using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;

namespace Retel.FactoryLayer.Backend.PLCFileService
{
    class Panel : HTTPServer
    {
        public Panel(String ip, String username, String password, List<Job> jobs, int timeoutAttempts, bool statistics, double statisticsIntervalInHours, List<String> mailList)
        {
            base.ip = ip;
            base.username = username;
            base.password = password;
            base.jobs = jobs;
            base.timeoutAttempts = timeoutAttempts;
            base.statistics = statistics;
            base.statisticsIntervalInHours = statisticsIntervalInHours;
            base.mailList = mailList;
        }

        public override void Schedule()
        {
            if (statistics && nextStatistic < DateTime.Now)
            {
                SendStatistic();
                nextStatistic = DateTime.Now.AddHours(statisticsIntervalInHours);
            }
            int threadId = Thread.CurrentThread.ManagedThreadId;
            //if the next execution time of a job is before the current time, execute the job
            foreach (Job job in this.jobs)
            {
                if (PLCFileService.watchdog != null)
                {
                    PLCFileService.watchdog.NotifyThreadHeartbeat(threadId);
                }

                if (job.GetNextExecutionDate() < DateTime.Now)
                {
                    PLCFileService.msgLog.LogMessage("Executing job: " + job.GetName(), Common.MessageLogger.LogLevel.DEBUG);
                    job.AddExecute();
                    if (this.sessionkey == null)
                    {
                        this.sessionkey = GetSessionKey();
                        if (this.sessionkey == null)
                        {
                            job.SetNextExecutionDate();
                            continue;
                        }
                    }
                    Dictionary<String, DateTime> data;
                    try
                    {
                        data = GetData(arguments: job.GetArguments());
                    }
                    catch (Exception)
                    {
                        data = null;
                    }


                    if (PLCFileService.watchdog != null)
                    {
                        PLCFileService.watchdog.NotifyThreadHeartbeat(threadId);
                    }


                    if (data == null)
                    {
                        PLCFileService.msgLog.LogMessage("Failed to get data for: " + this.ip + ", skipping job.", Common.MessageLogger.LogLevel.WARN);
                        job.SetNextExecutionDate();
                        continue;
                    }

                    job.Execute(this.ip, data, this.sessionkey);

                }
            }
        }

        protected override Dictionary<string, DateTime> GetData(int tries = 1, Dictionary<string, string> arguments = null)
        {
            //try as many times at timeout attempts are configured, if it failed send a timeout mail
            if (tries > timeoutAttempts)
            {
                SendTimeoutMail();
                return null;
            }

            int threadId = Thread.CurrentThread.ManagedThreadId;
            if (PLCFileService.watchdog != null)
            {
                PLCFileService.watchdog.NotifyThreadHeartbeat(threadId);
            }


            Dictionary<String, DateTime> result = new Dictionary<String, DateTime>();
            string html = String.Empty;
            try
            {
                //send request to userfiles site to grab the userfiles of the html file
                WebRequest request = WebRequest.Create("http://" + this.ip + "/Browse.html");
                request.Headers.Add("Cookie", "coming_from_login=false; " + this.sessionkey);
                request.Credentials = CredentialCache.DefaultCredentials;
                ((HttpWebRequest)request).UserAgent = ".NET Framework Example Client";
                request.Timeout = 5000;
                request.Method = "GET";
                WebResponse response = request.GetResponse();

                //convert response to html
                Stream data = response.GetResponseStream();

                using (StreamReader sr = new StreamReader(data))
                {
                    html = sr.ReadToEnd();
                }
            }
            catch (Exception)
            {
                PLCFileService.msgLog.LogMessage("Timeout while retrieving data. (" + tries + " out of " + timeoutAttempts + ")", Common.MessageLogger.LogLevel.WARN);
                this.sessionkey = GetSessionKey();
                return GetData(tries + 1);

            }

            //get all folders on the webserver
            Dictionary<string, string> folders = ListFolders(html);

            //check which of the folders will be downloaded
            foreach(string folder in arguments["folders"].Split(';'))
            {
                if(folders.Keys.Contains(folder))
                {
                    //get all files of that folder
                    Dictionary<string, DateTime> files = GetFiles(folders[folder]);
                    foreach (string file in files.Keys)
                        result.Add(file, files[file]);
                }
            }

            if (result.Count() == 0)
            {
                PLCFileService.msgLog.LogMessage("Timeout while retrieving data, requesting new sessionkey. (" + tries + " out of " + timeoutAttempts + ")", Common.MessageLogger.LogLevel.WARN);
                this.sessionkey = GetSessionKey();
                return GetData(tries + 1);
            }


            return result;
        }

        private Dictionary<string, DateTime> GetFiles(string link)
        {
            //get all files from the link to the folder
            Dictionary<string, DateTime> result = new Dictionary<string, DateTime>();

            String html;

            WebRequest request = WebRequest.Create("http://" + this.ip + link);
            request.Headers.Add("Cookie", "coming_from_login=false; " + this.sessionkey);
            request.Credentials = CredentialCache.DefaultCredentials;
            ((HttpWebRequest)request).UserAgent = ".NET Framework Example Client";
            request.Timeout = 5000;
            request.Method = "GET";
            WebResponse response = request.GetResponse();

            //convert response to html
            Stream data = response.GetResponseStream();

            using (StreamReader sr = new StreamReader(data))
            {
                html = sr.ReadToEnd();
            }

            String pattern = @"<TR>\r\n<TD><IMG(.+?)TR>";
            MatchCollection matches = Regex.Matches(html, pattern, RegexOptions.Singleline);

            foreach(Match m in matches)
            {
                //check if the link is a file, if yes get the date and name and return it
                bool isFile = Regex.IsMatch(m.Value, @"\/Images\/File.gif", RegexOptions.Singleline);

                if (isFile)
                {
                    String name = Regex.Match(m.Value, @"<A href='(.+?)\?UP", RegexOptions.Singleline).Groups[1].Value;
                    string dateString = Regex.Match(m.Value, "... ... .. ..:..:.. ....", RegexOptions.Singleline).Groups[0].Value;

                    DateTime date = DateTime.ParseExact(dateString, "ddd MMM dd HH:mm:ss yyyy", CultureInfo.InvariantCulture);
                    result.Add(name, date);

                }

            }


            return result;
        }

        private Dictionary<string, string> ListFolders(string data)
        {
            Dictionary<string, string> result = new Dictionary<string, string>();
            Dictionary<string, string> folderQueue = new Dictionary<string, string>();

            //search the html for hyperlinks directed to the root folders
            string pattern = @"<TR class='Storage'(.*?)TR>";
            MatchCollection matches = Regex.Matches(data, pattern, RegexOptions.Singleline);
            Dictionary<string, string> folders = new Dictionary<string, string>();

            foreach (Match m in matches)
            {
                //Get the Filename and links of the root folders
                String name = Regex.Match(m.Value, @"<font face=""Tahoma"" color=""#000000"" size=""2"">(.+?)</font>").Groups[1].Value;
                String link = Regex.Match(m.Value, "<A HREF=\"(.+?)\"><b>").Groups[1].Value;
                folderQueue.Add(name, link);
            }


            String folderData;
            //search all folders for new folders, if new folders are found they are placed in the folderQueue and after a folder is searched it will move to the result dictionary
            while (folderQueue.Count() > 0)
            {
                KeyValuePair<string, string> folder = folderQueue.First();

                //send request to folder site to grab the folders of the html file
                WebRequest request = WebRequest.Create("http://" + this.ip + folder.Value);
                request.Headers.Add("Cookie", "coming_from_login=false; " + this.sessionkey);
                request.Credentials = CredentialCache.DefaultCredentials;
                ((HttpWebRequest)request).UserAgent = ".NET Framework Example Client";
                request.Timeout = 5000;
                request.Method = "GET";
                WebResponse response;
                try
                {
                    response = request.GetResponse();
                }
                catch(Exception)
                {
                    folderQueue.Remove(folder.Key);
                    continue;
                }


                //convert response to html
                Stream stream = response.GetResponseStream();

                using (StreamReader sr = new StreamReader(stream))
                {
                    folderData = sr.ReadToEnd();
                }

                pattern = @"<TR>\r\n<TD><IMG(.+?)TR>";
                matches = Regex.Matches(folderData, pattern, RegexOptions.Singleline);

                //find all links with a folder picture to identify between folders and files
                foreach(Match m in matches)
                {
                    bool isFolder = Regex.IsMatch(m.Value, @"\/Images\/Directory.gif", RegexOptions.Singleline);
                    if(isFolder)
                    {
                        //filter name and link on webserver, remove the "go back" folder -> Folder with name ".."
                        string name = Regex.Match(m.Value, @"BROWSE'>(.+?)<\/A>", RegexOptions.Singleline).Groups[1].Value;
                        string link = Regex.Match(m.Value, @"<A href='(?!\/browse.html)(.+?)'>", RegexOptions.Singleline).Groups[1].Value;
                        if(!name.Equals("") && !name.Equals("..") && !link.Equals(""))
                            folderQueue.Add(name, link);
                    }
                }



                result.Add(folder.Key, folder.Value);
                folderQueue.Remove(folder.Key);
            }

            return result;
        }
    }
}