/* CommentPool.cs
 * part of zaaReloaded2
 * 
 * Copyright 2015-2017 Daniel Kraus
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace zaaReloaded2.Controller.Comments
{
    /// <summary>
    /// A pool of comments.
    /// </summary>
    class CommentPool
    {
        #region Singleton

        /// <summary>
        /// Gets the singleton instance of the CommentPool.
        /// </summary>
        public static CommentPool Default
        {
            get
            {
                return _instance;
            }
        }

        private static readonly CommentPool _instance = new CommentPool();

        #endregion

        #region Properties

        /// <summary>
        /// Gets the number of ItemComments in the pool.
        /// </summary>
        public int Count { get { return _itemComments.Count; } }

        #endregion

        #region Event

        public event EventHandler<ItemCommentEventArgs> FillInComment;

        #endregion

        #region Constructor

        /// <summary>
        /// Static constructor to support the singleton implementation.
        /// </summary>
        /// <remarks>
        /// See http://csharpindepth.com/Articles/General/Singleton.aspx#cctor
        /// </remarks>
        static CommentPool() { }

        private CommentPool()
        {
            _itemComments = new List<ItemComment>();
        }

        #endregion

        #region Methods

        /// <summary>
        /// Clear the pool of ItemComments and sets the event handler
        /// to null.
        /// </summary>
        public void Reset()
        {
            _itemComments.Clear();
            FillInComment = null;
        }

        /// <summary>
        /// Retrieves the ItemComment for a given definitionString;
        /// creates a new ItemComment object if necessary.
        /// </summary>
        /// <param name="definitionString"></param>
        /// <returns>ItemComment derived from the
        /// <paramref name="definitionString"/></returns>
        public ItemComment GetCommentFor(string definitionString)
        {
            ItemComment itemComment = _itemComments.FirstOrDefault(
                i => i.Definition == definitionString);
            if (itemComment == null)
            {
                itemComment = ItemComment.FromDefinitionString(definitionString);
                if (itemComment != null)
                {
                    _itemComments.Add(itemComment);
                    itemComment.FillInComment += itemComment_FillInComment;
                }
            }
            return itemComment;
        }

        #endregion

        #region Private methods

        protected virtual void itemComment_FillInComment(object sender, ItemCommentEventArgs e)
        {
            OnFillInComment(e);
        }

        #endregion

        #region Protected methods

        protected virtual void OnFillInComment(ItemCommentEventArgs args)
        {
            EventHandler<ItemCommentEventArgs> h = FillInComment;
            if (h != null)
            {
                h(this, args);
            }
        }

        #endregion

        #region Fields

        List<ItemComment> _itemComments;

        #endregion
    }
}