using System;
using System.Collections.Generic;
using System.Linq;
using RPGCore.Core;
using RPGCore.Core.Objects;
using RPGCoreCommon.DynamicValues;
using RPGCoreCommon.Helpers;
using RPGCoreCommon.Helpers.CustomTypes;
using RPGCoreCommon.Settings;
using UnityEngine;

namespace RPGCore.Stats.ObjectModules.StatsObjectModule
{
    [Serializable]
    public class StatsModule : ObjectModule<BaseObject>
    {
        [SerializeField]
        [SerializableDictionary("Stat Definition", "Base Value", isKeyEditable: false)]
        private SerializableDictionary<StatDefinitionSO, int> _serializedStats;
        
        private Dictionary<StatDefinitionSO, StatValue> _stats = new();
        private List<StatDefinitionSO> _queue = new();
            
#if UNITY_EDITOR

        private void OnValidate()
        {
            FixSerializedStats();
        }

        private void FixSerializedStats()
        {
            // fixing only when variable is serialized (sometimes OnValidate can be called before deserializing on project open)
            if (_serializedStats == null) return;
            
            // All stat definitions that should be added to this object...
            var correctStats = SettingsManager.Get<StatsSettings>().allStats
                .Where(stat => stat)
                .Where(stat => stat.attachedTo.type.IsAssignableFrom(parent.GetType()))
                .ToList();
            
            //... but also remember that some of them can override other's, overriden ones should not be here
            correctStats.Select(stat => stat.overrides)
                .Where(overridenStat => overridenStat)
                .ForEach(overridenStat => correctStats.Remove(overridenStat));
            
            // ADD MISSING
            var missingStats = correctStats.Except(_serializedStats.Keys).ToList();
            if (missingStats.Any())
            {
                missingStats.ForEach(missingStat => _serializedStats.Add(missingStat, 0));
                var missingStatsString = string.Join(", ", missingStats.Select(s => s.name));
                Debug.LogWarning($"[StatsModule] automatically adding missing stats: {missingStatsString}", parent);
                UnityEditor.EditorUtility.SetDirty(parent.gameObject);
            }
            
            // REMOVE INVALID
            var invalidStats = _serializedStats.Keys.Except(correctStats).ToList();
            if (invalidStats.Any())
            {
                invalidStats.ForEach(invalidStat => _serializedStats.Remove(invalidStat));
                var invalidStatsString = string.Join(", ", invalidStats.Select(missingStat => missingStat.name));
                Debug.LogWarning($"[StatsModule] automatically removing invalid stats: {invalidStatsString}", parent);
                UnityEditor.EditorUtility.SetDirty(parent.gameObject);
                
            }
        }
        
#endif
        
        [DynamicValueProvider]
        internal StatValue StatValueProvider(string name)
        {
            return _stats.GetValueOrDefault(_stats.Keys.FirstOrDefault(def => def.name == name));
        }

        private void Awake()
        {
            // Create instances of all stats that will be used runtime
            CreateStats();
        }

        private void Start()
        {
            // First stats refresh
            _stats.Keys.ForEach(AddToQueueRefresh);
            QueueRefresh();
        }

        private void FixedUpdate()
        {
            if (_queue.Count > 0) QueueRefresh();
        }

        /// <summary>
        /// Really important part - we create stats for runtime usage.
        /// <see cref="StatDefinitionSO"/> can also override another one, in that case <see cref="StatValue"/>
        /// uses main definition, but it is visible as that overriden one.
        /// </summary>
        private void CreateStats()
        {
            _serializedStats.DictForEach((statDefinition, baseValue) =>
            {
                var baseDefinition = statDefinition.GetBaseDefinition();
                var statValue = new StatValue(statDefinition, baseValue, parent);
                statValue.sourceContext.SetSource("object", parent);
                _stats.Add(baseDefinition, statValue);
            });
        }

        /// <summary>
        /// Returns runtime values for given stat definition.
        /// </summary>
        /// <param name="statDefinitionSO">Runtime stats will be found by this definition (or overriden definition if given)</param>
        /// <returns>Stat values (baseValue, value, resource)</returns>
        public StatValue Get(StatDefinitionSO statDefinitionSO)
        {
#if UNITY_EDITOR
            if (!UnityEditor.EditorApplication.isPlaying) CreateStats();
#endif
            return _stats.GetValueOrDefault(statDefinitionSO.GetBaseDefinition());
        }

        /// <summary>
        /// Refreshing stats, every stat only once even if queued multiple times.
        /// To ensure that dependencies should be refreshed before definition that is using it.
        /// </summary>
        private void QueueRefresh()
        {
            _queue
                .Select(def => Get(def).definition)
                .Sort((d1, d2) => d2.dependencies.Contains(d1) ? - 1 : d1.dependencies.Contains(d2) ? 1 : 0)
                .Select(Get)
                .ForEach(stat => stat.Refresh());
            _queue.Clear();
        }

        /// <summary>
        /// Select <see cref="StatDefinitionSO"/> along with its dependencies to refresh next frame.
        /// </summary>
        public void AddToQueueRefresh(StatDefinitionSO statDefinitionSO)
        {
            statDefinitionSO = statDefinitionSO.GetBaseDefinition();
            
            // Add definition to refresh queue
            if (!_queue.Contains(statDefinitionSO)) _queue.Add(statDefinitionSO);
            
            // All definitions that uses this one as dependency should be refreshed too
            _stats.Keys
                .Where(otherStatDefinition => otherStatDefinition.dependencies.Contains(statDefinitionSO))
                .ForEach(AddToQueueRefresh);
        }
    }
}