using SMTPServer;
using System;
using System.Collections.Generic;
using System.Net.Sockets;
using System.Text;
using System.Linq;

namespace MailServer.SMTPServer
{
    class SmtpServerSession : SmtpSession
    {
        private bool Initialized { get; set; }
        private string SenderHostname { get; set; }

        private bool MailFromSet { get; set; }
        private string MailFrom { get; set; }

        private List<string> Recipients { get; set; }

        private bool WaitForData { get; set; }
        private string Data { get; set; }
        private bool FreeLine { get; set; }

        private bool AuthActive { get; set; }
        private string Username { get; set; }
        private string Password { get; set; }
        private bool Authenticated { get; set; }

        public SmtpServerSession(TcpClient client) : base(client) {
            Recipients = new List<string>();
            SendResponse(ResponseCodes.C220, Configuration.Hostname + " Welcome to SimpleMail DotNetCore based AIO MailServer");
            NewLine += SmtpServerSession_NewLine;
        }

        private void SmtpServerSession_NewLine(string line)
        {
            try
            {
                var command = new SmtpCommand(line);

                if (WaitForData)
                {
#if DEBUG
                    bool dataend = false;
                    if (command.Command.Equals("DATAEND"))
                    {
                        dataend = true;
                    }
#endif
                    FreeLine = true;
                    if (!FreeLine && command.Command.Equals("FREELINE"))
                    {
                        FreeLine = true;
                        return;
                    }
                    else if ((FreeLine && command.Command.Equals("JUSTADOT")) || dataend)
                    {
                        SendResponse(ResponseCodes.C250, "OK");
                        foreach (var r in Recipients)
                        {
                            var split = r.Split('@');
                            var name = split[0];
                            var domain = split[1];

                            using (var context = new MysqlDB())
                            {
                                context.Database.EnsureCreated();
                                int accountId = 0;

                                var dmn = context.Domains.Where(x => x.Domain.Equals(domain));
                                var domainidx = dmn.FirstOrDefault().Id;

                                var res = context.Accounts.Where(x => x.Domain.Equals(domainidx) && x.Name.Equals(name));
                                if (res.Count() < 1)
                                {
                                    var res2 = context.Aliases.Where(x => x.SourceName.Equals(name) && x.SourceDomain.Equals(domain));
                                    if (res2.Count() < 1)
                                    {
                                        var res3 = context.Accounts.Where(x => x.Domain.Equals(domain) && x.CatchAll == true);
                                        if (res3.Count() < 1)
                                        {
                                            accountId = 0;
                                        }
                                        else
                                        {
                                            accountId = res3.FirstOrDefault().Id;
                                        }
                                    }
                                    else
                                    {
                                        accountId = res2.FirstOrDefault().DestinationAccount;
                                    }
                                }
                                else
                                {
                                    accountId = res.FirstOrDefault().Id;
                                }
                                int folderid = 0;

                                var res4 = context.Folders.Where(x => x.AccountId == accountId && x.StandardFolder == (int)StandardFolders.INBOX);
                                if (res4.Count() < 1)
                                {
                                    //ToDo ERROR
                                    folderid = 0;
                                }
                                else folderid = res4.FirstOrDefault().Id;

                                var nm = new Mails()
                                {
                                    AccountId = accountId,
                                    ReceiveDate = DateTime.Now,
                                    Data = Data,
                                    SendedByServerIp = IPEndPoint.Address.ToString(),
                                    From = MailFrom,
                                    To = r,
                                    Folder = folderid
                                };
                                context.Mails.Add(nm);
                                context.SaveChangesAsync();
                            }

                            MailFromSet = false;
                            Recipients.Clear();
                            WaitForData = false;
                            return;
                        }
                        SendResponse(ResponseCodes.C250, "OK");
                        return;
                    }
                    else
                    {
                        Data += command.Command;

                        foreach (var s in command.Parameters)
                        {
                            Data += " " + s;
                        }

                        Data += "\r\n";
                        FreeLine = false;
                    }
                    return;
                }

                switch (command.Command.ToUpper())
                {
                    case "EHLO":
                        if (command.Parameters.Length < 1)
                        {
                            SendResponse(ResponseCodes.C501, "Hostname Required");
                            return;
                        }
                        SenderHostname = command.Parameters[0];
                        Initialized = true;
                        SendExtensionResponse(Extensions.PIPELINING);

                        if (Configuration.STARTTLS_Active)
                        {
#pragma warning disable CS0162 // Unerreichbarer Code wurde entdeckt.
                            SendExtensionResponse(Extensions.STARTTLS);
#pragma warning restore CS0162 // Unerreichbarer Code wurde entdeckt.
                        }

                        SendResponse(ResponseCodes.C250, "SIZE " + (Configuration.MaxMessageSizeInKb * 1000).ToString());
                        return;
                    case "HELO":
                        if (command.Parameters.Length < 1)
                        {
                            SendResponse(ResponseCodes.C501, "Hostname Required");
                            return;
                        }
                        SenderHostname = command.Parameters[0];
                        Initialized = true;
                        SendResponse(ResponseCodes.C250, "OK");
                        return;
                    case "RSET":
                        //ToDo 
                        return;
                    case "QUIT":
                        SendResponse(ResponseCodes.C221, Configuration.Hostname + " closing transmission channel");
                        CloseAll();
                        return;
                }

                if (Initialized)
                {
                    switch (command.Command.ToUpper())
                    {
                        case "MAIL":
                            if (command.Parameters.Length < 1)
                            {
                                SendResponse(ResponseCodes.C501);
                                return;
                            }
                            if (!command.Parameters[0].ToUpper().StartsWith("FROM"))
                            {
                                SendResponse(ResponseCodes.C501);
                                return;
                            }
                            if (command.Parameters.Length == 1)
                            {
                                var m = command.Parameters[0].Split(':');
                                if (m.Length != 2)
                                {
                                    SendResponse(ResponseCodes.C501);
                                    return;
                                }
                                MailFrom = m[1];
                            }
                            else if (command.Parameters.Length == 2)
                            {
                                MailFrom = command.Parameters[1];
                            }
                            else
                            {
                                SendResponse(ResponseCodes.C501);
                                return;
                            }

                            MailFrom.Replace("<", String.Empty);
                            MailFrom.Replace(">", String.Empty);
                            MailFromSet = true;
                            SendResponse(ResponseCodes.C250, "OK");
                            return;
                    }

                    if (MailFromSet)
                    {
                        switch (command.Command.ToUpper())
                        {
                            case "RCPT":
                                if (command.Parameters.Length < 1)
                                {
                                    SendResponse(ResponseCodes.C501);
                                    return;
                                }
                                if (!command.Parameters[0].ToUpper().StartsWith("TO"))
                                {
                                    SendResponse(ResponseCodes.C501);
                                    return;
                                }

                                var rcpt = "";
                                if (command.Parameters.Length == 1)
                                {
                                    var m = command.Parameters[0].Split(':');
                                    if (m.Length != 2)
                                    {
                                        SendResponse(ResponseCodes.C501);
                                        return;
                                    }
                                    rcpt = m[1];
                                }
                                else if (command.Parameters.Length == 2)
                                {
                                    rcpt = command.Parameters[1];
                                }
                                else
                                {
                                    SendResponse(ResponseCodes.C501);
                                    return;
                                }

                                rcpt = rcpt.Replace("<", String.Empty);
                                rcpt = rcpt.Replace(">", String.Empty);

                                var split = rcpt.Split('@');
                                if (split.Length != 2)
                                {
                                    SendResponse(ResponseCodes.C501);
                                    return;
                                }

                                using (var context = new MysqlDB())
                                {
                                    context.Database.EnsureCreated();
                                    var res = context.Domains.Where(x => x.Domain.Equals(split[1]));
                                    if (res.Count() < 1)
                                    {
                                        SendResponse(ResponseCodes.C550, "No such user here");
                                        return;
                                    }
                                }

                                Recipients.Add(rcpt);
                                SendResponse(ResponseCodes.C250, "OK");
                                return;
                        }

                        if (Recipients.Count > 0)
                        {
                            switch (command.Command.ToUpper())
                            {
                                case "DATA":
                                    SendResponse(ResponseCodes.C354, "Start mail input, end with <CRLF>.<CRLF>");
                                    WaitForData = true;
                                    return;
                            }
                        }
                    }
                    SendResponse(ResponseCodes.C500, command.Command);
                    //throw new NotImplementedException();
                }
            } catch (Exception e)
            {
                Logging.AddException(e);
                SendResponse(ResponseCodes.C554, "internal error");
                SendResponse(ResponseCodes.C221, "Closing Transmission");
                CloseAll();
            }
        }
        
        private void ClearFields()
        {
            //ToDo einbauen
        }

    }
}