namespace MeterVault.Core.Tests.Analysis;

/// <summary>Fixed instants in the zones the interval and coverage tests reason about.</summary>
internal static class AnalysisTestTime
{
    public static readonly TimeZoneInfo Berlin = TimeZoneInfo.FindSystemTimeZoneById("Europe/Berlin");

    public static readonly TimeZoneInfo NewYork = TimeZoneInfo.FindSystemTimeZoneById("America/New_York");

    /// <summary>A wall-clock time in <paramref name="zone"/> as an instant.</summary>
    public static DateTimeOffset Local(TimeZoneInfo zone, int year, int month, int day, int hour = 0, int minute = 0, int second = 0)
    {
        var wall = new DateTime(year, month, day, hour, minute, second);
        return new DateTimeOffset(wall, zone.GetUtcOffset(wall));
    }

    public static DateTimeOffset InBerlin(int year, int month, int day, int hour = 0, int minute = 0, int second = 0) =>
        Local(Berlin, year, month, day, hour, minute, second);

    public static DateTimeOffset Utc(int year, int month, int day, int hour = 0, int minute = 0) =>
        new(year, month, day, hour, minute, 0, TimeSpan.Zero);

    /// <summary>The local calendar date an instant falls on.</summary>
    public static DateOnly LocalDate(DateTimeOffset instant, TimeZoneInfo zone) =>
        DateOnly.FromDateTime(TimeZoneInfo.ConvertTime(instant, zone).DateTime);
}