using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System;

namespace UnityEditor.Experimental.ScriptableRenderLoop
{	
	public class MaterialUpgrader
	{
		string m_OldShader;
		string m_NewShader;

		Dictionary<string, string> m_TextureRename = new Dictionary<string, string>();
		Dictionary<string, string> m_FloatRename = new Dictionary<string, string>();
		Dictionary<string, string> m_ColorRename = new Dictionary<string, string>();

		[Flags]
		public enum UpgradeFlags
		{
			None = 0,
			LogErrorOnNonExistingProperty = 1,
			CleanupNonUpgradedProperties = 2,
		}

		public void Upgrade(Material material, UpgradeFlags flags)
		{
			Material newMaterial;
			if ((flags & UpgradeFlags.CleanupNonUpgradedProperties) != 0)
			{
				newMaterial = new Material(Shader.Find (m_NewShader));
			}
			else
			{
				newMaterial = UnityEngine.Object.Instantiate(material) as Material;
				newMaterial.shader = Shader.Find (m_NewShader);
			}

			Convert(material, newMaterial);

			material.shader = Shader.Find (m_NewShader);
			material.CopyPropertiesFromMaterial (newMaterial);
			UnityEngine.Object.DestroyImmediate (newMaterial);
		}

		// Overridable function to implement custom material upgrading functionality
		public virtual void Convert(Material srcMaterial, Material dstMaterial)
		{
			foreach (var t in m_TextureRename)
				dstMaterial.SetTexture (t.Value, srcMaterial.GetTexture (t.Key));

			foreach (var t in m_FloatRename)
				dstMaterial.SetFloat (t.Value, srcMaterial.GetFloat(t.Key));

			foreach (var t in m_ColorRename)
				dstMaterial.SetColor (t.Value, srcMaterial.GetColor(t.Key));
		}

		public void RenameShader(string oldName, string newName)
		{
			m_OldShader = oldName;
			m_NewShader = newName;
		}

		public void RenameTexture(string oldName, string newName)
		{
			m_TextureRename[oldName] = newName;
		}

		public void RenameFloat(string oldName, string newName)
		{
			m_FloatRename[oldName] = newName;				
		}

		public void RenameColor(string oldName, string newName)
		{
			m_ColorRename[oldName] = newName;
		}

		static bool IsMaterialPath(string path)
		{
			return path.EndsWith (".mat", StringComparison.OrdinalIgnoreCase);
		}

		static MaterialUpgrader GetUpgrader(List<MaterialUpgrader> upgraders, Material material)
		{
			if (material == null || material.shader == null)
				return null;

			string shaderName = material.shader.name;
			for (int i = 0;i != upgraders.Count;i++)
			{
				if (upgraders[i].m_OldShader == shaderName)
					return upgraders[i];
			}

			return null;
		}

		//@TODO: Only do this when it exceeds memory consumption...
		static void SaveAssetsAndFreeMemory()
		{
			AssetDatabase.SaveAssets();
			GC.Collect();
			EditorUtility.UnloadUnusedAssetsImmediate();
			AssetDatabase.Refresh();
		}

		static public void UpgradeProjectFolder(List<MaterialUpgrader> upgraders, string progressBarName)
		{
			int totalMaterialCount = 0;
			foreach ( string s in UnityEditor.AssetDatabase.GetAllAssetPaths() )
			{
				if (IsMaterialPath(s))
					totalMaterialCount++;
			}

			int materialIndex = 0;
			foreach ( string path in UnityEditor.AssetDatabase.GetAllAssetPaths() )
			{
				if (IsMaterialPath(path))
				{
					materialIndex++;
					if ( UnityEditor.EditorUtility.DisplayCancelableProgressBar(progressBarName, string.Format( "({0} of {1}) {2}", materialIndex, totalMaterialCount, path ), ( float )materialIndex / ( float )totalMaterialCount ) )
						break;

					Material m = UnityEditor.AssetDatabase.LoadMainAssetAtPath( path ) as Material;
					Upgrade (m, upgraders, UpgradeFlags.None);

					SaveAssetsAndFreeMemory();
				}
			}

			UnityEditor.EditorUtility.ClearProgressBar();
		}

		public static void Upgrade(Material material, MaterialUpgrader upgrader, UpgradeFlags flags)
		{
			var upgraders = new List<MaterialUpgrader> ();
			upgraders.Add (upgrader);
			Upgrade (material, upgraders, flags);
		}

		public static void Upgrade(Material material, List<MaterialUpgrader> upgraders, UpgradeFlags flags)
		{
			var upgrader = GetUpgrader (upgraders, material);
			if (upgrader != null)
				upgrader.Upgrade (material, flags);
		}

		public static void UpgradeSelection(List<MaterialUpgrader> upgraders, string progressBarName)
		{
			string lastMaterialName = "";
			var selection = Selection.objects;
			for (int i = 0; i < selection.Length;i++)
			{

				if ( UnityEditor.EditorUtility.DisplayCancelableProgressBar(progressBarName, string.Format( "({0} of {1}) {2}", i, selection.Length, lastMaterialName ), ( float )i / ( float )selection.Length ) )
					break;

				var material = selection[i] as Material;
				Upgrade (material, upgraders, UpgradeFlags.None);
				if (material != null)
					lastMaterialName = material.name;
			}

			UnityEditor.EditorUtility.ClearProgressBar();
		}
	}	
}