feat: show a special color for availabilities without a known template

packages/flutter_availability/lib/src/config/availability_options.dart

@@ -91,6 +91,7 @@ class AvailabilityColors {
   /// If a color is not provided the color will be taken from the theme
   const AvailabilityColors({
     this.selectedDayColor,
+    this.customAvailabilityColor,
     this.blankDayColor,
     this.outsideMonthTextColor,
     this.textDarkColor,
@@ -111,6 +112,11 @@ class AvailabilityColors {
   /// The background color of the days that are selected in the calendar
   final Color? selectedDayColor;
 
+  /// The background color of the days that have an availability without a
+  /// template. This color is also shown when a template has been deleted.
+  /// If not provided the color will be the theme's
+  final Color? customAvailabilityColor;
+
   /// The background color of the days in the current month
   /// that have no availability and are not selected
   final Color? blankDayColor;

packages/flutter_availability/lib/src/config/availability_translations.dart

@@ -15,6 +15,7 @@ class AvailabilityTranslations {
     required this.editAvailabilityButton,
     required this.templateLegendTitle,
     required this.templateSelectionLabel,
+    required this.availabilityWithoutTemplateLabel,
     required this.overviewScreenTitle,
     required this.createTemplateButton,
     required this.templateScreenTitle,
@@ -51,6 +52,7 @@ class AvailabilityTranslations {
     this.editAvailabilityButton = "Edit availability",
     this.templateLegendTitle = "Templates",
     this.templateSelectionLabel = "Selected day(s)",
+    this.availabilityWithoutTemplateLabel = "Availabilty without template",
     this.createTemplateButton = "Create a new template",
     this.overviewScreenTitle = "Availability",
     this.templateScreenTitle = "Templates",
@@ -94,6 +96,9 @@ class AvailabilityTranslations {
   /// The text for the selected days in the template legend
   final String templateSelectionLabel;
 
+  /// The label for the availabilities without a template in the template legend
+  final String availabilityWithoutTemplateLabel;
+
   /// The title on the overview screen
   final String overviewScreenTitle;
 

packages/flutter_availability/lib/src/ui/widgets/calendar.dart

@@ -171,7 +171,9 @@ List<CalendarDay> _mapAvailabilitiesToCalendarDays(
             );
         return CalendarDay(
           date: availability.availabilityModel.startDate,
-          color: Color(availability.template?.color ?? 0),
+          color: availability.template != null
+              ? Color(availability.template!.color)
+              : null,
           templateDeviation: templateIsDeviated,
           isSelected: false,
         );

packages/flutter_availability/lib/src/ui/widgets/calendar_grid.dart

@@ -76,10 +76,13 @@ class CalendarGrid extends StatelessWidget {
           ),
           itemBuilder: (context, index) {
             var day = calendarDays[index];
+            var dayColor = day.color ??
+                colors.customAvailabilityColor ??
+                colorScheme.secondary;
             var textColor = day.outsideMonth && !day.isSelected
                 ? colors.outsideMonthTextColor ?? colorScheme.onSurface
                 : _getTextColor(
-                    day.color,
+                    dayColor,
                     colors.textLightColor ?? Colors.white,
                     colors.textDarkColor,
                   );
@@ -89,7 +92,7 @@ class CalendarGrid extends StatelessWidget {
               onTap: () => onDayTap(day.date),
               child: DecoratedBox(
                 decoration: BoxDecoration(
-                  color: day.color,
+                  color: dayColor,
                   borderRadius: BorderRadius.circular(5),
                   border: Border.all(
                     color: day.isSelected && !day.outsideMonth
@@ -137,7 +140,8 @@ class CalendarDay {
   final bool isSelected;
 
   /// The color of the day
-  final Color color;
+  /// If there is no template for an availability the color will be null
+  final Color? color;
 
   /// Whether there is an availability on this day and it deviates from the
   /// used template

packages/flutter_availability/lib/src/ui/widgets/template_legend.dart

@@ -41,6 +41,9 @@ class _TemplateLegendState extends State<TemplateLegend> {
     var templatesAvailable =
         !templatesLoading && (widget.availabilities.data?.isNotEmpty ?? false);
     var templates = widget.availabilities.data?.getUniqueTemplates() ?? [];
+    var existAvailabilitiesWithoutTemplate = widget.availabilities.data
+            ?.any((element) => element.template == null) ??
+        false;
 
     void onDrawerHeaderClick() {
       if (!templatesAvailable && !_templateDrawerOpen) {
@@ -125,11 +128,25 @@ class _TemplateLegendState extends State<TemplateLegend> {
                             itemCount: templates.length + 2,
                             itemBuilder: (context, index) {
                               if (index == 0) {
-                                return _TemplateLegendItem(
+                                return Column(
-                                  name: translations.templateSelectionLabel,
+                                  children: [
-                                  backgroundColor: colors.selectedDayColor ??
+                                    _TemplateLegendItem(
-                                      colorScheme.primaryFixedDim,
+                                      name: translations.templateSelectionLabel,
-                                  borderColor: colorScheme.primary,
+                                      backgroundColor:
+                                          colors.selectedDayColor ??
+                                              colorScheme.primaryFixedDim,
+                                      borderColor: colorScheme.primary,
+                                    ),
+                                    if (existAvailabilitiesWithoutTemplate) ...[
+                                      _TemplateLegendItem(
+                                        name: translations
+                                            .availabilityWithoutTemplateLabel,
+                                        backgroundColor:
+                                            colors.customAvailabilityColor ??
+                                                colorScheme.secondary,
+                                      ),
+                                    ],
+                                  ],
                                 );
                               }
                               if (index == templates.length + 1) {