using System;
using System.Collections.Generic;
using System.IO;
using Module.NavigationTool.Editor.Utilities;
using UnityEditor;
using UnityEngine;
using Object = UnityEngine.Object;

namespace Module.NavigationTool.Editor.Favorite
{
    [Serializable]
    internal sealed class Favorites : ISerializationCallbackReceiver
    {
        public static readonly string PREF_ID = "PREF_FAVORITE_LIST";

        public List<Entry> entries;
        
        public Favorites()
        {
            entries = new List<Entry>();
            string json = EditorProjectPrefs.GetString(PREF_ID);

            if (!string.IsNullOrEmpty(json))
                EditorJsonUtility.FromJsonOverwrite(json, this);
        }

        void ISerializationCallbackReceiver.OnBeforeSerialize()
        {
        }

        void ISerializationCallbackReceiver.OnAfterDeserialize()
        {
            var guidToEntry = new Dictionary<string, Entry>(entries.Count);
            
            for (var i = 0; i < entries.Count; i++)
            {
                Entry e = entries[i];
                guidToEntry.Add(e.guid, e);
            }

            for (var i = 0; i < entries.Count; i++)
            {
                Entry e = entries[i];
                
                if (e.isAsset)
                    continue;
                
                for (int j = e.children.Count - 1; j >= 0; j--)
                {
                    Entry c = guidToEntry[e.children[j].guid];

                    if (c != null)
                    {
                        e.children[j].entry = c;
                        c.parent = e;
                    }
                    else
                    {
                        e.children.RemoveAt(j);
                    }
                }
            }

            for (var i = 0; i < entries.Count; i++)
            {
                Entry e = entries[i];

                if (e.indentLevel != 0 && e.parent == null)
                    e.indentLevel = 0;
            }
        }
        
        public void Add(string guid, Entry toParent = null)
        {
            if (InternalAddEntry(Entry.CreateAsset(guid), toParent))
                Save();
        }
        
        public void AddFolder(string name, Entry toParent = null)
        {
            if (InternalAddEntry(Entry.CreateFolder(name), toParent))
                Save();
        }
        
        private bool InternalAddEntry(Entry e, Entry toParent)
        {
            e.Refresh();
            
            if (!e.valid)
                return false;
            
            entries.Add(e);

            if (toParent != null && toParent.isAsset)
                toParent = toParent.parent;

            if (toParent != null)
            {
                e.parent = toParent;
                e.indentLevel = toParent.indentLevel + 1;
                toParent.AddChild(e);
            }

            return true;
        }

        public void AddRange(string[] guids, Entry toParent = null)
        {
            var isDirty = false;
            
            for (var i = 0; i < guids.Length; i++)
            {
                if (InternalAddEntry(Entry.CreateAsset(guids[i]), toParent))
                    isDirty = true;
            }

            if (isDirty)
                Save();
        }

        public void AddRangeByPath(string[] paths, Entry toParent = null)
        {
            var isDirty = false;
            
            for (var i = 0; i < paths.Length; i++)
            {
                string guid = AssetDatabase.AssetPathToGUID(paths[i]);

                if (InternalAddEntry(Entry.CreateAsset(guid), toParent))
                    isDirty = true;
            }

            if (isDirty)
                Save();
        }

        public void Remove(Entry e)
        {
            if (InternalRemove(e))
                Save();
        }

        private bool InternalRemove(Entry e)
        {
            if (!entries.Remove(e))
                return false;

            e.parent?.RemoveChild(e);

            if (!e.isAsset)
            {
                for (int i = e.children.Count - 1; i >= 0; i--)
                {
                    InternalRemove(e.children[i].entry);
                }
            }

            return true;
        }

        public void Move(Entry e, Entry toParent)
        {
            InternalMove(e, toParent);
            Save();
        }

        private void InternalMove(Entry e, Entry toParent)
        {
            if (e.parent != null)
            {
                e.parent.RemoveChild(e);
                e.parent = null;
                e.indentLevel = 0;
            }

            if (toParent != null && toParent.isAsset)
                toParent = toParent.parent;

            if (toParent != null)
            {
                toParent.AddChild(e);
                e.parent = toParent;
                e.indentLevel = e.parent.indentLevel + 1;
            }

            InternalMoveIndentLevel(e);
        }

        private void InternalMoveIndentLevel(Entry parent)
        {
            if (parent.isAsset)
                return;

            for (var i = 0; i < parent.children.Count; i++)
            {
                parent.children[i].entry.indentLevel = parent.indentLevel + 1;
                InternalMoveIndentLevel(parent.children[i].entry);
            }
        }

        public Object GetObject(Entry entry)
        {
            string path = AssetDatabase.GUIDToAssetPath(entry.assetGuid);
            return AssetDatabase.LoadMainAssetAtPath(path);
        }

        private void Sort()
        {
            entries.Sort((e0, e1) =>
            {
                int compare = e0.isAsset.CompareTo(e1.isAsset);

                if (compare == 0)
                    compare = string.Compare(e0.lowerName, e1.lowerName, StringComparison.Ordinal);

                return compare;
            });
        }
        
        public void Save()
        {
            Sort();
            string json = EditorJsonUtility.ToJson(this, false);
            EditorProjectPrefs.SetString(PREF_ID, json);
        }

        /// <summary>
        /// Class: Entry
        /// </summary>
        [Serializable]
        public sealed class Entry : ISerializationCallbackReceiver
        {
            public string guid;
            public string assetGuid;
            public string name;
            public bool isAsset;
            public bool expanded;
            public int indentLevel;
            public List<Child> children;
            
            [NonSerialized]
            public bool valid;
            [NonSerialized]
            public Entry parent;
            [NonSerialized]
            public GUIContent content;
            [NonSerialized]
            public string lowerName;

            private Entry(string assetGuid, string name, bool isAsset)
            {
                guid = Guid.NewGuid().ToString();
                this.assetGuid = assetGuid;
                this.name = name;
                this.isAsset = isAsset;
                
                if (!isAsset)
                {
                    expanded = true;
                    children = new List<Child>();
                }
            }
            
            void ISerializationCallbackReceiver.OnBeforeSerialize()
            {
            }

            void ISerializationCallbackReceiver.OnAfterDeserialize()
            {
                if (isAsset)
                    children = null;

                Refresh();
            }

            public void Refresh()
            {
                if (isAsset)
                {
                    string path = AssetDatabase.GUIDToAssetPath(assetGuid);
                    name = Path.GetFileNameWithoutExtension(path);
                    lowerName = name.ToLower();
                    valid = AssetDatabase.LoadMainAssetAtPath(path) != null;
                    content = new GUIContent(name, FavoritesGUIUtility.GetIcon(path), path);
                }
                else
                {
                    valid = true;
                    content = new GUIContent(name, FavoritesGUIUtility.GetFolderIcon());    
                }
            }
            
            public void AddChild(Entry entry)
            {
                children.Add(new Child(entry));
                children.Sort((c0, c1) =>
                {
                    int compare = c0.entry.isAsset.CompareTo(c1.entry.isAsset);

                    if (compare == 0)
                        compare = string.Compare(c0.entry.lowerName, c1.entry.lowerName, StringComparison.Ordinal);

                    return compare;
                });
            }

            public void RemoveChild(Entry entry)
            {
                for (int i = children.Count - 1; i >= 0; i--)
                {
                    if (children[i].entry == entry)
                        children.RemoveAt(i);
                }
            }

            public static Entry CreateFolder(string name)
            {
                return new Entry(string.Empty, name, false);
            }

            public static Entry CreateAsset(string assetGuid)
            {
                return new Entry(assetGuid, string.Empty, true);
            }

            /// <summary>
            /// Class: Entry child
            /// </summary>
            [Serializable]
            public sealed class Child
            {
                public string guid;
                [NonSerialized]
                public Entry entry;

                public Child(Entry entry)
                {
                    guid = entry.guid;
                    this.entry = entry;
                }
            }
        }
    }
}