namespace LehrerApp.Core.Services;

public class SchoolYearService
{
    public string CurrentSchoolYear()
    {
        var now = DateTime.Today;
        return FormatSchoolYear(now.Month >= 8 ? now.Year : now.Year - 1);
    }
    public string FormatSchoolYear(int startYear) =>
        $"{startYear}/{(startYear + 1) % 100:D2}";
    public DateOnly SchoolYearStart(string sy) =>
        new(int.Parse(sy.Split('/')[0]), 8, 1);
    public DateOnly SchoolYearEnd(string sy) =>
        new(int.Parse(sy.Split('/')[0]) + 1, 7, 31);
    public List<string> RecentSchoolYears(int count = 5)
    {
        var now = DateTime.Today;
        var cur = now.Month >= 8 ? now.Year : now.Year - 1;
        return Enumerable.Range(0, count).Select(i => FormatSchoolYear(cur - i)).ToList();
    }
}