using System;
using System.Collections.Concurrent;
using System.IO;
using System.Xml.Linq;

namespace Kreta.Framework.Caching
{
    public sealed class StringResourcesCache : Cache
    {
        private const int DefaultLcid = 1038; // magyar
        private const string StringResourcesFileName = "StringResources.kres";

        private ConcurrentDictionary<string, string> cache;

        public StringResourcesCache(CacheManager cacheManager) : base(cacheManager)
        {
            cache = new ConcurrentDictionary<string, string>();
            LoadCache();
        }

        private string GetStringResourcesKey(int id, int lcid)
        {
            return $"{id}¤{lcid}";
        }

        private void LoadCache()
        {
            string[] stringResourcesFilePath = Directory.GetFiles(AppDomain.CurrentDomain.BaseDirectory, StringResourcesFileName, SearchOption.AllDirectories);
            if (stringResourcesFilePath.Length == 0)
            {
                throw new Exception($"Not found {StringResourcesFileName} file!");
            }

            var root = XElement.Load(stringResourcesFilePath[0]);

            foreach (XElement text in root.Elements())
            {
                foreach (XElement language in text.Elements())
                {
                    string stringResourcesKey = GetStringResourcesKey(Convert.ToInt32(text.Attribute("ID").Value), Convert.ToInt32(language.Attribute("LCID").Value));
                    string value = language.Value.Replace("\n", "<br/>");

                    cache.AddOrUpdate(stringResourcesKey, key => value, (k, v) => value);
                }
            }
        }

        private static string GetDefaultText(int id, int lcid)
        {
            return $"Nincs fordítása -> ID:{id} - LCID:{lcid}!";
        }

        public string Get(int id, int lcid)
        {
            return Get(id, lcid, GetDefaultText(id, lcid));
        }

        public string Get(int id, int lcid, string defaultText)
        {
            var result = cache.GetOrAdd(GetStringResourcesKey(id, lcid), key => GetDefaultText(id, lcid));

            if (result == null && lcid != DefaultLcid)
            {
                result = cache.GetOrAdd(GetStringResourcesKey(id, DefaultLcid), key => GetDefaultText(id, DefaultLcid));
            }

            if (result == null)
            {
                result = defaultText;
            }

            return result;
        }

        public override void Reset()
        {
            cache.Clear();
        }
    }
}