date_time_extensions.dart

import 'package:intl/intl.dart';

extension DateTimeX on DateTime {
  bool get isToday {
    return now.day == day && now.month == month && now.year == year;
  }

  bool get isYesterday {
    return now.day - 1 == day && now.month == month && now.year == year;
  }

  bool get isInThisWeek {
    return (now.day - day).abs() < 7 && now.month == month && now.year == year;
  }

  bool get isInThisYear => year == now.year;

  DateTime get now => DateTime.now();

  bool get isInThePastHour => isToday && now.hour == hour;
  
  // The day of this DateTime relative to now. Just the day or the month
  // date depending on whcih is further. Useful for separating a group 
  // of activities (chat messages for example) in the same day.
  String get dayDisplay {
    if (isToday) return 'Today';
    if (isYesterday) return 'Yesterday';
    final format = 'EEEE${isInThisWeek ? '' : ', d MMM'}'
        '${isInThisYear ? '' : ', yyyy'}';
    return DateFormat(format).format(this);
  }

  // The time or day relative to now. 
  // Useful for dates on lists of snippets
  String get overviewDisplay {
    if (isInThePastHour) {
      final mins = now.difference(this).inMinutes;
      return mins == 0 ? 'Now' : '$mins min${mins == 1 ? '' : 's'}';
    }
    if (isYesterday) return 'Yesterday';

    final String format;
    if (isToday) {
      format = 'HH:mm';
    } else if (isInThisWeek) {
      format = 'EEE';
    } else if (isInThisYear) {
      format = 'MMM d';
    } else {
      format = 'MMM yyyy';
    }
    return DateFormat(format).format(this);
  }
  
  // The exact time relative till now. Prefixes day, month, or year
  // as is necessary. Useful for details.
  String get timeDisplay {
    if (isYesterday) return 'Yesterday ${DateFormat('HH:mm').format(this)}';

    final String format;
    if (isToday) {
      format = 'HH:mm';
    } else if (isInThisWeek) {
      format = 'EEE HH:mm';
    } else if (isInThisYear) {
      format = 'MMM d, HH:mm';
    } else {
      format = 'dd/MM/yy, HH:mm';
    }
    return DateFormat(format).format(this);
  }
}