Reverts "Add ability to provide selectableDayPredicate for showDateRangePicker (#150355)" (#154089)

Reverts: flutter/flutter#150355
Initiated by: chingjun
Reason for reverting: this is breaking an internal test.
Original PR Author: Chuckame

Reviewed By: {victorsanni, MitchellGoodwin}

This change reverts the following previous change:
- Closes #63973
- Now able to provide a `selectableDayPredicate`
- No breaking change (same behavior as before if not set)
- Reuse the same feature as the DatePicker: non-selectable days are greyed and not clickable
- Reuse the same error message as if the user set a wrong date range
- Made public `CalendarDateRangePicker`, actually the same for `CalendarDatePicker`, to allow using the range picker outside the `showDateRangePicker` bottom sheet modal

## Examples
- Disable days after the next non selectable day when start day has been selected

https://github.com/flutter/flutter/assets/16419143/2a2be325-1e2f-470c-8b17-b4ed5b2ad43e

- Select a range including non-selectable days

<img width="363" alt="image" src="https://github.com/flutter/flutter/assets/16419143/21e32def-46f0-41d6-974f-281a0405e28e">

Author: auto-submit[bot]

packages/flutter/lib/src/material/date_picker.dart

@@ -1012,18 +1012,6 @@ class _DatePickerHeader extends StatelessWidget {
   }
 }
 
-/// Signature for predicating enabled dates in date range pickers.
-///
-/// The [selectedStartDay] and [selectedEndDay] are the currently selected start
-/// and end dates of a date range, which conditionally enables or disables each
-/// date in the picker based on the user selection. (Example: in a hostel's room
-/// selection, you are not able to select the end date after the next
-/// non-selectable day).
-///
-/// See [showDateRangePicker], which has a [SelectableDayForRangePredicate]
-/// parameter used to specify allowable days in the date range picker.
-typedef SelectableDayForRangePredicate = bool Function(DateTime day, DateTime? selectedStartDay, DateTime? selectedEndDay);
-
 /// Shows a full screen modal dialog containing a Material Design date range
 /// picker.
 ///
@@ -1152,8 +1140,11 @@ Future<DateTimeRange?> showDateRangePicker({
   TextInputType keyboardType = TextInputType.datetime,
   final Icon? switchToInputEntryModeIcon,
   final Icon? switchToCalendarEntryModeIcon,
-  SelectableDayForRangePredicate? selectableDayPredicate,
 }) async {
+  assert(
+    initialDateRange == null || !initialDateRange.start.isAfter(initialDateRange.end),
+    "initialDateRange's start date must not be after it's end date.",
+  );
   initialDateRange = initialDateRange == null ? null : DateUtils.datesOnly(initialDateRange);
   firstDate = DateUtils.dateOnly(firstDate);
   lastDate = DateUtils.dateOnly(lastDate);
@@ -1177,16 +1168,6 @@ Future<DateTimeRange?> showDateRangePicker({
     initialDateRange == null || !initialDateRange.end.isAfter(lastDate),
     "initialDateRange's end date must be on or before lastDate $lastDate.",
   );
-  assert(
-    initialDateRange == null || selectableDayPredicate == null ||
-      selectableDayPredicate(initialDateRange.start, initialDateRange.start, initialDateRange.end),
-    "initialDateRange's start date must be selectable.",
-  );
-  assert(
-    initialDateRange == null || selectableDayPredicate == null ||
-      selectableDayPredicate(initialDateRange.end, initialDateRange.start, initialDateRange.end),
-    "initialDateRange's end date must be selectable.",
-  );
   currentDate = DateUtils.dateOnly(currentDate ?? DateTime.now());
   assert(debugCheckHasMaterialLocalizations(context));
 
@@ -1195,7 +1176,6 @@ Future<DateTimeRange?> showDateRangePicker({
     firstDate: firstDate,
     lastDate: lastDate,
     currentDate: currentDate,
-    selectableDayPredicate: selectableDayPredicate,
     initialEntryMode: initialEntryMode,
     helpText: helpText,
     cancelText: cancelText,
@@ -1304,7 +1284,6 @@ class DateRangePickerDialog extends StatefulWidget {
     this.restorationId,
     this.switchToInputEntryModeIcon,
     this.switchToCalendarEntryModeIcon,
-    this.selectableDayPredicate,
   });
 
   /// The date range that the date range picker starts with when it opens.
@@ -1433,9 +1412,6 @@ class DateRangePickerDialog extends StatefulWidget {
   /// {@macro flutter.material.date_picker.switchToCalendarEntryModeIcon}
   final Icon? switchToCalendarEntryModeIcon;
 
-  /// Function to provide full control over which [DateTime] can be selected.
-  final SelectableDayForRangePredicate? selectableDayPredicate;
-
   @override
   State<DateRangePickerDialog> createState() => _DateRangePickerDialogState();
 }
@@ -1498,14 +1474,18 @@ class _DateRangePickerDialogState extends State<DateRangePickerDialog> with Rest
 
         case DatePickerEntryMode.input:
           // Validate the range dates
-          if (_selectedStart.value != null && _selectedEnd.value != null && _selectedStart.value!.isAfter(_selectedEnd.value!)) {
-            _selectedEnd.value = null;
-          }
-          if (_selectedStart.value != null && !_isDaySelectable(_selectedStart.value!)) {
+          if (_selectedStart.value != null &&
+              (_selectedStart.value!.isBefore(widget.firstDate) || _selectedStart.value!.isAfter(widget.lastDate))) {
             _selectedStart.value = null;
             // With no valid start date, having an end date makes no sense for the UI.
             _selectedEnd.value = null;
-          } else if (_selectedEnd.value != null && !_isDaySelectable(_selectedEnd.value!)) {
+          }
+          if (_selectedEnd.value != null &&
+              (_selectedEnd.value!.isBefore(widget.firstDate) || _selectedEnd.value!.isAfter(widget.lastDate))) {
+            _selectedEnd.value = null;
+          }
+          // If invalid range (start after end), then just use the start date
+          if (_selectedStart.value != null && _selectedEnd.value != null && _selectedStart.value!.isAfter(_selectedEnd.value!)) {
             _selectedEnd.value = null;
           }
           _entryMode.value = DatePickerEntryMode.calendar;
@@ -1517,16 +1497,6 @@ class _DateRangePickerDialogState extends State<DateRangePickerDialog> with Rest
     });
   }
 
-  bool _isDaySelectable(DateTime day) {
-    if (day.isBefore(widget.firstDate) || day.isAfter(widget.lastDate)) {
-      return false;
-    }
-    if (widget.selectableDayPredicate == null) {
-      return true;
-    }
-    return widget.selectableDayPredicate!(day, _selectedStart.value, _selectedEnd.value);
-  }
-
   void _handleStartDateChanged(DateTime? date) {
     setState(() => _selectedStart.value = date);
   }
@@ -1565,7 +1535,6 @@ class _DateRangePickerDialogState extends State<DateRangePickerDialog> with Rest
           selectedEndDate: _selectedEnd.value,
           firstDate: widget.firstDate,
           lastDate: widget.lastDate,
-          selectableDayPredicate: widget.selectableDayPredicate,
           currentDate: widget.currentDate,
           onStartDateChanged: _handleStartDateChanged,
           onEndDateChanged: _handleEndDateChanged,
@@ -1618,7 +1587,6 @@ class _DateRangePickerDialogState extends State<DateRangePickerDialog> with Rest
                     initialEndDate: _selectedEnd.value,
                     firstDate: widget.firstDate,
                     lastDate: widget.lastDate,
-                    selectableDayPredicate: widget.selectableDayPredicate,
                     onStartDateChanged: _handleStartDateChanged,
                     onEndDateChanged: _handleEndDateChanged,
                     autofocus: true,
@@ -1714,15 +1682,13 @@ class _CalendarRangePickerDialog extends StatelessWidget {
     required this.onCancel,
     required this.confirmText,
     required this.helpText,
-    required this.selectableDayPredicate,
     this.entryModeButton,
   });
 
   final DateTime? selectedStartDate;
   final DateTime? selectedEndDate;
   final DateTime firstDate;
   final DateTime lastDate;
-  final SelectableDayForRangePredicate? selectableDayPredicate;
   final DateTime? currentDate;
   final ValueChanged<DateTime> onStartDateChanged;
   final ValueChanged<DateTime?> onEndDateChanged;
@@ -1847,7 +1813,6 @@ class _CalendarRangePickerDialog extends StatelessWidget {
           currentDate: currentDate,
           onStartDateChanged: onStartDateChanged,
           onEndDateChanged: onEndDateChanged,
-          selectableDayPredicate: selectableDayPredicate,
         ),
       ),
     );
@@ -1873,7 +1838,6 @@ class _CalendarDateRangePicker extends StatefulWidget {
     DateTime? initialEndDate,
     required DateTime firstDate,
     required DateTime lastDate,
-    required this.selectableDayPredicate,
     DateTime? currentDate,
     required this.onStartDateChanged,
     required this.onEndDateChanged,
@@ -1904,9 +1868,6 @@ class _CalendarDateRangePicker extends StatefulWidget {
   /// The latest allowable [DateTime] that the user can select.
   final DateTime lastDate;
 
-  /// Function to provide full control over which [DateTime] can be selected.
-  final SelectableDayForRangePredicate? selectableDayPredicate;
-
   /// The [DateTime] representing today. It will be highlighted in the day grid.
   final DateTime currentDate;
 
@@ -1917,7 +1878,7 @@ class _CalendarDateRangePicker extends StatefulWidget {
   final ValueChanged<DateTime?>? onEndDateChanged;
 
   @override
-  State<_CalendarDateRangePicker> createState() => _CalendarDateRangePickerState();
+  _CalendarDateRangePickerState createState() => _CalendarDateRangePickerState();
 }
 
 class _CalendarDateRangePickerState extends State<_CalendarDateRangePicker> {
@@ -2020,7 +1981,6 @@ class _CalendarDateRangePickerState extends State<_CalendarDateRangePicker> {
       lastDate: widget.lastDate,
       displayedMonth: month,
       onChanged: _updateSelection,
-      selectableDayPredicate: widget.selectableDayPredicate,
     );
   }
 
@@ -2409,7 +2369,6 @@ class _MonthItem extends StatefulWidget {
     required this.firstDate,
     required this.lastDate,
     required this.displayedMonth,
-    required this.selectableDayPredicate,
   }) : assert(!firstDate.isAfter(lastDate)),
        assert(selectedDateStart == null || !selectedDateStart.isBefore(firstDate)),
        assert(selectedDateEnd == null || !selectedDateEnd.isBefore(firstDate)),
@@ -2442,8 +2401,6 @@ class _MonthItem extends StatefulWidget {
   /// The month whose days are displayed by this picker.
   final DateTime displayedMonth;
 
-  final SelectableDayForRangePredicate? selectableDayPredicate;
-
   @override
   _MonthItemState createState() => _MonthItemState();
 }
@@ -2509,10 +2466,7 @@ class _MonthItemState extends State<_MonthItem> {
   Widget _buildDayItem(BuildContext context, DateTime dayToBuild, int firstDayOffset, int daysInMonth) {
     final int day = dayToBuild.day;
 
-    final bool isDisabled = dayToBuild.isAfter(widget.lastDate) ||
-      dayToBuild.isBefore(widget.firstDate) ||
-      widget.selectableDayPredicate != null &&
-      !widget.selectableDayPredicate!(dayToBuild, widget.selectedDateStart, widget.selectedDateEnd);
+    final bool isDisabled = dayToBuild.isAfter(widget.lastDate) || dayToBuild.isBefore(widget.firstDate);
     final bool isRangeSelected = widget.selectedDateStart != null && widget.selectedDateEnd != null;
     final bool isSelectedDayStart = widget.selectedDateStart != null && dayToBuild.isAtSameMomentAs(widget.selectedDateStart!);
     final bool isSelectedDayEnd = widget.selectedDateEnd != null && dayToBuild.isAtSameMomentAs(widget.selectedDateEnd!);
@@ -2754,7 +2708,7 @@ class _DayItemState extends State<_DayItem> {
     if (widget.isSelectedDayStart || widget.isSelectedDayEnd) {
       // The selected start and end dates gets a circle background
       // highlight, and a contrasting text color.
-      itemStyle = itemStyle?.apply(color: dayForegroundColor);
+      itemStyle = textTheme.bodyMedium?.apply(color: dayForegroundColor);
       decoration = BoxDecoration(
         color: dayBackgroundColor,
         shape: BoxShape.circle,
@@ -2777,15 +2731,12 @@ class _DayItemState extends State<_DayItem> {
         style: _HighlightPainterStyle.highlightAll,
         textDirection: textDirection,
       );
-      if (widget.isDisabled) {
-        itemStyle = itemStyle?.apply(color: colorScheme.onSurface.withOpacity(0.38));
-      }
     } else if (widget.isDisabled) {
-      itemStyle = itemStyle?.apply(color: colorScheme.onSurface.withOpacity(0.38));
+      itemStyle = textTheme.bodyMedium?.apply(color: colorScheme.onSurface.withOpacity(0.38));
     } else if (widget.isToday) {
       // The current day gets a different text color and a circle stroke
       // border.
-      itemStyle = itemStyle?.apply(color: colorScheme.primary);
+      itemStyle = textTheme.bodyMedium?.apply(color: colorScheme.primary);
       decoration = BoxDecoration(
         border: Border.all(color: colorScheme.primary),
         shape: BoxShape.circle,
@@ -3071,7 +3022,6 @@ class _InputDateRangePicker extends StatefulWidget {
     required DateTime lastDate,
     required this.onStartDateChanged,
     required this.onEndDateChanged,
-    required this.selectableDayPredicate,
     this.helpText,
     this.errorFormatText,
     this.errorInvalidText,
@@ -3145,8 +3095,6 @@ class _InputDateRangePicker extends StatefulWidget {
   /// {@macro flutter.material.datePickerDialog}
   final TextInputType keyboardType;
 
-  final SelectableDayForRangePredicate? selectableDayPredicate;
-
   @override
   _InputDateRangePickerState createState() => _InputDateRangePickerState();
 }
@@ -3226,22 +3174,12 @@ class _InputDateRangePickerState extends State<_InputDateRangePicker> {
   String? _validateDate(DateTime? date) {
     if (date == null) {
       return widget.errorFormatText ?? MaterialLocalizations.of(context).invalidDateFormatLabel;
-    } else if (!_isDaySelectable(date)) {
+    } else if (date.isBefore(widget.firstDate) || date.isAfter(widget.lastDate)) {
       return widget.errorInvalidText ?? MaterialLocalizations.of(context).dateOutOfRangeLabel;
     }
     return null;
   }
 
-  bool _isDaySelectable(DateTime day) {
-    if (day.isBefore(widget.firstDate) || day.isAfter(widget.lastDate)) {
-      return false;
-    }
-    if (widget.selectableDayPredicate == null) {
-      return true;
-    }
-    return widget.selectableDayPredicate!(day, _startDate, _endDate);
-  }
-
   void _updateController(TextEditingController controller, String text, bool selectText) {
     TextEditingValue textEditingValue = controller.value.copyWith(text: text);
     if (selectText) {