From 8237eda13d6682b0b8befbb08852fa2a1c6eb1f7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Rudowicz?= <michal.rudowicz@fl9.eu>
Date: Tue, 5 Mar 2024 23:01:38 +0100
Subject: [PATCH] Join filters etc. to limit numbers of goroutines that aren't
 needed

References: https://todo.sr.ht/~michalr/hswro-alarm-bot/7
---
 filters.go      | 74 +++++++++++++------------------------------------
 filters_test.go |  8 +++---
 main.go         |  9 ++----
 3 files changed, 26 insertions(+), 65 deletions(-)

diff --git a/filters.go b/filters.go
index cd64446..9c7cbff 100644
--- a/filters.go
+++ b/filters.go
@@ -6,10 +6,24 @@ import (
 	"git.sr.ht/~michalr/go-satel"
 )
 
-func FilterByType(ev <-chan satel.Event, allowedTypes []satel.ChangeType) <-chan satel.Event {
+func isBasicEventElementOkay(basicEventElement satel.BasicEventElement, allowedTypes []satel.ChangeType, allowedIndexes []int) bool {
+	for _, allowedType := range allowedTypes {
+		if allowedType == basicEventElement.Type {
+			return true
+		}
+	}
+	for _, allowedIndex := range allowedIndexes {
+		if allowedIndex == basicEventElement.Index {
+			return true
+		}
+	}
+	return false
+}
+
+func FilterByTypeOrIndex(ev <-chan satel.Event, allowedTypes []satel.ChangeType, allowedIndexes []int) <-chan satel.Event {
 	returnChan := make(chan satel.Event)
 
-	if len(allowedTypes) == 0 {
+	if (len(allowedTypes) == 0) && (len(allowedIndexes) == 0) {
 		// no allowed types == all types are allowed
 		go func() {
 			for e := range ev {
@@ -22,45 +36,8 @@ func FilterByType(ev <-chan satel.Event, allowedTypes []satel.ChangeType) <-chan
 			for e := range ev {
 				retEv := satel.Event{BasicEvents: make([]satel.BasicEventElement, 0)}
 				for _, basicEventElement := range e.BasicEvents {
-					for _, allowedType := range allowedTypes {
-						if allowedType == basicEventElement.Type {
-							retEv.BasicEvents = append(retEv.BasicEvents, basicEventElement)
-							continue
-						}
-					}
-				}
-				if len(retEv.BasicEvents) != 0 {
-					returnChan <- retEv
-				}
-			}
-			close(returnChan)
-		}()
-	}
-
-	return returnChan
-}
-
-func FilterByIndex(ev <-chan satel.Event, allowedIndexes []int) <-chan satel.Event {
-	returnChan := make(chan satel.Event)
-
-	if len(allowedIndexes) == 0 {
-		// no allowed indexes == all indexes are allowed
-		go func() {
-			for e := range ev {
-				returnChan <- e
-			}
-			close(returnChan)
-		}()
-	} else {
-		go func() {
-			for e := range ev {
-				retEv := satel.Event{BasicEvents: make([]satel.BasicEventElement, 0)}
-				for _, basicEventElement := range e.BasicEvents {
-					for _, allowedIndex := range allowedIndexes {
-						if allowedIndex == basicEventElement.Index {
-							retEv.BasicEvents = append(retEv.BasicEvents, basicEventElement)
-							continue
-						}
+					if isBasicEventElementOkay(basicEventElement, allowedTypes, allowedIndexes) {
+						retEv.BasicEvents = append(retEv.BasicEvents, basicEventElement)
 					}
 				}
 				if len(retEv.BasicEvents) != 0 {
@@ -93,20 +70,7 @@ func FilterByLastSeen(ev <-chan satel.Event, dataStore *DataStore, logger *log.L
 				returnChan <- retEv
 			}
 		}
-		close(returnChan)
-	}()
-
-	return returnChan
-}
-
-func CallWhenClosed(ev <-chan satel.Event, cbk func()) <-chan satel.Event {
-	returnChan := make(chan satel.Event)
-
-	go func() {
-		for e := range ev {
-			returnChan <- e
-		}
-		cbk()
+		logger.Print("Satel disconnected.")
 		close(returnChan)
 	}()
 
diff --git a/filters_test.go b/filters_test.go
index 3e5a5d6..32470e4 100644
--- a/filters_test.go
+++ b/filters_test.go
@@ -18,7 +18,7 @@ func TestSatelEventTypeFiltering(t *testing.T) {
 
 	go func() {
 		wg.Add(1)
-		for e := range FilterByType(testEvents, []satel.ChangeType{satel.ArmedPartition, satel.PartitionFireAlarm}) {
+		for e := range FilterByTypeOrIndex(testEvents, []satel.ChangeType{satel.ArmedPartition, satel.PartitionFireAlarm}, []int{}) {
 			receivedEvents = append(receivedEvents, e)
 		}
 		wg.Done()
@@ -46,7 +46,7 @@ func TestSatelEventTypeFiltering_NoAllowedEventTypesMeansAllAreAllowed(t *testin
 
 	go func() {
 		wg.Add(1)
-		for e := range FilterByType(testEvents, []satel.ChangeType{}) {
+		for e := range FilterByTypeOrIndex(testEvents, []satel.ChangeType{}, []int{}) {
 			receivedEvents = append(receivedEvents, e)
 		}
 		wg.Done()
@@ -72,7 +72,7 @@ func TestSatelIndexFiltering(t *testing.T) {
 
 	go func() {
 		wg.Add(1)
-		for e := range FilterByIndex(testEvents, []int{1, 3}) {
+		for e := range FilterByTypeOrIndex(testEvents, []satel.ChangeType{}, []int{1, 3}) {
 			receivedEvents = append(receivedEvents, e)
 		}
 		wg.Done()
@@ -101,7 +101,7 @@ func TestSatelIndexFiltering_NoAllowedEventTypesMeansAllAreAllowed(t *testing.T)
 
 	go func() {
 		wg.Add(1)
-		for e := range FilterByIndex(testEvents, []int{}) {
+		for e := range FilterByTypeOrIndex(testEvents, []satel.ChangeType{}, []int{}) {
 			receivedEvents = append(receivedEvents, e)
 		}
 		wg.Done()
diff --git a/main.go b/main.go
index 6512a54..6bb2199 100644
--- a/main.go
+++ b/main.go
@@ -153,12 +153,9 @@ func main() {
 
 	go CloseSatelOnCtrlC(s)
 
-	for e := range FilterByIndex(FilterByType(
-		FilterByLastSeen(
-			CallWhenClosed(s.Events, func() { logger.Print("Satel disconnected.") }),
-			&dataStore, log.New(os.Stderr, "FilterByLastSeen", log.Lmicroseconds)),
-		allowedTypes),
-		allowedIndexes) {
+	for e := range FilterByTypeOrIndex(
+		FilterByLastSeen(s.Events, &dataStore, log.New(os.Stderr, "FilterByLastSeen", log.Lmicroseconds)),
+		allowedTypes, allowedIndexes) {
 		logger.Print("Received change from SATEL: ", e)
 		for _, chatId := range chatIds {
 			sendTgMessage(tgEvents, e.BasicEvents, chatId)