using System;
using System.Collections.Generic;
using System.Linq;
#if UNITY_EDITOR
using UnityEditor;
#endif
using UnityEngine.Graphing;

namespace UnityEngine.MaterialGraph
{
    [Title("Input/Texture Node")]
    public class TextureNode : PropertyNode, IGeneratesBodyCode, IGeneratesVertexShaderBlock, IGeneratesVertexToFragmentBlock
    {
        protected const string kUVSlotName = "UV";
        protected const string kOutputSlotRGBAName = "RGBA";
        protected const string kOutputSlotRName = "R";
        protected const string kOutputSlotGName = "G";
        protected const string kOutputSlotBName = "B";
        protected const string kOutputSlotAName = "A";

        public const int UvSlotId = 0;
        public const int OutputSlotRgbaId = 1;
        public const int OutputSlotRId = 2;
        public const int OutputSlotGId = 3;
        public const int OutputSlotBId = 4;
        public const int OutputSlotAId = 5;

        [SerializeField]
        private string m_SerializedTexture;

        [SerializeField]
        private TextureType m_TextureType;

        [Serializable]
        private class TextureHelper
        {
            public Texture2D texture;
        }

        public override bool hasPreview { get { return true; } }

#if UNITY_EDITOR
        public Texture2D defaultTexture
        {
            get
            {
                if (string.IsNullOrEmpty(m_SerializedTexture))
                    return null;

                var tex = new TextureHelper();
                EditorJsonUtility.FromJsonOverwrite(m_SerializedTexture, tex);
                return tex.texture;
            }
            set
            {
                if (defaultTexture == value)
                    return;

                var tex = new TextureHelper();
                tex.texture = value;
                m_SerializedTexture = EditorJsonUtility.ToJson(tex, true);

                if (onModified != null)
                {
                    onModified(this);
                }
            }
        }
#else
        public Texture2D defaultTexture {get; set; }
#endif

        public TextureType textureType
        {
            get { return m_TextureType; }
            set
            {
                if (m_TextureType == value)
                    return;


                m_TextureType = value;
                if (onModified != null)
                {
                    onModified(this);
                }
            }
        }

        public TextureNode()
        {
            name = "Texture";
            UpdateNodeAfterDeserialization();
        }

        public sealed override void UpdateNodeAfterDeserialization()
        {
            AddSlot(new MaterialSlot(OutputSlotRgbaId, kOutputSlotRGBAName, kOutputSlotRGBAName, SlotType.Output, SlotValueType.Vector4, Vector4.zero));
            AddSlot(new MaterialSlot(OutputSlotRId, kOutputSlotRName, kOutputSlotRName, SlotType.Output, SlotValueType.Vector1, Vector4.zero));
            AddSlot(new MaterialSlot(OutputSlotGId, kOutputSlotGName, kOutputSlotGName, SlotType.Output, SlotValueType.Vector1, Vector4.zero));
            AddSlot(new MaterialSlot(OutputSlotBId, kOutputSlotBName, kOutputSlotBName, SlotType.Output, SlotValueType.Vector1, Vector4.zero));
            AddSlot(new MaterialSlot(OutputSlotAId, kOutputSlotAName, kOutputSlotAName, SlotType.Output, SlotValueType.Vector1, Vector4.zero));

            AddSlot(new MaterialSlot(UvSlotId, kUVSlotName, kUVSlotName, SlotType.Input, SlotValueType.Vector2, Vector4.zero));
            RemoveSlotsNameNotMatching(validSlots);
        }

        protected int[] validSlots
        {
            get { return new[] {OutputSlotRgbaId, OutputSlotRId, OutputSlotGId, OutputSlotBId, OutputSlotAId, UvSlotId}; }
        }

        // Node generations
        public virtual void GenerateNodeCode(ShaderGenerator visitor, GenerationMode generationMode)
        {
            var uvSlot = FindInputSlot<MaterialSlot>(UvSlotId);
            if (uvSlot == null)
                return;

            var uvName = "IN.meshUV0.xy";

            var edges = owner.GetEdges(uvSlot.slotReference).ToList();

            if (edges.Count > 0)
            {
                var edge = edges[0];
                var fromNode = owner.GetNodeFromGuid<AbstractMaterialNode>(edge.outputSlot.nodeGuid);
                uvName = ShaderGenerator.AdaptNodeOutput(fromNode, edge.outputSlot.slotId, ConcreteSlotValueType.Vector2, true);
            }

            string body = "tex2D (" + propertyName + ", " + uvName + ")";
            if (m_TextureType == TextureType.Bump)
                body = precision + "4(UnpackNormal(" + body + "), 0)";
            visitor.AddShaderChunk(precision + "4 " + GetVariableNameForNode() + " = " + body + ";", true);
        }

        public override string GetVariableNameForSlot(int slotId)
        {
            string slotOutput;
            switch (slotId)
            {
                case OutputSlotRId:
                    slotOutput = ".r";
                    break;
                case OutputSlotGId:
                    slotOutput = ".g";
                    break;
                case OutputSlotBId:
                    slotOutput = ".b";
                    break;
                case OutputSlotAId:
                    slotOutput = ".a";
                    break;
                default:
                    slotOutput = "";
                    break;
            }
            return GetVariableNameForNode() + slotOutput;
        }

        public override void CollectPreviewMaterialProperties(List<PreviewProperty> properties)
        {
            properties.Add(GetPreviewProperty());
        }

        public void GenerateVertexToFragmentBlock(ShaderGenerator visitor, GenerationMode generationMode)
        {
            var uvSlot = FindInputSlot<MaterialSlot>(UvSlotId);
            if (uvSlot == null)
                return;

            var edges = owner.GetEdges(uvSlot.slotReference);
            if (!edges.Any())
                UVNode.StaticGenerateVertexToFragmentBlock(visitor, generationMode);
        }

        public void GenerateVertexShaderBlock(ShaderGenerator visitor, GenerationMode generationMode)
        {
            var uvSlot = FindInputSlot<MaterialSlot>(UvSlotId);
            if (uvSlot == null)
                return;

            var edges = owner.GetEdges(uvSlot.slotReference);
            if (!edges.Any())
                UVNode.GenerateVertexShaderBlock(visitor);
        }

        // Properties
        public override void GeneratePropertyBlock(PropertyGenerator visitor, GenerationMode generationMode)
        {
            visitor.AddShaderProperty(
                new TexturePropertyChunk(
                    propertyName,
                    description,
                    defaultTexture, m_TextureType,
                    PropertyChunk.HideState.Visible,
                    exposedState == ExposedState.Exposed ?
                    TexturePropertyChunk.ModifiableState.Modifiable
                    : TexturePropertyChunk.ModifiableState.NonModifiable));
        }

        public override void GeneratePropertyUsages(ShaderGenerator visitor, GenerationMode generationMode)
        {
            visitor.AddShaderChunk("sampler2D " + propertyName + ";", true);
        }

        /*
            public override bool DrawSlotDefaultInput(Rect rect, Slot inputSlot)
            {
                var uvSlot = FindInputSlot(kUVSlotName);
                if (uvSlot != inputSlot)
                    return base.DrawSlotDefaultInput(rect, inputSlot);


                var rectXmax = rect.xMax;
                rect.x = rectXmax - 70;
                rect.width = 70;

                EditorGUI.DrawRect(rect, new Color(0.0f, 0.0f, 0.0f, 0.7f));
                GUI.Label(rect, "From Mesh");

                return false;
            }
            */

        public override PreviewProperty GetPreviewProperty()
        {
            return new PreviewProperty
                   {
                       m_Name = propertyName,
                       m_PropType = PropertyType.Texture2D,
                       m_Texture = defaultTexture
                   };
        }

        public override PropertyType propertyType { get { return PropertyType.Texture2D; } }
    }
}