fixed designs and flow

lib/models/availability.dart

@@ -1,21 +1,97 @@
-enum DayBlock { morning, afternoon, evening }
+/// What a worker has said about a given day.
+///
+/// Three states rather than an on/off switch, because "I can work" and "I want
+/// work" are different answers and Auto-Match treats them differently: an
+/// available day is one it may fill, a preferred day is one it should fill
+/// first.
+enum DayAvailability { available, prefers, unavailable }
 
-extension DayBlockX on DayBlock {
+extension DayAvailabilityX on DayAvailability {
   String get label => switch (this) {
-    DayBlock.morning => 'Morning',
-    DayBlock.afternoon => 'Afternoon',
-    DayBlock.evening => 'Evening',
+    DayAvailability.available => 'Available',
+    DayAvailability.prefers => 'Prefers to work',
+    DayAvailability.unavailable => 'Unavailable',
   };
 
-  String get window => switch (this) {
-    DayBlock.morning => '04:00 - 12:00',
-    DayBlock.afternoon => '12:00 - 18:00',
-    DayBlock.evening => '18:00 - 24:00',
+  /// The line under the option, in the picker.
+  String get blurb => switch (this) {
+    DayAvailability.available => 'Can be scheduled any time',
+    DayAvailability.prefers => 'Wants shifts — optionally within a time window',
+    DayAvailability.unavailable => 'Marked off (vacation, sick, personal)',
   };
 
-  int get hours => switch (this) {
-    DayBlock.morning => 8,
-    DayBlock.afternoon => 6,
-    DayBlock.evening => 6,
+  /// The line under the date, once the day is set.
+  String get summary => switch (this) {
+    DayAvailability.available => 'Can be scheduled any time',
+    DayAvailability.prefers => 'Wants shifts',
+    DayAvailability.unavailable => 'Not available',
   };
 }
+
+/// The hours a worker would rather be given, on a day they want work.
+///
+/// Both ends are optional and independent: "from 6pm, any end" is a normal
+/// thing to want, and forcing a full range would make the worker invent one.
+/// Null at both ends means any time, which is also the default.
+class PreferredWindow {
+  const PreferredWindow({this.from, this.to});
+
+  /// Hour of the day, 0-23. Null is "any time".
+  final int? from;
+  final int? to;
+
+  static const any = PreferredWindow();
+
+  bool get isAnyTime => from == null && to == null;
+
+  /// How the window reads on its own, as a label.
+  String get label {
+    if (isAnyTime) return 'Any time';
+    if (from != null && to != null) return '${_hhmm(from!)} - ${_hhmm(to!)}';
+    if (from != null) return 'From ${_hhmm(from!)}';
+    return 'Until ${_hhmm(to!)}';
+  }
+
+  /// How the window reads inside a sentence — "look for shifts $sentence
+  /// first". The label does not survive being dropped mid-sentence: "look for
+  /// From 09:00 first" is not English.
+  String get sentence {
+    if (isAnyTime) return 'at any time';
+    if (from != null && to != null) {
+      return 'between ${_hhmm(from!)} and ${_hhmm(to!)}';
+    }
+    if (from != null) return 'from ${_hhmm(from!)}';
+    return 'until ${_hhmm(to!)}';
+  }
+
+  PreferredWindow copyWith({
+    int? from,
+    int? to,
+    bool clearFrom = false,
+    bool clearTo = false,
+  }) => PreferredWindow(
+    from: clearFrom ? null : (from ?? this.from),
+    to: clearTo ? null : (to ?? this.to),
+  );
+
+  static String _hhmm(int hour) => '${hour.toString().padLeft(2, '0')}:00';
+}
+
+/// A day's answer: the status, and the window if one was given.
+class DayPlan {
+  const DayPlan({
+    this.status = DayAvailability.unavailable,
+    this.window = PreferredWindow.any,
+  });
+
+  final DayAvailability status;
+
+  /// Only meaningful while [status] is [DayAvailability.prefers]; kept across
+  /// a status change so flipping away and back does not lose the hours.
+  final PreferredWindow window;
+
+  bool get isSet => status != DayAvailability.unavailable;
+
+  DayPlan copyWith({DayAvailability? status, PreferredWindow? window}) =>
+      DayPlan(status: status ?? this.status, window: window ?? this.window);
+}