comunicmobile/lib/ui/widgets/forez_presence_calendar_widget.dart

import 'package:comunic/lists/forez_presences_set.dart';
import 'package:comunic/utils/date_utils.dart' as date_utils;
/// Forez presence calendar widget
///
/// This widget is used only by Forez groups
///
/// @author Pierre Hubert
import 'package:flutter/material.dart';
import 'package:table_calendar/table_calendar.dart';

enum CalendarDisplayMode { SINGLE_USER, MULTIPLE_USERS }

extension DateOnlyCompare on DateTime {
  bool isSameDate(DateTime other) => date_utils.isSameDate(this, other);
}

class PresenceCalendarWidget extends StatefulWidget {
  final PresenceSet presenceSet;
  final void Function(DateTime) onDayClicked;
  final CalendarDisplayMode mode;
  final DateTime selectedDay;

  const PresenceCalendarWidget({
    Key key,
    @required this.presenceSet,
    this.onDayClicked,
    this.mode = CalendarDisplayMode.SINGLE_USER,
    this.selectedDay,
  })  : assert(presenceSet != null),
        assert(mode != null),
        super(key: key);

  @override
  _PresenceCalendarWidgetState createState() => _PresenceCalendarWidgetState();
}

class _PresenceCalendarWidgetState extends State<PresenceCalendarWidget> {
  var selectedDay = DateTime.now();

  @override
  void didUpdateWidget(covariant PresenceCalendarWidget oldWidget) {
    super.didUpdateWidget(oldWidget);

    if (oldWidget.selectedDay != widget.selectedDay) {
      selectedDay = widget.selectedDay;
      setState(() {});
    }
  }

  @override
  Widget build(BuildContext context) {
    return TableCalendar(
      firstDay: DateTime.utc(2020, 01, 01),
      lastDay: DateTime.now().add(Duration(days: 365 * 2)),
      selectedDayPredicate: (d) => d == selectedDay,
      locale: "fr_FR",
      weekendDays: [],
      onHeaderTapped: _pickDate,
      calendarBuilders: CalendarBuilders(
        defaultBuilder: _dayBuilder,
        todayBuilder: _dayBuilder,
        selectedBuilder: _dayBuilder,
      ),
      onDaySelected: _selectedDay,
      availableCalendarFormats: const {CalendarFormat.month: "Mois"},
      focusedDay: selectedDay,
      onPageChanged: (s) {
        setState(() {
          selectedDay = s;
        });
      },
    );
  }

  void _pickDate(DateTime date) async {
    final pickedDate = await showDatePicker(
      context: context,
      initialDate: date,
      firstDate: DateTime.now().subtract(Duration(days: 20)),
      lastDate: DateTime.now().add(Duration(days: 365 * 5)),
    );

    setState(() {
      if (pickedDate != null) selectedDay = pickedDate;
    });
  }

  Widget _dayBuilder(BuildContext context, DateTime date, DateTime focusedDay) {
    if (widget.presenceSet.containsDate(date)) {
      // Show the number of users who are present
      if (widget.mode == CalendarDisplayMode.MULTIPLE_USERS)
        return Stack(
          children: [
            CellWidget(
              text: date.day.toString(),
              color: Colors.green,
              textColor: Colors.white,
              circle: false,
              selected: date.isSameDate(widget.selectedDay),
            ),
            Positioned(
              child: Material(
                child: Padding(
                  padding: const EdgeInsets.all(2.0),
                  child: Text(widget.presenceSet.countAtDate(date).toString()),
                ),
                textStyle: TextStyle(color: Colors.white),
                color: Colors.red,
              ),
              bottom: 4,
              right: 4,
            ),
          ],
        );

      // Only show green circle
      else
        return CellWidget(
          text: date.day.toString(),
          color: Colors.green,
          textColor: Colors.white,
        );
    }

    return CellWidget(
      text: date.day.toString(),
      selected: date.isSameDate(widget.selectedDay),
    );
  }

  void _selectedDay(DateTime selecteDay, DateTime focusedDay) {
    if (widget.onDayClicked != null) widget.onDayClicked(selecteDay);
    setState(() {});
  }
}

class CellWidget extends StatelessWidget {
  final String text;
  final Color color;
  final Color textColor;
  final bool circle;
  final bool selected;

  const CellWidget({
    Key key,
    @required this.text,
    this.color,
    this.textColor,
    this.circle = true,
    this.selected,
  })  : assert(text != null),
        super(key: key);

  @override
  Widget build(BuildContext context) {
    return AnimatedContainer(
      duration: const Duration(milliseconds: 250),
      decoration: _buildCellDecoration(),
      margin: const EdgeInsets.all(6.0),
      alignment: Alignment.center,
      child: Text(
        text,
        textAlign: TextAlign.center,
        style: TextStyle(color: selected ?? false ? Colors.white : textColor),
      ),
    );
  }

  Decoration _buildCellDecoration() => BoxDecoration(
        shape: circle ? BoxShape.circle : BoxShape.rectangle,
        color: selected ?? false ? Colors.deepPurple : color,
      );
}