package settings

import (
	"context"
	"fmt"
	"os"
	"testing"
	"time"
)

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)
loop:
	for range 5 {
		select {
		case <-t.Context().Done():
			t.Fatalf("error: %v\n", t.Context().Err())
		case <-time.After(time.Millisecond * 50):
			if want, got := value, monitor.GetValue(); want == got {
				break loop
			}
		}
	}
	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|os.O_CREATE, 0664)
	if err != nil {
		t.Fatalf("error opening file writer to append settings: %v\n", err)
	}
	_, err = fmt.Fprintf(f, "\n%s=%s\n", key, value)
	if err != nil {
		t.Fatalf("error appending to file: %v\n", err)
	}
	err = f.Close()
	if err != nil {
		t.Fatalf("error closing %s: %v\n", TheSettings.GetFilename(), err)
	}
	err = TheSettings.Update()
	if err != nil {
		t.Fatalf("error updating the settings: %v\n", err)
	}
	for range 5 {
		select {
		case <-t.Context().Done():
			t.Fatalf("error: %v\n", t.Context().Err())
		case <-time.After(time.Millisecond * 50):
			if want, got := value, monitor.GetValue(); want != got {
				t.Fatalf("error: wanted %q; got %q\n", want, got)
			}
		}
	}
	if want, got := value, monitor.GetValue(); want != got {
		t.Fatalf("error: wanted %q; got %q\n", want, got)
	}
}

func TestInsertOrTimeout(t *testing.T) {
	ctx, cancel := context.WithCancel(t.Context())
	defer cancel()
	channel := make(chan string, 1)
	defer close(channel)
	err := insertOrTimeout(ctx, channel, "first string")
	if err != nil {
		t.Fatalf("error: %v\n", err)
	}
	select {
	case <-ctx.Done():
		t.Fatalf("error: %v\n", ctx.Err())
	case _, ok := <-channel:
		if !ok {
			t.Fatalf("error: channel closed earlier than expected...\n")
		}
	}
	cancel()
	<-ctx.Done()
	err = insertOrTimeout(ctx, channel, "second string")
	if err == nil {
		t.Fatalf("error: inserted after ctx.Done\n")
	}

}