From ff32bb064b38a0c95489f63a98a16147c95bc7ed Mon Sep 17 00:00:00 2001
From: Julius Kirsch <Julius@skirsch.de>
Date: Fri, 22 Aug 2025 10:13:04 +0200
Subject: [PATCH] feat: delete lines, wip

---
 TextControlBox-TestApp/MainWindow.xaml.cs     |  2 +
 .../Core/CoreTextControlBox.xaml.cs           |  5 +++
 TextControlBox/Core/Text/TextActionManager.cs | 39 ++++++++++++++++++-
 TextControlBox/Test/TextTests.cs              | 36 ++++++++++++++++-
 TextControlBox/TextControlBox.cs              | 12 ++++++
 5 files changed, 92 insertions(+), 2 deletions(-)

diff --git a/TextControlBox-TestApp/MainWindow.xaml.cs b/TextControlBox-TestApp/MainWindow.xaml.cs
index 98ea45f..d8a70e1 100644
--- a/TextControlBox-TestApp/MainWindow.xaml.cs
+++ b/TextControlBox-TestApp/MainWindow.xaml.cs
@@ -23,6 +23,8 @@ public MainWindow()
             textbox.NumberOfSpacesForTab = 4;
             textbox.Loaded += Textbox_Loaded;
 
+            textbox.DeleteLines(0, 5);
+
             //ActionGrouping();
         }
 
diff --git a/TextControlBox/Core/CoreTextControlBox.xaml.cs b/TextControlBox/Core/CoreTextControlBox.xaml.cs
index 78abb3a..9a98ecc 100644
--- a/TextControlBox/Core/CoreTextControlBox.xaml.cs
+++ b/TextControlBox/Core/CoreTextControlBox.xaml.cs
@@ -747,6 +747,11 @@ public bool DeleteLine(int line)
         return textActionManager.DeleteLine(line);
     }
 
+    public bool DeleteLines(int start, int count)
+    {
+        return textActionManager.DeleteLines(start, count);
+    }
+
     public bool AddLine(int line, string text)
     {
         return textActionManager.AddLine(line, text);
diff --git a/TextControlBox/Core/Text/TextActionManager.cs b/TextControlBox/Core/Text/TextActionManager.cs
index 42d9f44..940e8e9 100644
--- a/TextControlBox/Core/Text/TextActionManager.cs
+++ b/TextControlBox/Core/Text/TextActionManager.cs
@@ -1,4 +1,5 @@
-using Microsoft.UI.Input;
+using Collections.Pooled;
+using Microsoft.UI.Input;
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -508,6 +509,42 @@ public bool DeleteLine(int line)
             return true;
         }
 
+        public bool DeleteLines(int start, int count)
+        {
+            if (start < 0 || count <= 0 || start >= textManager.LinesCount)
+                return false;
+
+            if (start + count > textManager.LinesCount)
+                count = textManager.LinesCount - start;
+
+            if (longestLineManager.longestIndex >= start && longestLineManager.longestIndex < start + count)
+                longestLineManager.needsRecalculation = true;
+
+            //whole text is selected:
+            if (textManager.LinesCount == count)
+            {
+                undoRedo.RecordUndoAction(() =>
+                {
+                    textManager.SetLineText(0, "");
+                    if (count > 1)
+                        textManager.RemoveRange(start, count);
+
+                }, start, start + count, 0);
+            }
+            else
+            {
+                undoRedo.RecordUndoAction(() =>
+                {
+                    textManager.RemoveRange(start, count);
+                }, start, start + count, 0);
+            }
+
+            eventsManager.CallTextChanged();
+            canvasUpdateManager.UpdateText();
+            return true;
+        }
+
+
         public bool AddLine(int line, string text)
         {
             if (line > textManager.LinesCount || line < 0)
diff --git a/TextControlBox/Test/TextTests.cs b/TextControlBox/Test/TextTests.cs
index 5e612f2..f3cf5fa 100644
--- a/TextControlBox/Test/TextTests.cs
+++ b/TextControlBox/Test/TextTests.cs
@@ -55,6 +55,8 @@ public override Func<bool>[] GetAllTests()
                 this.Test_33,
                 this.Test_34,
                 this.Test_35,
+                this.Test_36,
+                this.Test_37,
                 ];
         }
 
@@ -570,7 +572,6 @@ public bool Test_33()
             return res.undo && res.redo && textBefore.Equals(coreTextbox.GetText());
         }
 
-
         public bool Test_34()
         {
             Debug.WriteLine("Undo Grouping");
@@ -623,5 +624,38 @@ public bool Test_35()
 
             return res.undo && res.redo && textBefore.Equals(coreTextbox.GetText());
         }
+
+        public bool Test_36()
+        {
+            Debug.WriteLine("Delete all Lines");
+
+            coreTextbox.SetText("Line1\nLine2\nLine3\nLine4\nLine5");
+            string textBefore = coreTextbox.GetText();
+
+            coreTextbox.DeleteLines(0,5);
+
+            var res = CheckUndoRedo();
+            coreTextbox.Undo();
+
+            var count = coreTextbox.GetText().Split("\r\n");
+
+            return res.undo && res.redo && textBefore.Equals(coreTextbox.GetText()) && count.Length == 1;
+        }
+        public bool Test_37()
+        {
+            Debug.WriteLine("Delete 0-3 Lines");
+
+            coreTextbox.SetText("Line1\nLine2\nLine3\nLine4\nLine5");
+            string textBefore = coreTextbox.GetText();
+
+            coreTextbox.DeleteLines(0, 3);
+
+            var res = CheckUndoRedo();
+            coreTextbox.Undo();
+
+            var count = coreTextbox.GetText().Split("\r\n");
+
+            return res.undo && res.redo && textBefore.Equals(coreTextbox.GetText()) && count.Length == 2;
+        }
     }
 }
\ No newline at end of file
diff --git a/TextControlBox/TextControlBox.cs b/TextControlBox/TextControlBox.cs
index 041eb53..d7a56b3 100644
--- a/TextControlBox/TextControlBox.cs
+++ b/TextControlBox/TextControlBox.cs
@@ -345,6 +345,18 @@ public bool DeleteLine(int line)
         return coreTextBox.DeleteLine(line);
     }
 
+    /// <summary>
+    /// Deletes the lines specified by the zero based start from the textbox until the start + count line
+    /// This action will record an undo step
+    /// </summary>
+    /// <param name="start">The beginning of the line to delete</param>
+    /// <param name="count">The amount of lines to delete</param>
+    /// <returns>Returns true if the line was deleted successfully and false if not</returns>
+    public bool DeleteLines(int start, int count)
+    {
+        return coreTextBox.DeleteLines(start, count);
+    }
+
     /// <summary>
     /// Adds a new line with the text specified
     /// This action will record an undo step