Chat/ChatController/Core/OwnChatCache.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Media;

namespace ChatController.Core
{
    public class OwnChatCache
    {
        // Key-> "group-127" oder "user-938"
        private Dictionary<string, ImageSourceCacheObject> _ImageSources  = new Dictionary<string, ImageSourceCacheObject>();

        // Key-> "group-127" oder "user-938"
        private Dictionary<string, BitmapCacheObject> _Bitmaps = new Dictionary<string, BitmapCacheObject>();

        private static OwnChatCache _Instance;

        private OwnChatCache() { }

        public static OwnChatCache GetInstance()
        {
            return _Instance ?? (_Instance = new OwnChatCache());
        }

        public void ClearAll()
        {
            ClearImageSources();
            ClearBitmaps();
        }

        public void ClearImageSources()
        {
            _ImageSources.Clear();
        }

        public void ClearBitmaps()
        {
            _Bitmaps.Clear();
        }

        public ImageSource GetImageSourceFromCache(string key)
        {
            if(key == null || _ImageSources == null || !_ImageSources.ContainsKey(key))
            {
                return null;
            }

            var imageSourceCacheObject = _ImageSources[key];

            var expirationDate = imageSourceCacheObject.ExpirationDate;

            return expirationDate < DateTime.Now ? null : imageSourceCacheObject.Image;
        }

        public void AddImageToCache(string key, ImageSource imageSource)
        {
            if(_ImageSources == null)
            {
                _ImageSources = new Dictionary<string, ImageSourceCacheObject>();
            }

            var newImageSourceCacheObject = new ImageSourceCacheObject(imageSource);

            if(_ImageSources.ContainsKey(key))
            {
                _ImageSources[key] = newImageSourceCacheObject;
            }
            else
            {
                _ImageSources.Add(key, newImageSourceCacheObject);
            }
        }

        public Bitmap GetBitmapFromCache(string key)
        {
            if(key == null || _Bitmaps == null || !_Bitmaps.ContainsKey(key))
            {
                return null;
            }

            var bitmapCacheObject = _Bitmaps[key];

            var expirationDate = bitmapCacheObject.ExpirationDate;

            return expirationDate < DateTime.Now ? null : bitmapCacheObject.Bitmap;
        }

        public void AddBitmapToCache(string key, Bitmap bitmap)
        {
            if(_Bitmaps == null)
            {
                _Bitmaps = new Dictionary<string, BitmapCacheObject>();
            }

            var newBitmapCacheObject = new BitmapCacheObject(bitmap);

            if(_Bitmaps.ContainsKey(key))
            {
                _Bitmaps[key] = newBitmapCacheObject;
            }
            else
            {
                _Bitmaps.Add(key, newBitmapCacheObject);
            }
        }
    }

    public class ImageSourceCacheObject
    {
        public DateTime ExpirationDate { get; }

        public ImageSource Image { get; }

        public ImageSourceCacheObject(ImageSource imageSource)
        {
            ExpirationDate = DateTime.Now.AddYears(1);
            Image = imageSource;
        }
    }

    public class BitmapCacheObject
    {
        public DateTime ExpirationDate { get; }

        public Bitmap Bitmap { get; }

        public BitmapCacheObject(Bitmap bitmap)
        {
            ExpirationDate = DateTime.Now.AddYears(1);
            Bitmap = bitmap;
        }
    }
}