From bee7760d29e884dff532828e3bbb1f1d71fd3d6d Mon Sep 17 00:00:00 2001
From: Andrei Zavatski <megaman9919@gmail.com>
Date: Tue, 10 Sep 2019 01:36:25 +0300
Subject: [PATCH] Make MaxPages value a bindable

---
 .../UserInterface/TestScenePageSelector.cs    | 47 ++++++++++---------
 .../Graphics/UserInterface/PageSelector.cs    | 40 ++++++++++++----
 2 files changed, 57 insertions(+), 30 deletions(-)

diff --git a/osu.Game.Tests/Visual/UserInterface/TestScenePageSelector.cs b/osu.Game.Tests/Visual/UserInterface/TestScenePageSelector.cs
index cb83fbd028..14cb27c97e 100644
--- a/osu.Game.Tests/Visual/UserInterface/TestScenePageSelector.cs
+++ b/osu.Game.Tests/Visual/UserInterface/TestScenePageSelector.cs
@@ -15,35 +15,40 @@ namespace osu.Game.Tests.Visual.UserInterface
             typeof(PageSelector)
         };
 
+        private readonly PageSelector pageSelector;
+
         public TestScenePageSelector()
         {
-            Child = new PageSelector(200)
+            Child = pageSelector = new PageSelector
             {
                 Anchor = Anchor.Centre,
                 Origin = Anchor.Centre,
             };
 
-            AddStep("1 max pages", () => redraw(1));
-            AddStep("10 max pages", () => redraw(10));
-            AddStep("200 max pages, current 199", () => redraw(200, 199));
-            AddStep("200 max pages, current 201", () => redraw(200, 201));
-            AddStep("200 max pages, current -10", () => redraw(200, -10));
-        }
-
-        private void redraw(int maxPages, int currentPage = 0)
-        {
-            Clear();
-
-            var selector = new PageSelector(maxPages)
+            AddStep("10 max pages", () => setMaxPages(10));
+            AddStep("200 max pages, current 199", () =>
             {
-                Anchor = Anchor.Centre,
-                Origin = Anchor.Centre,
-            };
-
-            if (currentPage != 0)
-                selector.CurrentPage.Value = currentPage;
-
-            Add(selector);
+                setMaxPages(200);
+                setCurrentPage(199);
+            });
+            AddStep("200 max pages, current 201", () =>
+            {
+                setMaxPages(200);
+                setCurrentPage(201);
+            });
+            AddStep("200 max pages, current -10", () =>
+            {
+                setMaxPages(200);
+                setCurrentPage(-10);
+            });
+            AddStep("-10 max pages", () =>
+            {
+                setMaxPages(-10);
+            });
         }
+
+        private void setMaxPages(int maxPages) => pageSelector.MaxPages.Value = maxPages;
+
+        private void setCurrentPage(int currentPage) => pageSelector.CurrentPage.Value = currentPage;
     }
 }
diff --git a/osu.Game/Graphics/UserInterface/PageSelector.cs b/osu.Game/Graphics/UserInterface/PageSelector.cs
index 9db6366ad6..66f51a6dad 100644
--- a/osu.Game/Graphics/UserInterface/PageSelector.cs
+++ b/osu.Game/Graphics/UserInterface/PageSelector.cs
@@ -20,17 +20,15 @@ namespace osu.Game.Graphics.UserInterface
     public class PageSelector : CompositeDrawable
     {
         public readonly BindableInt CurrentPage = new BindableInt(1);
+        public readonly BindableInt MaxPages = new BindableInt(1);
 
-        private readonly int maxPages;
         private readonly FillFlowContainer itemsFlow;
 
         private readonly Button previousPageButton;
         private readonly Button nextPageButton;
 
-        public PageSelector(int maxPages)
+        public PageSelector()
         {
-            this.maxPages = maxPages;
-
             AutoSizeAxes = Axes.Both;
             InternalChild = new FillFlowContainer
             {
@@ -59,24 +57,48 @@ namespace osu.Game.Graphics.UserInterface
         {
             base.LoadComplete();
 
-            CurrentPage.BindValueChanged(_ => redraw(), true);
+            MaxPages.BindValueChanged(pagesAmount => onMaxPagesChanged(pagesAmount.NewValue), true);
+            CurrentPage.BindValueChanged(page => onCurrentPageChanged(page.NewValue), true);
         }
 
-        private void redraw()
+        private void onMaxPagesChanged(int pagesAmount)
         {
-            if (CurrentPage.Value > maxPages)
+            if (pagesAmount < 1)
             {
-                CurrentPage.Value = maxPages;
+                MaxPages.Value = 1;
                 return;
             }
 
-            if (CurrentPage.Value < 1)
+            if (CurrentPage.Value > pagesAmount)
+            {
+                CurrentPage.Value = pagesAmount;
+                return;
+            }
+
+            redraw();
+        }
+
+        private void onCurrentPageChanged(int newPage)
+        {
+            if (newPage > MaxPages.Value)
+            {
+                CurrentPage.Value = MaxPages.Value;
+                return;
+            }
+
+            if (newPage < 1)
             {
                 CurrentPage.Value = 1;
                 return;
             }
 
+            redraw();
+        }
+
+        private void redraw()
+        {
             int newPage = CurrentPage.Value;
+            int maxPages = MaxPages.Value;
 
             previousPageButton.Enabled.Value = newPage != 1;
             nextPageButton.Enabled.Value = newPage != maxPages;