using Microsoft.Extensions.Configuration;
using MP.Core.Conf;
using MP.Data.DbModels;
using MP.Data.Repository.FluxLog;
using Newtonsoft.Json;
using NLog;
using StackExchange.Redis;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Data;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using ZiggyCreatures.Caching.Fusion;

namespace MP.Data.Services
{
    /// <summary>
    /// Classe accesso processi traduzione
    /// </summary>
    public class TranslateSrv : BaseServ
    {
        #region Public Constructors

        public TranslateSrv(
            IConfiguration configuration,
            IConnectionMultiplexer redConn,
            IFusionCache cache,
            Repository.MpVoc.IMpVocRepository mpVocRepository
            ) : base(configuration, cache, redConn)
        {
            _mpVocRepository = mpVocRepository;
        }

        #endregion Public Constructors

        #region Public Methods

        /// <summary>
        /// Esegue traduzione dato vocabolario da Lingua + Lemma
        /// </summary>
        /// <param name="lemma"></param>
        /// <param name="lingua"></param>
        /// <returns></returns>
        public string Traduci(string lemma, string lingua = "IT")
        {
            if (string.IsNullOrWhiteSpace(lemma)) return string.Empty;
            if (string.IsNullOrWhiteSpace(lingua)) return lemma;

            string linguaKey = lingua.ToLowerInvariant().Trim();
            string cacheKey = $"vocab:{linguaKey}";

            // FusionCache gestisce il lock e recupera l'intero dizionario della lingua.
            // Se è in L1 (Memory), restituisce l'oggetto C# istantaneamente.
            // Se non c'è, passa a L2 (Redis) o invoca la factory per caricarlo.
            var dizionarioLingua = _cache.GetOrSet<Dictionary<string, string>>(
                cacheKey,
                _ => _mpVocRepository.VocabolarioGetLang(linguaKey),
                options => options
                    .SetDuration(TimeSpan.FromHours(8))      // Durata logica della cache
                    .SetFailSafe(true, TimeSpan.FromHours(1)) // Se Redis/DB è giù, usa i vecchi dati L1
            );

            // Ricerca O(1) nel dizionario in memoria
            if (dizionarioLingua != null && dizionarioLingua.TryGetValue(lemma, out var traduzione))
            {
                return traduzione;
            }

            // Fallback: se la parola non è censita, restituisce il lemma originale (lingua + lemma)
            return $"{lingua}_{lemma}";
        }


#if false
        /// <summary>
        /// Recupero elenco config
        /// </summary>
        /// <returns></returns>
        public async Task<List<ConfigModel>> ConfigGetAll()
        {
            string source = "DB";
            Stopwatch sw = new Stopwatch();
            sw.Start();
            List<ConfigModel>? result = new List<ConfigModel>();
            // cerco in _redisConn...
            string currKey = $"{redisBaseKey}:Conf";
            RedisValue rawData = await _redisDb.StringGetAsync(currKey);
            //if (!string.IsNullOrEmpty($"{rawData}"))
            if (rawData.HasValue)
            {
                result = JsonConvert.DeserializeObject<List<ConfigModel>>($"{rawData}");
                source = "REDIS";
            }
            else
            {
                result = await _mpVocRepository.ConfigGetAllAsync();
                // serializzo e salvo...
                rawData = JsonConvert.SerializeObject(result);
                _redisDb.StringSet(currKey, rawData, LongCache);
            }
            if (result == null)
            {
                result = new List<ConfigModel>();
            }
            sw.Stop();
            Log.Debug($"ConfigGetAllAsync | {source} | {sw.Elapsed.TotalMilliseconds}ms");
            return result;
        } 
#endif

        /// <summary>
        /// Pulizia cache Redis (tutta)
        /// </summary>
        /// <returns></returns>
        public async Task<bool> FlushCache()
        {
#if false
            RedisValue pattern = new RedisValue($"{redisBaseKey}:*");
            bool answ = await ExecFlushRedisPattern(pattern);
            // rileggo vocabolario!
            var rawData = await VocabolarioGetAll();
            DictVocab = rawData.ToDictionary(kvp => $"{kvp.Lingua}_{kvp.Lemma}".ToUpper(), kvp => kvp.Traduzione);
            return answ; 
#endif
            return await FlushFusionCacheAsync();
        }

        /// <summary>
        /// Pulizia cache Redis per chiave specifica (da redisBaseKey...)
        /// </summary>
        /// <returns></returns>
        public async Task<bool> FlushCache(string KeyReq)
        {
#if false
            RedisValue pattern = new RedisValue($"{redisBaseKey}:{KeyReq}:*");
            bool answ = await ExecFlushRedisPattern(pattern);
            return answ; 
#endif
            return await FlushFusionCacheAsync(KeyReq);
        }

        /// <summary>
        /// Cancellazione FusionCache (totale)
        /// </summary>
        /// <returns></returns>
        private async Task<bool> FlushFusionCacheAsync()
        {
            await _cache.ClearAsync(allowFailSafe: false);
            return true;
        }

        /// <summary>
        /// Cancellazione FusionCache dato singolo tag
        /// </summary>
        /// <returns></returns>
        private async Task<bool> FlushFusionCacheAsync(string tag)
        {
            if (string.IsNullOrWhiteSpace(tag)) return false;

            await _cache.RemoveByTagAsync(tag);
            return true;
        }

        /// <summary>
        /// Cancellazione FusionCache dato elenco tags
        /// </summary>
        /// <returns></returns>
        private async Task<bool> FlushFusionCacheAsync(List<string> listTags)
        {
            if (listTags == null || listTags.Count == 0) return false;

            // Generiamo i Task di rimozione ed eseguiamoli in parallelo su Redis/L1
            var tasks = listTags
                .Where(tag => !string.IsNullOrWhiteSpace(tag))
                .Select(tag => _cache.RemoveByTagAsync(tag).AsTask());

            await Task.WhenAll(tasks);
            return true;
        }

        /// <summary>
        /// Recupero elenco config
        /// </summary>
        /// <returns></returns>
        public async Task<List<LingueModel>> LingueGetAll()
        {
            string currKey = $"{redisBaseKey}:Lang";

            return await GetOrFetchAsync(
                operationName: "LingueGetAll",
                cacheKey: currKey,
                expiration: GetRandTOut(redisShortTimeCache),
                fetchFunc: async () => await _mpVocRepository.LingueGetAllAsync() ?? new(),
                tagList: [currKey]
            );

#if false
            string source = "DB";
            Stopwatch sw = new Stopwatch();
            sw.Start();
            List<LingueModel>? result = new List<LingueModel>();
            // cerco in _redisConn...
            string currKey = $"{redisBaseKey}:Lang";
            RedisValue rawData = await _redisDb.StringGetAsync(currKey);
            //if (!string.IsNullOrEmpty($"{rawData}"))
            if (rawData.HasValue)
            {
                result = JsonConvert.DeserializeObject<List<LingueModel>>($"{rawData}");
                source = "REDIS";
            }
            else
            {
                result = await _mpVocRepository.LingueGetAllAsync();
                // serializzo e salvo...
                rawData = JsonConvert.SerializeObject(result);
                _redisDb.StringSet(currKey, rawData, UltraLongCache);
            }
            if (result == null)
            {
                result = new List<LingueModel>();
            }
            sw.Stop();
            Log.Debug($"LingueGetAll | {source} | {sw.Elapsed.TotalMilliseconds}ms");
            return result; 
#endif
        }

#if false
        /// <summary>
        /// Traduzione termine
        /// </summary>
        /// <param name="lemma"></param>
        /// <param name="lingua"></param>
        /// <returns></returns>
        public string Traduci(string lemma, string lingua = "IT")
        {
            string answ = $"[{lemma}.{lingua}]";
            string key = $"{lingua}_{lemma}".ToUpper();
            if (DictVocab.ContainsKey(key))
            {
                answ = DictVocab[key];
            }
            return answ;
        } 
#endif

        /// <summary>
        /// Recupero elenco config
        /// </summary>
        /// <returns></returns>
        public async Task<List<VocabolarioModel>> VocabolarioGetAll()
        {
            string currKey = $"{redisBaseKey}:VocAll";

            return await GetOrFetchAsync(
                operationName: "VocabolarioGetAll",
                cacheKey: currKey,
                expiration: GetRandTOut(redisShortTimeCache),
                fetchFunc: async () => await _mpVocRepository.VocabolarioGetAllAsync() ?? new(),
                tagList: [currKey]
            );


#if false
            string source = "DB";
            Stopwatch sw = new Stopwatch();
            sw.Start();
            List<VocabolarioModel>? result = new List<VocabolarioModel>();
            // cerco in _redisConn...
            string currKey = $"{redisBaseKey}:Voc";
            RedisValue rawData = await _redisDb.StringGetAsync(currKey);
            //if (!string.IsNullOrEmpty($"{rawData}"))
            if (rawData.HasValue)
            {
                result = JsonConvert.DeserializeObject<List<VocabolarioModel>>($"{rawData}");
                source = "REDIS";
            }
            else
            {
                result = await _mpVocRepository.VocabolarioGetAllAsync();
                // serializzo e salvo...
                rawData = JsonConvert.SerializeObject(result);
                _redisDb.StringSet(currKey, rawData, UltraLongCache);
            }
            if (result == null)
            {
                result = new List<VocabolarioModel>();
            }
            sw.Stop();
            Log.Debug($"VocabolarioGetAll | {source} | {sw.Elapsed.TotalMilliseconds}ms");
            return result; 
#endif
        }

        #endregion Public Methods

        #region Protected Fields

#if false
        /// <summary>
        /// Vocabolario x recupero rapido traduzioni
        /// </summary>
        protected static Dictionary<string, string> DictVocab = new Dictionary<string, string>(); 
#endif

        #endregion Protected Fields

        #region Protected Methods

        #endregion Protected Methods

        #region Private Fields

        private static Logger Log = LogManager.GetCurrentClassLogger();

        private string redisBaseKey = "MP:Voc:Cache";

        private readonly Repository.MpVoc.IMpVocRepository _mpVocRepository;

        #endregion Private Fields

        #region Private Methods


#if false
        /// <summary>
        /// Esegue flush memoria _redisConn dato pat2Flush
        /// </summary>
        /// <param name="pat2Flush"></param>
        /// <returns></returns>
        private async Task<bool> ExecFlushRedisPattern(RedisValue pat2Flush)
        {
            bool answ = false;
            var masterEndpoint = _redisConn.GetEndPoints()
                                          .Where(ep => _redisConn.GetServer(ep).IsConnected && !_redisConn.GetServer(ep).IsReplica)
                                          .FirstOrDefault();

            // sepattern è "*" elimino intero DB...
            if (masterEndpoint != null && (pat2Flush.Equals(new RedisValue("*")) || pat2Flush == RedisValue.Null))
            {
                _redisConn.GetServer(masterEndpoint).FlushDatabase(database: _redisDb.Database);
            }
            else
            {
                var server = _redisConn.GetServer(masterEndpoint);
                var keys = server.Keys(database: _redisDb.Database, pattern: pat2Flush, pageSize: 1000);

                var deleteTasks = new List<Task>();
                foreach (var key in keys)
                {
                    deleteTasks.Add(_redisDb.KeyDeleteAsync(key));
                    if (deleteTasks.Count >= 1000)
                    {
                        await Task.WhenAll(deleteTasks);
                        deleteTasks.Clear();
                    }
                }
                if (deleteTasks.Count > 0)
                {
                    await Task.WhenAll(deleteTasks);
                }
            }
            answ = true;

            return answ;
        } 
#endif

        #endregion Private Methods
    }
}