Open Source Extensible Enterprise n-tier Application Framework with Multilayered Architecture

using System;
using SiberTek.Xenta.Data;
using SiberTek.Xenta.Data.Providers;
using SiberTek.Xenta.Entities;
using SiberTek.Xenta.Entities.Collections;
using SiberTek.Xenta.Enums;
using SiberTek.Xenta.Events;
using SiberTek.Xenta.Exceptions;
using SiberTek.Xenta.Utils;

namespace SiberTek.Xenta.Managers
{
    /// <summary>
    /// Contains methods to manage forums
    /// </summary>
    public class ForumManager : IManager
    {
        #region Fields
        private static ForumManager _instance = null;
        private IForumDataProvider _dataProvider;
        private bool _initialized;
        #endregion

        #region Constructors
        private ForumManager()
        {
            _dataProvider = null;
            _initialized = false;
        }
        #endregion

        #region Events
        public event EntityEventHandler ForumCreated;
        public event EntityEventHandler ForumUpdated;
        public event EntityEventHandler ForumDeleted;
        #endregion

        #region Properties
        public static ForumManager Instance
        {
            get
            {
                if(_instance == null)
                {
                    _instance = new ForumManager();
                }
                return _instance;
            }
        }

        private IForumDataProvider DataProvider
        {
            get
            {
                return _dataProvider;
            }
        }
        #endregion

        #region Methods
        public void Initialize()
        {
            if(!_initialized)
            {
                _dataProvider = DataAccessManager.GetProviderInstance<IForumDataProvider>("ForumDataProvider");

                _initialized = true;
            }
        }

        public ForumInfo CreateForum(int parentForumID, string title, string description, int displayOrder, bool isActive)
        {
            if(parentForumID != 0 && GetForum(parentForumID) == null)
            {
                throw new XentaException("Forum does not exist", (int)ForumError.ForumDoesNotExist);
            }

            title = StringHelper.TrimToLength(title, 1000);
            ForumInfo forum = null;
            int forumID;

            if(DataProvider.InsertForum(parentForumID, title, description, displayOrder, isActive, DateTime.UtcNow, DateTime.UtcNow, out forumID))
            {
                forum = GetForum(forumID);

                FireForumCreated(forum);

                if(parentForumID != 0)
                {
                    foreach(RoleInfo role in RoleManager.Instance.GetAllRoles(true))
                    {
                        if(IsRoleAssignedToForum(parentForumID, role.RoleID))
                        {
                            AssignRoleToForum(forumID, role.RoleID);
                        }
                    }
                }
            }
            return forum;
        }

        public bool AssignRoleToForum(int forumID, int roleID)
        {
            if(RoleManager.Instance.GetRole(roleID) == null)
            {
                return false;
            }

            ForumInfo forum = GetForum(forumID);
            bool res = false;

            if(forum != null)
            {
                if(IsRoleAssignedToForum(forumID, roleID))
                {
                    res = true;
                }
                else
                {
                    res = DataProvider.InsertForumRoleMapping(forumID, roleID);
                }
                if(res)
                {
                    foreach(ForumInfo childForum in forum.ChildForums)
                    {
                        AssignRoleToForum(childForum.ForumID, roleID);
                    }
                    foreach(ForumTopicInfo topic in forum.Topics)
                    {
                        ForumTopicManager.Instance.AssignRoleToForumTopic(topic.TopicID, roleID);
                    }
                }
            }

            return res;
        }

        public ForumInfo GetForum(int forumID)
        {
            return DataMapper.Map(DataProvider.GetForum(forumID));
        }

        public ForumInfoCollection GetAllForums()
        {
            return GetAllForums(false);
        }

        public ForumInfoCollection GetAllForums(bool showHidden)
        {
            return GetAllForums(null, null, null, showHidden);
        }

        public ForumInfoCollection GetForumsByParentForumID(int parentForumID)
        {
            return GetForumsByParentForumID(parentForumID, false);
        }

        public ForumInfoCollection GetForumsByParentForumID(int parentForumID, bool showHidden)
        {
            return GetAllForums(parentForumID, null, null, showHidden);
        }

        public ForumInfoCollection GetAllForums(int? parentForumID, DateTime? createdOnStart, DateTime? createdOnEnd, bool showHidden)
        {
            return DataMapper.Map(DataProvider.GetAllForums(parentForumID, createdOnStart, createdOnEnd, showHidden));
        }

        public bool IsRoleAssignedToForum(int forumID, int roleID)
        {
            return DataProvider.ForumRoleMappingExists(forumID, roleID);
        }

        public ForumInfo UpdateForum(int forumID, int parentForumID, string title, string description, int displayOrder, bool isActive)
        {
            ForumInfo forum = GetForum(forumID);
            
            if(forum == null)
            {
                throw new XentaException("Forum does not exist", (int)ForumError.ForumDoesNotExist);
            }
            if(parentForumID != 0 && GetForum(parentForumID) == null)
            {
                throw new XentaException("Forum does not exist", (int)ForumError.ForumDoesNotExist);
            }

            title = StringHelper.TrimToLength(title, 1000);

            if(DataProvider.UpdateForum(forumID, parentForumID, title, description, displayOrder, isActive, forum.CreatedOn, DateTime.UtcNow))
            {
                forum = GetForum(forumID);

                FireForumUpdated(forum);
            }
            return forum;
        }

        public void DeleteForum(int forumID)
        {
            ForumInfo forum = GetForum(forumID);

            if(forum != null)
            {
                FireForumDeleted(forum);

                foreach(RoleInfo role in RoleManager.Instance.GetAllRoles(true))
                {
                    if(IsRoleAssignedToForum(forumID, role.RoleID))
                    {
                        UnassignRoleFromForum(forumID, role.RoleID);
                    }
                }

                DataProvider.DeleteForum(forumID);
            }
        }

        public void UnassignRoleFromForum(int forumID, int roleID)
        {
            ForumInfo forum = GetForum(forumID);

            if(forum != null)
            {
                foreach(ForumInfo childForum in forum.ChildForums)
                {
                    UnassignRoleFromForum(childForum.ForumID, roleID);
                }
                foreach(ForumTopicInfo topic in forum.Topics)
                {
                    ForumTopicManager.Instance.UnassignRoleFromForumTopic(topic.TopicID, roleID);
                }

                DataProvider.DeleteForumRoleMapping(forumID, roleID);
            }
        }
        #endregion

        #region Utilties
        private void FireForumCreated(ForumInfo forum)
        {
            if(ForumCreated != null)
            {
                ForumCreated(this, new EntityEventArgs(forum));
            }
        }

        private void FireForumUpdated(ForumInfo forum)
        {
            if(ForumUpdated != null)
            {
                ForumUpdated(this, new EntityEventArgs(forum));
            }
        }

        private void FireForumDeleted(ForumInfo forum)
        {
            if(ForumDeleted != null)
            {
                ForumDeleted(this, new EntityEventArgs(forum));
            }
        }
        #endregion
    }
}