// Remove removes the unit from state, calling EnsureDead first, then Remove.
// It will fail if the unit is not present.
func (u *Unit) Remove() error {
	var result params.ErrorResults
	args := params.Entities{
		Entities: []params.Entity{{Tag: u.tag}},
	}
	err := u.st.call("Remove", args, &result)
	if err != nil {
		return err
	}
	return result.OneError()
}

// DestroyAllSubordinates destroys all subordinates of the unit.
func (u *Unit) DestroyAllSubordinates() error {
	var result params.ErrorResults
	args := params.Entities{
		Entities: []params.Entity{{Tag: u.tag}},
	}
	err := u.st.call("DestroyAllSubordinates", args, &result)
	if err != nil {
		return err
	}
	return result.OneError()
}

// EnsureDead sets the machine lifecycle to Dead if it is Alive or
// Dying. It does nothing otherwise.
func (m *Machine) EnsureDead() error {
	var result params.ErrorResults
	args := params.Entities{
		Entities: []params.Entity{{Tag: m.tag}},
	}
	err := m.st.call("EnsureDead", args, &result)
	if err != nil {
		return err
	}
	return result.OneError()
}

// SetPassword sets the unit's password.
func (u *Unit) SetPassword(password string) error {
	var result params.ErrorResults
	args := params.EntityPasswords{
		Changes: []params.EntityPassword{
			{Tag: u.tag, Password: password},
		},
	}
	err := u.st.call("SetPasswords", args, &result)
	if err != nil {
		return err
	}
	return result.OneError()
}

// SetStatus sets the status of the unit.
func (u *Unit) SetStatus(status params.Status, info string, data params.StatusData) error {
	var result params.ErrorResults
	args := params.SetStatus{
		Entities: []params.EntityStatus{
			{Tag: u.tag, Status: status, Info: info, Data: data},
		},
	}
	err := u.st.call("SetStatus", args, &result)
	if err != nil {
		return err
	}
	return result.OneError()
}

// ClosePort sets the policy of the port with protocol and number to
// be closed.
//
// TODO: We should really be opening and closing ports on machines,
// rather than units.
func (u *Unit) ClosePort(protocol string, number int) error {
	var result params.ErrorResults
	args := params.EntitiesPorts{
		Entities: []params.EntityPort{
			{Tag: u.tag, Protocol: protocol, Port: number},
		},
	}
	err := u.st.call("ClosePort", args, &result)
	if err != nil {
		return err
	}
	return result.OneError()
}

// SetMachineAddresses sets the machine determined addresses of the machine.
func (m *Machine) SetMachineAddresses(addresses []instance.Address) error {
	var result params.ErrorResults
	args := params.SetMachinesAddresses{
		MachineAddresses: []params.MachineAddresses{
			{Tag: m.Tag(), Addresses: addresses},
		},
	}
	err := m.st.call("SetMachineAddresses", args, &result)
	if err != nil {
		return err
	}
	return result.OneError()
}

// LeaveScope signals that the unit has left its scope in the relation.
// After the unit has left its relation scope, it is no longer a member
// of the relation; if the relation is dying when its last member unit
// leaves, it is removed immediately. It is not an error to leave a scope
// that the unit is not, or never was, a member of.
func (ru *RelationUnit) LeaveScope() error {
	var result params.ErrorResults
	args := params.RelationUnits{
		RelationUnits: []params.RelationUnit{{
			Relation: ru.relation.tag,
			Unit:     ru.unit.tag,
		}},
	}
	err := ru.st.call("LeaveScope", args, &result)
	if err != nil {
		return err
	}
	return result.OneError()
}

// SetPassword sets the password associated with the agent's entity.
func (m *Entity) SetPassword(password string) error {
	var results params.ErrorResults
	args := params.EntityPasswords{
		Changes: []params.EntityPassword{{
			Tag:      m.tag,
			Password: password,
		}},
	}
	err := m.st.caller.Call("Agent", "", "SetPasswords", args, &results)
	if err != nil {
		return err
	}
	return results.OneError()
}

// SetCharmURL marks the unit as currently using the supplied charm URL.
// An error will be returned if the unit is dead, or the charm URL not known.
func (u *Unit) SetCharmURL(curl *charm.URL) error {
	if curl == nil {
		return fmt.Errorf("charm URL cannot be nil")
	}
	var result params.ErrorResults
	args := params.EntitiesCharmURL{
		Entities: []params.EntityCharmURL{
			{Tag: u.tag, CharmURL: curl.String()},
		},
	}
	err := u.st.call("SetCharmURL", args, &result)
	if err != nil {
		return err
	}
	return result.OneError()
}

// SetInstanceInfo sets the provider specific instance id, nonce,
// metadata, networks and interfaces for this machine. Once set, the
// instance id cannot be changed.
func (m *Machine) SetInstanceInfo(
	id instance.Id, nonce string, characteristics *instance.HardwareCharacteristics,
	networks []params.Network, interfaces []params.NetworkInterface,
) error {
	var result params.ErrorResults
	args := params.InstancesInfo{
		Machines: []params.InstanceInfo{{
			Tag:             m.tag,
			InstanceId:      id,
			Nonce:           nonce,
			Characteristics: characteristics,
			Networks:        networks,
			Interfaces:      interfaces,
		}},
	}
	err := m.st.call("SetInstanceInfo", args, &result)
	if err != nil {
		return err
	}
	return result.OneError()
}