Chat/ChatController/Core/OwnChatCache.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Windows.Media;
using ChatController.Extensions;

namespace ChatController.Core
{
    public class OwnChatCache
    {
        public static string BaseUri { get; set; }
        public long? LoggedOnUserId { get; set; }

        private static readonly object _Lock = new object();

        private ImageSource _DocumentThumbnail;
        public ImageSource DocumentThumbnail
        {
            get => _DocumentThumbnail;
            set
            {
                lock(_Lock)
                {
                    if(!(value is null) && _DocumentThumbnail is null)
                    {
                        _DocumentThumbnail = value;
                    }
                }
            }
        }

        private ImageSource _ImagePlaceholder;
        public ImageSource ImagePlaceholder
        {
            get => _ImagePlaceholder;
            set
            {
                lock(_Lock)
                {
                    if(!(value is null) && _ImagePlaceholder is null)
                    {
                        _ImagePlaceholder = value;
                    }
                }
            }
        }


        private Dictionary<DefaultAvatarType, ImageSource> _DefaultAvatars = new Dictionary<DefaultAvatarType, ImageSource>();

        private List<ProfilePictureObject> _AvatarCache = new List<ProfilePictureObject>();

        private List<long> EmployeesWithDefaultAvatar = new List<long>();
        private List<long> ClientsWithDefaultAvatar = new List<long>();

        public void AddAvatar(string uri, ImageSource avatar, long? userId, int? groupId)
        {
            lock(_Lock)
            {
                if(uri is null || avatar is null)
                {
                    return;
                }

                if(_AvatarCache is null)
                {
                    _AvatarCache = new List<ProfilePictureObject>();
                }

                if(!string.IsNullOrWhiteSpace(BaseUri))
                {
                    if(_DefaultAvatars is null)
                    {
                        _DefaultAvatars = new Dictionary<DefaultAvatarType, ImageSource>();
                    }

                    if(uri.Equals($"{BaseUri}/ownChat_avatar_employee.png"))
                    {
                        _DefaultAvatars.AddAndIgnoreDuplicates(DefaultAvatarType.Employee, avatar);
                        if(userId.HasValue)
                        {
                            EmployeesWithDefaultAvatar.AddIfNotIn(userId.Value);
                        }
                    }

                    if(uri.Equals($"{BaseUri}/ownChat_avatar_employee_group.png"))
                    {
                        _DefaultAvatars.AddAndIgnoreDuplicates(DefaultAvatarType.EmployeeGroup, avatar);
                    }

                    if(uri.Equals($"{BaseUri}/ownChat_avatar_client.png"))
                    {
                        _DefaultAvatars.AddAndIgnoreDuplicates(DefaultAvatarType.Client, avatar);
                        if(userId.HasValue)
                        {
                            ClientsWithDefaultAvatar.AddIfNotIn(userId.Value);
                        }
                    }

                    if(uri.Equals($"{BaseUri}/ownChat_avatar_client_group.png"))
                    {
                        _DefaultAvatars.AddAndIgnoreDuplicates(DefaultAvatarType.ClientGroup, avatar);
                    }
                }

                if(!_AvatarCache.Any(ppo => ppo.Uri.Equals(uri) && ppo.UserId == userId && ppo.GroupId == groupId))
                {
                    _AvatarCache.Add(new ProfilePictureObject(userId, uri, avatar, groupId));
                }
            }
        }

        public ImageSource GetAvatar(string uri, long? userId, int? groupId)
        {
            lock(_Lock)
            {
                if(uri is null || _AvatarCache is null)
                {
                    return null;
                }

                if(!string.IsNullOrWhiteSpace(BaseUri))
                {
                    if(_DefaultAvatars is null)
                    {
                        _DefaultAvatars = new Dictionary<DefaultAvatarType, ImageSource>();
                    }

                    if(uri.Equals($"{BaseUri}/ownChat_avatar_employee.png"))
                    {
                        if(userId.HasValue)
                        {
                            EmployeesWithDefaultAvatar.AddIfNotIn(userId.Value);
                        }

                        return _DefaultAvatars[DefaultAvatarType.Employee];
                    }

                    if(uri.Equals($"{BaseUri}/ownChat_avatar_employee_group.png"))
                    {
                        return _DefaultAvatars[DefaultAvatarType.EmployeeGroup];
                    }

                    if(uri.Equals($"{BaseUri}/ownChat_avatar_client.png"))
                    {
                        if(userId.HasValue)
                        {
                            ClientsWithDefaultAvatar.AddIfNotIn(userId.Value);
                        }

                        return _DefaultAvatars[DefaultAvatarType.Client];
                    }

                    if(uri.Equals($"{BaseUri}/ownChat_avatar_client_group.png"))
                    {
                        return _DefaultAvatars[DefaultAvatarType.ClientGroup];
                    }
                }

                return _AvatarCache.FirstOrDefault(f => uri.Equals(f.Uri) && f.UserId == userId && f.GroupId == groupId)?.ProfilePicture;
            }
        }

        /// <summary>
        /// Gibt das Profilbild des Absenders einer Nachricht in Gruppenchats zurück
        /// </summary>
        /// <param name="userId">UserId des Absenders einer Nachricht</param>
        /// <returns>Profilbild des Absenders einer Nachricht mit der angegebenen UserId</returns>
        public ImageSource GetAvatarByUserId(long userId)
        {
            lock(_Lock)
            {
                var profilePicture = _AvatarCache.FirstOrDefault(f => f.UserId.HasValue && f.UserId.Value.Equals(userId))?.ProfilePicture;

                if(!(profilePicture is null))
                {
                    return profilePicture;
                }

                if(EmployeesWithDefaultAvatar.Contains(userId))
                {
                    profilePicture = _DefaultAvatars[DefaultAvatarType.Employee];
                }

                if(ClientsWithDefaultAvatar.Contains(userId))
                {
                    profilePicture = _DefaultAvatars[DefaultAvatarType.Client];
                }

                return profilePicture;
            }
        }

        public bool IsAvatarInCache(string uri, long? userId, int? groupId)
        {
            lock(_Lock)
            {
                if(uri is null)
                {
                    return false;
                }

                if(!string.IsNullOrWhiteSpace(BaseUri))
                {
                    if(_DefaultAvatars is null)
                    {
                        _DefaultAvatars = new Dictionary<DefaultAvatarType, ImageSource>();
                    }

                    if(uri.Equals($"{BaseUri}/ownChat_avatar_employee.png"))
                    {
                        return _DefaultAvatars.ContainsKey(DefaultAvatarType.Employee);
                    }

                    if(uri.Equals($"{BaseUri}/ownChat_avatar_employee_group.png"))
                    {
                        return _DefaultAvatars.ContainsKey(DefaultAvatarType.EmployeeGroup);
                    }

                    if(uri.Equals($"{BaseUri}/ownChat_avatar_client.png"))
                    {
                        return _DefaultAvatars.ContainsKey(DefaultAvatarType.Client);
                    }

                    if(uri.Equals($"{BaseUri}/ownChat_avatar_client_group.png"))
                    {
                        return _DefaultAvatars.ContainsKey(DefaultAvatarType.ClientGroup);
                    }
                }

                return _AvatarCache?.Any(a => uri.Equals(a.Uri) && a.UserId == userId && a.GroupId == groupId) ?? false;
            }
        }



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

        private readonly Dictionary<long, ProfilePictureObject> _UserProfilePictures = new Dictionary<long, ProfilePictureObject>();

        private static OwnChatCache _Instance;

        private OwnChatCache() { }

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

        public ImageSource GetImageSourceFromCache(string key, string name, CacheCategory cacheCategory)
        {
            lock(_Lock)
            {
                if(key is null || _ImageSourceCache is null || !_ImageSourceCache.ContainsKey(key))
                {
                    return null;
                }
            
                var imageSourceCacheObject = _ImageSourceCache[key].GetCachedImageSource(cacheCategory, name);

                return imageSourceCacheObject?.Image;
            }
        }

        public void AddImageToCache(string key, ImageSource imageSource, CacheCategory cacheCategory, string name)
        {
            lock(_Lock)
            {
                if(_ImageSourceCache is null)
                {
                    _ImageSourceCache = new Dictionary<string, ImageSourceCacheStorage>();
                }

                if(!_ImageSourceCache.ContainsKey(key))
                {
                    _ImageSourceCache.Add(key, new ImageSourceCacheStorage());
                }

                _ImageSourceCache[key].AddImageSourceToCachedObjects(imageSource, cacheCategory, name);
            }
        }

        public void AddProfilePictureToCache(string key, ImageSource imageSource, string profilePicturePath)
        {
            lock(_Lock)
            {
                if(!_ImageSourceCache.ContainsKey(key))
                {
                    _ImageSourceCache.Add(key, new ImageSourceCacheStorage());
                }
            
                _ImageSourceCache[key].SetCachedProfilePicture(imageSource, profilePicturePath);
            }
        }

        public ImageSource GetCachedProfilePicture(string key, string uri)
        {
            lock(_Lock)
            {
                foreach (var kvp in _ImageSourceCache)
                {
                    if(!string.IsNullOrWhiteSpace(uri) && uri.ToLower().Contains("ownchat") && kvp.Value.ProfilePicturePath == uri)
                    {
                        return kvp.Value.GetCachedProfilePicture();
                    }
                }
                
                return _ImageSourceCache.ContainsKey(key) ? 
                       _ImageSourceCache[key].GetCachedProfilePicture() : 
                       null;
            }
        }

        public void AddUserProfilePictureToCache(ImageSource imageSource, long userId, string uri)
        {
            lock(_Lock)
            {
                if(!_UserProfilePictures.ContainsKey(userId))
                {
                    Debug.WriteLine($"+++>OwnChatCache.AddUserProfilePictureToCache: Füge Avatar zum Cache hinzu {userId}");
                    _UserProfilePictures.Add(userId, new ProfilePictureObject(userId, uri, imageSource, null));
                }
                else
                {
                    Debug.WriteLine($">>>OwnChatCache.AddUserProfilePictureToCache: Cache enthält bereits den Avatar von {userId}");
                }
            }
        }

        public ProfilePictureObject GetUserProfilePictureFromCache(long userId)
        {
            lock(_Lock)
            {
                return _UserProfilePictures.ContainsKey(userId) ? _UserProfilePictures[userId] : null;
            }
        }

        public bool IsUserProfilePictureInCache(long userId)
        {
            lock(_Lock)
            {
                return _UserProfilePictures.ContainsKey(userId);
            }
        }
    }

    public class ProfilePictureObject
    {
        public long? UserId { get; set; }

        public string Uri { get; set; }

        public ImageSource ProfilePicture { get; set; }

        public int? GroupId { get; set; }

        public ProfilePictureObject(long? userId, string uri, ImageSource profilePicture, int? groupId)
        {
            GroupId = groupId;
            UserId = userId;
            Uri = uri;
            ProfilePicture = profilePicture;
        }
    }

    public class ImageSourceCacheStorage
    {
        private ImageSourceCacheObject _ProfilePicture;

        public string ProfilePicturePath { get; set; }

        public ImageSource GetCachedProfilePicture()
        {
            return _ProfilePicture?.ExpirationDate > DateTime.Now ? _ProfilePicture.Image : null;
        }

        public void SetCachedProfilePicture(ImageSource avatarImageSource, string profilePicturePath)
        {
            if(!(avatarImageSource is null) && !string.IsNullOrWhiteSpace(profilePicturePath))
            {
                ProfilePicturePath = profilePicturePath;
                _ProfilePicture = new ImageSourceCacheObject(avatarImageSource, CacheCategory.ProfilePicture);
            }
        }

        public Dictionary<CacheCategory, Dictionary<string, ImageSourceCacheObject>> CachedObjects { get; set; }

        public ImageSourceCacheStorage()
        {
            CachedObjects = new Dictionary<CacheCategory, Dictionary<string, ImageSourceCacheObject>>();
        }

        public ImageSourceCacheObject GetCachedImageSource(CacheCategory cacheCategory, string name)
        {
            if(CachedObjects.ContainsKey(cacheCategory) && CachedObjects[cacheCategory].ContainsKey(name))
            {
                var imageSourceCacheObject = CachedObjects[cacheCategory][name];

                return imageSourceCacheObject?.ExpirationDate > DateTime.Now ? imageSourceCacheObject : null;
            }

            return null;
        }

        public void AddImageSourceToCachedObjects(ImageSource imageSource, CacheCategory cacheCategory, string name)
        {
            if(CachedObjects is null)
            {
                CachedObjects = new Dictionary<CacheCategory, Dictionary<string, ImageSourceCacheObject>>();
            }

            var newImageSourceCacheObject = new ImageSourceCacheObject(imageSource, cacheCategory);

            if(CachedObjects.ContainsKey(cacheCategory) )
            {
                if (CachedObjects[cacheCategory].ContainsKey(name))
                {
                    CachedObjects[cacheCategory][name] = newImageSourceCacheObject;
                }
                else
                {
                    CachedObjects[cacheCategory].Add(name, newImageSourceCacheObject);
                }
            }
            else
            {
                CachedObjects.Add(cacheCategory, new Dictionary<string, ImageSourceCacheObject> { {name, newImageSourceCacheObject } });
            }
        }
    }

    public class ImageSourceCacheObject
    {
        public CacheCategory CacheCategory { get; }

        public DateTime ExpirationDate { get; }

        public ImageSource Image { get; }

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

    public enum CacheCategory
    {
        ProfilePicture,
        Thumbnail,
        MessageAttachment
    }

    public enum DefaultAvatarType
    {
        Employee = 0,
        EmployeeGroup = 1, 
        Client = 2,
        ClientGroup = 3
    }
}