From c26c479334eee6bbaa6f396d4fde4b1e175b85a7 Mon Sep 17 00:00:00 2001
From: Volodymyr Lisovskyi <erehonvl@gmail.com>
Date: Tue, 21 May 2024 16:09:53 +0200
Subject: [PATCH] feat: for last page add calculate if first page starting at 1

---
 src/Sinch/Core/Utils.cs         | 21 +++++++++++++++++++--
 tests/Sinch.Tests/UtilsTests.cs | 16 ++++++++++++++++
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/src/Sinch/Core/Utils.cs b/src/Sinch/Core/Utils.cs
index c65b337..b9fb55a 100644
--- a/src/Sinch/Core/Utils.cs
+++ b/src/Sinch/Core/Utils.cs
@@ -73,9 +73,20 @@ public static T ParseEnum<T>(string value)
             throw new InvalidOperationException($"Failed to parse {enumType.Name} enum for value {value}");
         }
 
-        public static bool IsLastPage(int page, int pageSize, int totalCount)
+        public static bool IsLastPage(int page, int pageSize, int totalCount, PageStart pageStart = PageStart.Zero)
         {
-            return (page + 1) * pageSize >= totalCount;
+            switch (pageStart)
+            {
+                case PageStart.Zero:
+                    page += 1;
+                    break;
+                case PageStart.First:
+                    break;
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(pageStart), pageStart, null);
+            }
+
+            return page * pageSize >= totalCount;
         }
 
         public static string ToSnakeCaseQueryString<T>(T obj) where T : class
@@ -178,4 +189,10 @@ public static void ThrowNullDeserialization(Type type)
             throw new InvalidOperationException($"{type.Name} deserialization result is null");
         }
     }
+
+    internal enum PageStart
+    {
+        Zero = 0,
+        First = 1,
+    }
 }
diff --git a/tests/Sinch.Tests/UtilsTests.cs b/tests/Sinch.Tests/UtilsTests.cs
index 282b166..02806d8 100644
--- a/tests/Sinch.Tests/UtilsTests.cs
+++ b/tests/Sinch.Tests/UtilsTests.cs
@@ -25,6 +25,22 @@ public void NotLastPage()
             Utils.IsLastPage(4, 1, 6).Should().BeFalse();
         }
 
+        [Fact]
+        public void LastPageFirst()
+        {
+            Utils.IsLastPage(1, 10, 2, PageStart.First).Should().BeTrue();
+            Utils.IsLastPage(1, 10, 9, PageStart.First).Should().BeTrue();
+            Utils.IsLastPage(4, 1, 4, PageStart.First).Should().BeTrue();
+        }
+
+        [Fact]
+        public void NotLastPageFirst()
+        {
+            Utils.IsLastPage(1, 10, 12, PageStart.First).Should().BeFalse();
+            Utils.IsLastPage(1, 10, 11, PageStart.First).Should().BeFalse();
+            Utils.IsLastPage(4, 1, 6, PageStart.First).Should().BeFalse();
+        }
+
 
         class Root
         {