From 042ea6d4208cfe0749131544454309d5f6d091e4 Mon Sep 17 00:00:00 2001
From: mars <mars@tebibyte.media>
Date: Fri, 14 Apr 2023 22:15:48 -0400
Subject: [PATCH] Better handling of EOF

---
 src/actions.rs |  4 ++--
 src/buffer.rs  | 43 ++++++++++++++++++++++++++-----------------
 2 files changed, 28 insertions(+), 19 deletions(-)

diff --git a/src/actions.rs b/src/actions.rs
index bc6e2f9..bb1c9a2 100644
--- a/src/actions.rs
+++ b/src/actions.rs
@@ -168,11 +168,11 @@ pub fn redo(state: &mut State) {
 
 pub fn delete_char_backward(state: &mut State) {
     state.move_cursor(Direction::Left);
-    state.buffer.remove(state.cursor);
+    state.buffer.remove_char(state.cursor);
 }
 
 pub fn delete_char_forward(state: &mut State) {
-    state.buffer.remove(state.cursor);
+    state.buffer.remove_char(state.cursor);
 }
 
 pub fn insert_newline(state: &mut State) {
diff --git a/src/buffer.rs b/src/buffer.rs
index 3ca275c..e9fa751 100644
--- a/src/buffer.rs
+++ b/src/buffer.rs
@@ -90,11 +90,6 @@ impl Buffer {
 
         let mut line_buf = Vec::<u8>::with_capacity(text_width);
         for (row, line) in (0..rows).zip(self.text.lines_at(scroll.line)) {
-            // only the last line is empty and should be skipped
-            if line.len_chars() == 0 {
-                break;
-            }
-
             let row = row as usize + scroll.line;
             let is_selected = row == cursor.line;
 
@@ -104,13 +99,19 @@ impl Buffer {
                 linenr_style
             };
 
+            let linenr = if line.len_chars() > 0 {
+                format!("{:>width$} ", row, width = linenr_width as usize)
+            } else {
+                // only the last line is empty
+                format!("{:>width$}", "~", width = linenr_width as usize)
+            };
+
             let line_style = if is_selected {
                 styles.get_scope("ui.cursorline.primary").clone()
             } else {
                 Default::default()
             };
 
-            let linenr = format!("{:width$} ", row, width = linenr_width as usize);
             linenr_style.print_styled(out, &linenr)?;
 
             let lhs = scroll.column;
@@ -149,10 +150,12 @@ impl Buffer {
         Ok(gutter_width)
     }
 
-    pub fn remove(&mut self, cursor: Cursor) {
+    pub fn remove_char(&mut self, cursor: Cursor) {
         let index = self.cursor_to_char(cursor);
-        self.text.remove(index..=index);
-        self.style_dirty = true;
+        if index < self.text.len_chars() {
+            self.text.remove(index..=index);
+            self.style_dirty = true;
+        }
     }
 
     pub fn insert_char(&mut self, cursor: Cursor, c: char) {
@@ -222,7 +225,13 @@ impl Buffer {
     }
 
     pub fn clamped_cursor(&self, cursor: Cursor) -> Cursor {
-        let line_end = self.text.line(cursor.line).len_chars().saturating_sub(1);
+        let line_len = self.text.line(cursor.line).len_chars();
+
+        let line_end = if cursor.line + 1 == self.text.len_lines() {
+            line_len
+        } else {
+            line_len.saturating_sub(1)
+        };
 
         Cursor {
             line: cursor.line,
@@ -248,7 +257,7 @@ impl Buffer {
                 }
             }
             Direction::Down => {
-                if cursor.line + 2 < self.text.len_lines() {
+                if cursor.line + 1 < self.text.len_lines() {
                     cursor.line += 1;
                 }
             }
@@ -259,13 +268,13 @@ impl Buffer {
             }
             Direction::Right => {
                 let line = self.text.line(cursor.line);
-                if cursor.column + 2 > line.len_chars() {
-                    if enable_linewrap && cursor.line + 2 < self.text.len_lines() {
-                        cursor.line += 1;
-                        cursor.column = 0;
-                    }
-                } else {
+                if cursor.line + 1 == self.text.len_lines() && cursor.column < line.len_chars() {
                     cursor.column += 1;
+                } else if cursor.column + 1 < line.len_chars() {
+                    cursor.column += 1
+                } else if enable_linewrap && cursor.line + 1 < self.text.len_lines() {
+                    cursor.line += 1;
+                    cursor.column = 0;
                 }
             }
         }