using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Web.UI.WebControls.WebParts;
using System.Xml;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Publishing;
using Microsoft.SharePoint.WebPartPages;
using Taloyhtio.CondoUpdate.Common;
using WebPart = System.Web.UI.WebControls.WebParts.WebPart;

namespace CondoUpdate.AddLatestUpdatesWPOnCondoFrontPage
{
    public class UpdaterImpl : ICondoUpdater
    {
        private readonly Guid WHATSNEW_WP_FEATURE_ID = new Guid("fb91c317-6ddf-4063-abf4-923d9728f708");

        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)
        {
            this.info("Opening Condo '{0}'...", url);
            using (var site = new SPSite(url))
            {
                using (var condoWeb = site.OpenWeb())
                {
                    if (!condoWeb.Exists || string.Compare(condoWeb.Url, url, true) != 0)
                    {
                        this.warn("Condo site '{0}' doesn't exist. It will be ignored", url);
                        return;
                    }

                    if (!PublishingWeb.IsPublishingWeb(condoWeb))
                    {
                        this.warn("Condo site '{0}' is not publishing web. It will be ignored", url);
                        return;
                    }
                    var pweb = PublishingWeb.GetPublishingWeb(condoWeb);
                    this.info("Condo '{0}' was sucessfully opened", url);

                    this.ensureFeatureActivated(site);
                    this.addWebPart(pweb);
                }
            }
        }

        private void addWebPart(PublishingWeb pweb)
        {
            SPLimitedWebPartManager webPartManager = null;
            try
            {
                this.info("Get start page");
                var file = pweb.DefaultPage;
                if (file == null)
                {
                    this.error("Start page is null. Site won't be updated");
                    return;
                }
                
                if (file.CheckOutStatus == SPFile.SPCheckOutStatus.None)
                {
                    this.info("Checkout start page");
                    file.CheckOut();
                }
                else
                {
                    // if file was checked out by another user, need undo check out and check in again in order to avoid errors
                    // when add web part
                    this.info("Start page is already checked out. Undo previous check out and check out it again");
                    file.UndoCheckOut();
                    file.CheckOut();
                }

                this.info("Get web part manager");
                webPartManager = file.GetLimitedWebPartManager(PersonalizationScope.Shared);
                if (webPartManager == null)
                {
                    this.error("Web part manager is null. Site won't be updated");
                    file.UndoCheckOut();
                    return;
                }

                this.info("Check is there already WhatsNewWebpart on the start page");
                var webParts = webPartManager.WebParts;
                if (webParts != null)
                {
                    foreach (WebPart wp in webParts)
                    {
                        if (wp.GetType().FullName == "Taloyhtio.WhatsNewWebpart.WhatsNewWebpart")
                        {
                            this.warn("WhatsNewWebpart already exist on start page. Site won't be updated");
                            file.UndoCheckOut();
                            return;
                        }
                    }
                }
                this.info("WhatsNewWebpart not found on the start page");

                this.info("Open webpart file");
                using (var fs = new MemoryStream(Encoding.UTF8.GetBytes(File.ReadAllText("WhatsNewWebpart.webpart"))))
                {
                    using (var reader = new XmlTextReader(fs))
                    {
                        string error;
                        WebPart wp = webPartManager.ImportWebPart(reader, out error);
                        if (wp == null)
                        {
                            this.error("Imported web part is null. Site '{0}' won't be updated. Error message: {1}", pweb.Web.Url, error);
                            file.UndoCheckOut();
                            return;
                        }
                        this.info("Add web part");
                        webPartManager.AddWebPart(wp, "LeftColumnZone", 0);
                        this.info("Save changes");
                        webPartManager.SaveChanges(wp);
                    }
                }

                this.info("Checkin file");
                file.CheckIn("Whats new web part is added");
                file.Update();
                file.Publish("Whats new web part is added");
                this.info("Web part was sucessfully added");
            }
            catch (Exception x)
            {
                this.error("Error occured when add web part to the '{0}' site:\n{1}\n{2}", pweb.Web.Url, x.Message, x.StackTrace);
                var file = pweb.DefaultPage;
                if (file.CheckOutStatus != SPFile.SPCheckOutStatus.None)
                {
                    file.UndoCheckOut();
                }
            }
            finally
            {
                if (webPartManager != null)
                {
                    if (webPartManager.Web != null)
                    {
                        webPartManager.Web.Dispose();
                    }
                    webPartManager.Dispose();
                }
            }
        }

        private void ensureFeatureActivated(SPSite site)
        {
            this.info("Check does site contains What's new web part feature or not..");
            if (!site.Features.Cast<SPFeature>().Any(f => f.DefinitionId == WHATSNEW_WP_FEATURE_ID))
            {
                this.info("Site doesn't contain What's new web part feature. Try to activate it..");
                site.Features.Add(WHATSNEW_WP_FEATURE_ID);
                this.info("What's new web part feature was sucesfully activated on site");
            }
            else
            {
                this.info("Site already contains What's new web part feature. It won't be activated again");
            }
        }

        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 });
            }
        }
    }
}