From 5c439c38f40b7a8815a9802732698b2e90c70741 Mon Sep 17 00:00:00 2001
From: Stephanie Gredell <s.raide@gmail.com>
Date: Wed, 24 Jan 2024 23:42:01 -0800
Subject: [PATCH] Initial commit of paginator class

---
 app/src/main/java/musicbot/Paginator.java | 65 +++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 app/src/main/java/musicbot/Paginator.java

diff --git a/app/src/main/java/musicbot/Paginator.java b/app/src/main/java/musicbot/Paginator.java
new file mode 100644
index 0000000..fa9fd6e
--- /dev/null
+++ b/app/src/main/java/musicbot/Paginator.java
@@ -0,0 +1,65 @@
+package musicbot;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Paginator {
+
+  public static class PaginatedItems<T>  {
+    private List<T> list = new ArrayList<T>();
+    private static boolean isLastPage = true;
+    private static int nextPageNum;
+
+    public void set(List<T> items){
+      list = items;
+    }
+
+    public void setNextPageNum(final int nextPage) {
+      nextPageNum = nextPage;
+    }
+
+    public int getNextPageNum() {
+      return nextPageNum;
+    }
+
+    public void setIsLastPage(final boolean isLastPageBool) {
+      isLastPage = isLastPageBool;
+    }
+
+    public boolean isIsLastPage() {
+      return isLastPage;
+    }
+
+    public List<T> get() {
+      return list;
+    }
+  }
+
+  public <E> PaginatedItems<E> paginate(
+      final List<E> tracks,
+      final int numItemsPerPage,
+      final int pageNumber
+  ) {
+    if (tracks.isEmpty()) {
+      return new PaginatedItems<>();
+    }
+
+    final int maxSize = tracks.size();
+    final int maxPage = (int) Math.floor(maxSize / numItemsPerPage);
+    final int maxIndex = numItemsPerPage * pageNumber;
+    final int baseIndex = maxIndex - numItemsPerPage;
+    final int nextPage = pageNumber + 1;
+    final PaginatedItems<E> paginatedItems = new PaginatedItems<>();
+
+    if (nextPage <= maxPage) {
+      paginatedItems.set(tracks.subList(baseIndex, maxIndex));
+      paginatedItems.setIsLastPage(false);
+      paginatedItems.setNextPageNum(nextPage);
+    } else {
+      paginatedItems.set(tracks.subList(maxIndex, maxSize));
+      paginatedItems.setIsLastPage(true);
+    }
+
+    return paginatedItems;
+  }
+}