namespace Blog;

/// <summary>
/// Short human renderings of numbers that would otherwise be printed raw.
/// </summary>
public static class Format
{
    /// <summary>
    /// A duration as the largest two units that carry information — "3d 4h", "1h 4m", "3m 20s",
    /// "42s" — matching what the bot itself prints in chat. Null renders as "?", since a duration
    /// we don't know is not the same as one of zero.
    /// </summary>
    public static string Duration(TimeSpan? span)
    {
        if (span is not { } value) return "?";
        if (value < TimeSpan.Zero) value = TimeSpan.Zero;

        return value switch
        {
            { TotalDays: >= 1 } => $"{(int)value.TotalDays}d {value.Hours}h",
            { TotalHours: >= 1 } => $"{(int)value.TotalHours}h {value.Minutes}m",
            { TotalMinutes: >= 1 } => $"{(int)value.TotalMinutes}m {value.Seconds}s",
            _ => $"{(int)value.TotalSeconds}s"
        };
    }
}