algorithm - 如何查找从现在开始到特定工作日的最近的将来日期？

Question

我有一个约会管理方案，其中有一个人的availableWeekDays列表字段，可以在工作日的工作日进行预订。例如，如果星期一有空，我在availableWeekDays列表中的值为1。
我已经使用DateTime将currentDate存储在DateTime.now()变量中。
我要做的是首先看一下今天的工作日是否与某人的availableWeekDay相匹配。如果是，则bookingDate有效，否则我必须与人的工作日一起寻找最近的将来日期。我尝试了以下解决方案，但由于我正在使用第一个索引，因此它可以工作一周。

void main() {
  
  DateTime bookingDate = DateTime.now();
  int availableWeekDays = [1,4,7];
  
  getDate(){
    if(bookingDate.weekday == availableWeekDays[0]){
      print("Available on $bookingDate ");
    } else {
      bookingDate = bookingDate.add(Duration(days: 1));
      getDate();
    }
  }
  
  getDate();
  
}

我想找到列表中所有平日中最接近的将来日期。

Answer 1

DateTime findNearestWeekday(List<int> availableWeekdays) {
  assert(availableWeekdays.isNotEmpty);

  var date = DateTime.now();
  final weekday = date.weekday;

  for (var num in availableWeekdays) {
    if (num == date.weekday) {
      return date;
    } else if (date.weekday < num) {
      return date.add(Duration(days: num - weekday));
    }
  }

  /// I have assumed that you will always have a sorted list of available
  /// weekdays, in case you do not have a sorted list, either you can sort
  /// the list first or just use this line (instead of the last one),
  ///
  /// ```dart
  /// import 'dart:math'; /// Add on Top of file.
  ///
  /// return date.add(Duration(days: 7 - weekday + availableWeekdays.reduce(min)))
  /// ```
  ///
  /// I will prefer to pre sort the array before storing it somewhere,
  /// because it will add an additional dependency dart:math


  return date.add(Duration(days: 7 - weekday + availableWeekdays[0]));
}