Frequency navigation db

src/AppCommon/FileTime.App.Database/LiteDb/Queryable.cs

@@ -0,0 +1,51 @@
+using System.Linq.Expressions;
+using LiteDB;
+
+namespace FileTime.App.Database.LiteDb;
+
+public class Queryable<T> : IQueryable<T>
+{
+    private readonly ILiteQueryable<T> _collection;
+    private int SkipCount { get; init; }
+    private int TakeCount { get; init; }
+
+    public Queryable(ILiteQueryable<T> collection)
+    {
+        _collection = collection;
+    }
+
+    public IQueryable<T> Where(Expression<Func<T, bool>> predicate) => new Queryable<T>(_collection.Where(predicate));
+    public IQueryable<T> OrderBy<TSelector>(Expression<Func<T, TSelector>> order) => new Queryable<T>(_collection.OrderBy(order));
+    public IQueryable<T> OrderByDescending<TSelector>(Expression<Func<T, TSelector>> order) => new Queryable<T>(_collection.OrderByDescending(order));
+    public IQueryable<T> Skip(int skip) => new Queryable<T>(_collection) {SkipCount = skip};
+    public IQueryable<T> Take(int take) => new Queryable<T>(_collection) {TakeCount = take};
+    public IQueryable<T> Include<TResult>(Expression<Func<T, TResult>> selector) => new Queryable<T>(_collection.Include(selector));
+
+    private ILiteQueryableResult<TCollection> ApplySkipAndTake<TCollection>(ILiteQueryableResult<TCollection> collection)
+    {
+        if (SkipCount > 0)
+        {
+            collection = collection.Skip(SkipCount);
+        }
+
+        if (TakeCount > 0)
+        {
+            collection = collection.Limit(TakeCount);
+        }
+
+        return collection;
+    }
+
+
+    public IQueryableResult<TResult> Select<TResult>(Expression<Func<T, TResult>> selector) => new QueryableResult<TResult>(ApplySkipAndTake(_collection.Select(selector)));
+
+    public int Count() => ApplySkipAndTake(_collection).Count();
+    public bool Exists() => ApplySkipAndTake(_collection).Exists();
+    public T First() => ApplySkipAndTake(_collection).First();
+    public T FirstOrDefault() => ApplySkipAndTake(_collection).FirstOrDefault();
+    public T Single() => ApplySkipAndTake(_collection).Single();
+    public T SingleOrDefault() => ApplySkipAndTake(_collection).SingleOrDefault();
+    public IEnumerable<T> ToEnumerable() => ApplySkipAndTake(_collection).ToEnumerable();
+    public List<T> ToList() => ApplySkipAndTake(_collection).ToList();
+    public T[] ToArray() => ApplySkipAndTake(_collection).ToArray();
+}