using System;
using System.Linq;
using System.Collections.Generic;
using UnityEditor.Graphing;
using UnityEditor.ShaderGraph.Drawing;
using UnityEditor.ShaderGraph.Drawing.Controls;
using UnityEngine;
using UnityEngine.Experimental.UIElements;

namespace UnityEditor.ShaderGraph
{
    [Serializable]
    [Title("Master", "Unlit")]
    public class UnlitMasterNode : MasterNode<IUnlitSubShader>, IMayRequirePosition
    {
        public const string ColorSlotName = "Color";
        public const string AlphaSlotName = "Alpha";
        public const string AlphaClipThresholdSlotName = "AlphaClipThreshold";
        public const string PositionName = "Position";

        public const int ColorSlotId = 0;
        public const int AlphaSlotId = 7;
        public const int AlphaThresholdSlotId = 8;
        public const int PositionSlotId = 9;

        [SerializeField]
        SurfaceType m_SurfaceType;

        public SurfaceType surfaceType
        {
            get { return m_SurfaceType; }
            set
            {
                if (m_SurfaceType == value)
                    return;

                m_SurfaceType = value;
                Dirty(ModificationScope.Graph);
            }
        }

        [SerializeField]
        AlphaMode m_AlphaMode;

        public AlphaMode alphaMode
        {
            get { return m_AlphaMode; }
            set
            {
                if (m_AlphaMode == value)
                    return;

                m_AlphaMode = value;
                Dirty(ModificationScope.Graph);
            }
        }

        [SerializeField]
        bool m_TwoSided;

        public ToggleData twoSided
        {
            get { return new ToggleData(m_TwoSided); }
            set
            {
                if (m_TwoSided == value.isOn)
                    return;
                m_TwoSided = value.isOn;
                Dirty(ModificationScope.Graph);
            }
        }

        public UnlitMasterNode()
        {
            UpdateNodeAfterDeserialization();
        }

        public override string documentationURL
        {
            get { return "https://github.com/Unity-Technologies/ShaderGraph/wiki/Unlit-Master-Node"; }
        }

        public sealed override void UpdateNodeAfterDeserialization()
        {
            base.UpdateNodeAfterDeserialization();
            name = "Unlit Master";
            AddSlot(new PositionMaterialSlot(PositionSlotId, PositionName, PositionName, CoordinateSpace.Object, ShaderStageCapability.Vertex));
            AddSlot(new ColorRGBMaterialSlot(ColorSlotId, ColorSlotName, ColorSlotName, SlotType.Input, Color.grey, ShaderStageCapability.Fragment));
            AddSlot(new Vector1MaterialSlot(AlphaSlotId, AlphaSlotName, AlphaSlotName, SlotType.Input, 1, ShaderStageCapability.Fragment));
            AddSlot(new Vector1MaterialSlot(AlphaThresholdSlotId, AlphaClipThresholdSlotName, AlphaClipThresholdSlotName, SlotType.Input, 0f, ShaderStageCapability.Fragment));

            // clear out slot names that do not match the slots
            // we support
            RemoveSlotsNameNotMatching(
                new[]
            {
                PositionSlotId,
                ColorSlotId,
                AlphaSlotId,
                AlphaThresholdSlotId
            });
        }

        protected override VisualElement CreateCommonSettingsElement()
        {
            return new UnlitSettingsView(this);
        }

        public NeededCoordinateSpace RequiresPosition(ShaderStageCapability stageCapability)
        {
            List<MaterialSlot> slots = new List<MaterialSlot>();
            GetSlots(slots);
            
            List<MaterialSlot> validSlots = new List<MaterialSlot>();
            for(int i = 0; i < slots.Count; i++)
            {
                if(slots[i].stageCapability != ShaderStageCapability.All && slots[i].stageCapability != stageCapability)
                    continue;
                
                validSlots.Add(slots[i]);
            }
            return validSlots.OfType<IMayRequirePosition>().Aggregate(NeededCoordinateSpace.None, (mask, node) => mask | node.RequiresPosition(stageCapability));
        }
    }
}