@using System.Globalization

<time datetime="@DateTimeOffset.ToString("o", CultureInfo.InvariantCulture)"
      data-relative="@ToTimeAgo(DateTimeOffset)"
      data-initial="@Format"
      @attributes="InputAttributes">
    @GetDisplayDate()
</time>

@code {
    public enum DateDisplayFormat
    {
        Relative,
        Localized
    }

    [Parameter, EditorRequired]
    public DateTimeOffset DateTimeOffset { get; set; }

    [Parameter]
    public DateDisplayFormat Format { get; set; }

    [Parameter(CaptureUnmatchedValues = true)]
    public Dictionary<string, object>? InputAttributes { get; set; }

    private static string ToTimeAgo(DateTimeOffset date) => ToTimeAgo(DateTimeOffset.UtcNow - date);

    private static string ToTimeAgo(DateTime date) => ToTimeAgo(DateTimeOffset.UtcNow - date);

    private static string ToTimeAgo(TimeSpan diff) =>
        diff.TotalSeconds > 0 ? $"{TimeString(diff)} ago" : $"in {TimeString(diff.Negate())}";

    private static string TimeString(TimeSpan timeSpan)
    {
        if (timeSpan.TotalMinutes < 1)
        {
            return $"{(int)timeSpan.TotalSeconds} second{Plural((int)timeSpan.TotalSeconds)}";
        }
        if (timeSpan.TotalHours < 1)
        {
            return $"{(int)timeSpan.TotalMinutes} minute{Plural((int)timeSpan.TotalMinutes)}";
        }
        return timeSpan.Days < 1
            ? $"{(int)timeSpan.TotalHours} hour{Plural((int)timeSpan.TotalHours)}"
            : $"{(int)timeSpan.TotalDays} day{Plural((int)timeSpan.TotalDays)}";
    }

    private static string Plural(int value)
    {
        return value == 1 ? string.Empty : "s";
    }

    private string GetDisplayDate() =>
        Format == DateDisplayFormat.Relative
            ? ToTimeAgo(DateTimeOffset)
            : DateTimeOffset.ToString("g", CultureInfo.InvariantCulture);
}