package audio

import "testing"

func TestReadSamplesSinceReturnsOnlyNewSamples(t *testing.T) {
	r := &Recorder{
		pcmBuf: pcm16LE(0, 16384, -32768),
	}

	samples, nextOffset := r.ReadSamplesSince(1)
	if nextOffset != 3 {
		t.Fatalf("next offset = %d, want 3", nextOffset)
	}
	if len(samples) != 2 {
		t.Fatalf("sample count = %d, want 2", len(samples))
	}
	if samples[0] != 0.5 {
		t.Fatalf("samples[0] = %f, want 0.5", samples[0])
	}
	if samples[1] != -1 {
		t.Fatalf("samples[1] = %f, want -1", samples[1])
	}
}

func TestReadSamplesSinceClampsOffset(t *testing.T) {
	r := &Recorder{
		pcmBuf: pcm16LE(0, 16384),
	}

	samples, nextOffset := r.ReadSamplesSince(99)
	if nextOffset != 2 {
		t.Fatalf("next offset = %d, want 2", nextOffset)
	}
	if len(samples) != 0 {
		t.Fatalf("sample count = %d, want 0", len(samples))
	}
}

func pcm16LE(values ...int16) []byte {
	buf := make([]byte, len(values)*2)
	for i, value := range values {
		buf[i*2] = byte(value)
		buf[i*2+1] = byte(value >> 8)
	}
	return buf
}