From a5d5d38606a394fc0c2c95300a5e5836a25d78e6 Mon Sep 17 00:00:00 2001
From: Florian Thienel <ftl@thecodingflow.com>
Date: Sun, 15 Sep 2024 15:50:21 +0200
Subject: [PATCH] make sure SetView is called only once, otherwise fail fast

---
 core/bandmap/bandmap.go       |  6 ++++--
 core/callinfo/callinfo.go     |  7 +++++--
 core/entry/entry.go           | 11 +++++------
 core/newcontest/newcontest.go |  7 +++++--
 core/parrot/parrot.go         | 11 ++++++++---
 core/rate/rate.go             |  7 +++++--
 core/score/score.go           |  7 +++++--
 core/settings/settings.go     |  7 +++++--
 8 files changed, 42 insertions(+), 21 deletions(-)

diff --git a/core/bandmap/bandmap.go b/core/bandmap/bandmap.go
index 2f1662c..45c4d37 100644
--- a/core/bandmap/bandmap.go
+++ b/core/bandmap/bandmap.go
@@ -156,8 +156,10 @@ func (m *Bandmap) Close() {
 
 func (m *Bandmap) SetView(view View) {
 	if view == nil {
-		m.view = new(nullView)
-		return
+		panic("bandmap.Bandmap.SetView must not be called with nil")
+	}
+	if _, ok := m.view.(*nullView); !ok {
+		panic("bandmap.Bandmap.SetView was already called")
 	}
 
 	m.view = view
diff --git a/core/callinfo/callinfo.go b/core/callinfo/callinfo.go
index 721f55c..a1866f5 100644
--- a/core/callinfo/callinfo.go
+++ b/core/callinfo/callinfo.go
@@ -102,9 +102,12 @@ type View interface {
 
 func (c *Callinfo) SetView(view View) {
 	if view == nil {
-		c.view = new(nullView)
-		return
+		panic("callinfo.Callinfo.SetView must not be called with nil")
+	}
+	if _, ok := c.view.(*nullView); !ok {
+		panic("callinfo.Callinfo.SetView was already called")
 	}
+
 	c.view = view
 	c.view.SetPredictedExchangeFields(c.theirExchangeFields)
 }
diff --git a/core/entry/entry.go b/core/entry/entry.go
index 4b4a7b9..30981e7 100644
--- a/core/entry/entry.go
+++ b/core/entry/entry.go
@@ -165,9 +165,12 @@ func (c *Controller) emitCallsignLogged(callsign string, frequency core.Frequenc
 
 func (c *Controller) SetView(view View) {
 	if view == nil {
-		c.view = &nullView{}
-		return
+		panic("entry.Controller.SetView must not be called with nil")
+	}
+	if _, ok := c.view.(*nullView); !ok {
+		panic("entry.Controller.SetView was already called")
 	}
+
 	c.view = view
 	c.Clear()
 	c.refreshUTC()
@@ -301,10 +304,6 @@ func (c *Controller) StartAutoRefresh() {
 
 func (c *Controller) refreshUTC() {
 	c.asyncRunner(func() {
-		if c.view == nil {
-			return
-		}
-
 		utc := c.clock.Now().UTC()
 		c.view.SetUTC(utc.Format("15:04"))
 	})
diff --git a/core/newcontest/newcontest.go b/core/newcontest/newcontest.go
index 0a8eb90..3619bb1 100644
--- a/core/newcontest/newcontest.go
+++ b/core/newcontest/newcontest.go
@@ -42,9 +42,12 @@ type Controller struct {
 
 func (c *Controller) SetView(view View) {
 	if view == nil {
-		c.view = new(nullview)
-		return
+		panic("newcontest.Controller.SetView must not be called with nil")
 	}
+	if c.view != nil {
+		panic("newcontest.Controller.SetView was already called")
+	}
+
 	c.view = view
 }
 
diff --git a/core/parrot/parrot.go b/core/parrot/parrot.go
index 451f147..913bb56 100644
--- a/core/parrot/parrot.go
+++ b/core/parrot/parrot.go
@@ -73,10 +73,15 @@ func (p *Parrot) Notify(listener any) {
 }
 
 func (p *Parrot) SetView(view View) {
-	p.view = view
-	if view != nil {
-		view.SetParrotActive(p.active)
+	if view == nil {
+		panic("parrot.Parrot.SetView must not be called with nil")
+	}
+	if p.view != nil {
+		panic("parrot.Parrot.SetView was already called")
 	}
+
+	p.view = view
+	view.SetParrotActive(p.active)
 }
 
 func (p *Parrot) SetInterval(interval time.Duration) {
diff --git a/core/rate/rate.go b/core/rate/rate.go
index d21be31..5e7c252 100644
--- a/core/rate/rate.go
+++ b/core/rate/rate.go
@@ -69,9 +69,12 @@ func (c *Counter) StartAutoRefresh() {
 
 func (c *Counter) SetView(view View) {
 	if view == nil {
-		c.view = new(nullView)
-		return
+		panic("rate.Counter.SetView must not be called with nil")
+	}
+	if _, ok := c.view.(*nullView); !ok {
+		panic("rate.Counter.SetView was already called")
 	}
+
 	c.view = view
 	c.view.SetGoals(c.qsosGoal, c.pointsGoal, c.multisGoal)
 	c.view.ShowRate(c.QSORate)
diff --git a/core/score/score.go b/core/score/score.go
index f928baa..77bd6ff 100644
--- a/core/score/score.go
+++ b/core/score/score.go
@@ -97,9 +97,12 @@ func (c *Counter) Result() int {
 
 func (c *Counter) SetView(view View) {
 	if view == nil {
-		c.view = new(nullView)
-		return
+		panic("score.Counter.SetView must not be called with nil")
+	}
+	if _, ok := c.view.(*nullView); !ok {
+		panic("score.Counter.SetView was already called")
 	}
+
 	c.view = view
 	c.view.SetGoals(c.contestPointsGoal, c.contestMultisGoal)
 	c.view.ShowScore(c.readScore) // READ
diff --git a/core/settings/settings.go b/core/settings/settings.go
index 26bc7ef..8d31309 100644
--- a/core/settings/settings.go
+++ b/core/settings/settings.go
@@ -162,9 +162,12 @@ func (s *Settings) SetWriter(writer Writer) {
 
 func (s *Settings) SetView(view View) {
 	if view == nil {
-		s.view = new(nullView)
-		return
+		panic("settings.Settings.SetView must not be called with nil")
+	}
+	if _, ok := s.view.(*nullView); !ok {
+		panic("settings.Settings.SetView was already called")
 	}
+
 	s.view = view
 	s.showSettings()
 }