1 files changed, 154 insertions, 0 deletions
diff --git a/BackEnd/Timeline/Services/User/Avatar/UserAvatarService.cs b/BackEnd/Timeline/Services/User/Avatar/UserAvatarService.cs
new file mode 100644
index 00000000..4f943e3a
--- /dev/null
+++ b/BackEnd/Timeline/Services/User/Avatar/UserAvatarService.cs
@@ -0,0 +1,154 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using Timeline.Entities;
+using Timeline.Helpers.Cache;
+using Timeline.Models;
+using Timeline.Services.Data;
+using Timeline.Services.Imaging;
+
+namespace Timeline.Services.User.Avatar
+{
+    public class UserAvatarService : IUserAvatarService
+    {
+        private readonly ILogger<UserAvatarService> _logger;
+        private readonly DatabaseContext _database;
+        private readonly IBasicUserService _basicUserService;
+        private readonly IDefaultUserAvatarProvider _defaultUserAvatarProvider;
+        private readonly IImageService _imageService;
+        private readonly IDataManager _dataManager;
+        private readonly IClock _clock;
+
+        public UserAvatarService(
+            ILogger<UserAvatarService> logger,
+            DatabaseContext database,
+            IBasicUserService basicUserService,
+            IDefaultUserAvatarProvider defaultUserAvatarProvider,
+            IImageService imageValidator,
+            IDataManager dataManager,
+            IClock clock)
+        {
+            _logger = logger;
+            _database = database;
+            _basicUserService = basicUserService;
+            _defaultUserAvatarProvider = defaultUserAvatarProvider;
+            _imageService = imageValidator;
+            _dataManager = dataManager;
+            _clock = clock;
+        }
+
+        public async Task<ICacheableDataDigest> GetAvatarDigest(long userId)
+        {
+            var usernameChangeTime = await _basicUserService.GetUsernameLastModifiedTimeAsync(userId);
+
+            var entity = await _database.UserAvatars.Where(a => a.UserId == userId).Select(a => new { a.DataTag, a.LastModified }).SingleOrDefaultAsync();
+
+            if (entity is null)
+            {
+                var defaultAvatarDigest = await _defaultUserAvatarProvider.GetDefaultAvatarDigest();
+                return new CacheableDataDigest(defaultAvatarDigest.ETag, new DateTime[] { usernameChangeTime, defaultAvatarDigest.LastModified }.Max());
+            }
+            else if (entity.DataTag is null)
+            {
+                var defaultAvatarDigest = await _defaultUserAvatarProvider.GetDefaultAvatarDigest();
+                return new CacheableDataDigest(defaultAvatarDigest.ETag, new DateTime[] { usernameChangeTime, defaultAvatarDigest.LastModified, entity.LastModified }.Max());
+            }
+            else
+            {
+                return new CacheableDataDigest(entity.DataTag, new DateTime[] { usernameChangeTime, entity.LastModified }.Max());
+            }
+        }
+
+        public async Task<ByteData> GetAvatar(long userId)
+        {
+            await _basicUserService.ThrowIfUserNotExist(userId);
+
+            var entity = await _database.UserAvatars.Where(a => a.UserId == userId).SingleOrDefaultAsync();
+
+            if (entity is null || entity.DataTag is null)
+            {
+                return await _defaultUserAvatarProvider.GetDefaultAvatar();
+            }
+
+            var data = await _dataManager.GetEntryAndCheck(entity.DataTag, $"This is required by avatar of {userId}.");
+
+            if (entity.Type is null)
+            {
+                var format = await _imageService.DetectFormatAsync(data);
+                entity.Type = format.DefaultMimeType;
+                await _database.SaveChangesAsync();
+            }
+
+            return new ByteData(data, entity.Type);
+        }
+
+        public async Task<ICacheableDataDigest> SetAvatar(long userId, ByteData avatar)
+        {
+            if (avatar is null)
+                throw new ArgumentNullException(nameof(avatar));
+
+            await _imageService.ValidateAsync(avatar.Data, avatar.ContentType, true);
+
+            await _basicUserService.ThrowIfUserNotExist(userId);
+
+            var entity = await _database.UserAvatars.Where(a => a.UserId == userId).SingleOrDefaultAsync();
+
+            await using var transaction = await _database.Database.BeginTransactionAsync();
+
+            var tag = await _dataManager.RetainEntryAsync(avatar.Data);
+
+            var now = _clock.GetCurrentTime();
+
+            if (entity is null)
+            {
+                var newEntity = new UserAvatarEntity
+                {
+                    DataTag = tag,
+                    Type = avatar.ContentType,
+                    LastModified = now,
+                    UserId = userId
+                };
+                _database.Add(newEntity);
+            }
+            else
+            {
+                if (entity.DataTag is not null)
+                    await _dataManager.FreeEntryAsync(entity.DataTag);
+
+                entity.DataTag = tag;
+                entity.Type = avatar.ContentType;
+                entity.LastModified = now;
+            }
+
+            await _database.SaveChangesAsync();
+
+            await transaction.CommitAsync();
+
+            return new CacheableDataDigest(tag, now);
+        }
+
+        public async Task DeleteAvatar(long userId)
+        {
+            await _basicUserService.ThrowIfUserNotExist(userId);
+
+            var entity = await _database.UserAvatars.Where(a => a.UserId == userId).SingleOrDefaultAsync();
+
+            if (entity is null || entity.DataTag is null)
+                return;
+
+            await using var transaction = await _database.Database.BeginTransactionAsync();
+
+            await _dataManager.FreeEntryAsync(entity.DataTag);
+
+            entity.DataTag = null;
+            entity.Type = null;
+            entity.LastModified = _clock.GetCurrentTime();
+
+            await _database.SaveChangesAsync();
+
+            await transaction.CommitAsync();
+        }
+    }
+}