refactor v1, start support for more protocols and implement nak

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

internal/outpost/radius/eap/state.go

@@ -1,13 +1,17 @@
 package eap
 
 import (
+	"errors"
 	"slices"
 
 	"goauthentik.io/internal/outpost/radius/eap/protocol"
 )
 
+type ProtocolConstructor func() protocol.Payload
+
 type Settings struct {
-	ProtocolsToOffer []protocol.Type
+	Protocols        []ProtocolConstructor
+	ProtocolPriority []protocol.Type
 	ProtocolSettings map[protocol.Type]interface{}
 }
 
@@ -18,13 +22,23 @@ type StateManager interface {
 }
 
 type State struct {
-	ChallengesToOffer []protocol.Type
-	TypeState         map[protocol.Type]any
+	Protocols        []ProtocolConstructor
+	ProtocolIndex    int
+	ProtocolPriority []protocol.Type
+	TypeState        map[protocol.Type]any
+}
+
+func (st *State) GetNextProtocol() (protocol.Type, error) {
+	if st.ProtocolIndex >= len(st.ProtocolPriority) {
+		return protocol.Type(0), errors.New("no more protocols to offer")
+	}
+	return st.ProtocolPriority[st.ProtocolIndex], nil
 }
 
 func BlankState(settings Settings) *State {
 	return &State{
-		ChallengesToOffer: slices.Clone(settings.ProtocolsToOffer),
-		TypeState:         map[protocol.Type]any{},
+		Protocols:        slices.Clone(settings.Protocols),
+		ProtocolPriority: slices.Clone(settings.ProtocolPriority),
+		TypeState:        map[protocol.Type]any{},
 	}
 }