@namespace CitySim.DesignSystem
@using CitySim.Punchboard
@using Sandbox.UI
@inherits Panel

<root class="plotter-hand"><div class="plotter-hand-cards">@ChildContent</div></root>

@code
{
	/// <summary>Degrees between neighbouring cards.</summary>
	[Parameter] public float FanStep { get; set; } = 7f;

	/// <summary>How far a hovered card rises, in pixels.</summary>
	[Parameter] public float HoverLift { get; set; } = 18f;

	/// <summary>How far a selected card rises, in pixels.</summary>
	[Parameter] public float SelectedLift { get; set; } = 30f;

	// Per-card eased rotation and vertical offset.
	readonly Dictionary<Panel, (float rot, float y)> pose = new();

	public override void Tick()
	{
		base.Tick();

		// Updating a retiring card's transform keeps its CSS transition alive indefinitely.
		// Hand exits use the game's card-flight feedback; retired faces can disappear immediately.
		foreach (var retired in Descendants.OfType<PlotterCard>().Where(c=>c.IsDeleting).ToArray()) retired.Delete(true);
		var cards = Descendants.OfType<PlotterCard>().Where(c=>!c.IsDeleting).Cast<Panel>().ToList();
		var n = cards.Count;

		pose.Keys.Where( p => !cards.Contains( p ) ).ToList().ForEach( p => pose.Remove( p ) );

		for ( var i = 0; i < n; i++ )
		{
			var card = cards[i];
			var offset = i - (n - 1) * 0.5f;
			// Hand slots remain stationary while their cards move, keeping hover stable.
			var slot = card.Parent;
			var inSlot = slot != null && slot.HasClass( "hand-slot" );
			var active = card.HasClass( "selected" ) || card.HasFocus || card.Descendants.Any( p => p.HasFocus ) || (inSlot ? slot.HasHovered : card.HasHovered);
			var targetRot = active ? 0f : offset * FanStep;
			// Rest below the board edge; hover straightens and reveals the full face.
			var targetY = active ? (card.HasClass("selected") ? -SelectedLift : -HoverLift) : 72f + 6f * MathF.Abs(offset);

			pose.TryGetValue( card, out var current );
			if ( !pose.ContainsKey( card ) ) current = (targetRot, targetY);

			var k = Pb.Smooth( active ? 24f : 17f, Time.Delta );
			current = (current.rot + (targetRot - current.rot) * k, current.y + (targetY - current.y) * k);
			pose[card] = current;

			card.Style.Set( "transform", $"translateY({Pb.F( current.y )}px) rotate({Pb.F( current.rot )}deg)" );
			if ( inSlot ) slot.Style.Set( "z-index", active ? "5" : "1" );
			else card.Style.Set( "z-index", active ? "5" : "1" );
		}
	}
}