Improve Process impl

src/process.rs

@@ -269,6 +269,10 @@ impl Process {
         Ok(self.states.get(0).ok_or(anyhow::Error::msg("Empty state list"))?.commited_in)
     }
 
+    pub fn get_process_tip(&self) -> anyhow::Result<OutPoint> {
+        Ok(self.states.last().ok_or(anyhow::Error::msg("Empty state list"))?.commited_in)
+    }
+
     pub fn get_last_unspent_outpoint(&self) -> anyhow::Result<OutPoint> {
         if self.states.is_empty() { return Err(anyhow::Error::msg("Empty Process")); }
         let last_state = self.states.last().unwrap();
@@ -337,21 +341,30 @@ impl Process {
         self.states.last_mut()
     }
 
-    pub fn get_previous_state(&self, current_state: &ProcessState) -> Option<&ProcessState> {
-        // Find the index of the current state
-        let current_index = self
-            .states
-            .iter()
-            .position(|state| state == current_state)?;
+    /// If `state` is a concurrent state, parent is the last commited one
+    /// Otherwise it's just the state commited before
+    /// If it's the initial state we return `None`
+    pub fn get_parent_state(&self, target_commited_in: &OutPoint) -> Option<&ProcessState> {
+        let tip = self.get_process_tip().ok()?; // Use `?` for cleaner error handling.
 
-        // Check if there is a previous state
-        if current_index > 0 {
-            // Create a new Process with the previous state
-            let previous_state = self.get_state_at(current_index - 1).unwrap();
-            Some(&previous_state)
-        } else {
-            None // No previous state exists
+        // If the target is the current tip, return the last committed state.
+        if tip == *target_commited_in {
+            return self.get_latest_commited_state();
         }
+
+        // Iterate over the states to find the parent.
+        let mut parent_state = None;
+        for state in &self.states {
+            // Check if the current state's `commited_in` matches the target.
+            if state.commited_in == *target_commited_in {
+                return parent_state; // Return the parent state if found.
+            }
+            // Update the parent_state to the current state.
+            parent_state = Some(state);
+        }
+
+        // Return `None` if no matching state is found.
+        None
     }
 
     pub fn get_state_for_id(&self, state_id: &str) -> anyhow::Result<&ProcessState> {
@@ -360,7 +373,7 @@ impl Process {
             return Err(anyhow::Error::msg("process is empty".to_owned()));
         }
 
-        for p in self.get_latest_concurrent_states()? {
+        for p in &self.states {
             if state_id == p.state_id.as_str() { 
                 return Ok(p);
             }
@@ -375,7 +388,7 @@ impl Process {
             return Err(anyhow::Error::msg("process is empty".to_owned()));
         }
 
-        for p in self.get_latest_concurrent_states_mut()? {
+        for p in &mut self.states {
             if state_id == p.state_id.as_str() { 
                 return Ok(p);
             }