fix: keep imported MIDI in one region and expand project bars

src/util/midiUtil.test.ts

@@ -1,6 +1,8 @@
 import { describe, it, expect } from 'vitest';
 import { 
   beatsToBar, 
+  convertMidiToProject,
+  convertProjectToMidi,
   formatMidiEventLength,
   formatMidiEventPosition,
   MIDI_EVENT_TICKS_PER_BEAT,
@@ -13,6 +15,10 @@ import {
   pianoRollIndexToPitch,
   noteNameToPitch
 } from './midiUtil';
+import { KGProject } from '../core/KGProject';
+import { KGMidiTrack } from '../core/track/KGMidiTrack';
+import { KGMidiRegion } from '../core/region/KGMidiRegion';
+import { KGMidiNote } from '../core/midi/KGMidiNote';
 
 describe('midiUtil', () => {
   describe('beatsToBar', () => {
@@ -195,6 +201,166 @@ describe('midiUtil', () => {
     });
   });
 
+  describe('convertMidiToProject', () => {
+    const createRoundTripTrack = (notes: Array<{
+      startBeat: number;
+      endBeat: number;
+      pitch: number;
+      velocity: number;
+    }>, options?: {
+      trackName?: string;
+      trackId?: number;
+      trackIndex?: number;
+      project?: KGProject;
+    }) => {
+      const project = options?.project ?? new KGProject('Source Project', 64, 0, 132, { numerator: 4, denominator: 4 }, 'D major');
+      const track = new KGMidiTrack(options?.trackName ?? 'Lead', options?.trackId ?? 1, 'acoustic_grand_piano');
+      track.setTrackIndex(options?.trackIndex ?? project.getTracks().length);
+      const region = new KGMidiRegion(
+        `region-${options?.trackId ?? 1}`,
+        String(track.getId()),
+        track.getTrackIndex(),
+        `${track.getName()} Source`,
+        0,
+        Math.max(...notes.map(note => note.endBeat), 0)
+      );
+
+      notes.forEach((note, index) => {
+        region.addNote(new KGMidiNote(
+          `note-${options?.trackId ?? 1}-${index}`,
+          note.startBeat,
+          note.endBeat,
+          note.pitch,
+          note.velocity
+        ));
+      });
+
+      track.addRegion(region);
+      project.getTracks().push(track);
+      return { project, track };
+    };
+
+    const importProject = (project: KGProject) => convertMidiToProject(convertProjectToMidi(project));
+
+    it('imports a short track as a single region covering the full note range', () => {
+      const { project } = createRoundTripTrack([
+        { startBeat: 1, endBeat: 2.5, pitch: 60, velocity: 96 },
+        { startBeat: 6, endBeat: 7, pitch: 64, velocity: 88 },
+      ]);
+
+      const importedProject = importProject(project);
+      const importedTrack = importedProject.getTracks()[0] as KGMidiTrack;
+      const importedRegions = importedTrack.getRegions();
+
+      expect(importedRegions).toHaveLength(1);
+      expect(importedRegions[0].getStartFromBeat()).toBe(1);
+      expect(importedRegions[0].getLength()).toBe(6);
+      expect(importedRegions[0].getNotes()).toHaveLength(2);
+      expect(importedRegions[0].getNotes().map(note => note.getStartBeat())).toEqual([0, 5]);
+      expect(importedRegions[0].getNotes().map(note => note.getEndBeat())).toEqual([1.5, 6]);
+    });
+
+    it('imports a long track as a single region instead of chunking every four bars', () => {
+      const { project } = createRoundTripTrack([
+        { startBeat: 0, endBeat: 1, pitch: 60, velocity: 100 },
+        { startBeat: 20, endBeat: 21, pitch: 64, velocity: 100 },
+        { startBeat: 36, endBeat: 37, pitch: 67, velocity: 100 },
+      ]);
+
+      const importedProject = importProject(project);
+      const importedTrack = importedProject.getTracks()[0] as KGMidiTrack;
+      const importedRegions = importedTrack.getRegions();
+
+      expect(importedRegions).toHaveLength(1);
+      expect(importedRegions[0].getStartFromBeat()).toBe(0);
+      expect(importedRegions[0].getLength()).toBe(37);
+      expect(importedRegions[0].getNotes().map(note => note.getStartBeat())).toEqual([0, 20, 36]);
+    });
+
+    it('imports multiple MIDI tracks as separate tracks with one region each', () => {
+      const project = new KGProject('Ensemble', 64, 0, 110, { numerator: 4, denominator: 4 }, 'G major');
+      createRoundTripTrack([
+        { startBeat: 0, endBeat: 1, pitch: 60, velocity: 90 },
+      ], { project, trackName: 'Lead', trackId: 1, trackIndex: 0 });
+      createRoundTripTrack([
+        { startBeat: 8, endBeat: 10, pitch: 48, velocity: 80 },
+      ], { project, trackName: 'Bass', trackId: 2, trackIndex: 1 });
+
+      const importedProject = importProject(project);
+      const importedTracks = importedProject.getTracks() as KGMidiTrack[];
+
+      expect(importedTracks).toHaveLength(2);
+      expect(importedTracks[0].getRegions()).toHaveLength(1);
+      expect(importedTracks[1].getRegions()).toHaveLength(1);
+      expect(importedTracks[0].getRegions()[0].getStartFromBeat()).toBe(0);
+      expect(importedTracks[1].getRegions()[0].getStartFromBeat()).toBe(8);
+      expect(importedTracks[1].getRegions()[0].getNotes()[0].getStartBeat()).toBe(0);
+    });
+
+    it('preserves a note that crosses the old four-bar boundary inside the single imported region', () => {
+      const { project } = createRoundTripTrack([
+        { startBeat: 15.5, endBeat: 16.5, pitch: 72, velocity: 110 },
+        { startBeat: 18, endBeat: 19, pitch: 76, velocity: 105 },
+      ]);
+
+      const importedProject = importProject(project);
+      const importedTrack = importedProject.getTracks()[0] as KGMidiTrack;
+      const importedRegion = importedTrack.getRegions()[0];
+      const importedNotes = importedRegion.getNotes();
+
+      expect(importedTrack.getRegions()).toHaveLength(1);
+      expect(importedRegion.getStartFromBeat()).toBe(15.5);
+      expect(importedRegion.getLength()).toBe(3.5);
+      expect(importedNotes[0].getStartBeat()).toBe(0);
+      expect(importedNotes[0].getEndBeat()).toBe(1);
+      expect(importedNotes[1].getStartBeat()).toBe(2.5);
+      expect(importedNotes[1].getEndBeat()).toBe(3.5);
+    });
+
+    it('preserves imported tempo, time signature, and key signature metadata', () => {
+      const { project } = createRoundTripTrack([
+        { startBeat: 2, endBeat: 3, pitch: 60, velocity: 100 },
+      ], {
+        project: new KGProject('Meta Source', 64, 0, 147, { numerator: 3, denominator: 4 }, 'A major')
+      });
+
+      const importedProject = importProject(project);
+
+      expect(importedProject.getBpm()).toBe(147);
+      expect(importedProject.getTimeSignature()).toEqual({ numerator: 3, denominator: 4 });
+      expect(importedProject.getKeySignature()).toBe('A major');
+    });
+
+    it('expands max bars when imported MIDI extends beyond the current project length', () => {
+      const existingProject = new KGProject('Existing Project', 8, 0, 120, { numerator: 4, denominator: 4 }, 'C major');
+      const sourceProject = new KGProject('Long MIDI Source', 64, 0, 120, { numerator: 4, denominator: 4 }, 'C major');
+      createRoundTripTrack([
+        { startBeat: 0, endBeat: 1, pitch: 60, velocity: 100 },
+        { startBeat: 44, endBeat: 46, pitch: 64, velocity: 100 },
+      ], {
+        project: sourceProject
+      });
+
+      const importedProject = convertMidiToProject(convertProjectToMidi(sourceProject), existingProject);
+
+      expect(importedProject.getMaxBars()).toBe(12);
+    });
+
+    it('does not shrink max bars when imported MIDI fits within the current project length', () => {
+      const existingProject = new KGProject('Existing Project', 40, 0, 120, { numerator: 4, denominator: 4 }, 'C major');
+      const sourceProject = new KGProject('Short MIDI Source', 64, 0, 120, { numerator: 4, denominator: 4 }, 'C major');
+      createRoundTripTrack([
+        { startBeat: 4, endBeat: 6, pitch: 60, velocity: 100 },
+      ], {
+        project: sourceProject
+      });
+
+      const importedProject = convertMidiToProject(convertProjectToMidi(sourceProject), existingProject);
+
+      expect(importedProject.getMaxBars()).toBe(40);
+    });
+  });
+
   describe('edge cases and error handling', () => {
     it('should handle negative values gracefully', () => {
       expect(() => pitchToNoteNameString(-1)).not.toThrow();

src/util/midiUtil.ts

@@ -761,6 +761,7 @@ export const convertMidiToProject = (midiData: Uint8Array, existingProject?: KGP
   // Get existing tracks to calculate proper track indices
   const existingTracks = project.getTracks();
   const startingTrackIndex = existingTracks.length;
+  const importedTrackEndBeats: number[] = [];
   
   // Convert MIDI tracks to KGSP tracks
   let addedTrackCount = 0;
@@ -782,45 +783,51 @@ export const convertMidiToProject = (midiData: Uint8Array, existingProject?: KGP
     const kgTrack = new KGMidiTrack(trackName, trackId, instrument);
     kgTrack.setTrackIndex(actualTrackIndex);
     
-    // Group notes into regions (every 16 beats for now, could be more sophisticated)
-    const regions = groupNotesIntoRegions(midiTrack.notes, project.getTimeSignature());
-    
-    regions.forEach((regionData, regionIndex) => {
-      const regionId = generateUniqueId('KGMidiRegion');
-      const regionName = `${trackName} Region ${regionIndex + 1}`;
-      const region = new KGMidiRegion(
-        regionId,
-        trackId.toString(),
-        actualTrackIndex,
-        regionName,
-        regionData.startBeat,
-        regionData.length
+    const regionStartBeat = Math.min(...midiTrack.notes.map(note => note.startBeat));
+    const regionEndBeat = Math.max(...midiTrack.notes.map(note => note.endBeat));
+    importedTrackEndBeats.push(regionEndBeat);
+    const regionId = generateUniqueId('KGMidiRegion');
+    const regionName = `${trackName} Region`;
+    const region = new KGMidiRegion(
+      regionId,
+      trackId.toString(),
+      actualTrackIndex,
+      regionName,
+      regionStartBeat,
+      regionEndBeat - regionStartBeat
+    );
+
+    // Store imported notes relative to the region start while preserving their timing.
+    midiTrack.notes.forEach(midiNote => {
+      const noteId = generateUniqueId('KGMidiNote');
+      const relativeStartBeat = midiNote.startBeat - regionStartBeat;
+      const relativeEndBeat = midiNote.endBeat - regionStartBeat;
+
+      const kgNote = new KGMidiNote(
+        noteId,
+        relativeStartBeat,
+        relativeEndBeat,
+        midiNote.pitch,
+        midiNote.velocity
       );
-      
-      // Convert MIDI notes to KG notes (with relative timing)
-      regionData.notes.forEach(midiNote => {
-        const noteId = generateUniqueId('KGMidiNote');
-        const relativeStartBeat = midiNote.startBeat - regionData.startBeat;
-        const relativeEndBeat = midiNote.endBeat - regionData.startBeat;
-        
-        const kgNote = new KGMidiNote(
-          noteId,
-          relativeStartBeat,
-          relativeEndBeat,
-          midiNote.pitch,
-          midiNote.velocity
-        );
-        
-        region.addNote(kgNote);
-      });
-      
-      kgTrack.addRegion(region);
+
+      region.addNote(kgNote);
     });
+
+    kgTrack.addRegion(region);
     
     // Add track to project
     project.getTracks().push(kgTrack);
     addedTrackCount += 1;
   });
+
+  if (importedTrackEndBeats.length > 0) {
+    const beatsPerBar = project.getTimeSignature().numerator;
+    const requiredBars = Math.ceil(Math.max(...importedTrackEndBeats) / beatsPerBar);
+    if (requiredBars > project.getMaxBars()) {
+      project.setMaxBars(requiredBars);
+    }
+  }
   
   return project;
 };
@@ -850,12 +857,6 @@ interface ParsedMidiNote {
   velocity: number;
 }
 
-interface RegionData {
-  startBeat: number;
-  length: number;
-  notes: ParsedMidiNote[];
-}
-
 /**
  * Parses a MIDI binary file into a structured format
  */
@@ -1287,44 +1288,3 @@ function getKeySignatureFromMidi(sharpsFlats: number, majorMinor: number): KeySi
   // Default to C major
   return 'C major';
 }
-
-/**
- * Groups MIDI notes into regions based on timing
- */
-function groupNotesIntoRegions(notes: ParsedMidiNote[], timeSignature: TimeSignature): RegionData[] {
-  if (notes.length === 0) return [];
-  
-  // Sort notes by start time
-  const sortedNotes = [...notes].sort((a, b) => a.startBeat - b.startBeat);
-  
-  const regions: RegionData[] = [];
-  const beatsPerBar = timeSignature.numerator;
-  const regionLengthInBeats = beatsPerBar * 4; // 4 bars per region
-  
-  // Find the range of all notes
-  const firstNoteBeat = Math.floor(sortedNotes[0].startBeat);
-  const lastNoteBeat = Math.ceil(Math.max(...sortedNotes.map(n => n.endBeat)));
-  
-  // Create regions to cover all notes
-  for (let regionStart = Math.floor(firstNoteBeat / regionLengthInBeats) * regionLengthInBeats; 
-       regionStart < lastNoteBeat; 
-       regionStart += regionLengthInBeats) {
-    
-    const regionEnd = regionStart + regionLengthInBeats;
-    
-    // Find notes that belong to this region
-    const regionNotes = sortedNotes.filter(note => 
-      note.startBeat >= regionStart && note.startBeat < regionEnd
-    );
-    
-    if (regionNotes.length > 0) {
-      regions.push({
-        startBeat: regionStart,
-        length: regionLengthInBeats,
-        notes: regionNotes
-      });
-    }
-  }
-  
-  return regions;
-}