1 files changed, 50 insertions, 0 deletions
diff --git a/WindowedReader.cs b/WindowedReader.cs
new file mode 100644
index 0000000..99c6e01
--- /dev/null
+++ b/WindowedReader.cs
@@ -0,0 +1,50 @@
+using System.Reflection;
+
+namespace HyperBooru;
+
+public class WindowedReader<T> where T : class {
+    public int WindowSize { get; init; } = 200;
+
+    private LinkedList<T> window = new();
+    private IQueryable<T> DataSource { get; set; }
+
+    private object        loadLock         = new();
+    private Task          loadTask         = Task.CompletedTask;
+    private LoadOperation currentOperation = LoadOperation.None;
+
+    public WindowedReader(IQueryable<T> dataSource) =>
+        DataSource = dataSource;
+
+    private void DoLoad(LoadOperation operation) {
+        T? bookmark = null;
+        IQueryable<T> query = DataSource;
+
+        PropertyInfo orderProperty;
+
+        switch(operation) {
+            case LoadOperation.InitialLoad:
+                window = new(DataSource.Take(WindowSize));
+                break;
+            case LoadOperation.LoadPrevious:
+                bookmark = window.FirstOrDefault();
+                break;
+            case LoadOperation.LoadNext:
+                bookmark = window.LastOrDefault();
+                break;
+            default:
+                return;
+        }
+
+        if(bookmark is null) {
+            DoLoad(LoadOperation.InitialLoad);
+            return;
+        }
+    }
+}
+
+public enum LoadOperation {
+    None = 0,
+    InitialLoad,
+    LoadPrevious,
+    LoadNext
+}