vibesonic/internal/audiofeatures/extract_test.go

package audiofeatures

import (
	"context"
	"os/exec"
	"path/filepath"
	"strconv"
	"testing"
	"time"
)

func genTone(t *testing.T, dir, name string, freq float64, duration string) string {
	t.Helper()
	if _, err := exec.LookPath("ffmpeg"); err != nil {
		t.Skip("ffmpeg not installed, skipping audiofeatures integration test")
	}
	out := filepath.Join(dir, name)
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()
	cmd := exec.CommandContext(ctx, "ffmpeg", "-y",
		"-f", "lavfi", "-i", "sine=frequency="+strconv.FormatFloat(freq, 'f', -1, 64)+":duration="+duration,
		"-codec:a", "pcm_s16le", out,
	)
	if combined, err := cmd.CombinedOutput(); err != nil {
		t.Fatalf("ffmpeg failed: %v\n%s", err, combined)
	}
	return out
}

func TestAnalyzeLowVsHighToneHaveDifferentChromaPeak(t *testing.T) {
	dir := t.TempDir()
	lowPath := genTone(t, dir, "low.wav", 130.81, "1")    // C3
	highPath := genTone(t, dir, "high.wav", 1046.50, "1") // C6 — same pitch class, different octave

	low, err := Analyze(context.Background(), "", lowPath)
	if err != nil {
		t.Fatalf("Analyze(low): %v", err)
	}
	high, err := Analyze(context.Background(), "", highPath)
	if err != nil {
		t.Fatalf("Analyze(high): %v", err)
	}

	if high.SpectralCentroidHz <= low.SpectralCentroidHz {
		t.Errorf("expected the higher tone to have a higher spectral centroid: low=%.1f high=%.1f",
			low.SpectralCentroidHz, high.SpectralCentroidHz)
	}

	// Both tones are a C, just in different octaves: pitch-class energy
	// should peak at chroma bin 0 for both — a real, verifiable property
	// of the chroma computation, not a fuzzy assertion.
	if argmax(low.Chroma) != 0 {
		t.Errorf("low tone (C3) chroma peak = bin %d, want 0 (C)", argmax(low.Chroma))
	}
	if argmax(high.Chroma) != 0 {
		t.Errorf("high tone (C6) chroma peak = bin %d, want 0 (C)", argmax(high.Chroma))
	}
}

func TestAnalyzeDifferentPitchClassesHaveDifferentChromaPeak(t *testing.T) {
	dir := t.TempDir()
	cPath := genTone(t, dir, "c.wav", 261.63, "1")
	gPath := genTone(t, dir, "g.wav", 392.00, "1")

	c, err := Analyze(context.Background(), "", cPath)
	if err != nil {
		t.Fatalf("Analyze(C): %v", err)
	}
	g, err := Analyze(context.Background(), "", gPath)
	if err != nil {
		t.Fatalf("Analyze(G): %v", err)
	}

	if argmax(c.Chroma) != 0 {
		t.Errorf("C4 chroma peak = bin %d, want 0", argmax(c.Chroma))
	}
	if argmax(g.Chroma) != 7 {
		t.Errorf("G4 chroma peak = bin %d, want 7", argmax(g.Chroma))
	}
}

func TestAnalyzeLoudVsQuietHaveDifferentLoudness(t *testing.T) {
	if _, err := exec.LookPath("ffmpeg"); err != nil {
		t.Skip("ffmpeg not installed, skipping audiofeatures integration test")
	}
	dir := t.TempDir()
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	loud := filepath.Join(dir, "loud.wav")
	if out, err := exec.CommandContext(ctx, "ffmpeg", "-y", "-f", "lavfi",
		"-i", "sine=frequency=440:duration=1", "-af", "volume=1.0", "-codec:a", "pcm_s16le", loud).CombinedOutput(); err != nil {
		t.Fatalf("ffmpeg: %v\n%s", err, out)
	}
	quiet := filepath.Join(dir, "quiet.wav")
	if out, err := exec.CommandContext(ctx, "ffmpeg", "-y", "-f", "lavfi",
		"-i", "sine=frequency=440:duration=1", "-af", "volume=0.05", "-codec:a", "pcm_s16le", quiet).CombinedOutput(); err != nil {
		t.Fatalf("ffmpeg: %v\n%s", err, out)
	}

	loudF, err := Analyze(context.Background(), "", loud)
	if err != nil {
		t.Fatal(err)
	}
	quietF, err := Analyze(context.Background(), "", quiet)
	if err != nil {
		t.Fatal(err)
	}
	if loudF.LoudnessLUFS <= quietF.LoudnessLUFS {
		t.Errorf("loud=%.1f quiet=%.1f, want loud clip to measure louder", loudF.LoudnessLUFS, quietF.LoudnessLUFS)
	}
}

func TestAnalyzeShortClipLeavesTempoInvalid(t *testing.T) {
	dir := t.TempDir()
	// A single sine tone has no rhythmic/onset content at all — VibeSonic
	// must not fabricate a BPM for it.
	path := genTone(t, dir, "tone.wav", 440, "0.5")

	f, err := Analyze(context.Background(), "", path)
	if err != nil {
		t.Fatal(err)
	}
	if f.TempoValid {
		t.Errorf("expected TempoValid=false for a featureless 0.5s tone, got %.1f BPM", f.TempoBPM)
	}
}

func TestVectorLengthAndTempoZeroWhenInvalid(t *testing.T) {
	f := Features{TempoValid: false, TempoBPM: 999}
	v := f.Vector()
	if len(v) != 17 {
		t.Fatalf("Vector length = %d, want 17", len(v))
	}
	if v[0] != 0 {
		t.Errorf("Vector()[0] (tempo) = %v, want 0 when TempoValid=false", v[0])
	}
}

func argmax(v [12]float64) int {
	best := 0
	for i := 1; i < 12; i++ {
		if v[i] > v[best] {
			best = i
		}
	}
	return best
}