///
/// Copyright (c) 2020 Sensus Slovensko a.s.
///
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using System.Xml.Serialization;

namespace EventViewer
{
    /// <summary>
    /// Class to be serialized to an XML file...
    /// </summary>
	[XmlRootAttribute("EventViewer")]
    public class LocalSettings
    {
        static XmlSerializer serializer = XmlSerializer.FromTypes(new[] { typeof(LocalSettings) })[0];

        ///
        /// Configuration file ecryption/decryption key and initialization vector
        ///
        static byte[] key = new byte[] { 83, 254, 105, 64, 184, 201, 195, 127, 52, 99, 77, 45, 252, 132, 163, 156 };
        static byte[] IV = new byte[] { 189, 23, 137, 56, 204, 241, 242, 118, 28, 89, 9, 198, 224, 111, 186, 125 };

        /// Common
        public string ConnectionString;
        public bool NonAnonymousAccess;
        public string UserName;
        public string UsersDBConnString;
        public int RecentTimeDays;
        public string Language;

        /// MainWnd
        public int WndLeft;
        public int WndTop;
        public int WndWidth;
        public int WndHeight;
        public bool WndMaximized;

        public int ColWid1;
        public int ColWid2;
        public int ColWid3;
        public int ColWid4;
        public int ColWid5;
        public int ColWid6;

        public LocalSettings()
        {
        }

        public LocalSettings(bool createNew)
            : this()
        {
            /// Default settings

            /// Common
#if DEBUG
            ConnectionString = "SERVER=localhost; DATABASE=test-e; UID=root; PASSWORD=kraken; CHARSET=utf8";
            UsersDBConnString = "SERVER=localhost; DATABASE=test; UID=root; PASSWORD=kraken; CHARSET=utf8;";
#else
            ConnectionString = "SERVER=10.42.128.24; DATABASE=st_wr_shared_events; UID=v9305784; PASSWORD=p89344390; CHARSET=utf8";
            UsersDBConnString = "SERVER=10.42.128.24; DATABASE=st_wr_shared_config; UID=u9305784; PASSWORD=p89344390; CHARSET=utf8;";
#endif
            RecentTimeDays = 7;
            Language = "sk";

            /// MainWnd
            WndLeft = 20;
            WndTop = 20;
            WndWidth = 1250;
            WndHeight = 750;
            WndMaximized = false;

            ColWid1 = 80;
            ColWid2 = 50;
            ColWid3 = 100;
            ColWid4 = 60;
            ColWid5 = 70;
            ColWid6 = 500;
        }


        /// <summary>
        /// Load public fields of this class from the XML file.
        /// </summary>
        /// <param name="fileName">Name of the file.</param>
        /// <returns>
        /// LocalSettings object or null when Load() fails
        /// </returns>
		public static LocalSettings Load(string fileName)
        {
            try
            {
                bool isEncrypted = true;
				using (StreamReader reader = new StreamReader(fileName))
                {
                    isEncrypted = !reader.ReadLine().StartsWith("<?xml version=");
                    reader.Close();
                }

                if (isEncrypted)
                {
                    /// Write settings to a string
                    StringBuilder plain = new StringBuilder();

                    using (RijndaelManaged aes = new RijndaelManaged { Padding = PaddingMode.Zeros })
                    {
                        using (FileStream fsCrypt = new FileStream(fileName, FileMode.Open))
                        {
                            using (ICryptoTransform decryptor = aes.CreateDecryptor(key, IV))
                            {
                                using (CryptoStream cs = new CryptoStream(fsCrypt, decryptor, CryptoStreamMode.Read))
                                {
                                    using (MemoryStream mStream = new MemoryStream())
                                    {
                                        using (var writer = new BinaryWriter(mStream))
                                        {
                                            int data;
                                            while ((data = cs.ReadByte()) != -1)
                                            {
                                                if (data != 0) writer.Write((byte)data);
                                            }
                                            writer.Flush();
                                            mStream.Position = 0;

                                            using (var reader = new StreamReader(mStream))
                                            {
                                                LocalSettings ls = serializer.Deserialize(reader) as LocalSettings;
                                                //log.WarnFormat("Succesfully loaded and decrypted from '{0}'", fileName);
                                                return ls;
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
                else
                {
                    using (StreamReader reader = new StreamReader(fileName))
                    {
                        LocalSettings ls = serializer.Deserialize(reader) as LocalSettings;
                        //log.WarnFormat("Succesfully loaded from '{0}'", fileName);
                        return ls;
                    }
                }
            }
            catch (Exception)
            {
                //log.ErrorFormat("Failed to load from '{0}': {1}", fileName, e.Message);
                return null;
            }
        }

        /// <summary>
        /// Save public fields of this class to the XML file.
        /// </summary>
        public void Save()
        {
            try
            {
#if false
                /// Write settings to an unencrypted file
                using (TextWriter writer = new StreamWriter(Program.LocalSettingsFileName))
                {
                    serializer.Serialize(writer, this);
                    log.Warn("LocalSettings succesfully saved");
                }
#else
                /// Encrypt and write to file 'Program.LocalSettingsFileName'
                using (RijndaelManaged aes = new RijndaelManaged { Padding = PaddingMode.Zeros })
                {
                    using (FileStream fsCrypt = new FileStream(Program.LocalSettingsFileName, FileMode.Create))
                    {
                        using (ICryptoTransform encryptor = aes.CreateEncryptor(key, IV))
                        {
                            using (CryptoStream cs = new CryptoStream(fsCrypt, encryptor, CryptoStreamMode.Write))
                            {
                                using (MemoryStream mStream = new MemoryStream())
                                {
                                    using (var writer = new StreamWriter(mStream))
                                    {
                                        /// Serialize and write settings to a memory stream
                                        serializer.Serialize(writer, this);
                                        writer.Flush();
                                        mStream.Position = 0;

                                        using (var reader = new StreamReader(mStream))
                                        {
                                            /// Encrypt and write to file 'Program.LocalSettingsFileName'
                                            int data;
                                            while ((data = mStream.ReadByte()) != -1) cs.WriteByte((byte)data);

                                            //log.WarnFormat("Succesfully encrypted and saved to '{0}'", Program.LocalSettingsFileName);
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
#endif
            }
            catch (Exception)
            {
                //log.ErrorFormat("Failed to save to '{0}': {1}", Program.LocalSettingsFileName, e.Message);
            }
        }
    }
}