add request logic in wiki overlay

osu.Game/Overlays/WikiOverlay.cs

@@ -1,17 +1,107 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.Threading;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Game.Online.API;
+using osu.Game.Online.API.Requests;
+using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Overlays.Wiki;
+using osu.Game.Overlays.Wiki.Markdown;
 
 namespace osu.Game.Overlays
 {
     public class WikiOverlay : OnlineOverlay<WikiHeader>
     {
+        private const string index_path = "Main_Page";
+
+        private readonly Bindable<string> path = new Bindable<string>(index_path);
+
+        [Cached]
+        private readonly Bindable<APIWikiPage> wikiData = new Bindable<APIWikiPage>();
+
+        [Resolved]
+        private IAPIProvider api { get; set; }
+
+        private GetWikiRequest request;
+
+        private CancellationTokenSource cancellationToken;
+
+        private bool displayUpdateRequired = true;
+
         public WikiOverlay()
             : base(OverlayColourScheme.Orange, false)
         {
         }
 
+        private void onPathChanged(ValueChangedEvent<string> e)
+        {
+            cancellationToken?.Cancel();
+            request?.Cancel();
+
+            request = new GetWikiRequest(e.NewValue);
+
+            Loading.Show();
+
+            request.Success += response => Schedule(() => onSuccess(response));
+
+            api.PerformAsync(request);
+        }
+
+        private void onSuccess(APIWikiPage response)
+        {
+            wikiData.Value = response;
+            LoadDisplay(new WikiMarkdownContainer
+            {
+                RelativeSizeAxes = Axes.X,
+                AutoSizeAxes = Axes.Y,
+                CurrentPath = $"{path.Value}/",
+                Text = response.Markdown,
+            });
+        }
+
         protected override WikiHeader CreateHeader() => new WikiHeader();
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+            path.BindValueChanged(onPathChanged);
+        }
+
+        protected override void PopIn()
+        {
+            base.PopIn();
+
+            if (displayUpdateRequired)
+            {
+                path.TriggerChange();
+                displayUpdateRequired = false;
+            }
+        }
+
+        protected override void PopOutComplete()
+        {
+            base.PopOutComplete();
+            displayUpdateRequired = true;
+        }
+
+        protected void LoadDisplay(Drawable display)
+        {
+            ScrollFlow.ScrollToStart();
+            LoadComponentAsync(display, loaded =>
+            {
+                Child = loaded;
+                Loading.Hide();
+            }, (cancellationToken = new CancellationTokenSource()).Token);
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            cancellationToken?.Cancel();
+            request?.Cancel();
+            base.Dispose(isDisposing);
+        }
     }
 }