event listeners working

eventListener.go

@@ -1,4 +1,122 @@
 package gomeassistant
 
 // TODO: impl eventListener. could probably create generic listener struct for
-// code reuse between eventListener and entityListener
+// code reuse between eventListener and eventListener
+
+import (
+	"encoding/json"
+	"log"
+	"time"
+
+	"github.com/golang-module/carbon"
+	ws "github.com/saml-dev/gome-assistant/internal/websocket"
+)
+
+type eventListener struct {
+	eventTypes   []string
+	callback     eventListenerCallback
+	betweenStart string
+	betweenEnd   string
+	throttle     time.Duration
+	lastRan      carbon.Carbon
+}
+
+type eventListenerCallback func(*Service, EventData)
+
+type EventData struct {
+	Type         string
+	RawEventJSON []byte
+}
+
+/* Methods */
+
+func EventListenerBuilder() eventListenerBuilder1 {
+	return eventListenerBuilder1{eventListener{
+		lastRan: carbon.Now().StartOfCentury(),
+	}}
+}
+
+type eventListenerBuilder1 struct {
+	eventListener
+}
+
+func (b eventListenerBuilder1) EventType(ets ...string) eventListenerBuilder2 {
+	b.eventTypes = ets
+	return eventListenerBuilder2(b)
+}
+
+type eventListenerBuilder2 struct {
+	eventListener
+}
+
+func (b eventListenerBuilder2) Call(callback eventListenerCallback) eventListenerBuilder3 {
+	b.eventListener.callback = callback
+	return eventListenerBuilder3(b)
+}
+
+type eventListenerBuilder3 struct {
+	eventListener
+}
+
+func (b eventListenerBuilder3) OnlyBetween(start string, end string) eventListenerBuilder3 {
+	b.eventListener.betweenStart = start
+	b.eventListener.betweenEnd = end
+	return b
+}
+
+func (b eventListenerBuilder3) OnlyAfter(start string) eventListenerBuilder3 {
+	b.eventListener.betweenStart = start
+	return b
+}
+
+func (b eventListenerBuilder3) OnlyBefore(end string) eventListenerBuilder3 {
+	b.eventListener.betweenEnd = end
+	return b
+}
+
+func (b eventListenerBuilder3) Throttle(s TimeString) eventListenerBuilder3 {
+	d, err := time.ParseDuration(string(s))
+	if err != nil {
+		log.Fatalf("Couldn't parse string duration passed to Throttle(): \"%s\" see https://pkg.go.dev/time#ParseDuration for valid time units", s)
+	}
+	b.eventListener.throttle = d
+	return b
+}
+
+func (b eventListenerBuilder3) Build() eventListener {
+	return b.eventListener
+}
+
+type BaseEventMsg struct {
+	Event struct {
+		EventType string `json:"event_type"`
+	} `json:"event"`
+}
+
+/* Functions */
+func callEventListeners(app *app, msg ws.ChanMsg) {
+	baseEventMsg := BaseEventMsg{}
+	json.Unmarshal(msg.Raw, &baseEventMsg)
+	listeners, ok := app.eventListeners[baseEventMsg.Event.EventType]
+	if !ok {
+		// no listeners registered for this event type
+		return
+	}
+
+	for _, l := range listeners {
+		// Check conditions
+		if c := CheckWithinTimeRange(l.betweenStart, l.betweenEnd); c.fail {
+			return
+		}
+		if c := CheckThrottle(l.throttle, l.lastRan); c.fail {
+			return
+		}
+
+		eventData := EventData{
+			Type:         baseEventMsg.Event.EventType,
+			RawEventJSON: msg.Raw,
+		}
+		go l.callback(app.service, eventData)
+		l.lastRan = carbon.Now()
+	}
+}