ignoring and retrying)",
					addr.String(), state.AddressStateUnavailable, err,
				)
				continue
			}
			logger.Tracef(
				"setting address %q to %q and retrying",
				addr.String(), state.AddressStateUnavailable,
			)
			continue
		}
		logger.Infof(
			"allocated address %q on instance %q and subnet %q",
			addr.String(), instId, subnetId,
		)
		err = p.setAllocatedOrRelease(addr, environ, instId, container, subnetId, macAddress)
		if err != nil {
			// Something went wrong - retry.
			continue
		}
		return addr, nil
	}
}

func (s *SubnetSuite) assertSubnetMatchesInfo(c *gc.C, subnet *state.Subnet, info state.SubnetInfo) {
	c.Assert(subnet.ProviderId(), gc.Equals, info.ProviderId)
	c.Assert(subnet.CIDR(), gc.Equals, info.CIDR)
	c.Assert(subnet.VLANTag(), gc.Equals, info.VLANTag)
	c.Assert(subnet.AllocatableIPLow(), gc.Equals, info.AllocatableIPLow)
	c.Assert(subnet.AllocatableIPHigh(), gc.Equals, info.AllocatableIPHigh)
	c.Assert(subnet.AvailabilityZone(), gc.Equals, info.AvailabilityZone)
	c.Assert(subnet.String(), gc.Equals, info.CIDR)
	c.Assert(subnet.GoString(), gc.Equals, info.CIDR)
	c.Assert(subnet.SpaceName(), gc.Equals, info.SpaceName)
}

func (s *SubnetSuite) addIPAddressForSubnet(c *gc.C, ipAddress string, subnet *state.Subnet) {
	_, err := s.State.AddIPAddress(network.NewAddress(ipAddress), subnet.ID())
	c.Assert(err, jc.ErrorIsNil)
}

func (s *SubnetSuite) removeSubnetAndAssertNotFound(c *gc.C, subnet *state.Subnet) {
	err := subnet.Remove()
	c.Assert(err, jc.ErrorIsNil)
	s.assertSubnetWithCIDRNotFound(c, subnet.CIDR())
}

func (s *SubnetSuite) refreshAndAssertSubnetLifeIs(c *gc.C, subnet *state.Subnet, expectedLife state.Life) {
	err := subnet.Refresh()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(subnet.Life(), gc.Equals, expectedLife)
}

func (s *SubnetSuite) ensureDeadAndAssertLifeIsDead(c *gc.C, subnet *state.Subnet) {
	err := subnet.EnsureDead()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(subnet.Life(), gc.Equals, state.Dead)
}