package config

import (
	"os"
	"path/filepath"
	"testing"
)

func TestDefaultValidate(t *testing.T) {
	cfg := Default()
	if err := cfg.Validate(); err != nil {
		t.Fatalf("default config invalid: %v", err)
	}
}

func TestLoadAndValidate(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "config.json")
	if err := os.WriteFile(path, []byte(`{"audio":{"toneLeftHz":900,"toneRightHz":1700,"toneAmplitude":0.3},"fm":{"frequencyMHz":99.9},"backend":{"kind":"file","outputPath":"out.f32"},"control":{"listenAddress":"127.0.0.1:8088"}}`), 0o644); err != nil {
		t.Fatalf("write config: %v", err)
	}
	cfg, err := Load(path)
	if err != nil {
		t.Fatalf("load config: %v", err)
	}
	if cfg.Audio.ToneLeftHz != 900 {
		t.Fatalf("unexpected left tone: %v", cfg.Audio.ToneLeftHz)
	}
}

func TestValidateRejectsBadFrequency(t *testing.T) {
	cfg := Default()
	cfg.FM.FrequencyMHz = 200
	if err := cfg.Validate(); err == nil {
		t.Fatal("expected validation error")
	}
}

func TestValidateRejectsBadPreEmphasis(t *testing.T) {
	cfg := Default()
	cfg.FM.PreEmphasisUS = 150
	if err := cfg.Validate(); err == nil {
		t.Fatal("expected validation error for preEmphasisUS > 100")
	}
}

func TestDefaultPreEmphasis(t *testing.T) {
	cfg := Default()
	if cfg.FM.PreEmphasisUS != 50 {
		t.Fatalf("expected default preEmphasisUS=50, got %.0f", cfg.FM.PreEmphasisUS)
	}
}

func TestDefaultFMModulation(t *testing.T) {
	cfg := Default()
	if !cfg.FM.FMModulationEnabled {
		t.Fatal("expected FM modulation enabled by default")
	}
	if cfg.FM.MaxDeviationHz != 75000 {
		t.Fatalf("expected default maxDeviationHz=75000, got %.0f", cfg.FM.MaxDeviationHz)
	}
}