1 files changed, 117 insertions, 0 deletions
diff --git a/code/pawn/Player.Use.cs b/code/pawn/Player.Use.cs
new file mode 100644
index 0000000..3f35052
--- /dev/null
+++ b/code/pawn/Player.Use.cs
@@ -0,0 +1,117 @@
+using Sandbox;
+
+namespace MurderGame;
+
+public partial class Player
+{
+	public Entity Using { get; protected set; }
+
+	protected virtual void TickPlayerUse()
+	{
+		// This is serverside only
+		if ( !Game.IsServer ) return;
+
+		// Turn prediction off
+		using ( Prediction.Off() )
+		{
+			if ( Input.Pressed( "use" ) )
+			{
+				Using = FindUsable();
+
+				if ( Using == null )
+				{
+					UseFail();
+					return;
+				}
+			}
+
+			if ( !Input.Down( "use" ) )
+			{
+				StopUsing();
+				return;
+			}
+
+			if ( !Using.IsValid() )
+				return;
+
+			// If we move too far away or something we should probably ClearUse()?
+
+			//
+			// If use returns true then we can keep using it
+			//
+			if ( Using is IUse use && use.OnUse( this ) )
+				return;
+
+			StopUsing();
+		}
+	}
+
+	/// <summary>
+	/// Player tried to use something but there was nothing there.
+	/// Tradition is to give a disappointed boop.
+	/// </summary>
+	protected virtual void UseFail()
+	{
+		PlaySound( "player_use_fail" );
+	}
+
+	/// <summary>
+	/// If we're using an entity, stop using it
+	/// </summary>
+	protected virtual void StopUsing()
+	{
+		Using = null;
+	}
+
+	/// <summary>
+	/// Returns if the entity is a valid usable entity
+	/// </summary>
+	protected bool IsValidUseEntity( Entity e )
+	{
+		if ( e == null ) return false;
+		if ( e is not IUse use ) return false;
+		if ( !use.IsUsable( this ) ) return false;
+
+		return true;
+	}
+
+	/// <summary>
+	/// Find a usable entity for this player to use
+	/// </summary>
+	protected virtual Entity FindUsable()
+	{
+		// First try a direct 0 width line
+		var tr = Trace.Ray( EyePosition, EyePosition + EyeRotation.Forward * 85 )
+			.Ignore( this )
+			.Run();
+
+		// See if any of the parent entities are usable if we ain't.
+		var ent = tr.Entity;
+		while ( ent.IsValid() && !IsValidUseEntity( ent ) )
+		{
+			ent = ent.Parent;
+		}
+
+		// Nothing found, try a wider search
+		if ( !IsValidUseEntity( ent ) )
+		{
+			tr = Trace.Ray( EyePosition, EyePosition + EyeRotation.Forward * 85 )
+			.Radius( 2 )
+			.Ignore( this )
+			.Run();
+
+			// See if any of the parent entities are usable if we ain't.
+			ent = tr.Entity;
+			while ( ent.IsValid() && !IsValidUseEntity( ent ) )
+			{
+				ent = ent.Parent;
+			}
+		}
+
+		// Still no good? Bail.
+		if ( !IsValidUseEntity( ent ) ) return null;
+
+		return ent;
+	}
+}
+