using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Xml.Serialization;
using Microsoft.SharePoint;
using Taloyhtio.CondoUpdate.Common;

namespace CondoUpdate.SetAlertsToResponsibleUsers
{
    public class UpdaterImpl : ICondoUpdater
    {
        private const string KESKUSTELU = "Keskustelu";
        private const string KESKUSTELU_OTHER = "Huomioitavaa ja kommentteja";
        private const string DOCUMENTS = "Asiakirjojen lähetys tilitoimistolle";
        public event EventHandler<LogEventArgs> OnNotify;

        public void Update(object args)
        {
            string url = args as string;
            if (string.IsNullOrEmpty(url))
            {
                this.warn("Url is empty");
                return;
            }

            try
            {
                this.updateImpl(url);
            }
            catch (Exception x)
            {
                this.error("Error occured during updating of Condo '{0}':\n{1}\n{2}", url, x.Message, x.StackTrace);
            }
        }

        private void updateImpl(string url)
        {
            using (var site = new SPSite(url))
            {
                using (var web = site.OpenWeb())
                {
                    var discussionGroups = new List<string>();
                    var documentsGroups = new List<string>();

                    string visitorsGroup = getVisitorsGroupName(web);
                    if (isGroupExist(web, visitorsGroup))
                    {
                        discussionGroups.Add(visitorsGroup);
                    }

                    string membersGroup = getMembersGroupName(web);
                    if (isGroupExist(web, membersGroup))
                    {
                        discussionGroups.Add(membersGroup);
                    }

                    string responsibleAccountantGroup = getResponsibleAccountantsGroupName(web);
                    if (isGroupExist(web, responsibleAccountantGroup))
                    {
                        discussionGroups.Add(responsibleAccountantGroup);
                        documentsGroups.Add(responsibleAccountantGroup);
                    }

                    var list = web.Lists.Cast<SPList>().FirstOrDefault(l => string.Compare(l.Title, KESKUSTELU, true) == 0);
                    if (list != null)
                    {
                        fixAlerts(web, list, KESKUSTELU, discussionGroups);
                    }

                    list = web.Lists.Cast<SPList>().FirstOrDefault(l => string.Compare(l.Title, KESKUSTELU_OTHER, true) == 0);
                    if (list != null)
                    {
                        fixAlerts(web, list, KESKUSTELU_OTHER, discussionGroups);
                    }

                    list = web.Lists.Cast<SPList>().FirstOrDefault(l => string.Compare(l.Title, DOCUMENTS, true) == 0);
                    if (list != null)
                    {
                        fixAlerts(web, list, DOCUMENTS, documentsGroups);
                    }
                }
            }
        }

        private void fixAlerts(SPWeb web, SPList list, string customAlertName, List<string> groups)
        {
            var alerts = web.Alerts;
            foreach (SPAlert a in alerts)
            {
                if (a.ListID != list.ID)
                {
                    continue;
                }
                if (!shouldFix(a, customAlertName))
                {
                    continue;
                }

                string groupsString = Serialize(groups);
                a.Properties["alertgroups"] = groupsString;
                a.Update();
            }
        }

        private bool isGroupExist(SPWeb web, string groupName)
        {
            return web.SiteGroups.Cast<SPGroup>().Any(g => string.Compare(g.Name, groupName, true) == 0);
        }

        private string Serialize<T>(T objToSerialize) where T : class
        {
            if (objToSerialize == null)
            {
                throw new ArgumentNullException("objToSerialize");
            }
            var serializer = new XmlSerializer(typeof(T));
            var writer = new StringWriter();
            serializer.Serialize(writer, objToSerialize);
            return writer.ToString();
        }

        private static string getMembersGroupName(SPWeb web)
        {
            return string.Format("{0} - Jäsenet", web.Title);
        }

        private static string getVisitorsGroupName(SPWeb web)
        {
            return string.Format("{0} - Työntekijät", web.Title);
        }

        private static string getResponsibleAccountantsGroupName(SPWeb web)
        {
            return string.Format("{0} - Responsible accountants", web.Title);
        }

        private bool shouldFix(SPAlert a, string customAlertName)
        {
            if (string.Compare(a.Title, customAlertName, true) == 0)
            {
                return true;
            }
            if (a.User == null)
            {
                return false;
            }
            return (string.Compare(a.User.LoginName, "tallier:company alerts owner", true) == 0);
        }

        private void info(string msg, params object[] args)
        {
            this.notify(LogLevel.Info, msg, args);
        }

        private void warn(string msg, params object[] args)
        {
            this.notify(LogLevel.Warn, msg, args);
        }

        private void error(string msg, params object[] args)
        {
            this.notify(LogLevel.Error, msg, args);
        }

        private void notify(LogLevel level, string msg, params object[] args)
        {
            this.notify(level, string.Format(msg, args));
        }

        private void notify(LogLevel level, string msg)
        {
            if (this.OnNotify != null)
            {
                this.OnNotify(this, new LogEventArgs { LogLevel = level, Message = msg });
            }
        }
    }
}