using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Linq;
using System.IO;
using System.ServiceProcess;
using System.Text;
using System.Threading.Tasks;
using System.Timers;

using log4net;

using bsmd.database;
using bsmd.email;


namespace bsmd.ExcelReadService
{    

    public partial class ExcelReadService : ServiceBase
    {
        private Timer _timer;
        private object _timerlock = new object();
        private bool processRunning = false;
        private ILog _log = LogManager.GetLogger(typeof(ExcelReadService));

        public ExcelReadService()
        {
            Directory.SetCurrentDirectory(AppDomain.CurrentDomain.BaseDirectory);
            InitializeComponent();
        }

        protected override void OnStart(string[] args)
        {
            this.EventLog.Source = this.ServiceName;
            this.EventLog.Log = "Application";
            this.Init(args);
            this.EventLog.WriteEntry("EU-NOAD Excel Read Service started.", EventLogEntryType.Information);
            this.DoOnce();
        }

        private void Init(string[] args)
        {
            this._timer = new Timer();
            this._timer.Interval = Properties.Settings.Default.SleepSeconds * 1000;
            this._timer.Elapsed += _timer_Elapsed;
            this._timer.Enabled = true;
        }

        private void _timer_Elapsed(object sender, ElapsedEventArgs e)
        {
            lock (this._timerlock)
            {
                if (this.processRunning) return;
                else this.processRunning = true;
            }

            if (DBManager.Instance.Connect(Properties.Settings.Default.ConnectionString))
            {

                try
                {
                    string messageId = "";
                    string attachmentLocalPath = "";
                    string mailSender = "";

                    using (BSMDPopClient bsmdPopClient = new BSMDPopClient())
                    {
                        if (!bsmdPopClient.IsConnected)
                        {
                            _log.Error("cannot connect to pop3 server, aborting!");
                            this.Stop();
                        }

                        // check and download next e-Mail, saving attachment
                        while (bsmdPopClient.ReceiveSingleMail(out attachmentLocalPath, out messageId, out mailSender))
                        {

                            bool readResult;
                            string readMessage = "";
                            MessageCore messageCore = null;

                            // try to read/import attachment
                            using(ExcelReader reader = new ExcelReader(attachmentLocalPath))
                            {
                                readResult = Util.ProcessSheet(reader, out readMessage, out messageCore);
                                if(!readResult)
                                    _log.Error("Excel sheet could not be interpreted");
                            }

                            // set messagecore to createreport and let reportGenerator create a reply

                            // remove e-Mail
                            _log.InfoFormat("deleting mail with messageId {0}", messageId);
                            _log.InfoFormat("mail delete {0}", bsmdPopClient.DeleteMessageByMessageId(messageId) ? "successful" : "failed");

                            // remove attachment
                            _log.InfoFormat("removing local file {0}", attachmentLocalPath);
                            // File.Delete(attachmentLocalPath);

                        }
                    }

                    DBManager.Instance.Disconnect();
                }
                catch (Exception ex)
                {
                    _log.ErrorFormat("Exception occurred: {0}", ex.ToString());
                }
            }
            else
            {
                this.EventLog.WriteEntry("ReportService stopped: DB connection failed", EventLogEntryType.Error);
                this.Stop();
            }

            lock (this._timerlock)
            {
                this.processRunning = false;
            }

        }

        protected override void OnStop()
        {
        }

        internal void DoOnce()
        {
            this._timer_Elapsed(null, null);
        }

    }
}