add small tool that plays a sound when item passing the filter is found in the ground

cmd/itemwatcher/internal/watcher.go

@@ -0,0 +1,88 @@
+package itemwatcher
+
+import (
+	"context"
+	"github.com/faiface/beep"
+	"github.com/faiface/beep/speaker"
+	"github.com/faiface/beep/wav"
+	"github.com/hectorgimenez/d2go/pkg/itemfilter"
+	"github.com/hectorgimenez/d2go/pkg/memory"
+	"github.com/hectorgimenez/d2go/pkg/nip"
+	"log"
+	"os"
+	"time"
+)
+
+type Watcher struct {
+	gr                     *memory.GameReader
+	rules                  []nip.Rule
+	alreadyNotifiedItemIDs map[int]interface{}
+}
+
+func NewWatcher(gr *memory.GameReader, rules []nip.Rule) *Watcher {
+	return &Watcher{gr: gr, rules: rules}
+}
+
+func (w *Watcher) Start(ctx context.Context) error {
+	w.alreadyNotifiedItemIDs = make(map[int]interface{}, 0)
+	audioBuffer, err := initAudio()
+	if err != nil {
+		return err
+	}
+
+	for {
+		select {
+		case <-ctx.Done():
+			return nil
+		default:
+			time.Sleep(100 * time.Millisecond)
+
+			d := w.gr.GetData()
+			for _, i := range d.Items.Ground {
+				if !itemfilter.Evaluate(i, w.rules) {
+					continue
+				}
+
+				if _, found := w.alreadyNotifiedItemIDs[int(i.UnitID)]; found {
+					continue
+				}
+
+				log.Printf("%s: Item detected: %s. Quality: %s", time.Now().Format(time.RFC3339), i.Name, i.Quality.ToString())
+
+				w.alreadyNotifiedItemIDs[int(i.UnitID)] = nil
+				speaker.Play(audioBuffer.Streamer(0, audioBuffer.Len()))
+			}
+
+			// Cleanup the already notified list when item is out of range
+			for k := range w.alreadyNotifiedItemIDs {
+				found := false
+				for _, i := range d.Items.Ground {
+					if int(i.UnitID) == k {
+						found = true
+					}
+				}
+				if !found {
+					delete(w.alreadyNotifiedItemIDs, k)
+				}
+			}
+		}
+	}
+}
+
+func initAudio() (*beep.Buffer, error) {
+	f, err := os.Open("assets/ching.wav")
+	if err != nil {
+		return nil, err
+	}
+
+	streamer, format, err := wav.Decode(f)
+	if err != nil {
+		return nil, err
+	}
+	err = speaker.Init(format.SampleRate, format.SampleRate.N(time.Second/10))
+	buffer := beep.NewBuffer(format)
+	buffer.Append(streamer)
+	streamer.Close()
+
+	return buffer, nil
+}