feat: polish phase 7 forms and schedules

lib/features/schedules/schedule_form_logic.dart

@@ -0,0 +1,147 @@
+class ScheduleWeekdayOption {
+  final int backendValue;
+  final String shortLabel;
+  final String fullLabel;
+
+  const ScheduleWeekdayOption({
+    required this.backendValue,
+    required this.shortLabel,
+    required this.fullLabel,
+  });
+}
+
+const scheduleWeekdayOptions = <ScheduleWeekdayOption>[
+  ScheduleWeekdayOption(
+    backendValue: 1,
+    shortLabel: 'Пн',
+    fullLabel: 'понедельник',
+  ),
+  ScheduleWeekdayOption(
+    backendValue: 2,
+    shortLabel: 'Вт',
+    fullLabel: 'вторник',
+  ),
+  ScheduleWeekdayOption(backendValue: 3, shortLabel: 'Ср', fullLabel: 'среда'),
+  ScheduleWeekdayOption(
+    backendValue: 4,
+    shortLabel: 'Чт',
+    fullLabel: 'четверг',
+  ),
+  ScheduleWeekdayOption(
+    backendValue: 5,
+    shortLabel: 'Пт',
+    fullLabel: 'пятница',
+  ),
+  ScheduleWeekdayOption(
+    backendValue: 6,
+    shortLabel: 'Сб',
+    fullLabel: 'суббота',
+  ),
+  ScheduleWeekdayOption(
+    backendValue: 0,
+    shortLabel: 'Вс',
+    fullLabel: 'воскресенье',
+  ),
+];
+
+DateTime defaultOnceScheduleTime({DateTime? now}) {
+  final base = now ?? DateTime.now();
+  final candidate = base.add(const Duration(hours: 4));
+  final roundedMinute = ((candidate.minute + 4) ~/ 5) * 5;
+  final normalized = DateTime(
+    candidate.year,
+    candidate.month,
+    candidate.day,
+    candidate.hour,
+    roundedMinute,
+  );
+  return normalized.isAfter(base)
+      ? normalized
+      : normalized.add(const Duration(minutes: 5));
+}
+
+String? validateOnceSchedule(DateTime? scheduledAt, {DateTime? now}) {
+  if (scheduledAt == null) {
+    return 'Выберите дату и время';
+  }
+  final threshold = (now ?? DateTime.now()).add(const Duration(minutes: 1));
+  if (!scheduledAt.isAfter(threshold)) {
+    return 'Нужна дата хотя бы на минуту вперёд';
+  }
+  return null;
+}
+
+String? validateCronSchedule({
+  required int? hour,
+  required int? minute,
+  required Set<int> weekdays,
+}) {
+  if (hour == null || hour < 0 || hour > 23) {
+    return 'Час должен быть от 0 до 23';
+  }
+  if (minute == null || minute < 0 || minute > 59) {
+    return 'Минута должна быть от 0 до 59';
+  }
+  if (weekdays.isEmpty) {
+    return 'Выберите хотя бы один день недели';
+  }
+  return null;
+}
+
+String serializeCronWeekdays(Set<int> weekdays) {
+  if (weekdays.length == scheduleWeekdayOptions.length) {
+    return '*';
+  }
+  final sorted = weekdays.toList()..sort();
+  return sorted.join(',');
+}
+
+String describeCronWeekdays(Set<int> weekdays) {
+  if (weekdays.isEmpty) {
+    return 'дни не выбраны';
+  }
+  if (weekdays.length == scheduleWeekdayOptions.length) {
+    return 'каждый день';
+  }
+  final weekdaySet = weekdays.toSet();
+  final selected = scheduleWeekdayOptions
+      .where((option) => weekdaySet.contains(option.backendValue))
+      .map((option) => option.shortLabel)
+      .toList();
+  return selected.join(', ');
+}
+
+String describeCronWeekdaysExpression(String? value) {
+  if (value == null || value.isEmpty || value == '*') {
+    return 'каждый день';
+  }
+
+  final weekdays = value
+      .split(',')
+      .map((item) => int.tryParse(item.trim()))
+      .whereType<int>()
+      .toSet();
+  if (weekdays.isEmpty) {
+    return value;
+  }
+
+  return describeCronWeekdays(weekdays);
+}
+
+String formatLocalScheduleDateTime(DateTime value) {
+  String pad(int number) => number.toString().padLeft(2, '0');
+  return '${pad(value.day)}.${pad(value.month)}.${value.year} ${pad(value.hour)}:${pad(value.minute)}';
+}
+
+String formatRunAtLabel(String? value) {
+  if (value == null || value.isEmpty) {
+    return 'время не указано';
+  }
+
+  final parsed = DateTime.tryParse(value);
+  if (parsed == null) {
+    return value;
+  }
+
+  return formatLocalScheduleDateTime(parsed.toLocal());
+}