using System.Linq;
using UnityEngine;

namespace UnityEditor.Graphs.Material
{
	abstract class Function3Input : 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, GetInputSlot1Name ()));
			AddSlot (new Slot (SlotType.InputSlot, GetInputSlot2Name ()));
			AddSlot (new Slot (SlotType.InputSlot, GetInputSlot3Name ()));
		}

		protected virtual string GetInputSlot1Name() { return "Input1"; }
		protected virtual string GetInputSlot2Name() { return "Input2"; }
		protected virtual string GetInputSlot3Name() { return "Input3"; }
		protected virtual string GetOutputSlotName() { return "Output"; }

		protected abstract string GetFunctionName();

		public void GenerateNodeCode(ShaderGenerator visitor, GenerationMode generationMode)
		{
			var outputSlot = FindOutputSlot (GetOutputSlotName ());
			var inputSlot1 = FindInputSlot (GetInputSlot1Name ());
			var inputSlot2 = FindInputSlot (GetInputSlot2Name ());
			var inputSlot3 = FindInputSlot (GetInputSlot3Name ());

			if (inputSlot1 == null || inputSlot2 == null || inputSlot3 == null || outputSlot == null)
			{
				Debug.LogError("Invalid slot configuration on node: " + name);
				return;
			}

			string input1Value = GetSlotValue(inputSlot1, generationMode);
			string input2Value = GetSlotValue(inputSlot2, generationMode);
			string input3Value = GetSlotValue(inputSlot2, generationMode);

			visitor.AddShaderChunk(precision + "4 " + GetOutputVariableNameForSlot(outputSlot, generationMode) + " = " + GetFunctionCallBody(input1Value, input2Value, input3Value) + ";", true);
		}

		protected virtual string GetFunctionCallBody(string inputValue1, string inputValue2, string inputValue3)
		{
			return GetFunctionName() + " (" + inputValue1 + ", " + inputValue2 + ", " + inputValue3 + ")";
		}
	}
}