using System;
using System.Collections.Generic;
using System.Reflection;
using UnityEditor.Rendering.Universal.ShaderGUI;
using UnityEngine;
using UnityEngine.Rendering.Universal;

namespace UnityEditor.Rendering.Universal
{
    class MaterialModificationProcessor : AssetModificationProcessor
    {
        static void OnWillCreateAsset(string asset)
        {
            if (!asset.ToLowerInvariant().EndsWith(".mat"))
            {
                return;
            }
            MaterialPostprocessor.s_CreatedAssets.Add(asset);
        }
    }

    class MaterialReimporter : Editor
    {
        const string Key = "LWRP-material-upgrader";

        [InitializeOnLoadMethod]
        static void ReimportAllMaterials()
        {
            //Check to see if the upgrader has been run for this project/LWRP version
            PackageManager.PackageInfo lwrpInfo = PackageManager.PackageInfo.FindForAssembly(Assembly.GetAssembly(typeof(UniversalRenderPipeline)));
            var lwrpVersion = lwrpInfo.version;
            var curUpgradeVersion = PlayerPrefs.GetString(Key);

            if (curUpgradeVersion != lwrpVersion)
            {
                string[] guids = AssetDatabase.FindAssets("t:material", null);

                foreach (var asset in guids)
                {
                    var path = AssetDatabase.GUIDToAssetPath(asset);
                    AssetDatabase.ImportAsset(path);
                }
                PlayerPrefs.SetString(Key, lwrpVersion);
            }
        }
    }

    class MaterialPostprocessor : AssetPostprocessor
    {
        public static List<string> s_CreatedAssets = new List<string>();

        static void OnPostprocessAllAssets(string[] importedAssets, string[] deletedAssets, string[] movedAssets, string[] movedFromAssetPaths)
        {
            var upgradeLog = "UniversalRP Material log:";
            var upgradeCount = 0;

            foreach (var asset in importedAssets)
            {

                if (!asset.ToLowerInvariant().EndsWith(".mat"))
                {
                    continue;
                }

                var material = (Material)AssetDatabase.LoadAssetAtPath(asset, typeof(Material));
                if (!ShaderUtils.IsLWShader(material.shader))
                {
                    continue;
                }

                ShaderPathID id = ShaderUtils.GetEnumFromPath(material.shader.name);
                var wasUpgraded = false;
                var assetVersions = AssetDatabase.LoadAllAssetsAtPath(asset);
                AssetVersion assetVersion = null;
                foreach (var subAsset in assetVersions)
                {
                    if(subAsset.GetType() == typeof(AssetVersion))
                        assetVersion = subAsset as AssetVersion;
                }
                var debug = "\n" + material.name;

                if (!assetVersion)
                {
                    wasUpgraded = true;
                    assetVersion = ScriptableObject.CreateInstance<AssetVersion>();
                    if (s_CreatedAssets.Contains(asset))
                    {
                        assetVersion.version = k_Upgraders.Length;
                        s_CreatedAssets.Remove(asset);
                        InitializeLatest(material, id);
                    }
                    else
                    {
                        assetVersion.version = 0;
                    }

                    assetVersion.hideFlags = HideFlags.HideInHierarchy | HideFlags.HideInInspector | HideFlags.NotEditable;
                    AssetDatabase.AddObjectToAsset(assetVersion, asset);
                    debug += " initialized.";
                }

                while (assetVersion.version < k_Upgraders.Length)
                {
                    k_Upgraders[assetVersion.version](material, id);
                    debug += $" upgrading:v{assetVersion.version} to v{assetVersion.version + 1}";
                    assetVersion.version++;
                    wasUpgraded = true;
                }

                if (wasUpgraded)
                {
                    upgradeLog += debug;
                    upgradeCount++;
                    EditorUtility.SetDirty(assetVersion);
                }
            }

            // Don't print the log as we don't have any way to figure out if a material us upgraded or just created
            //if(upgradeCount > 0)
            //    Debug.Log(upgradeLog);
        }

        static readonly Action<Material, ShaderPathID>[] k_Upgraders = { UpgradeV1 };

        static void InitializeLatest(Material material, ShaderPathID id)
        {

        }

        static void UpgradeV1(Material material, ShaderPathID shaderID)
        {
            var shaderPath = ShaderUtils.GetShaderPath(shaderID);
            var upgradeFlag = MaterialUpgrader.UpgradeFlags.LogMessageWhenNoUpgraderFound;

            switch (shaderID)
            {
                case ShaderPathID.Unlit:
                    MaterialUpgrader.Upgrade(material, new UnlitUpdaterV1(shaderPath), upgradeFlag);
                    UnlitShader.SetMaterialKeywords(material);
                    break;
                case ShaderPathID.SimpleLit:
                    MaterialUpgrader.Upgrade(material, new SimpleLitUpdaterV1(shaderPath), upgradeFlag);
                    SimpleLitShader.SetMaterialKeywords(material, SimpleLitGUI.SetMaterialKeywords);
                    break;
                case ShaderPathID.Lit:
                    MaterialUpgrader.Upgrade(material, new LitUpdaterV1(shaderPath), upgradeFlag);
                    LitShader.SetMaterialKeywords(material, LitGUI.SetMaterialKeywords);
                    break;
                case ShaderPathID.ParticlesLit:
                    MaterialUpgrader.Upgrade(material, new ParticleUpdaterV1(shaderPath), upgradeFlag);
                    ParticlesLitShader.SetMaterialKeywords(material, LitGUI.SetMaterialKeywords, ParticleGUI.SetMaterialKeywords);
                    break;
                case ShaderPathID.ParticlesSimpleLit:
                    MaterialUpgrader.Upgrade(material, new ParticleUpdaterV1(shaderPath), upgradeFlag);
                    ParticlesSimpleLitShader.SetMaterialKeywords(material, SimpleLitGUI.SetMaterialKeywords, ParticleGUI.SetMaterialKeywords);
                    break;
                case ShaderPathID.ParticlesUnlit:
                    MaterialUpgrader.Upgrade(material, new ParticleUpdaterV1(shaderPath), upgradeFlag);
                    ParticlesUnlitShader.SetMaterialKeywords(material, null, ParticleGUI.SetMaterialKeywords);
                    break;
            }
        }
    }

    // Upgaders v1
    #region UpgradersV1

    internal class LitUpdaterV1 : MaterialUpgrader
    {
        public static void UpdateLitDetails(Material material)
        {
            if (material == null)
                throw new ArgumentNullException("material");

            if(material.GetTexture("_MetallicGlossMap") || material.GetTexture("_SpecGlossMap") || material.GetFloat("_SmoothnessTextureChannel") >= 0.5f)
                material.SetFloat("_Smoothness", material.GetFloat("_GlossMapScale"));
            else
                material.SetFloat("_Smoothness", material.GetFloat("_Glossiness"));

        }

        public LitUpdaterV1(string oldShaderName)
        {
            if (oldShaderName == null)
                throw new ArgumentNullException("oldShaderName");

            string standardShaderPath = ShaderUtils.GetShaderPath(ShaderPathID.Lit);

            RenameShader(oldShaderName, standardShaderPath, UpdateLitDetails);

            RenameTexture("_MainTex", "_BaseMap");
            RenameColor("_Color", "_BaseColor");
            RenameFloat("_GlossyReflections", "_EnvironmentReflections");
        }
    }

    internal class UnlitUpdaterV1 : MaterialUpgrader
    {
        static Shader bakedLit = Shader.Find(ShaderUtils.GetShaderPath(ShaderPathID.BakedLit));

        public static void UpgradeToUnlit(Material material)
        {
            if (material == null)
                throw new ArgumentNullException("material");

            if (material.GetFloat("_SampleGI") != 0)
            {
                material.shader = bakedLit;
                material.EnableKeyword("_NORMALMAP");
            }
        }

        public UnlitUpdaterV1(string oldShaderName)
        {
            if (oldShaderName == null)
                throw new ArgumentNullException("oldShaderName");

            RenameShader(oldShaderName, ShaderUtils.GetShaderPath(ShaderPathID.Unlit), UpgradeToUnlit);

            RenameTexture("_MainTex", "_BaseMap");
            RenameColor("_Color", "_BaseColor");
        }
    }

    internal class SimpleLitUpdaterV1 : MaterialUpgrader
    {
        public SimpleLitUpdaterV1(string oldShaderName)
        {
            if (oldShaderName == null)
                throw new ArgumentNullException("oldShaderName");

            RenameShader(oldShaderName, ShaderUtils.GetShaderPath(ShaderPathID.SimpleLit), UpgradeToSimpleLit);

            RenameTexture("_MainTex", "_BaseMap");
            RenameColor("_Color", "_BaseColor");
            RenameFloat("_SpecSource", "_SpecularHighlights");
            RenameFloat("_Shininess", "_Smoothness");
        }

        public static void UpgradeToSimpleLit(Material material)
        {
            if (material == null)
                throw new ArgumentNullException("material");

            var smoothnessSource = 1 - (int)material.GetFloat("_GlossinessSource");
            material.SetFloat("_SmoothnessSource" ,smoothnessSource);
            if (material.GetTexture("_SpecGlossMap") == null)
            {
                var col = material.GetColor("_SpecColor");
                var colBase = material.GetColor("_Color");
                var smoothness = material.GetFloat("_Shininess");

                if (material.GetFloat("_Surface") == 0)
                {
                    if (smoothnessSource == 1)
                        colBase.a = smoothness;
                    else
                        col.a = smoothness;
                    material.SetColor("_BaseColor", colBase);
                }

                material.SetColor("_BaseColor", colBase);
                material.SetColor("_SpecColor", col);
            }
        }
    }

    internal class ParticleUpdaterV1 : MaterialUpgrader
    {
        public ParticleUpdaterV1(string shaderName)
        {
            if (shaderName == null)
                throw new ArgumentNullException("oldShaderName");

            RenameShader(shaderName, shaderName, ParticleUpgrader.UpdateSurfaceBlendModes);

            RenameTexture("_MainTex", "_BaseMap");
            RenameColor("_Color", "_BaseColor");
            RenameFloat("_FlipbookMode", "_FlipbookBlending");

            switch (ShaderUtils.GetEnumFromPath(shaderName))
            {
                case ShaderPathID.ParticlesLit:
                    RenameFloat("_Glossiness", "_Smoothness");
                    break;
                case ShaderPathID.ParticlesSimpleLit:
                    RenameFloat("_Glossiness", "_Smoothness");
                    break;
                case ShaderPathID.ParticlesUnlit:
                    break;
            }
        }
    }

    #endregion

}