package synth_test

import (
	"testing"

	"github.com/netsynth/netsynth/synth"
)

func TestOscillatorAdvance(t *testing.T) {
	harmonics := []synth.HarmonicDef{{Ratio: 1, Amplitude: 1.0}, {Ratio: 2, Amplitude: 0.5}}
	osc := synth.NewOscillator(440.0, synth.SampleRate)

	hasPos := false
	hasNeg := false
	for i := 0; i < 100; i++ {
		s := osc.Advance(harmonics)
		if s > 0 {
			hasPos = true
		}
		if s < 0 {
			hasNeg = true
		}
	}
	if !hasPos || !hasNeg {
		t.Errorf("expected both positive and negative samples; hasPos=%v hasNeg=%v", hasPos, hasNeg)
	}
}

func TestOscillatorPhaseWrap(t *testing.T) {
	harmonics := []synth.HarmonicDef{{Ratio: 1, Amplitude: 1.0}}
	osc := synth.NewOscillator(440.0, synth.SampleRate)

	for i := 0; i < synth.SampleRate; i++ {
		osc.Advance(harmonics)
	}
	p := osc.Phase()
	if p < 0 || p >= 1.0 {
		t.Errorf("expected phase in [0, 1), got %.6f", p)
	}
}

func TestOscillatorDistinctFreqs(t *testing.T) {
	harmonics := []synth.HarmonicDef{{Ratio: 1, Amplitude: 1.0}}
	osc65 := synth.NewOscillator(65.0, synth.SampleRate)
	osc440 := synth.NewOscillator(440.0, synth.SampleRate)

	same := true
	for i := 0; i < 100; i++ {
		s65 := osc65.Advance(harmonics)
		s440 := osc440.Advance(harmonics)
		if s65 != s440 {
			same = false
			break
		}
	}
	if same {
		t.Error("expected oscillators at 65 Hz and 440 Hz to produce different sample sequences")
	}
}