using System;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Xml;
using Kreta.Framework.Logging;
using Kreta.Resources;

namespace Kreta.Framework
{
    public enum SystemType
    {
        [Display(Name = nameof(EnumsResource.Ismeretlen), ResourceType = typeof(EnumsResource))]
        Ismeretlen = -1,

        [Display(Name = nameof(EnumsResource.Teszt), ResourceType = typeof(EnumsResource))]
        Teszt = 0,

        [Display(Name = nameof(EnumsResource.KlebelsbergKozpont), ResourceType = typeof(EnumsResource))]
        KK = 1,

        [Display(Name = nameof(EnumsResource.NemzetiSzakkepzesiEsFelnottkepzesiHivatal), ResourceType = typeof(EnumsResource))]
        NSZFH = 2,

        [Display(Name = nameof(EnumsResource.HermanOttoIntezet), ResourceType = typeof(EnumsResource))]
        HOI = 3,

        [Display(Name = nameof(EnumsResource.Azure), ResourceType = typeof(EnumsResource))]
        AZURE = 4,

        [Display(Name = nameof(EnumsResource.Azure), ResourceType = typeof(EnumsResource))]
        NSZFH_EMA = 5
    }

    /// <summary>
    /// Néhány alaptulajdonság van felvéve, aztan majd lehet bővíteni.
    /// </summary>
    public class Configuration : ILogConfig
    {
        /// <summary>
        /// Configuration constuctor
        /// </summary>
        /// <param name="configurationNode">the main "config" node</param>
        public Configuration(XmlNode configurationNode)
        {
            var cfg = configurationNode;
            try
            {
                ConfigDocument = cfg;
                // ReSharper disable once DoNotCallOverridableMethodsInConstructor
                ReadConfig(cfg);
            }
            catch (InvalidConfigurationException)
            {
                throw;
            }
            catch (Exception exception)
            {
                throw new InvalidConfigurationException(exception);
            }
        }

        #region Beolvasás

        /// <summary>
        /// Reads configuration string.
        /// </summary>
        /// <param name="confignode">Server config</param>
        /// <param name="xpath">XPath location of node</param>
        /// <returns>Configuration value</returns>
        /// <exception cref="InvalidConfigurationException">Invalid configuration</exception>
        protected static string ReadString(XmlNode confignode, string xpath)
        {
            XmlNode current;
            if ((current = confignode.SelectSingleNode(xpath)) != null)
            {
                return current.InnerText;
            }
            throw new InvalidConfigurationException(string.Format("Missing configuration entry: {0}.", xpath));
        }

        /// <summary>
        /// Reads configuration string.
        /// </summary>
        /// <param name="confignode">Server config</param>
        /// <param name="xpath">XPath location of node</param>
        /// <param name="defaultValue">The default value if missing from configuration</param>
        /// <returns>Configuration value</returns>
        /// <exception cref="InvalidConfigurationException">Invalid configuration</exception>
        protected static string ReadString(XmlNode confignode, string xpath, string defaultValue)
        {
            XmlNode current;
            return (current = confignode.SelectSingleNode(xpath)) != null ? current.InnerText : defaultValue;
        }

        /// <summary>
        /// Reads configuration list.
        /// </summary>
        /// <param name="confignode">Server config</param>
        /// <param name="xpath">XPath location of node</param>
        /// <param name="listElementNode">Name of list element node</param>
        /// <returns>Configuration list</returns>
        protected static string[] ReadStrings(XmlNode confignode, string xpath, string listElementNode)
        {
            XmlNode current;
            if ((current = confignode.SelectSingleNode(xpath)) != null)
            {
                return (
                        from XmlNode node in current.ChildNodes
                        where node.Name.Equals(listElementNode, StringComparison.OrdinalIgnoreCase)
                        select node.InnerText)
                    .ToArray();
            }
            return null;
        }

        /// <summary>
        /// Reads configuration number.
        /// </summary>
        /// <param name="confignode">Server config</param>
        /// <param name="xpath">XPath location of node</param>
        /// <param name="defaultValue">The default value if missing from configuration, <c>null</c> value implies required node</param>
        /// <returns>Configuration value</returns>
        /// <exception cref="InvalidConfigurationException">
        /// Invalid configuration or <paramref name="defaultValue"/> is <c>null</c> and node is missing.
        /// </exception>
        protected static int ReadNumber(XmlNode confignode, string xpath, int? defaultValue = null)
        {
            XmlNode current;
            if ((current = confignode.SelectSingleNode(xpath)) != null)
            {
                if (int.TryParse(current.InnerText, out int innerNumber))
                {
                    return innerNumber;
                }
                throw new InvalidConfigurationException(string.Format("Invalid configuration entry: {0}.", xpath));
            }
            if (defaultValue != null)
            {
                return (int)defaultValue;
            }
            throw new InvalidConfigurationException(string.Format("Missing configuration entry: {0}.", xpath));
        }

        /// <summary>
        /// Reads configuration switch.
        /// </summary>
        /// <param name="confignode">Server config</param>
        /// <param name="xpath">XPath location of node</param>
        /// <param name="defaultValue">The default value if missing from configuration, <c>null</c> value implies required node</param>
        /// <returns>Configuration value</returns>
        /// <exception cref="InvalidConfigurationException">
        /// Invalid configuration or <paramref name="defaultValue"/> is <c>null</c> and node is missing.
        /// </exception>
        protected static bool ReadBool(XmlNode confignode, string xpath, bool? defaultValue = null)
        {
            XmlNode current;
            if ((current = confignode.SelectSingleNode(xpath)) != null)
            {
                if (bool.TryParse(current.InnerText, out var innerBool))
                {
                    return innerBool;
                }
                throw new InvalidConfigurationException(string.Format("Invalid configuration entry: {0}.", xpath));
            }
            if (defaultValue != null)
            {
                return (bool)defaultValue;
            }
            throw new InvalidConfigurationException(string.Format("Missing configuration entry: {0}.", xpath));
        }

        /// <summary>
        /// Reads configuration enumeration.
        /// </summary>
        /// <param name="confignode">Server config</param>
        /// <param name="xpath">XPath location of node</param>
        /// <param name="defaultValue">The default value if missing from configuration, <c>null</c> value implies required node</param>
        /// <returns>Configuration value</returns>
        /// <exception cref="InvalidConfigurationException">
        /// Invalid configuration or <paramref name="defaultValue"/> is <c>null</c> and node is missing.
        /// </exception>
        protected static TEnum ReadEnum<TEnum>(XmlNode confignode, string xpath, TEnum? defaultValue = null) where TEnum : struct
        {
            XmlNode current;
            if ((current = confignode.SelectSingleNode(xpath)) != null)
            {
                if (Enum.TryParse(current.InnerText, true, out TEnum innerEnum))
                {
                    return innerEnum;
                }
                throw new InvalidConfigurationException(string.Format("Invalid configuration entry: {0}.", xpath));
            }
            if (defaultValue != null)
            {
                return (TEnum)defaultValue;
            }
            throw new InvalidConfigurationException(string.Format("Missing configuration entry: {0}.", xpath));
        }

        protected virtual void ReadConfig(XmlNode confignode)
        {
            string xpath = "";
            try
            {
                // Kiszolgáló egyedi neve.
                xpath = @"/config/server/name";
                ServerName = ReadString(confignode, xpath);

                // Az adatbázis-kapcsolatot leíró karakterlánc.
                xpath = @"/config/server/dbconnection";
                DBConnection = ReadString(confignode, xpath);

                xpath = @"/config/server/globalapidbconnection";
                GlobalDbConnection = ReadString(confignode, xpath);

                // A naplózás szintje.
                xpath = @"/config/server/loglevel";
                ServerLogLevel = ReadEnum<LogLevel>(confignode, xpath);
#if !DEBUG
                // Release szerver legfeljebb INFO részletességű lehet.
                if (ServerLogLevel < LogLevel.INFO)
                {
                    ServerLogLevel = LogLevel.INFO;
                }
#endif

                // Munkamenet elévülési ideje.
                xpath = @"/config/server/sessiontimeout";
                SessionTimeout = ReadNumber(confignode, xpath);

                // Alapértelmezett nyelv.
                xpath = @"/config/server/lcid";
                LCID = ReadNumber(confignode, xpath, 1038);

                xpath = @"/config/server/logdbconnection";
                _logDbConnection = ReadString(confignode, xpath, DBConnection);

                // Konzolra való naplózás engedélyezése.
                xpath = @"/config/server/logtoconsole";
                LogToConsole = ReadBool(confignode, xpath, false);

                // A maximálisan lehozható rekordok száma.
                xpath = @"/config/server/maxrecordsperrequest";
                MaximalRecordCountPerRequest = ReadNumber(confignode, xpath, 200);

                xpath = @"/config/server/systemtype";
                SystemType = ReadEnum<SystemType>(confignode, xpath, SystemType.Ismeretlen);
            }
            catch (InvalidConfigurationException)
            {
                throw;
            }
            catch (Exception exception)
            {
                throw new InvalidConfigurationException(string.Format("Invalid configuration entry: {0}.", xpath), exception);
            }
        }
        #endregion

        #region Mezok

        string _logDbConnection;

        volatile int _sessionTimeout = 10;

        SystemType _systemType = SystemType.Ismeretlen;

        #endregion

        #region Tulajdonságok

        /// <summary>
        /// A kiszolgáló neve.
        /// </summary>
        public string ServerName { get; private set; }

        string dbconnection = null;
        /// <summary>
        /// Adatbáziskapcsolat-leíró karakterlánc.
        /// </summary>
        public string DBConnection
        {
            get
            {
                return dbconnection;
            }
            set
            {
                dbconnection = value;

                System.Data.SqlClient.SqlConnectionStringBuilder builder = new System.Data.SqlClient.SqlConnectionStringBuilder(dbconnection);
                DatabaseName = builder.InitialCatalog;
            }
        }

        public string GlobalDbConnection { get; set; }

        public string DatabaseName { get; set; }

        /// <summary>
        /// A kiszolgáló naplózási szintje.
        /// </summary>
        public LogLevel ServerLogLevel { get; private set; }

        /// <summary>
        /// A kiszolgáló alapértelmezett régiókódja.
        /// </summary>
        public int LCID { get; private set; }

        /// <summary>
        /// Munkamenet elévülési ideje, percben.
        /// </summary>
        public int SessionTimeout
        {
            get { return _sessionTimeout; }
            set { _sessionTimeout = value; }
        }

        /// <summary>
        /// Rendszer típus
        /// </summary>
        public SystemType SystemType
        {
            get { return _systemType; }
            set { _systemType = value; }
        }

        /// <summary>
        /// A konfiguráció, mint XML dokumentum.
        /// </summary>
        public XmlNode ConfigDocument { get; private set; }

        /// <summary>
        /// Az egy kérésben maximálisan megengedett felhozott rekordok száma.
        /// </summary>
        public int MaximalRecordCountPerRequest { get; set; }

        /// <summary>
        /// Naplózás konzolra.
        /// </summary>
        public bool LogToConsole { get; private set; }

        #endregion

        #region ILogConfig

        /// <summary>
        /// A kiszolgáló naplózási szintje.
        /// </summary>
        LogLevel ILogConfig.LogLevel { get { return ServerLogLevel; } }

        string ILogConfig.ConnectionString { get { return _logDbConnection; } }

        #endregion
    }
}