package shadow

import (
	"context"
	"testing"
	"time"

	"github.com/alicebob/miniredis/v2"
	"github.com/redis/go-redis/v9"
)

func newTestStore(t *testing.T) *Store {
	t.Helper()
	mr := miniredis.RunT(t)
	rdb := redis.NewClient(&redis.Options{Addr: mr.Addr()})
	t.Cleanup(func() { rdb.Close() })
	return New(rdb)
}

// markOnline seeds Redis the way device-control-service's Touch() would,
// without depending on that service's code.
func markOnline(t *testing.T, s *Store, deviceID string, lastSeen time.Time) {
	t.Helper()
	ctx := context.Background()
	if err := s.rdb.SAdd(ctx, knownDevicesKey, deviceID).Err(); err != nil {
		t.Fatalf("seed known device: %v", err)
	}
	if err := s.rdb.Set(ctx, statusKey(deviceID), StatusOnline, 0).Err(); err != nil {
		t.Fatalf("seed status: %v", err)
	}
	if err := s.rdb.Set(ctx, lastSeenKey(deviceID), lastSeen.Unix(), 0).Err(); err != nil {
		t.Fatalf("seed last_seen: %v", err)
	}
}

func TestKnownDevices_ListsSeededDevices(t *testing.T) {
	ctx := context.Background()
	s := newTestStore(t)
	markOnline(t, s, "d1", time.Now())
	markOnline(t, s, "d2", time.Now())

	got, err := s.KnownDevices(ctx)
	if err != nil {
		t.Fatalf("known devices: %v", err)
	}
	if len(got) != 2 {
		t.Fatalf("got %d known devices, want 2 (%v)", len(got), got)
	}
}

func TestMarkOfflineIfStale(t *testing.T) {
	ctx := context.Background()
	s := newTestStore(t)
	markOnline(t, s, "d1", time.Now())

	changed, err := s.MarkOfflineIfStale(ctx, "d1", time.Hour)
	if err != nil {
		t.Fatalf("mark offline (not stale): %v", err)
	}
	if changed {
		t.Fatal("device just touched should not be considered stale")
	}

	changed, err = s.MarkOfflineIfStale(ctx, "d1", -time.Second) // any age counts as stale
	if err != nil {
		t.Fatalf("mark offline (stale): %v", err)
	}
	if !changed {
		t.Fatal("expected status to flip to offline")
	}

	// Already offline: a second call should report no further change.
	changed, err = s.MarkOfflineIfStale(ctx, "d1", -time.Second)
	if err != nil {
		t.Fatalf("mark offline (already offline): %v", err)
	}
	if changed {
		t.Fatal("expected no change once already offline")
	}
}

func TestMarkOfflineIfStale_UnknownDeviceIsNoop(t *testing.T) {
	ctx := context.Background()
	s := newTestStore(t)

	changed, err := s.MarkOfflineIfStale(ctx, "ghost", time.Second)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if changed {
		t.Fatal("unknown device should never be reported as changed")
	}
}