package shadow

import (
	"context"
	"encoding/json"
	"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)
}

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

	if err := s.PatchDesiredState(ctx, "d1", map[string]any{"power": "on"}); err != nil {
		t.Fatalf("first patch: %v", err)
	}
	if err := s.PatchDesiredState(ctx, "d1", map[string]any{"level": 42.0}); err != nil {
		t.Fatalf("second patch: %v", err)
	}

	raw, err := s.rdb.Get(ctx, desiredKey("d1")).Result()
	if err != nil {
		t.Fatalf("get: %v", err)
	}
	var got map[string]any
	if err := json.Unmarshal([]byte(raw), &got); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if got["power"] != "on" || got["level"] != 42.0 {
		t.Fatalf("got %+v, want power=on and level=42", got)
	}
}

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

	becameOnline, err := s.Touch(ctx, "d1")
	if err != nil {
		t.Fatalf("touch: %v", err)
	}
	if !becameOnline {
		t.Fatal("expected first touch to report an online transition")
	}

	becameOnline, err = s.Touch(ctx, "d1")
	if err != nil {
		t.Fatalf("second touch: %v", err)
	}
	if becameOnline {
		t.Fatal("expected second touch (already online) to report no transition")
	}

	ids, err := s.KnownDevices(ctx)
	if err != nil {
		t.Fatalf("known devices: %v", err)
	}
	if len(ids) != 1 || ids[0] != "d1" {
		t.Fatalf("got known devices %+v, want [d1]", ids)
	}
}

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

	if _, err := s.Touch(ctx, "d1"); err != nil {
		t.Fatalf("touch: %v", err)
	}

	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")
	}
}