using System;
using System.Collections.Generic;
using System.Configuration;
using System.IO;
using System.Linq;
using System.Security.Principal;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Administration;

namespace SetAlertTemplate
{
    // This console application is used in CustomAlertHandler.AlertTemplateConfigurator in order to update
    // list's alert template for using custom alert handler for it. Direct update of alert template's xml
    // throws Access denied exception so we need to do it in separate process without Sharepoint context
    class Program
    {
        private const int CODE_SUCCESS = 0;
        private const int CODE_ERROR = 1;

        private static int Main(string[] args)
        {
            log("==================================");
            if (args.Length != 2)
            {
                log("Arguments missing. Correct usage: .exe {templateId} {templateXml}");
                return CODE_ERROR;
            }

            string farmAdminDomain = ConfigurationManager.AppSettings["FarmAdminDomain"];
            if (string.IsNullOrEmpty(farmAdminDomain))
            {
                log("FarmAdminDomain not specified");
                return CODE_ERROR;
            }
            string farmAdminUsername = ConfigurationManager.AppSettings["FarmAdminUsername"];
            if (string.IsNullOrEmpty(farmAdminUsername))
            {
                log("FarmAdminUsername not specified");
                return CODE_ERROR;
            }
            string farmAdminPwdEncrypted = ConfigurationManager.AppSettings["FarmAdminPwd"];
            if (string.IsNullOrEmpty(farmAdminPwdEncrypted))
            {
                log("FarmAdminPwd not specified");
                return CODE_ERROR;
            }

            string farmAdminPwd = CredentialsCryptographer.Decrypt(farmAdminPwdEncrypted);
            if (string.IsNullOrEmpty(farmAdminPwd))
            {
                log("FarmAdminPwd not correct");
                return CODE_ERROR;
            }

            string templateID = args[0];
            if (string.IsNullOrEmpty(templateID))
            {
                log("templateID not specified");
                return CODE_ERROR;
            }

            string templateXml = args[1];
            if (string.IsNullOrEmpty(templateXml))
            {
                log("templateXml not specified");
                return CODE_ERROR;
            }

            log("Current process identity: '{0}'", WindowsIdentity.GetCurrent().Name);
            log("Template id: '{0}'", templateID);
            log("Template xml: '{0}'", templateXml);
            try
            {
                bool result = true;
                foreach (var template in new SPAlertTemplateCollection(SPWebService.ContentService))
                {
                    if (template != null && template.Properties.ContainsKey("FriendlyName") && string.Compare(template.Properties["FriendlyName"].ToString(), templateID, true) == 0)
                    {
                        try
                        {
                            // code for updating alert templates (SPPersistedObjects) should run under farm admin
                            using (new Impersonator(farmAdminUsername, farmAdminDomain, farmAdminPwd))
                            {
                                log("Impersonated process identity: '{0}'", WindowsIdentity.GetCurrent().Name);
                                log("Updating template '{0}'", (template.Properties.ContainsKey("FriendlyName") ? template.Properties["FriendlyName"].ToString() : template.DisplayName));
                                templateXml.Replace("'", "\"");
                                template.Xml = templateXml;
                                template.Update();
                                log("Templated updated");
                            }
                        }
                        catch (Exception x)
                        {
                            log("Error occured during updating of alert template: {0}\n{1}", x.Message, x.StackTrace);
                            result = false;
                        }
                    }
                }

                return (result ? CODE_SUCCESS : CODE_ERROR);
            }
            catch (Exception x)
            {
                log("Error occured during enumerating alert templates: {0}\n{1}", x.Message, x.StackTrace);
                return CODE_ERROR;
            }
        }

        internal static void log(string msg, params object[] args)
        {
            try
            {
                if (args.Length > 0)
                {
                    msg = string.Format(msg, args);
                }
                msg = string.Format("{0} (thread id: {1})\t{2}\n", DateTime.Now.ToString("yyyy.MM.dd HH:mm:ss"), Thread.CurrentThread.ManagedThreadId, msg);
                File.AppendAllText("c:/temp/_customalerthandler_setalerttemplate.txt", msg);
            }
            catch (Exception x)
            {
                Console.WriteLine("{0}\n{1}", x.Message, x.StackTrace);
            }
        }
    }
}