From edb74a66fd43dc8cd4d3c7d5af748b0acc294af5 Mon Sep 17 00:00:00 2001
From: Timo Volkmann <timo.tvm@gmail.com>
Date: Sat, 7 Nov 2020 12:19:00 +0100
Subject: [PATCH] added dispatcher.go

---
 dispatcher/dispatcher.go | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 dispatcher/dispatcher.go

diff --git a/dispatcher/dispatcher.go b/dispatcher/dispatcher.go
new file mode 100644
index 0000000..bcfcba5
--- /dev/null
+++ b/dispatcher/dispatcher.go
@@ -0,0 +1,39 @@
+package dispatcher
+
+import "errors"
+
+type Dispatcher struct {
+	listeners map[int16]chan string
+	counter   int16
+}
+
+func New() Dispatcher {
+	return Dispatcher{
+		listeners: map[int16]chan string{},
+		counter:   0,
+	}
+}
+
+func (d *Dispatcher) Publish(message string) {
+	for _, ch := range d.listeners {
+		ch <- message
+	}
+}
+
+func (d *Dispatcher) Subscribe() (id int16, receiver <-chan string) {
+	key := d.counter
+	d.counter++
+	rec := make(chan string)
+	d.listeners[key] = rec
+	return key, rec
+}
+
+func (d *Dispatcher) Unsubscribe(id int16) error {
+	receiver, ok := d.listeners[id]
+	if !ok {
+		return errors.New("no subscription with id")
+	}
+	delete(d.listeners, id)
+	close(receiver)
+	return nil
+}