using UnityEngine;

namespace UnityEditor.Graphs.Material
{
	abstract class Function1Input : BaseMaterialNode, IGeneratesBodyCode
	{
		public override bool hasPreview
		{
			get { return true; }
		}

		public override void Init()
		{
			base.Init ();
			AddSlot (new Slot (SlotType.OutputSlot, GetOutputSlotName ()));
			AddSlot (new Slot (SlotType.InputSlot, GetInputSlotName ()));
		}

		protected virtual string GetInputSlotName() {return "Input";}
		protected virtual string GetOutputSlotName () {return "Output";}

		protected abstract string GetFunctionName ();

		public void GenerateNodeCode(ShaderGenerator visitor, GenerationMode generationMode)
		{
			var outputSlot = FindOutputSlot (GetOutputSlotName ());
			var inputSlot = FindInputSlot (GetInputSlotName ());

			if (inputSlot == null || outputSlot == null)
			{
				Debug.LogError ("Invalid slot configuration on node: " + name);
				return;
			}

			bool inputConnected = inputSlot.edges.Count > 0;

			string inputValue;
			if (inputConnected)
			{
				var inputDateProvider = inputSlot.edges[0].fromSlot.node as BaseMaterialNode;
				inputValue = inputDateProvider.GetOutputVariableNameForSlot (inputSlot.edges[0].fromSlot, generationMode);
			}
			else
			{
				var defaultValue = GetSlotDefaultValue(inputSlot.name);
				inputValue = defaultValue.GetDefaultValue (generationMode);
			}

			visitor.AddShaderChunk(precision + "4 " + GetOutputVariableNameForSlot(outputSlot, generationMode) + " = " + GetFunctionCallBody(inputValue) + ";", true);
		}

		protected virtual string GetFunctionCallBody (string inputValue)
		{
			return GetFunctionName() + " (" + inputValue + ")";
		}
	}
}