using UnityEngine.Graphing;
using System.Collections.Generic;
using System.Linq;

namespace UnityEngine.MaterialGraph
{
    [Title("Channel/Swizzle")]
    public class SwizzleNode : Function1Input
    {
        public enum SwizzleChannel
        {
            R = 0,
            G = 1,
            B = 2,
            A = 3,
        }

        [SerializeField]
        private SwizzleChannel[] m_SwizzleChannels = new SwizzleChannel[4] { SwizzleChannel.R, SwizzleChannel.G, SwizzleChannel.B, SwizzleChannel.A };

        public SwizzleChannel[] swizzleChannels
        {
            get { return m_SwizzleChannels; }
            set
            {
                if (m_SwizzleChannels == value)
                    return;

                m_SwizzleChannels = value;
                if (onModified != null)
                {
                    onModified(this, ModificationScope.Graph);
                }
            }
        }

        public SwizzleNode()
        {
            name = "Swizzle";
        }

        protected override string GetFunctionName()
        {
            return "";
        }

        protected override string GetFunctionCallBody(string inputValue)
        {
            string[] channelNames = { "r", "g", "b", "a" };
            var inputSlot = FindInputSlot<MaterialSlot>(InputSlotId);
            var outputSlot = FindOutputSlot<MaterialSlot>(OutputSlotId);

            if (inputSlot == null)
                return "1.0";
            if (outputSlot == null)
                return "1.0";

            int numInputChannels = (int)inputSlot.concreteValueType;
            int numOutputChannels = (int)outputSlot.concreteValueType;
            if (owner.GetEdges(inputSlot.slotReference).ToList().Count() == 0)
                numInputChannels = 0;
            if (owner.GetEdges(outputSlot.slotReference).ToList().Count() == 0)
                numOutputChannels = 0;

            if (numOutputChannels == 0)
            {
                return "1.0";
            }

            string outputString = precision + "4(";
            //float4(1.0,1.0,1.0,1.0)
            if (numInputChannels == 0)
            {
                outputString += "1.0, 1.0, 1.0, 1.0).";
            }
            else
            {
                //float4(arg1.
                outputString += inputValue + ".";

                //float4(arg1.xy
                int i = 0;
                for (; i < numInputChannels; ++i)
                {
                    int channel = (int)m_SwizzleChannels[i];
                    outputString += channelNames[channel];
                }

                //float4(arg1.xy, 1.0, 1.0)
                for (; i < 4; i++)
                {
                    outputString += ", 1.0";
                }
                outputString += ").";
            }

            //float4(arg1.xy, 1.0, 1.0).rg
            for (int j = 0; j < numOutputChannels; ++j)
            {
                outputString += channelNames[j];
            }
            return outputString;
        }
    }
}