using System;
using System.Collections.Generic;
using System.Globalization;
using System.Threading;

namespace Kreta.Framework
{
    [Serializable]
    public class LanguageContext
    {
        const int Hungarian = 1038;
        const int Zulu = 1077;
        const int Urdu = 1056;

        [ThreadStatic]
        static LanguageContext m_Current;

        static LanguageContext m_DefaultLanguageContext;

        static Dictionary<string, int> m_LanguageIndexes;

        readonly int m_LCID;
        CultureInfo m_RegionSettings;

        public LanguageContext(int lcid)
        {
            m_LCID = lcid;
            SetCulture(CultureInfo.GetCultureInfo(lcid == Zulu || lcid == Urdu ? Hungarian : lcid)); /* A urdu és zulu nyelvet kvázi magyarnak tekintjük. */
        }

        public LanguageContext() : this(LanguageContext.DefaultLanguageContext.LCID)
        {
        }

        void SetCulture(CultureInfo cultureInfo)
        {
            if (cultureInfo.IsNeutralCulture)
            {
                SetCulture(CultureInfo.CreateSpecificCulture(cultureInfo.Name));
            }
            m_RegionSettings = cultureInfo;
        }

        static int GetLanguageIndex(CultureInfo cultureInfo)
        {
            string key = cultureInfo.Name.ToLower();
            if (m_LanguageIndexes.TryGetValue(key, out int value))
            {
                return value;
            }

            if (!cultureInfo.IsNeutralCulture)
            {
                return GetLanguageIndex(cultureInfo.Parent);
            }

            return 0;
        }

        static void InitializeLanguageIndexes()
        {
            Dictionary<string, int> result = new Dictionary<string, int>();
            //          using( SDA.DataProvider.SDAConnection connection = SDAServer.Instance.CreateConnection() ) 
            //          {
            //              connection.Open();
            //              using( SDA.DataProvider.SDACommand command = connection.CreateCommand() ) 
            //              {
            //                  command.CommandText = @"
            //if exists (select 1 from sys.tables where name = 'T_SYSTEMPARAMETER') 
            //begin
            //  select C_VALUE from T_SYSTEMPARAMETER where C_NAME = 'LANGUAGES'
            //end";
            //                  string temp = command.ExecuteScalar() as string;
            //                  if( temp != null ) 
            //                  {
            //                      string[] languages = temp.Split( ',', ';' );
            //                      for( int index = 0; index < languages.Length; index++ ) 
            //                      {
            //                          result[languages[index].Trim().ToLower()] = index;
            //                      }
            //                  }
            //              }
            //          }
            m_LanguageIndexes = result;
        }

        public static void Initialize(LanguageContext defaultLanguageContext)
        {
            DefaultLanguageContext = defaultLanguageContext;
            InitializeLanguageIndexes();
        }

        public static LanguageContext DefaultLanguageContext
        {
            get
            {
                if (m_DefaultLanguageContext == null)
                {
                    m_DefaultLanguageContext = new LanguageContext(Thread.CurrentThread.CurrentCulture.LCID);
                }
                return m_DefaultLanguageContext;
            }
            set
            {
                m_DefaultLanguageContext = value ?? throw new ArgumentNullException(nameof(value));
            }
        }

        public static LanguageContext Current
        {
            get
            {
                if (m_Current != null)
                {
                    return m_Current;
                }

                if (UserContext.Instance != null)
                {
                    LanguageContext current = UserContext.Instance.LanguageContext;
                    if (current != null)
                    {
                        return current;
                    }
                }
                return DefaultLanguageContext;
            }
            set
            {
                m_Current = value;
            }
        }

        public CultureInfo RegionSettings
        {
            get
            {
                return m_RegionSettings;
            }
        }

        public int LCID
        {
            get
            {
                return m_LCID;
            }
        }

        /// <summary>
        /// A nyelv rendszerparaméterben definiált indexe.
        /// </summary>
        public int LanguageIndex
        {
            get
            {
                return GetLanguageIndex(m_RegionSettings);
            }
        }
    }
}