Business Days

Calculate business days with weekend and holiday awareness.

Basic Usage

using Pragmatic.Temporal;

var calculator = new TemporalCalculator();
var today = LocalDate.Today;

// Add 5 business days (skips weekends)
var delivery = calculator.AddBusinessDays(today, 5);

// Count business days between dates
var workDays = calculator.CountBusinessDays(startDate, endDate);

Holiday Providers

No Holidays (Default)

var calculator = new TemporalCalculator(); // Uses NoHolidaysProvider

Static Holiday Provider

Define holidays manually:

var holidays = new StaticHolidayProvider(new[]
{
    new Holiday(new LocalDate(2024, 1, 1), "New Year's Day"),
    new Holiday(new LocalDate(2024, 12, 25), "Christmas"),
    new Holiday(new LocalDate(2024, 12, 26), "Boxing Day")
});

var calculator = new TemporalCalculator(holidays);

Custom Holiday Provider

Implement IHolidayProvider for dynamic holidays:

public class DatabaseHolidayProvider : IHolidayProvider
{
    private readonly IHolidayRepository _repository;

    public DatabaseHolidayProvider(IHolidayRepository repository)
    {
        _repository = repository;
    }

    public IEnumerable<Holiday> GetHolidays(LocalDate from, LocalDate to)
    {
        return _repository.GetHolidays(from, to);
    }

    public bool IsHoliday(LocalDate date)
    {
        return _repository.IsHoliday(date);
    }
}

TemporalCalculator Methods

AddBusinessDays

var calculator = new TemporalCalculator(holidayProvider);

// Add positive days (forward)
var future = calculator.AddBusinessDays(today, 10);

// Add negative days (backward)
var past = calculator.AddBusinessDays(today, -5);

CountBusinessDays

// Count business days in a range (inclusive)
var count = calculator.CountBusinessDays(startDate, endDate);

IsBusinessDay

var date = new LocalDate(2024, 12, 25);
var isWorking = calculator.IsBusinessDay(date); // false (Christmas)

GetNextBusinessDay

// Get next business day (may be today if today is a business day)
var next = calculator.GetNextBusinessDay(date);

// Get next business day (always after given date)
var nextAfter = calculator.GetNextBusinessDay(date, includeToday: false);

GetPreviousBusinessDay

var previous = calculator.GetPreviousBusinessDay(date);

Integration with DI

// Register in Startup/Program.cs
services.AddSingleton<IHolidayProvider>(sp =>
{
    return new StaticHolidayProvider(GetCountryHolidays("US"));
});
services.AddSingleton<TemporalCalculator>();

// Inject in services
public class DeliveryService
{
    private readonly TemporalCalculator _calculator;

    public DeliveryService(TemporalCalculator calculator)
    {
        _calculator = calculator;
    }

    public LocalDate CalculateDeliveryDate(LocalDate orderDate, int businessDays)
    {
        return _calculator.AddBusinessDays(orderDate, businessDays);
    }
}

Country-Specific Holidays

Common pattern for multi-country support:

public class CountryHolidayProvider : IHolidayProvider
{
    private readonly string _countryCode;
    private readonly IHolidayDataSource _dataSource;

    public CountryHolidayProvider(string countryCode, IHolidayDataSource dataSource)
    {
        _countryCode = countryCode;
        _dataSource = dataSource;
    }

    public IEnumerable<Holiday> GetHolidays(LocalDate from, LocalDate to)
    {
        return _dataSource.GetHolidays(_countryCode, from, to);
    }
}

// Usage
var usHolidays = new CountryHolidayProvider("US", dataSource);
var ukHolidays = new CountryHolidayProvider("GB", dataSource);

Holiday Definition

public readonly struct Holiday
{
    public LocalDate Date { get; }
    public string Name { get; }
    public bool IsObserved { get; }  // For observed holidays (e.g., Monday after Sunday)

    public Holiday(LocalDate date, string name, bool isObserved = false)
    {
        Date = date;
        Name = name;
        IsObserved = isObserved;
    }
}

Testing Business Days

public class DeliveryCalculationTests
{
    private readonly TemporalCalculator _calculator;

    public DeliveryCalculationTests()
    {
        var holidays = new StaticHolidayProvider(new[]
        {
            new Holiday(new LocalDate(2024, 12, 25), "Christmas")
        });
        _calculator = new TemporalCalculator(holidays);
    }

    [Fact]
    public void AddBusinessDays_SkipsWeekend()
    {
        var friday = new LocalDate(2024, 6, 14); // Friday
        var result = _calculator.AddBusinessDays(friday, 1);

        result.Should().Be(new LocalDate(2024, 6, 17)); // Monday
    }

    [Fact]
    public void AddBusinessDays_SkipsHoliday()
    {
        var tuesday = new LocalDate(2024, 12, 24); // Tuesday before Christmas
        var result = _calculator.AddBusinessDays(tuesday, 1);

        result.Should().Be(new LocalDate(2024, 12, 26)); // Thursday (skips Christmas)
    }
}