feat: added pitch bend automation (linear interpolation)

src/util/midiAutomationUtil.test.ts

@@ -0,0 +1,127 @@
+import { describe, expect, it } from 'vitest';
+import {
+  bakeMidiAutomationPointsInWindow,
+  collectRegionMidiAutomationPoints,
+  normalizeMidiAutomationPoints,
+  resolveMidiAutomationValueAtBeat,
+  type MidiAutomationPoint,
+} from './midiAutomationUtil';
+
+const defaultOptions = {
+  maxIntervalMs: 10,
+  bpm: 120,
+  defaultValue: 8192,
+};
+
+describe('midiAutomationUtil', () => {
+  it('normalizes points and keeps the last duplicate beat', () => {
+    const points: MidiAutomationPoint[] = [
+      { beat: 2, value: 1000 },
+      { beat: 1, value: 2000 },
+      { beat: 2, value: 3000 },
+    ];
+
+    expect(normalizeMidiAutomationPoints(points)).toEqual([
+      { beat: 1, value: 2000 },
+      { beat: 2, value: 3000 },
+    ]);
+  });
+
+  it('holds the default value before the first point', () => {
+    const points = [{ beat: 4, value: 0 }];
+
+    expect(resolveMidiAutomationValueAtBeat(points, 2, 8192)).toBe(8192);
+  });
+
+  it('interpolates linearly between two points', () => {
+    const points = [
+      { beat: 0, value: 8192 },
+      { beat: 4, value: 0 },
+    ];
+
+    expect(resolveMidiAutomationValueAtBeat(points, 2, 8192)).toBe(4096);
+  });
+
+  it('holds the last value after the final point', () => {
+    const points = [{ beat: 1, value: 2048 }];
+
+    expect(resolveMidiAutomationValueAtBeat(points, 8, 8192)).toBe(2048);
+  });
+
+  it('collects region-local points into absolute beats', () => {
+    const collected = collectRegionMidiAutomationPoints([
+      { startBeat: 4, points: [{ beat: 0.5, value: 7000 }] },
+      { startBeat: 1, points: [{ beat: 0.25, value: 6000 }] },
+    ]);
+
+    expect(collected).toEqual([
+      { beat: 1.25, value: 6000 },
+      { beat: 4.5, value: 7000 },
+    ]);
+  });
+
+  it('bakes dense points according to the requested ms interval', () => {
+    const points = [
+      { beat: 0, value: 8192 },
+      { beat: 1, value: 0 },
+    ];
+
+    expect(bakeMidiAutomationPointsInWindow(points, 0, 1, { ...defaultOptions, maxIntervalMs: 20 })).toHaveLength(25);
+    expect(bakeMidiAutomationPointsInWindow(points, 0, 1, { ...defaultOptions, maxIntervalMs: 10 })).toHaveLength(50);
+    expect(bakeMidiAutomationPointsInWindow(points, 0, 1, { ...defaultOptions, maxIntervalMs: 5 })).toHaveLength(100);
+  });
+
+  it('treats flat segments as holds without adding interior baked points', () => {
+    const points = [
+      { beat: 0, value: 4096 },
+      { beat: 4, value: 4096 },
+    ];
+
+    expect(bakeMidiAutomationPointsInWindow(points, 0, 4, { ...defaultOptions, maxIntervalMs: 10 })).toEqual([
+      { beat: 0, value: 4096 },
+    ]);
+  });
+
+  it('collapses consecutive baked points with the same value', () => {
+    const points = [
+      { beat: 0.5, value: 8192 },
+      { beat: 1, value: 4096 },
+      { beat: 2, value: 4096 },
+      { beat: 3, value: 0 },
+    ];
+
+    expect(bakeMidiAutomationPointsInWindow(points, 0, 4, { ...defaultOptions, maxIntervalMs: 500 })).toEqual([
+      { beat: 0, value: 8192 },
+      { beat: 1, value: 4096 },
+      { beat: 3, value: 0 },
+    ]);
+  });
+
+  it('keeps later changing segments after skipping a flat segment', () => {
+    const points = [
+      { beat: 0, value: 4096 },
+      { beat: 2, value: 4096 },
+      { beat: 4, value: 0 },
+    ];
+
+    const baked = bakeMidiAutomationPointsInWindow(points, 0, 4, { ...defaultOptions, maxIntervalMs: 500 });
+
+    expect(baked).toEqual([
+      { beat: 0, value: 4096 },
+      { beat: 3, value: 2048 },
+    ]);
+  });
+
+  it('adds a window anchor and preserves the correct loop boundary value', () => {
+    const points = [
+      { beat: 2, value: 0 },
+      { beat: 6, value: 8192 },
+    ];
+
+    const baked = bakeMidiAutomationPointsInWindow(points, 4, 8, { ...defaultOptions, maxIntervalMs: 500 });
+
+    expect(baked[0]).toEqual({ beat: 4, value: 4096 });
+    expect(baked.some(point => point.beat === 5 && point.value === 6144)).toBe(true);
+    expect(baked.some(point => point.beat === 6 && point.value === 8192)).toBe(true);
+  });
+});