using System.Collections.Generic;
using UnityEngine;
using TMPro;
using System;
using static CommunicationEvents;
using System.Linq;
using UnityEngine.UI;
using System.Collections;
using MoreLinq;
using System.ComponentModel;
using UnityEditor;
using System.Reflection;

public class DisplayFacts : MonoBehaviour, ISerializationCallbackReceiver
{
    private static DisplayFacts _instance;
    public static DisplayFacts Instance
    {
        get => _instance;
        private set { _instance ??= value; }
    }

    //cannot populate static dict while serialization => "singelton"
    public static Dictionary<Type, GameObject> PrefabDictionary { get => Instance._PrefabDictionary; }
    private Dictionary<Type, GameObject> _PrefabDictionary = new();

    public static Dictionary<string, GameObject> displayedFacts = new();

    [SerializeField] private Transform factscreenContent;
    [SerializeField] private GameObject factSpotPrefab;

    private bool sortDescending = false;
    private bool showGrouped = false;
    private bool showOnlyFavorites = false;

    #region ISerializationCallbackReceiver
    [ReadOnly(true), SerializeField]
    private List<string> PrefabtTypeReadonly;
    [SerializeField]
    private List<GameObject> PrefabDataConfig;

    public void OnBeforeSerialize()
    {
        PrefabtTypeReadonly = TypeExtensions<Fact>.UAssemblyInheritenceTypes.Select(type => type.ToString()).ToList();
        PrefabtTypeReadonly.Sort(); //for convinience

        // if order has changed => do not forget
        var keys = _PrefabDictionary.Keys.Select(type => type.ToString()).ToList();
        var keys_permutation = PrefabtTypeReadonly.Select(type => keys.IndexOf(type)).ToArray();

        var vals = _PrefabDictionary.Values.ToArray();
        PrefabDataConfig = new(keys_permutation.Length);
        for (int i = 0; i < keys_permutation.Length; i++)
        {
            GameObject data = keys_permutation[i] < 0
                ? null
                : vals[keys_permutation[i]];

            if (PrefabDataConfig.Count <= i)
                PrefabDataConfig.Add(data);
            else
                PrefabDataConfig[i] = data;
        }
    }

    public void OnAfterDeserialize()
    {
        _PrefabDictionary = new();
        for (int i = 0; i != Math.Min(PrefabtTypeReadonly.Count, PrefabDataConfig.Count); i++)
            // if (PrefabDataConfig[i] != null)
                _PrefabDictionary.TryAdd(
                    TypeExtensions<Fact>.UAssemblyInheritenceTypes.FirstOrDefault(type => type.ToString() == PrefabtTypeReadonly[i]),
                    PrefabDataConfig[i]
                );
    }
    #endregion ISerializationCallbackReceiver

    #region UnityMethods
    void Awake()
    {
        Instance = this; //first come, first serve

        AddFactEvent.AddListener(AddFact);
        RemoveFactEvent.AddListener(RemoveFact);
        //AnimateExistingFactEvent.AddListener(AnimateFact);
        FactFavorisation.ChangeFavoriteEvent.AddListener(OnFavoriteChange);
    }
    #endregion UnityMethods

    #region Implementation
    public void AddFact(Fact fact)
    {
        // index where the new display will be inserted
        int siblingIdx = sortDescending ? 0 : factscreenContent.childCount;
        if (showGrouped)
        {
            var facts = factscreenContent.GetComponentsInChildren<FactWrapper>().Select(f => f.Fact).ToList();
            if (!sortDescending)
                siblingIdx = GetIndexInSortedList(fact, facts);
            else
            {
                facts.Reverse();
                var _siblingIdx = GetIndexInSortedList(fact, facts);
                siblingIdx = factscreenContent.childCount - _siblingIdx;
            }
        }

        // create display
        var display = CreateDisplay(transform, fact);
        display.transform.localPosition = Vector3.zero;
        displayedFacts.TryAdd(fact.Id, display);

        // disable if showOnlyFavorites is true and fact is no favorite
        display.transform.parent.gameObject.SetActive(!(showOnlyFavorites && !display.GetComponent<FactFavorisation>().IsFavorite));

        display.transform.parent.transform.SetSiblingIndex(siblingIdx);
    }

    private GameObject CreateDisplay(Transform transform, Fact fact)
    {
        Type fact_type = fact.GetType();
        if(fact_type.IsConstructedGenericType)
            fact_type = fact_type.GetGenericTypeDefinition();

        var spot = Instantiate(factSpotPrefab, factscreenContent);
        return fact.instantiateDisplay(PrefabDictionary[fact_type], spot.transform);
    }

    public void RemoveFact(Fact fact)
    {
        // destroy factSpot (parent of displayed fact) and the fact display with it
        Destroy(displayedFacts[fact.Id].transform.parent.gameObject);
        displayedFacts.Remove(fact.Id);
    }

    public void AnimateFact(Fact fact)
    {
        var factIcon = displayedFacts[fact.Id];
        factIcon.GetComponentInChildren<ImageHintAnimation>().AnimationTrigger();
    }

    #region Sorting
    #region AscDesc
    public void AscDescChanged(Toggle t)
    {
        sortDescending = !sortDescending;
        factscreenContent.gameObject.ForAllChildren(child => child.transform.SetAsFirstSibling());
    }
    #endregion AscDesc

    #region Grouping
    public void GroupingChanged(Toggle t)
    {
        showGrouped = t.isOn;

        var vals = factscreenContent.gameObject.GetDirectChildren();
        var ordered = showGrouped
            ? vals.OrderBy(tr => tr.GetComponent<FactWrapper>().Fact, new FactTypeComparer()).ToList()
            : vals.OrderBy(tr => displayedFacts.Keys.ToList().IndexOf(tr.GetComponent<FactWrapper>().Fact.Id)).ToList();

        if (sortDescending)
            ordered.Reverse();

        for (int i = 0; i < ordered.Count; i++)
            ordered[i].transform.SetSiblingIndex(i);
    }

    private int GetIndexInSortedList(Fact f, List<Fact> toCheck)
    {
        var index = toCheck.BinarySearch(f, new FactTypeComparer());
        if (index < 0) index = ~index;
        return index;
    }

    internal class FactTypeComparer : IComparer<Fact>
    {
        /// <summary>
        /// Compare two facts by type and label
        /// </summary>
        /// <param name="x"></param>
        /// <param name="y"></param>
        /// <returns></returns>
        public int Compare(Fact x, Fact y)
        {
            if (x.GetType() == y.GetType()) // same type: compare labels
                return string.Compare(x.Label, y.Label);
            else // different types: compare type
                return string.Compare(x.GetType().ToString(), y.GetType().ToString());
        }
    }
    #endregion Grouping
    #endregion Sorting

    #region Favorites
    public void FavoritesFilterChanged(Toggle t)
    {
        showOnlyFavorites = t.isOn;

        if (!showOnlyFavorites) // show all
            displayedFacts.Values.ForEach(nFav => nFav.transform.parent.gameObject.SetActive(true));
        else
        {   // hide not favorites
            displayedFacts.Values
                 .Where(go => !go.GetComponent<FactFavorisation>().IsFavorite)
                 .ForEach(nFav => nFav.transform.parent.gameObject.SetActive(false));
        }
    }

    private void OnFavoriteChange(Fact changedFact, bool isFavourite)
    {
        if (!showOnlyFavorites)
            return;

        var id = changedFact.Id;
        if (displayedFacts.ContainsKey(id))
            displayedFacts[id].transform.parent.gameObject.SetActive(isFavourite);
    }
    #endregion Favorites

    #endregion Implementation
}