From d2805b655c7894e335b61e0a0b1e9680792b4ab1 Mon Sep 17 00:00:00 2001
From: Matthias Hochgatterer <matthias.hochgatterer@gmail.com>
Date: Wed, 29 Apr 2020 11:05:44 +0200
Subject: [PATCH] Add property to ignore updates of same characteristic values
 #128 #166

If a characteristic value is updated with the same value, it is ignored.
Only exception is the programmable switch event characteristic, which
requires that clients are notified even when updating with the same value.
---
 characteristic/characteristic.go            |  6 +++++-
 characteristic/characteristic_test.go       | 23 +++++++++++++++------
 characteristic/programmable_switch_event.go |  2 ++
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/characteristic/characteristic.go b/characteristic/characteristic.go
index fc72b339..74952f22 100644
--- a/characteristic/characteristic.go
+++ b/characteristic/characteristic.go
@@ -30,6 +30,7 @@ type Characteristic struct {
 	// unused
 	Events bool `json:"-"`
 
+	updateOnSameValue    bool // if true the update notifications
 	connValueUpdateFuncs []ConnChangeFunc
 	valueChangeFuncs     []ChangeFunc
 	valueGetFunc         GetFunc
@@ -124,8 +125,11 @@ func (c *Characteristic) updateValue(value interface{}, conn net.Conn, checkPerm
 		value = c.clampInt(value.(int))
 	}
 
+	if c.Value == value && !c.updateOnSameValue {
+		return
+	}
+
 	// Ignore new values from remote when permissions don't allow write and checkPerms is true
-	// Ignore value when not writable
 	if checkPerms && !c.isWritable() {
 		return
 	}
diff --git a/characteristic/characteristic_test.go b/characteristic/characteristic_test.go
index f5279e49..ca6e1519 100644
--- a/characteristic/characteristic_test.go
+++ b/characteristic/characteristic_test.go
@@ -117,21 +117,32 @@ func TestCharacteristicRemoteDelegate(t *testing.T) {
 	}
 }
 
-func TestValueChange(t *testing.T) {
-	c := NewBrightness()
-	c.Value = 5
+func TestValueChangeNoUPdate(t *testing.T) {
+	c := NewOn()
+	c.Value = true
 
 	changed := false
-	c.OnValueUpdateFromConn(func(conn net.Conn, c *Characteristic, new, old interface{}) {
+	c.OnValueUpdate(func(c *Characteristic, new, old interface{}) {
 		changed = true
 	})
 
+	c.UpdateValue(true)
+
+	if is, want := changed, false; is != want {
+		t.Fatalf("%v != %v", is, want)
+	}
+}
+
+func TestValueChange(t *testing.T) {
+	c := NewProgrammableSwitchEvent()
+	c.Value = ProgrammableSwitchEventSinglePress
+
+	changed := false
 	c.OnValueUpdate(func(c *Characteristic, new, old interface{}) {
 		changed = true
 	})
 
-	c.UpdateValue(5)
-	c.UpdateValueFromConnection(5, TestConn)
+	c.UpdateValue(ProgrammableSwitchEventSinglePress)
 
 	if is, want := changed, true; is != want {
 		t.Fatalf("%v != %v", is, want)
diff --git a/characteristic/programmable_switch_event.go b/characteristic/programmable_switch_event.go
index d0b926d5..80262af1 100644
--- a/characteristic/programmable_switch_event.go
+++ b/characteristic/programmable_switch_event.go
@@ -20,5 +20,7 @@ func NewProgrammableSwitchEvent() *ProgrammableSwitchEvent {
 
 	char.SetValue(0)
 
+	char.updateOnSameValue = true
+
 	return &ProgrammableSwitchEvent{char}
 }