continue dest handler

satrs-core/src/cfdp/dest.rs

@@ -1,12 +1,24 @@
 use super::{State, TransactionStep};
-use spacepackets::cfdp::{pdu::FileDirectiveType, PduType};
+use spacepackets::cfdp::{
+    pdu::{CommonPduConfig, FileDirectiveType},
+    PduType,
+};
 
 pub struct DestinationHandler {
     step: TransactionStep,
     state: State,
+    //pdu_conf: CommonPduConfig,
 }
 
 impl DestinationHandler {
+    pub fn new() -> Self {
+        Self {
+            step: TransactionStep::Idle,
+            state: State::Idle,
+            //pdu_conf: CommonPduConfig::new_with_defaults(),
+        }
+    }
+
     pub fn insert_packet(
         &mut self,
         pdu_type: PduType,
@@ -27,6 +39,7 @@ impl DestinationHandler {
     pub fn handle_file_data(&mut self, raw_packet: &[u8]) -> Result<(), ()> {
         Ok(())
     }
+
     pub fn handle_file_directive(
         &mut self,
         pdu_directive: FileDirectiveType,
@@ -38,8 +51,32 @@ impl DestinationHandler {
     pub fn state_machine(&mut self) {
         match self.state {
             State::Idle => todo!(),
-            State::BusyClass1Nacked => todo!(),
+            State::BusyClass1Nacked => self.fsm_nacked(),
             State::BusyClass2Acked => todo!(),
         }
     }
+
+    fn fsm_nacked(&self) {
+        match self.step {
+            TransactionStep::Idle => {
+                // TODO: Should not happen. Determine what to do later
+            }
+            TransactionStep::TransactionStart => {}
+            TransactionStep::ReceivingFileDataPdus => todo!(),
+            TransactionStep::SendingAckPdu => todo!(),
+            TransactionStep::TransferCompletion => todo!(),
+            TransactionStep::SendingFinishedPdu => todo!(),
+        }
+    }
+
+    /// Get the step, which denotes the exact step of a pending CFDP transaction when applicable.
+    pub fn step(&self) -> TransactionStep {
+        self.step
+    }
+
+    /// Get the step, which denotes whether the CFDP handler is active, and which CFDP class
+    /// is used if it is active.
+    pub fn state(&self) -> State {
+        self.state
+    }
 }