huge commit for advanced stats feature.

broke data out into its own library.
may be breaking changes with existing plugins

Data/Helpers/LookupCache.cs

@@ -0,0 +1,114 @@
+using Data.Abstractions;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using ILogger = Microsoft.Extensions.Logging.ILogger;
+
+namespace Data.Helpers
+{
+    public class LookupCache<T> : ILookupCache<T> where T : class, IUniqueId
+    {
+        private readonly ILogger _logger;
+        private readonly IDatabaseContextFactory _contextFactory;
+        private Dictionary<long, T> _cachedItems;
+        private readonly SemaphoreSlim _onOperation = new SemaphoreSlim(1, 1);
+
+        public LookupCache(ILogger<LookupCache<T>> logger, IDatabaseContextFactory contextFactory)
+        {
+            _logger = logger;
+            _contextFactory = contextFactory;
+        }
+
+        public async Task<T> AddAsync(T item)
+        {
+            await _onOperation.WaitAsync();
+            T existingItem = null;
+
+            if (_cachedItems.ContainsKey(item.Id))
+            {
+                existingItem = _cachedItems[item.Id];
+            }
+
+            if (existingItem != null)
+            {
+                _logger.LogDebug("Cached item already added for {type} {id} {value}", typeof(T).Name, item.Id,
+                    item.Value);
+                _onOperation.Release();
+                return existingItem;
+            }
+
+            try
+            {
+                _logger.LogDebug("Adding new {type} with {id} {value}", typeof(T).Name, item.Id, item.Value);
+                await using var context = _contextFactory.CreateContext();
+                context.Set<T>().Add(item);
+                await context.SaveChangesAsync();
+                _cachedItems.Add(item.Id, item);
+                return item;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Could not add item to cache for {type}", typeof(T).Name);
+                throw new Exception("Could not add item to cache");
+            }
+            finally
+            {
+                if (_onOperation.CurrentCount == 0)
+                {
+                    _onOperation.Release();
+                }
+            }
+        }
+
+        public async Task<T> FirstAsync(Func<T, bool> query)
+        {
+            await _onOperation.WaitAsync();
+
+            try
+            {
+                var cachedResult = _cachedItems.Values.Where(query);
+
+                if (cachedResult.Any())
+                {
+                    return cachedResult.FirstOrDefault();
+                }
+            }
+
+            catch
+            {
+            }
+
+            finally
+            {
+                if (_onOperation.CurrentCount == 0)
+                {
+                    _onOperation.Release(1);
+                }
+            }
+
+            return null;
+        }
+
+        public IEnumerable<T> GetAll()
+        {
+            return _cachedItems.Values;
+        }
+
+        public async Task InitializeAsync()
+        {
+            try
+            {
+                await using var context = _contextFactory.CreateContext();
+                _cachedItems = await context.Set<T>().ToDictionaryAsync(item => item.Id);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Could not initialize caching for {cacheType}", typeof(T).Name);
+            }
+        }
+    }
+}