From 93b3e4874b254885a12dbd5baa9d2d9fafca1d11 Mon Sep 17 00:00:00 2001
From: Pablo Fuentes <f.pablo1@hotmail.com>
Date: Mon, 1 Mar 2021 12:13:21 -0500
Subject: [PATCH] Allow custom themes to react theme variant changes, fixes
 #2006 (#2049)

---
 app/settings.go      | 36 ++++++++++++++++++-----------
 app/settings_test.go | 54 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 76 insertions(+), 14 deletions(-)

diff --git a/app/settings.go b/app/settings.go
index 8da8ccc207..01078999c6 100644
--- a/app/settings.go
+++ b/app/settings.go
@@ -139,26 +139,36 @@ func (s *settings) fileChanged() {
 }
 
 func (s *settings) setupTheme() {
-	if s.themeSpecified {
-		return
-	}
 	name := s.schema.ThemeName
 	if env := os.Getenv("FYNE_THEME"); env != "" {
-		s.themeSpecified = true
 		name = env
 	}
 
-	if name == "light" {
-		s.applyTheme(theme.LightTheme(), theme.VariantLight)
-	} else if name == "dark" {
-		s.applyTheme(theme.DarkTheme(), theme.VariantDark)
-	} else {
-		if defaultVariant() == theme.VariantLight {
-			s.applyTheme(theme.LightTheme(), theme.VariantLight)
-		} else {
-			s.applyTheme(theme.DarkTheme(), theme.VariantDark)
+	var variant fyne.ThemeVariant
+	effectiveTheme := s.theme
+	switch name {
+	case "light":
+		variant = theme.VariantLight
+		if !s.themeSpecified {
+			effectiveTheme = theme.LightTheme()
+		}
+	case "dark":
+		variant = theme.VariantDark
+		if !s.themeSpecified {
+			effectiveTheme = theme.DarkTheme()
+		}
+	default:
+		variant = defaultVariant()
+		if s.themeSpecified {
+			break
+		}
+		effectiveTheme = theme.DarkTheme()
+		if variant == theme.VariantLight {
+			effectiveTheme = theme.LightTheme()
 		}
 	}
+
+	s.applyTheme(effectiveTheme, variant)
 }
 
 func loadSettings() *settings {
diff --git a/app/settings_test.go b/app/settings_test.go
index ea2368883e..67592838c7 100644
--- a/app/settings_test.go
+++ b/app/settings_test.go
@@ -76,16 +76,68 @@ func TestOverrideTheme_IgnoresSettingsChange(t *testing.T) {
 	}
 	set.setupTheme()
 	assert.Equal(t, theme.LightTheme(), set.Theme())
+
+	err = set.loadFromFile(filepath.Join("testdata", "dark-theme.json"))
+	if err != nil {
+		t.Error(err)
+	}
+	set.setupTheme()
+	assert.Equal(t, theme.LightTheme(), set.Theme())
 	err = os.Setenv("FYNE_THEME", "")
 	if err != nil {
 		t.Error(err)
 	}
+}
+
+func TestCustomTheme(t *testing.T) {
+	type customTheme struct {
+		fyne.Theme
+	}
+	set := &settings{}
+	ctheme := &customTheme{theme.LightTheme()}
+	set.SetTheme(ctheme)
+
+	set.setupTheme()
+	assert.True(t, set.Theme() == ctheme)
+	assert.Equal(t, defaultVariant(), set.ThemeVariant())
+
+	err := set.loadFromFile(filepath.Join("testdata", "light-theme.json"))
+	if err != nil {
+		t.Error(err)
+	}
+	set.setupTheme()
+	assert.True(t, set.Theme() == ctheme)
+	assert.Equal(t, theme.VariantLight, set.ThemeVariant())
 
 	err = set.loadFromFile(filepath.Join("testdata", "dark-theme.json"))
 	if err != nil {
 		t.Error(err)
 	}
+	set.setupTheme()
+	assert.True(t, set.Theme() == ctheme)
+	assert.Equal(t, theme.VariantDark, set.ThemeVariant())
 
+	err = os.Setenv("FYNE_THEME", "light")
+	if err != nil {
+		t.Error(err)
+	}
 	set.setupTheme()
-	assert.Equal(t, theme.LightTheme(), set.Theme())
+	assert.True(t, set.Theme() == ctheme)
+	assert.Equal(t, theme.VariantLight, set.ThemeVariant())
+
+	err = os.Setenv("FYNE_THEME", "dark")
+	if err != nil {
+		t.Error(err)
+	}
+	set.setupTheme()
+	assert.True(t, set.Theme() == ctheme)
+	assert.Equal(t, theme.VariantDark, set.ThemeVariant())
+
+	err = os.Setenv("FYNE_THEME", "")
+	if err != nil {
+		t.Error(err)
+	}
+	set.setupTheme()
+	assert.True(t, set.Theme() == ctheme)
+	assert.Equal(t, theme.VariantDark, set.ThemeVariant())
 }