package settings

import (
	"fmt"
	"os"
	"testing"
)

func TestStringValueMonitor(t *testing.T) {
	key, value := "my key to monitor", "first value"
	monitor, err := NewValueMonitor(TheSettings, key, func(s string) (string, error) { return value, nil })
	if err != nil {
		t.Fatalf("error opening new value monitor: %v\n", err)
	}
	if want, got := value, monitor.GetValue(); want != got {
		t.Fatalf("error: wanted %q; got %q\n", want, got)
	}
	value = "second value"
	TheSettings.SetKeyValue(key, value)
	if want, got := value, monitor.GetValue(); want != got {
		t.Fatalf("error: wanted %q; got %q\n", want, got)
	}
	value = "third value"
	f, err := os.OpenFile(TheSettings.GetFilename(), os.O_APPEND|os.O_WRONLY, 0664)
	if err != nil {
		t.Fatalf("error opening file writer to append settings: %v\n", err)
	}
	_, err = f.WriteString(fmt.Sprintf("\n%s=%s\n", key, value))
	if err != nil {
		t.Fatalf("error appending to file: %v\n", err)
	}
	err = TheSettings.Update()
	if err != nil {
		t.Fatalf("error updating the settings: %v\n", err)
	}
	if want, got := value, monitor.GetValue(); want != got {
		t.Fatalf("error: wanted %q; got %q\n", want, got)
	}
}