using UnityEngine;
using UnityEditor;
using System;
using System.Reflection;
using System.Linq;
using System.Collections.Generic;

namespace MoreMountains.Tools
{
    public class MMInspectorGroupData
    {
        public bool GroupIsOpen;
        public MMInspectorGroupAttribute GroupAttribute;
        public List<SerializedProperty> PropertiesList = new List<SerializedProperty>();
        public HashSet<string> GroupHashSet = new HashSet<string>();
        public Color GroupColor;

        public void ClearGroup()
        {
            GroupAttribute = null;
            GroupHashSet.Clear();
            PropertiesList.Clear();
        }
    }

    /// <summary>
    /// A generic drawer for all MMMonoBehaviour, handles both the Group and RequiresConstantRepaint attributes
    /// </summary>
    [CanEditMultipleObjects]
    [CustomEditor(typeof(MMMonoBehaviour), true, isFallback = true)]
    public class MMMonoBehaviourDrawer : UnityEditor.Editor
    {
        public bool DrawerInitialized;
        public List<SerializedProperty> PropertiesList = new List<SerializedProperty>();
        public Dictionary<string, MMInspectorGroupData> GroupData = new Dictionary<string, MMInspectorGroupData>();
        
        private string[] _mmHiddenPropertiesToHide;
        private bool _hasMMHiddenProperties = false;
        private bool _requiresConstantRepaint;
        protected bool _shouldDrawBase = true;

        public override bool RequiresConstantRepaint()
        {
            return _requiresConstantRepaint;
        }

        protected virtual void OnEnable()
        {
            DrawerInitialized = false;
            if (!target || !serializedObject.targetObject)
            {
                return;
            }
            _requiresConstantRepaint = serializedObject.targetObject.GetType().GetCustomAttribute<MMRequiresConstantRepaintAttribute>() != null;
            
            MMHiddenPropertiesAttribute[] hiddenProperties = (MMHiddenPropertiesAttribute[])target.GetType().GetCustomAttributes(typeof(MMHiddenPropertiesAttribute), false);
            if (hiddenProperties != null && hiddenProperties.Length > 0 && hiddenProperties[0].PropertiesNames != null)
            {
                _mmHiddenPropertiesToHide = hiddenProperties[0].PropertiesNames;
                _hasMMHiddenProperties = true;
            }
        }

        protected virtual void OnDisable()
        {
            if (target == null)
            {
                return;    
            }
            foreach (KeyValuePair<string, MMInspectorGroupData> groupData in GroupData)
            {
                EditorPrefs.SetBool(string.Format($"{groupData.Value.GroupAttribute.GroupName}{groupData.Value.PropertiesList[0].name}{target.GetInstanceID()}"), groupData.Value.GroupIsOpen);
                groupData.Value.ClearGroup();
            }
        }

        public override void OnInspectorGUI()
        {
            serializedObject.Update();

            Initialization();
            DrawBase();
            DrawScriptBox();
            DrawContainer();
            DrawContents();

            serializedObject.ApplyModifiedProperties();            
        }

        protected virtual void Initialization()
        {
            if (DrawerInitialized)
            {
                return;
            }

            List<FieldInfo> fieldInfoList;
            MMInspectorGroupAttribute previousGroupAttribute = default;
            int fieldInfoLength = MMMonoBehaviourFieldInfo.GetFieldInfo(target, out fieldInfoList);

            for (int i = 0; i < fieldInfoLength; i++)
            {
                MMInspectorGroupAttribute group = Attribute.GetCustomAttribute(fieldInfoList[i], typeof(MMInspectorGroupAttribute)) as MMInspectorGroupAttribute;
                MMInspectorGroupData groupData;
                if (group == null)
                {
                    if (previousGroupAttribute != null && previousGroupAttribute.GroupAllFieldsUntilNextGroupAttribute)
                    {
                        _shouldDrawBase = false;
                        if (!GroupData.TryGetValue(previousGroupAttribute.GroupName, out groupData))
                        {
                            GroupData.Add(previousGroupAttribute.GroupName, new MMInspectorGroupData
                            {
                                GroupAttribute = previousGroupAttribute,
                                GroupHashSet = new HashSet<string> { fieldInfoList[i].Name },
                                GroupColor = MMColors.GetColorAt(previousGroupAttribute.GroupColorIndex)
                            });
                        }
                        else
                        {
                            groupData.GroupColor = MMColors.GetColorAt(previousGroupAttribute.GroupColorIndex);
                            groupData.GroupHashSet.Add(fieldInfoList[i].Name);
                        }
                    }

                    continue;
                }
                
                previousGroupAttribute = group;

                if (!GroupData.TryGetValue(group.GroupName, out groupData))
                {
                    bool groupIsOpen = EditorPrefs.GetBool(string.Format($"{group.GroupName}{fieldInfoList[i].Name}{target.GetInstanceID()}"), false);
                    GroupData.Add(group.GroupName, new MMInspectorGroupData
                    {
                        GroupAttribute = group,
                        GroupColor = MMColors.GetColorAt(previousGroupAttribute.GroupColorIndex),
                        GroupHashSet = new HashSet<string> { fieldInfoList[i].Name }, GroupIsOpen = groupIsOpen });
                }
                else
                {
                    groupData.GroupHashSet.Add(fieldInfoList[i].Name);
                    groupData.GroupColor = MMColors.GetColorAt(previousGroupAttribute.GroupColorIndex);
                }
            }

            SerializedProperty iterator = serializedObject.GetIterator();

            if (iterator.NextVisible(true))
            {
                do
                {
                    FillPropertiesList(iterator);
                } while (iterator.NextVisible(false));
            }

            DrawerInitialized = true;
        }

        protected virtual void DrawBase()
        {
            if (_shouldDrawBase)
            {
                DrawDefaultInspector();
                return;
            }
        }

        protected virtual void DrawScriptBox()
        {
            if (PropertiesList.Count == 0)
            {
                return;
            }

            using (new EditorGUI.DisabledScope("m_Script" == PropertiesList[0].propertyPath))
            {
                EditorGUILayout.PropertyField(PropertiesList[0], true);
            }
        }

        protected virtual void DrawContainer()
        {
            if (PropertiesList.Count == 0)
            {
                return;
            }

            foreach (KeyValuePair<string, MMInspectorGroupData> pair in GroupData)
            {
                this.DrawVerticalLayout(() => DrawGroup(pair.Value), MMMonoBehaviourDrawerStyle.ContainerStyle);
                EditorGUI.indentLevel = 0;
            }
        }

        protected virtual void DrawContents()
        {
            if (PropertiesList.Count == 0)
            {
                return;
            }

            EditorGUILayout.Space();
            for (int i = 1; i < PropertiesList.Count; i++)
            {
                if (_hasMMHiddenProperties && (!_mmHiddenPropertiesToHide.Contains(PropertiesList[i].name)))
                {
                    EditorGUILayout.PropertyField(PropertiesList[i], true);
                }
            }
        }

        protected virtual void DrawGroup(MMInspectorGroupData groupData)
        {
            Rect verticalGroup = EditorGUILayout.BeginVertical();

            var leftBorderRect = new Rect(verticalGroup.xMin + 5, verticalGroup.yMin - 10, 3f, verticalGroup.height + 20);
            leftBorderRect.xMin = 15f;
            leftBorderRect.xMax = 18f;
            EditorGUI.DrawRect(leftBorderRect, groupData.GroupColor); 

            groupData.GroupIsOpen = EditorGUILayout.Foldout(groupData.GroupIsOpen, groupData.GroupAttribute.GroupName, true, MMMonoBehaviourDrawerStyle.GroupStyle);

            if (groupData.GroupIsOpen)
            {
                EditorGUI.indentLevel = 0;

                for (int i = 0; i < groupData.PropertiesList.Count; i++)
                {
                    this.DrawVerticalLayout(() => DrawChild(i), MMMonoBehaviourDrawerStyle.BoxChildStyle);
                }
            }

            EditorGUILayout.EndVertical();

            void DrawChild(int i)
            {
                if ((_hasMMHiddenProperties) && (_mmHiddenPropertiesToHide.Contains(groupData.PropertiesList[i].name)))
                {
                    return;
                }
                EditorGUILayout.PropertyField(groupData.PropertiesList[i], new GUIContent(ObjectNames.NicifyVariableName(groupData.PropertiesList[i].name)), true);
            }
        }
        
        public void FillPropertiesList(SerializedProperty serializedProperty)
        {
            bool shouldClose = false;

            foreach (KeyValuePair<string, MMInspectorGroupData> pair in GroupData)
            {
                if (pair.Value.GroupHashSet.Contains(serializedProperty.name))
                {
                    SerializedProperty property = serializedProperty.Copy();
                    shouldClose = true;
                    pair.Value.PropertiesList.Add(property);
                    break;
                }
            }

            if (!shouldClose)
            {
                SerializedProperty property = serializedProperty.Copy();
                PropertiesList.Add(property);
            }
        }
    }    
}