using UnityEngine;
using UnityEditor;
using System;

public class ReferencesCleaner : EditorWindow
{
    private Material m_selectedMaterial;
    private SerializedObject m_serializedObject;

    [MenuItem("Window/ReferencesCleaner")]
    private static void Init()
    {
        GetWindow<ReferencesCleaner>("Ref. Cleaner");
    }

    protected virtual void OnEnable()
    {
        GetSelectedMaterial();
    }

    protected virtual void OnSelectionChange()
    {
        GetSelectedMaterial();
    }

    protected virtual void OnProjectChange()
    {
        GetSelectedMaterial();
    }

    protected virtual void OnGUI()
    {
        EditorGUIUtility.labelWidth = 200f;

        if (m_selectedMaterial == null)
        {
            EditorGUILayout.LabelField("No material selected");
            if(GUILayout.Button("Remove all"))
            {
                RemoveAllUnused();
            }
        }
        else
        {
            EditorGUILayout.Space();
            EditorGUILayout.LabelField("Selected material:",m_selectedMaterial.name);
            EditorGUILayout.LabelField("Shader:", m_selectedMaterial.shader.name);
            EditorGUILayout.Space();
            EditorGUILayout.LabelField("Properties");

            m_serializedObject.Update();

            EditorGUI.indentLevel++;

            EditorGUILayout.LabelField("Textures");
            EditorGUI.indentLevel++;
            ProcessProperties("m_SavedProperties.m_TexEnvs");
            EditorGUI.indentLevel--;

            EditorGUILayout.LabelField("Floats");
            EditorGUI.indentLevel++;
            ProcessProperties("m_SavedProperties.m_Floats");
            EditorGUI.indentLevel--;

            EditorGUILayout.LabelField("Colors");
            EditorGUI.indentLevel++;
            ProcessProperties("m_SavedProperties.m_Colors");
            EditorGUI.indentLevel--;

            EditorGUI.indentLevel--;
        }

        EditorGUIUtility.labelWidth = 0;
    }

    private static void RemoveAllUnused()
    {
        string[] materials = AssetDatabase.FindAssets("t:material");

        string path;
        long i = 0;
        long count = materials.LongLength;

        foreach (string mat in materials)
        {
            path = AssetDatabase.GUIDToAssetPath(mat);
            EditorUtility.DisplayProgressBar("Remove all unused materials", path, (float)i / count);
            RemoveAllUnused(AssetDatabase.LoadAssetAtPath<Material>(path));
            i++;
        }

        EditorUtility.ClearProgressBar();
    }

    private static void RemoveAllUnused(Material m)
    {
        SerializedObject serializedObject = new SerializedObject(m);
        RemoveAllUnusedProperties(m, serializedObject, "m_SavedProperties.m_TexEnvs");
        RemoveAllUnusedProperties(m, serializedObject, "m_SavedProperties.m_Floats");
        RemoveAllUnusedProperties(m, serializedObject, "m_SavedProperties.m_Colors");
        serializedObject.ApplyModifiedProperties();
    }

    private static void RemoveAllUnusedProperties(Material m, SerializedObject o, string path)
    {
        var properties = o.FindProperty(path);
        if (properties != null && properties.isArray)
        {
            for (int i = 0; i < properties.arraySize; i++)
            {
                string propName = properties.GetArrayElementAtIndex(i).displayName;
                bool exist = m.HasProperty(propName);

                if(!exist)
                {
                    properties.DeleteArrayElementAtIndex(i);
                }
            }
        }
    }

    private void ProcessProperties(string path)
    {
        var properties = m_serializedObject.FindProperty(path);
        if (properties != null && properties.isArray)
        {
            for (int i = 0; i < properties.arraySize; i++)
            {
                string propName = properties.GetArrayElementAtIndex(i).displayName;
                bool exist = m_selectedMaterial.HasProperty(propName);

                if (exist)
                {
                    EditorGUILayout.LabelField(propName, "Exist");
                }
                else
                {
                    using (new EditorGUILayout.HorizontalScope())
                    {
                        EditorGUILayout.LabelField(propName, "Old reference", "CN StatusWarn");
                        if (GUILayout.Button("Remove", GUILayout.Width(80f)))
                        {
                            properties.DeleteArrayElementAtIndex(i);
                            m_serializedObject.ApplyModifiedProperties();
                            GUIUtility.ExitGUI();
                        }
                    }

                }
            }
        }
    }

    private void GetSelectedMaterial()
    {
        m_selectedMaterial = Selection.activeObject as Material;
        if (m_selectedMaterial != null)
        {
            m_serializedObject = new SerializedObject(m_selectedMaterial);
        }

        Repaint();
    }
}