cards/CardPotion.cs
using Sandbox;
using System.Threading.Tasks;

public class CardPotion : Card
{
	public override bool ShouldHandleEvent( EventType eventType )
	{
		return eventType == EventType.Match && Manager.Instance.ChosenCards[1] == this;
	}

	public override async Task HandleEventAsync( EventType eventType )
	{
		Manager.Instance.PushEventMessage( this, eventType );

		await Task.DelayRealtime( 350 );

		Manager.Instance.PlayCardSfxBetween( "potion_drink", Manager.Instance.ChosenCards[0], Manager.Instance.ChosenCards[1], volume: 1f, pitch: Game.Random.Float( 0.95f, 1.05f ) );

		await Task.DelayRealtime( 500 );

		int halfHP = MathX.CeilToInt( (float)Manager.Instance.MaxHP / 2f );
		if ( Manager.Instance.HP <= halfHP )
		{
			var healAmount = halfHP - Manager.Instance.HP;

			Manager.Instance.SpawnHealHPFloater( healAmount, WorldPosition );

			await Manager.Instance.GainHP( healAmount );

			await Task.DelayRealtime( 400 );

			Manager.Instance.PlayCardSfxBetween( "potion_heal", Manager.Instance.ChosenCards[0], Manager.Instance.ChosenCards[1], volume: 1f, pitch: Game.Random.Float( 0.97f, 1.03f ) );
		}
		else
		{
			var lossAmount = Manager.Instance.HP - halfHP;

			Manager.Instance.SpawnLoseHPFloater( lossAmount, WorldPosition );

			await Manager.Instance.LoseHP( lossAmount );
		}

		await Task.DelayRealtime( 800 );

		Manager.Instance.PopEventMessage();
	}
}