using System.Globalization;

namespace PrivaPub.Domain.Media
{
	// A focal point as Mastodon's API takes it ("x,y", each within -1..1): finite numbers only, clamped to the frame. A NaN
	// once stored here made every status, timeline and Note holding the post fail to serialise, for every viewer.
	public static class FocalPoint
	{
		public static float[] Parse(string value)
		{
			if (value?.Split(',') is not [var x, var y]
				|| !float.TryParse(x, NumberStyles.Float, CultureInfo.InvariantCulture, out var fx) || !float.IsFinite(fx)
				|| !float.TryParse(y, NumberStyles.Float, CultureInfo.InvariantCulture, out var fy) || !float.IsFinite(fy))
				return default;
			return [Math.Clamp(fx, -1, 1), Math.Clamp(fy, -1, 1)];
		}

		/// <summary>Whether a stored focal point can be written out: two finite numbers.</summary>
		public static bool IsSound(float[] focus) => focus is [var x, var y] && float.IsFinite(x) && float.IsFinite(y);
	}
}