better handling of qt configuration files

bin/periodic/fix-theming

@@ -1,9 +1,5 @@
 #!/bin/bash
-while read -r line; do
-
-	case "$line" in
-		# When the system theme has been changed
-		'set: /Net/ThemeName')
+sync_theme() {
 	# Get the current system theme
 	theme=$(xfconf-query -c xsettings -p /Net/ThemeName)
 	# Find the best match for the xfwm4 theme that corresponds with the current system theme
@@ -14,27 +10,53 @@ while read -r line; do
 	xfconf-query -c xfwm4 -p /general/theme -n -t string -s "${xfwm4_theme#/}"
 	# Apply the current theme with gsettings
 	gsettings set org.gnome.desktop.interface gtk-theme "$theme"
-			;;
-		# When the icon theme has been changed
-		'set: /Net/IconThemeName')
+}
+
+setvalue() {
+	grep -qz "^\[Appearance\][^\[]*$1=$2" "$file" && return
+	if grep -qz "^\[Appearance\][^\[]*$1=" "$file"; then
+		sed -i "/\[Appearance\]/,/^\s*$1=/{s/^\s*$1=.*$/$1=$2/}" "$file"
+	else
+		sed -i "/\[Appearance\]/a $1=$2" "$file"
+	fi
+}
+
+sync_icon_theme() {
 	# Get the current icon theme
 	icon_theme=$(xfconf-query -c xsettings -p /Net/IconThemeName)
 	# Apply the same theme in qt5ct and qt6ct configuration
 	for file in "$HOME"/.config/qt5ct/qt5ct.conf "$HOME"/.config/qt6ct/qt6ct.conf; do
-				if [ -f "$file" ]; then
-					sed -i "s/^icon_theme=.*$/icon_theme=$icon_theme/" "$file"
+		# Create the config directory
+		dir=$(dirname "$file")
+		mkdir -p "$dir" || { echo "failed to make directory $dir"; continue; }
+		# Create the config file appropriately
+		if grep -q '^\[Appearance\]' "$file"; then
+			setvalue 'icon_theme' "$icon_theme"
+			setvalue 'style' 'gtk2'
+		elif grep -q '\S' "$file"; then
+			tail -n1 "$file" | grep -qx '\s*' && begin='' || begin='\n'
+			printf '%b[Appearance]\nicon_theme=%s\nstyle=gtk2\n' "$begin" "$icon_theme" >> "$file"
 		else
 			printf '[Appearance]\nicon_theme=%s\nstyle=gtk2\n' "$icon_theme" > "$file"
 		fi
 	done
-			;;
-		# When the system font has been changed
-		'set: /Gtk/FontName')
+}
+
+sync_font() {
 	# Get the current system font
 	font=$(xfconf-query -c xsettings -p /Gtk/FontName)
 	# Apply the same font for the title of xfce windows
 	xfconf-query -c xfwm4 -p /general/title_font -n -t string -s "$font"
-			;;
-	esac
+}
 
+sync_theme
+sync_icon_theme
+sync_font
+
+while read -r line; do
+	case "$line" in
+		'set: /Net/ThemeName') sync_theme ;;
+		'set: /Net/IconThemeName') sync_icon_theme ;;
+		'set: /Gtk/FontName') sync_font ;;
+	esac
 done < <(xfconf-query -c xsettings -m)