using NLog;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using System.Xml;

namespace MP.AppAuth
{
    /// <summary>
    ///     Object of this class gives you all the details about the update useful in handling the update logic yourself.
    /// </summary>
    public class UpdateInfoEventArgs : EventArgs
    {
        #region Public Properties

        /// <summary>
        ///     URL of the webpage specifying changes in the new update.
        /// </summary>
        public string ChangelogURL { get; set; }

        /// <summary>
        ///     Returns newest version of the application available to download.
        /// </summary>
        public Version CurrentVersion { get; set; }

        /// <summary>
        ///     Download URL of the update file.
        /// </summary>
        public string DownloadURL { get; set; }

        /// <summary>
        ///     Returns version of the application currently installed on the user's PC.
        /// </summary>
        public Version InstalledVersion { get; set; }

        /// <summary>
        ///     If new update is available then returns true otherwise false.
        /// </summary>
        public bool IsUpdateAvailable { get; set; }

        /// <summary>
        ///     Shows if the update is required or optional.
        /// </summary>
        public bool Mandatory { get; set; }

        #endregion Public Properties
    }

    /// <summary>
    /// Gestione update applicazioni
    /// </summary>
    public class UpdateMan
    {
        #region Private Fields

        private static NLog.Logger Log = LogManager.GetCurrentClassLogger();

        #endregion Private Fields

        #region Protected Fields

        protected bool doAuth = false;

        #endregion Protected Fields

        #region Public Fields

        /// <summary>
        /// Init classe
        /// </summary>
        public static UpdateMan obj = new UpdateMan();

        #endregion Public Fields

        #region Public Constructors

        /// <summary>
        /// Init classe
        /// </summary>
        public UpdateMan()
        { }

        /// <summary>
        /// Init classe
        /// </summary>
        /// <param name="user"></param>
        /// <param name="pwd"></param>
        public UpdateMan(string user, string pwd)
        {
            userName = user;
            passwd = pwd;
            doAuth = !string.IsNullOrEmpty($"{userName}{passwd}");
        }

        #endregion Public Constructors

        #region Protected Properties

        protected string passwd { get; set; } = "";
        protected string userName { get; set; } = "";

        #endregion Protected Properties

        #region Public Methods

        /// <summary>
        /// Effettua download ultima versione applicativo
        /// </summary>
        /// <param name="remoteUrl"></param>
        /// <param name="localRepo"></param>
        /// <param name="packName"></param>
        public long downloadLatest(string remoteUrl, string localRepo, string packName)
        {
            long size = 0;
            // verifico directory
            if (!Directory.Exists(localRepo))
            {
                Directory.CreateDirectory(localRepo);
            }
            string localFile = "";
            string localLast = "";
            string DownloadURL = "";
            try
            {
                // in primis scarico update info...
                UpdateInfoEventArgs updateData = getUpdateInfo(remoteUrl);
                if (updateData.IsUpdateAvailable)
                {
                    DownloadURL = updateData.DownloadURL;
                    localFile = string.Format(@"{0}\{1}_Build_{2}.zip", localRepo, packName, updateData.CurrentVersion);
                    localLast = string.Format(@"{0}\{1}.zip", localRepo, packName);
                    // scarica file e salva in directory locale...
                    using (var http = new HttpClient())
                    {
                        //var client = new WebClient();
                        //bool doAuth = !string.IsNullOrEmpty($"{userName}{passwd}");
                        if (doAuth)
                        {
                            //client.Credentials = new System.Net.NetworkCredential(userName, passwd);
                            http.DefaultRequestHeaders.Accept.Clear();
                            var byteArray = System.Text.ASCIIEncoding.UTF8.GetBytes($"{userName}:{passwd}");
                            http.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));
                        }
                        //client.DownloadFile(updateData.DownloadURL, localFile);

                        // url da chiamare
                        http.BaseAddress = new Uri(DownloadURL);
                        // lettura
                        var data = http.GetAsync(DownloadURL).Result;
                        using (var myReader = data.Content.ReadAsStreamAsync())
                        {
                            //var myReader = data.Content.ReadAsStreamAsync();
                            if (data.StatusCode != HttpStatusCode.OK)
                            {
                                Log.Info($"Errore in chiamata getUpdateInfo per URL {remoteUrl}: status code: {data.StatusCode}");
                            }
                            else
                            {
                                using (Stream outStream = File.OpenWrite(localFile))
                                {
                                    myReader.Result.CopyTo(outStream);
                                }
                                // ora lo copio come latest...
                                File.Copy(localFile, localLast, true);
                                // indico come fatto!
                                var thisFile = new FileInfo(localLast);
                                size = thisFile.Length;
                            }
                        }
                    }
                }
                else
                {
                    localFile = string.Format(@"{0}\Error.log", localRepo);
                    // scrivo file in area target...
                    using (StreamWriter sw = File.AppendText(localFile))
                    {
                        sw.WriteLine($"{DateTime.Now:yyyy-MM-dd HH:mm:ss} ATTENZIONE! Installer NON disponibile | {remoteUrl}");
                    }
                }
            }
            catch (Exception exc)
            {
                localFile = string.Format(@"{0}\Error.log", localRepo);
                // scrivo file in area target...
                using (StreamWriter sw = File.AppendText(localFile))
                {
                    sw.WriteLine($"{DateTime.Now:yyyy-MM-dd HH:mm:ss} Errore in fase di download installers{Environment.NewLine}XML: {remoteUrl}{Environment.NewLine}URL: {DownloadURL}");
                    sw.WriteLine(exc.ToString());
                }
            }
            return size;
        }

        /// <summary>
        /// Recupera l'ultima versione disponibile
        /// </summary>
        /// <param name="remoteUrl"></param>
        /// <returns></returns>
        public UpdateInfoEventArgs getUpdateInfo(string remoteUrl)
        {
            //bool doAuth = !string.IsNullOrEmpty($"{userName}{passwd}");

            UpdateInfoEventArgs args = new UpdateInfoEventArgs();
            Version CurrentVersion;
            bool Mandatory;
            XmlDocument recXml = new XmlDocument();
            try
            {
                // recupero dati
                using (var http = new HttpClient())
                {
                    if (doAuth)
                    {
                        http.DefaultRequestHeaders.Accept.Clear();
                        var byteArray = System.Text.ASCIIEncoding.UTF8.GetBytes($"{userName}:{passwd}");
                        http.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));
                    }
                    // url da chiamare
                    http.BaseAddress = new Uri(remoteUrl);
                    // lettura
                    var data = http.GetAsync(remoteUrl).Result;
                    var myReader = data.Content.ReadAsStreamAsync();
                    if (data.StatusCode != HttpStatusCode.OK)
                    {
                        Log.Info($"Errore in chiamata getUpdateInfo per URL {remoteUrl}: status code: {data.StatusCode}");
                    }
                    else
                    {
                        recXml.Load(myReader.Result);

                        XmlNodeList recData = recXml.SelectNodes("item");
                        if (recData != null)
                        {
                            foreach (XmlNode item in recData)
                            {
                                XmlNode appCastVersion = item.SelectSingleNode("version");
                                Version.TryParse(appCastVersion?.InnerText, out CurrentVersion);
                                args.CurrentVersion = CurrentVersion;
                                XmlNode appCastChangeLog = item.SelectSingleNode("changelog");
                                args.ChangelogURL = appCastChangeLog?.InnerText;
                                XmlNode appCastUrl = item.SelectSingleNode("url");
                                args.DownloadURL = appCastUrl?.InnerText;
                                XmlNode mandatory = item.SelectSingleNode("mandatory");
                                Boolean.TryParse(mandatory?.InnerText, out Mandatory);
                                args.Mandatory = Mandatory;
                                args.IsUpdateAvailable = true;
                            }
                        }
                    }
                }
            }
            catch (Exception exc)
            {
                Log.Info($"Eccezione in getUpdateInfo:{Environment.NewLine}{exc}");
                // metto versione = 0 + errore...
                args.IsUpdateAvailable = false;
                args.CurrentVersion = new Version("0.0.0.0");
            }
            return args;
        }

        #endregion Public Methods
    }
}