using System;
using UnityEngine;
using UnityEngine.Rendering;

namespace UnityEditor
{
    internal class LayeredLitGUI : LitGUI
    {
        private class Styles
        {
            public readonly GUIContent[] materialLayerLabels =
            {
                new GUIContent("Material Layer 0"),
                new GUIContent("Material Layer 1"),
                new GUIContent("Material Layer 2"),
                new GUIContent("Material Layer 3"),
            };
            public readonly GUIContent syncButton = new GUIContent("Re-Synchronize Layers", "Re-synchronize all layers's properties with the referenced Material");
            public readonly GUIContent layers = new GUIContent("Layers");
            public readonly GUIContent layerMapMask = new GUIContent("Layer Mask", "Layer mask (multiplied by vertex color)");
            public readonly GUIContent layerCount = new GUIContent("Layer Count", "Number of layers.");
        }

        static Styles s_Styles = null;
        private static Styles styles { get { if (s_Styles == null) s_Styles = new Styles(); return s_Styles; } }

        // Needed for json serialization to work
        [Serializable]
        internal struct SerializeableGUIDs
        {
            public string[] GUIDArray;
        }

        private const int kMaxLayerCount = 4;
        private const int kSyncButtonWidth = 58;
        private string kLayerMaskMap = "_LayerMaskMap";
        private string kLayerCount = "_LayerCount";

        private Material[] m_MaterialLayers = new Material[kMaxLayerCount];

        MaterialProperty layerCountProperty = null;
        MaterialProperty layerMaskMapProperty = null;

        int layerCount
        {
            set { layerCountProperty.floatValue = (float)value; }
            get { return (int)layerCountProperty.floatValue; }
        }

        void SynchronizeAllLayersProperties()
        {
            for (int i = 0; i < layerCount; ++i)
            {
                SynchronizeLayerProperties(i);
            }
        }

        void SynchronizeLayerProperties(int layerIndex)
        {
            Material material = m_MaterialEditor.target as Material;
            Material layerMaterial = m_MaterialLayers[layerIndex];

            if (layerMaterial != null)
            {
                Shader layerShader = layerMaterial.shader;
                int propertyCount = ShaderUtil.GetPropertyCount(layerShader);
                for (int i = 0; i < propertyCount; ++i)
                {
                    string propertyName = ShaderUtil.GetPropertyName(layerShader, i);
                    string layerPropertyName = propertyName + layerIndex;
                    if (material.HasProperty(layerPropertyName))
                    {
                        ShaderUtil.ShaderPropertyType type = ShaderUtil.GetPropertyType(layerShader, i);
                        switch (type)
                        {
                            case ShaderUtil.ShaderPropertyType.Color:
                            {
                                material.SetColor(layerPropertyName, layerMaterial.GetColor(propertyName));
                                break;
                            }
                            case ShaderUtil.ShaderPropertyType.Float:
                            case ShaderUtil.ShaderPropertyType.Range:
                            {
                                material.SetFloat(layerPropertyName, layerMaterial.GetFloat(propertyName));
                                break;
                            }
                            case ShaderUtil.ShaderPropertyType.Vector:
                            {
                                material.SetVector(layerPropertyName, layerMaterial.GetVector(propertyName));
                                break;
                            }
                            case ShaderUtil.ShaderPropertyType.TexEnv:
                            {
                                material.SetTexture(layerPropertyName, layerMaterial.GetTexture(propertyName));
                                break;
                            }
                        }
                    }
                }
            }
        }

        void InitializeMaterialLayers(AssetImporter materialImporter)
        {
            if (materialImporter.userData != string.Empty)
            {
                SerializeableGUIDs layersGUID = JsonUtility.FromJson<SerializeableGUIDs>(materialImporter.userData);
                if (layersGUID.GUIDArray.Length > 0)
                {
                    m_MaterialLayers = new Material[layersGUID.GUIDArray.Length];
                    for (int i = 0; i < layersGUID.GUIDArray.Length; ++i)
                    {
                        m_MaterialLayers[i] = AssetDatabase.LoadAssetAtPath(AssetDatabase.GUIDToAssetPath(layersGUID.GUIDArray[i]), typeof(Material)) as Material;
                    }
                }
            }
        }

        void SaveMaterialLayers(AssetImporter materialImporter)
        {
            SerializeableGUIDs layersGUID;
            layersGUID.GUIDArray = new string[m_MaterialLayers.Length];
            for (int i = 0; i < m_MaterialLayers.Length; ++i)
            {
                if (m_MaterialLayers[i] != null)
                    layersGUID.GUIDArray[i] = AssetDatabase.AssetPathToGUID(AssetDatabase.GetAssetPath(m_MaterialLayers[i].GetInstanceID()));
            }

            materialImporter.userData = JsonUtility.ToJson(layersGUID);
        }

        bool CheckInputOptionConsistency(string optionName, string[] shortNames, ref string outValueNames)
        {
            bool result = true;
            outValueNames = "";
            for (int i = 0; i < layerCount; ++i)
            {
                Material layer = m_MaterialLayers[i];
                if (layer != null)
                {
                    int currentValue = (int)layer.GetFloat(optionName); // All options are in fact enums
                    Debug.Assert(currentValue < shortNames.Length);
                    outValueNames += shortNames[currentValue] + "    ";

                    for (int j = i + 1; j < layerCount; ++j)
                    {
                        Material otherLayer = m_MaterialLayers[j];
                        if (otherLayer != null)
                        {
                            if (currentValue != (int)otherLayer.GetFloat(optionName))
                            {
                                result = false;
                            }
                        }
                    }
                }
                else
                {
                    outValueNames += "X    ";
                }
            }

            return result;
        }

        bool CheckInputMapConsistency(string mapName, ref string outValueNames)
        {
            bool result = true;
            outValueNames = "";
            for (int i = 0; i < layerCount; ++i)
            {
                Material layer = m_MaterialLayers[i];
                if (layer != null)
                {
                    bool currentValue = layer.GetTexture(mapName) != null;
                    outValueNames += (currentValue ? "Y" : "N") + "    ";

                    for (int j = i + 1; j < layerCount; ++j)
                    {
                        Material otherLayer = m_MaterialLayers[j];
                        if (otherLayer != null)
                        {
                            bool otherValue = otherLayer.GetTexture(mapName) != null;
                            if (currentValue != otherValue)
                            {
                                result = false;
                            }
                        }
                    }
                }
                else
                {
                    outValueNames += "N    ";
                }
            }

            return result;
        }

        void CheckLayerConsistency()
        {
            string optionValueNames = "";
            // We need to check consistency between all layers.
            // Each input options and each input maps might can result in different #defines in the shader so all of them need to be consistent
            // otherwise the result will be undetermined

            // Input options consistency
            string[] smoothnessSourceShortNames = { "Mask", "Albedo" };
            string[] emissiveModeShortNames = { "Color", "Mask" };
            string[] normalMapShortNames = { "Tan", "Obj" };
            string[] heightMapShortNames = { "Parallax", "Disp" };

            string warningInputOptions = "";
            if (!CheckInputOptionConsistency(kSmoothnessTextureChannelProp, smoothnessSourceShortNames, ref optionValueNames))
            {
                warningInputOptions += "Smoothness Source:    " + optionValueNames + "\n";
            }
            if (!CheckInputOptionConsistency(kEmissiveColorMode, emissiveModeShortNames, ref optionValueNames))
            {
                warningInputOptions += "Emissive Mode:    " + optionValueNames + "\n";
            }
            if (!CheckInputOptionConsistency(kNormalMapSpace, normalMapShortNames, ref optionValueNames))
            {
                warningInputOptions += "Normal Map Space:    " + optionValueNames + "\n";
            }
            if (!CheckInputOptionConsistency(kHeightMapMode, heightMapShortNames, ref optionValueNames))
            {
                warningInputOptions += "Height Map Mode:    " + optionValueNames + "\n";
            }

            if (warningInputOptions != string.Empty)
            {
                warningInputOptions = "Input Option Consistency Error:\n" + warningInputOptions;
            }

            // Check input maps consistency
            string warningInputMaps = "";

            if (!CheckInputMapConsistency(kNormalMap, ref optionValueNames))
            {
                warningInputMaps += "Normal Map:    " + optionValueNames + "\n";
            }
            if (!CheckInputMapConsistency(kMaskMap, ref optionValueNames))
            {
                warningInputMaps += "Mask Map:    " + optionValueNames + "\n";
            }
            if (!CheckInputMapConsistency(kspecularOcclusionMap, ref optionValueNames))
            {
                warningInputMaps += "Specular Occlusion Map:    " + optionValueNames + "\n";
            }
            if (!CheckInputMapConsistency(kEmissiveColorMap, ref optionValueNames))
            {
                warningInputMaps += "Emissive Color Map:    " + optionValueNames + "\n";
            }
            if (!CheckInputMapConsistency(kHeightMap, ref optionValueNames))
            {
                warningInputMaps += "Height Map:    " + optionValueNames + "\n";
            }

            if (warningInputMaps != string.Empty)
            {
                warningInputMaps = "Input Maps Consistency Error:\n" + warningInputMaps;
                if (warningInputOptions != string.Empty)
                    warningInputMaps = "\n" + warningInputMaps;
            }

            string warning = warningInputOptions + warningInputMaps;
            if (warning != string.Empty)
            {
                EditorGUILayout.HelpBox(warning, MessageType.Error);
            }
        }

        void SynchronizeInputOptions()
        {
            Material material = m_MaterialEditor.target as Material;

            // We synchronize input options with the firsts non null Layer (all layers should have consistent options)
            Material firstLayer = null;
            int i = 0;
            while (i < layerCount && !(firstLayer = m_MaterialLayers[i])) ++i;

            if (firstLayer != null)
            {
                material.SetFloat(kSmoothnessTextureChannelProp, firstLayer.GetFloat(kSmoothnessTextureChannelProp));
                material.SetFloat(kEmissiveColorMode, firstLayer.GetFloat(kEmissiveColorMode));
                material.SetFloat(kNormalMapSpace, firstLayer.GetFloat(kNormalMapSpace));
                material.SetFloat(kHeightMapMode, firstLayer.GetFloat(kHeightMapMode));
            }
        }

        bool LayersGUI(AssetImporter materialImporter)
        {
            Material material = m_MaterialEditor.target as Material;

            bool layerChanged = false;

            EditorGUI.indentLevel++;
            GUILayout.Label(styles.layers, EditorStyles.boldLabel);

            EditorGUI.BeginChangeCheck();
            int newLayerCount = EditorGUILayout.IntSlider(styles.layerCount, (int)layerCountProperty.floatValue, 2, 4);
            if (EditorGUI.EndChangeCheck())
            {
                Undo.RecordObject(material, "Change layer count");
                layerCountProperty.floatValue = (float)newLayerCount;
                SynchronizeAllLayersProperties();
                layerChanged = true;
            }

            m_MaterialEditor.TexturePropertySingleLine(styles.layerMapMask, layerMaskMapProperty);

            for (int i = 0; i < layerCount; i++)
            {
                EditorGUI.BeginChangeCheck();
                m_MaterialLayers[i] = EditorGUILayout.ObjectField(styles.materialLayerLabels[i], m_MaterialLayers[i], typeof(Material), true) as Material;
                if (EditorGUI.EndChangeCheck())
                {
                    Undo.RecordObject(materialImporter, "Change layer material");
                    SynchronizeLayerProperties(i);
                    layerChanged = true;
                }
            }

            EditorGUILayout.Space();
            GUILayout.BeginHorizontal();
            {
                GUILayout.FlexibleSpace();
                if (GUILayout.Button(styles.syncButton))
                {
                    SynchronizeAllLayersProperties();
                    layerChanged = true;
                }
            }
            GUILayout.EndHorizontal();

            EditorGUI.indentLevel--;

            return layerChanged;
        }

        protected override void SetupKeywordsForInputMaps(Material material)
        {
            // Find first non null layer
            int i = 0;
            while (i < layerCount && (m_MaterialLayers[i] == null)) ++i;

            if (i < layerCount)
            {
                SetKeyword(material, "_NORMALMAP", material.GetTexture(kNormalMap + i));
                SetKeyword(material, "_MASKMAP", material.GetTexture(kMaskMap + i));
                SetKeyword(material, "_SPECULAROCCLUSIONMAP", material.GetTexture(kspecularOcclusionMap + i));
                SetKeyword(material, "_EMISSIVE_COLOR_MAP", material.GetTexture(kEmissiveColorMap + i));
                SetKeyword(material, "_HEIGHTMAP", material.GetTexture(kHeightMap + i));
            }

            SetKeyword(material, "_LAYERMASKMAP", material.GetTexture(kLayerMaskMap));
        }

        void SetupMaterialForLayers(Material material)
        {
            if (layerCount == 4)
            {
                SetKeyword(material, "_LAYEREDLIT_4_LAYERS", true);
                SetKeyword(material, "_LAYEREDLIT_3_LAYERS", false);
            }
            else if (layerCount == 3)
            {
                SetKeyword(material, "_LAYEREDLIT_4_LAYERS", false);
                SetKeyword(material, "_LAYEREDLIT_3_LAYERS", true);
            }
            else
            {
                SetKeyword(material, "_LAYEREDLIT_4_LAYERS", false);
                SetKeyword(material, "_LAYEREDLIT_3_LAYERS", false);
            }
        }

        public override void OnGUI(MaterialEditor materialEditor, MaterialProperty[] props)
        {
            FindOptionProperties(props);
            layerMaskMapProperty = FindProperty(kLayerMaskMap, props);
            layerCountProperty = FindProperty(kLayerCount, props);

            m_MaterialEditor = materialEditor;

            m_MaterialEditor.serializedObject.Update();

            Material material = m_MaterialEditor.target as Material;
            AssetImporter materialImporter = AssetImporter.GetAtPath(AssetDatabase.GetAssetPath(material.GetInstanceID()));

            InitializeMaterialLayers(materialImporter);

            bool optionsChanged = false;
            EditorGUI.BeginChangeCheck();
            {
                ShaderOptionsGUI();
                EditorGUILayout.Space();
            }
            if (EditorGUI.EndChangeCheck())
            {
                optionsChanged = true;
            }

            bool layerChanged = LayersGUI(materialImporter);

            CheckLayerConsistency();

            if (layerChanged || optionsChanged)
            {
                SynchronizeInputOptions();

                foreach (var obj in m_MaterialEditor.targets)
                {
                    SetupMaterial((Material)obj);
                    SetupMaterialForLayers((Material)obj);
                }

                SaveMaterialLayers(materialImporter);
            }

            m_MaterialEditor.serializedObject.ApplyModifiedProperties();

            if (layerChanged)
            {
                materialImporter.SaveAndReimport();
            }
        }
    }
} // namespace UnityEditor