package main

import (
	"math"
	"testing"
	"time"
)

// Test decodeMuLaw basic functionality
func TestDecodeMuLaw(t *testing.T) {
	data := []byte{0x00, 0xFF, 0x7F, 0x80}
	pcm, err := decodeMuLaw(data)
	if err != nil {
		t.Fatalf("decodeMuLaw returned error: %v", err)
	}
	if len(pcm) != len(data) {
		t.Errorf("Expected %d samples, got %d", len(data), len(pcm))
	}
}

// Test Goertzel power calculation
func TestGoertzelPower(t *testing.T) {
	fs := 8000.0
	N := 100
	freq := 1000.0
	g := newGoertzel(freq, fs, N)
	signal := make([]float64, N)
	for i := range signal {
		signal[i] = math.Sin(2 * math.Pi * freq * float64(i) / fs)
	}
	power := g.Power(signal)
	if power <= 0 {
		t.Errorf("Expected positive power, got %f", power)
	}
}

// Test windowHann modifies slice
func TestWindowHann(t *testing.T) {
	x := []float64{1, 1, 1, 1}
	windowHann(x)
	for i, v := range x {
		if v == 1 {
			t.Errorf("windowHann did not modify value at index %d", i)
		}
	}
}

// Test rmsPCM returns correct RMS
func TestRmsPCM(t *testing.T) {
	buf := []int16{1000, -1000, 1000, -1000}
	rms := rmsPCM(buf)
	if rms < 900 || rms > 1100 {
		t.Errorf("Unexpected RMS value: %f", rms)
	}
}

// Test twoToneDetector reset
func TestTwoToneDetectorReset(t *testing.T) {
	d := newTwoToneDetector(8000, 100, 50, 0.65, 300, 1000, 3000, 5000)
	d.inA = true
	d.aFreq = 1000
	d.reset()
	if d.inA || d.aFreq != 0 {
		t.Errorf("reset did not clear state")
	}
}

// Test min function
func TestMin(t *testing.T) {
	if min(1, 2) != 1 {
		t.Errorf("min(1,2) should be 1")
	}
	if min(2, 1) != 1 {
		t.Errorf("min(2,1) should be 1")
	}
	if min(2, 2) != 2 {
		t.Errorf("min(2,2) should be 2")
	}
}

// Test saveToWAV (does not check file output, just runs function)
func TestSaveToWAV(t *testing.T) {
	data := make([]int16, 8000)
	for i := range data {
		data[i] = int16(i % 32768)
	}
	saveToWAV(data, 8000)
	// No assertion, just ensure no panic
}

// Test stepWindow returns expected values for silence
func TestStepWindowSilence(t *testing.T) {
	d := newTwoToneDetector(8000, 100, 50, 0.65, 300, 1000, 3000, 5000)
	buf := make([]int16, 100)
	t0 := time.Now()
	event, aFreq, aDur, bFreq, bDur := d.stepWindow(buf, t0)
	if event != "" || aFreq != 0 || aDur != 0 || bFreq != 0 || bDur != 0 {
		t.Errorf("stepWindow should return zero values for silence")
	}
}