using System;
using System.ComponentModel;
using System.Web;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using Microsoft.SharePoint;
using System.Web.UI.HtmlControls;
using System.Linq;
using Microsoft.SharePoint.Administration;

namespace SubscribeProject.SubsWebPart
{
    [ToolboxItemAttribute(false)]
    public class SubsWebPart : WebPart
    {
        #region Fields

        private string _linkText = "Подписаться на {0}";
        private Guid _listId;
        private string _succesText = "Вы успешно подписанны";
        private string _errorSubscribeText = "Произошла ошибка подписки";
        private string _cssClass = "subscribe-link";

        #endregion

        #region Properties
        [Personalizable(PersonalizationScope.Shared)]
        [WebBrowsable(true)]
        [Category("Display")]
        [WebDisplayName("Link Text")]
        [WebDescription("Link Text")]
        public string LinkText
        {
            get { return _linkText; }
            set { _linkText = value; }
        }
        [Personalizable(PersonalizationScope.Shared)]
        [WebBrowsable(true)]
        [Category("Display")]
        [WebDisplayName("List Id")]
        [WebDescription("List Id")]
        public Guid ListId
        {
            get { return _listId; }
            set { _listId = value; }
        }
        [Personalizable(PersonalizationScope.Shared)]
        [WebBrowsable(true)]
        [Category("Display")]
        [WebDisplayName("Succes text")]
        [WebDescription("Succes sudscribe text")]
        public string SuccessText
        {
            get { return _succesText; }
            set { _succesText = value; }
        }
        [Personalizable(PersonalizationScope.Shared)]
        [WebBrowsable(true)]
        [Category("Display")]
        [WebDisplayName("Error subscribe text")]
        [WebDescription("")]
        public string ErrorSubscribeText
        {
            get { return _errorSubscribeText; }
            set { _errorSubscribeText = value; }
        }
        [Personalizable(PersonalizationScope.Shared)]
        [WebBrowsable(true)]
        [Category("Display")]
        [WebDisplayName("CssClass")]
        [WebDescription("")]
        public string CustomizedCssClass
        {
            get { return _cssClass; }
            set { _cssClass = value; }
        }


        #endregion

        #region Methods
        protected override void CreateChildControls()
        {
            try
            {
                if (SPContext.Current.Web.CurrentUser != null)
                {
                    CssClass = CustomizedCssClass;
                    HttpRequest request = HttpContext.Current.Request;

                    if (ListId == new Guid())
                        if (SPContext.Current.List != null)
                            ListId = SPContext.Current.ListId;
                        else
                        {
                            Controls.Add(new HtmlAnchor { InnerText = "ListId is empty and current list is null" });
                            return;
                        }
                    if (!SPContext.Current.Web.CurrentUser.Alerts.Cast<SPAlert>().Any(x => x.ListID == ListId))
                        if (!string.IsNullOrEmpty(request.Form["subscriptionFlag"]) && request.Form["subscriptionFlag"] == "1")
                            Subscribe();
                        else
                            if (HttpContext.Current.User.Identity.IsAuthenticated)
                                AddSubscriptionLink();
                }
            }
            catch (Exception exc)
            {
                LogError(exc);
                Controls.Add(new HtmlAnchor { InnerText = ErrorSubscribeText });
            }
        }

        private void AddSubscriptionLink()
        {
            var htmlInputHidden = new Literal
                                      {
                                          Text =
                                              "<input id=\"subscriptionFlag\" name=\"subscriptionFlag\" type=\"hidden\" value=\"0\">"
                                      };
            Controls.Add(htmlInputHidden);

            HtmlAnchor subscribeLink = new HtmlAnchor();
            subscribeLink.InnerText = string.Format(LinkText,
                                                    SPContext.Current.List == null
                                                        ? ""
                                                        : SPContext.Current.List.Title);
            subscribeLink.HRef =
                "javascript:document.getElementById('subscriptionFlag').value='1';document.forms[0].submit()";
            Controls.Add(subscribeLink);
        }

        private void Subscribe()
        {
            SPUser user = SPContext.Current.Web.CurrentUser;
            if (user == null)
                Controls.Add(new HtmlAnchor { InnerText = "Current user is null" });
            else
            {
                if (user.Alerts.Cast<SPAlert>().Any(x => x.ListID == ListId))
                    Controls.Add(new HtmlAnchor { InnerText = "You already subscribed to this list" });
                else
                {
                    try
                    {
                        user.Alerts.Add(SPContext.Current.Web.Lists[ListId], SPEventType.Add, SPAlertFrequency.Immediate,
                                        SPAlertDeliveryChannels.Email);
                        Controls.Add(new HtmlAnchor { InnerText = SuccessText });
                    }
                    catch (Exception exc)
                    {
                        LogError(exc);
                        Controls.Add(new HtmlAnchor { InnerText = ErrorSubscribeText });
                    }
                }
            }
        }

        public static void LogError(Exception exc)
        {
            SPDiagnosticsCategory category = new SPDiagnosticsCategory("Subscribe link", TraceSeverity.High, EventSeverity.Error);
            SPDiagnosticsService service = SPDiagnosticsService.Local;
            service.WriteTrace(1, category, TraceSeverity.High, "SubscribeError: {0}, StackTrace: {1}", new { exc.Message, exc.StackTrace });
        }
        #endregion
    }
}