Update harmonic_engine.py

harmonic_engine.py

@@ -506,3 +506,50 @@ class MidiExporter:
             files[lane] = fname
 
         return files
+    
+    @staticmethod
+    def export_combined(progression_data, filename_prefix="session"):
+        """Export combined MIDI with both LH and RH as separate tracks"""
+        mid = mido.MidiFile(ticks_per_beat=480)
+        
+        # Track 1: LH/Bass
+        track_lh = mido.MidiTrack()
+        mid.tracks.append(track_lh)
+        track_lh.append(mido.MetaMessage('track_name', name='LH/Bass'))
+        
+        for chord_data in progression_data:
+            notes = chord_data['lh']
+            velocity = 70
+            
+            for n in notes:
+                n = max(0, min(127, n))
+                track_lh.append(mido.Message('note_on', note=n, velocity=velocity, time=0))
+            
+            if notes:
+                track_lh.append(mido.Message('note_off', note=max(0, min(127, notes[0])), velocity=0, time=1920))
+                for n in notes[1:]:
+                    n = max(0, min(127, n))
+                    track_lh.append(mido.Message('note_off', note=n, velocity=0, time=0))
+        
+        # Track 2: RH/Chords
+        track_rh = mido.MidiTrack()
+        mid.tracks.append(track_rh)
+        track_rh.append(mido.MetaMessage('track_name', name='RH/Chords'))
+        
+        for chord_data in progression_data:
+            notes = chord_data['rh']
+            velocity = 85
+            
+            for n in notes:
+                n = max(0, min(127, n))
+                track_rh.append(mido.Message('note_on', note=n, velocity=velocity, time=0))
+            
+            if notes:
+                track_rh.append(mido.Message('note_off', note=max(0, min(127, notes[0])), velocity=0, time=1920))
+                for n in notes[1:]:
+                    n = max(0, min(127, n))
+                    track_rh.append(mido.Message('note_off', note=n, velocity=0, time=0))
+        
+        fname = f"{filename_prefix}_COMPLETE.mid"
+        mid.save(fname)
+        return fname