Handle metronome volume

audio_engine/src/metronome.rs

@@ -68,6 +68,13 @@ impl Metronome {
         Ok(timing)
     }
 
+    pub fn set_click_volume(&mut self, click_volume: f32, persistence: &mut PersistenceManagerController) -> Result<()> {
+        let clamped = click_volume.clamp(0.0, 1.0);
+        persistence.update_metronome_volume(clamped)?;
+        self.click_volume = clamped;
+        Ok(())
+    }
+
     fn process_ppqn_ticks(
         &mut self,
         ps: &jack::ProcessScope,

audio_engine/src/midi.rs

@@ -38,11 +38,14 @@ pub fn process_events<F: ChunkFactory, const COLS: usize, const ROWS: usize>(
                         let value_num = u8::from(value);
 
                         match controller_num {
-                            // Expression Pedal A - Track Volume
+                            // Expression Pedals
                             1 => {
                                 process_handler.handle_pedal_a(value_num)?;
                             }
-                            // Button mappings (only process button presses - value > 0)
+                            2 => {
+                                process_handler.handle_pedal_b(value_num)?;
+                            }
+                            // Buttons
                             20 if value_num > 0 => {
                                 process_handler.handle_button_1()?;
                             }
@@ -79,19 +82,16 @@ pub fn process_events<F: ChunkFactory, const COLS: usize, const ROWS: usize>(
                             31 if value_num > 0 => {
                                 process_handler.handle_button_down()?;
                             }
-                            _ => {
                             // Other CC messages - ignore
+                            _ => {}
                         }
                     }
-                    }
-                    _ => {
                     // Other MIDI messages - ignore
+                    _ => {}
                 }
             }
-            }
-            Err(_) => {
             // Malformed MIDI messages - ignore
-            }
+            Err(_) => {}
         }
     }
 

audio_engine/src/persistence_manager.rs

@@ -14,6 +14,9 @@ pub enum PersistenceUpdate {
         row: usize,
         volume: f32,
     },
+    UpdateMetronomeVolume {
+        volume: f32,
+    }
 }
 
 impl PersistenceManagerController {
@@ -29,6 +32,15 @@ impl PersistenceManagerController {
             Err(_) => Err(LooperError::StateSave(std::panic::Location::caller())), // Channel closed
         }
     }
+
+    pub fn update_metronome_volume(&self, volume: f32) -> Result<()> {
+        let update = PersistenceUpdate::UpdateMetronomeVolume { volume: volume };
+        match self.sender.try_send(update) {
+            Ok(true) => Ok(()),
+            Ok(false) => Err(LooperError::StateSave(std::panic::Location::caller())), // Channel full
+            Err(_) => Err(LooperError::StateSave(std::panic::Location::caller())), // Channel closed
+        }
+    }
 }
 
 pub struct PersistenceManager {
@@ -105,6 +117,10 @@ impl PersistenceManager {
                     .send_modify(|state| state.track_volumes.set_volume(column, row, volume));
                 self.save_to_disk()?;
             }
+            PersistenceUpdate::UpdateMetronomeVolume { volume } => {
+                self.state
+                    .send_modify(|state| state.metronome.click_volume = volume);
+            }
         }
 
         Ok(())

audio_engine/src/process_handler.rs

@@ -58,6 +58,10 @@ impl<F: ChunkFactory, const COLS: usize, const ROWS: usize> ProcessHandler<F, CO
             .handle_volume_update(self.last_volume_setting, &controllers)
     }
 
+    pub fn handle_pedal_b(&mut self, value: u8) -> Result<()> {
+        self.metronome.set_click_volume(value as f32 / 127.0, &mut self.persistence)
+    }
+
     pub fn handle_button_1(&mut self) -> Result<()> {
         let controllers = TrackControllers::new(
             &self.post_record_controller,