From 9ac429aa26529af2f753d01fe6e4fe5046bdf30f Mon Sep 17 00:00:00 2001
From: Rose Hogenson <rosehogenson@posteo.net>
Date: Sat, 6 Jan 2024 13:57:32 -0800
Subject: Implement backspace.

---
 src/main.rs | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

(limited to 'src/main.rs')

diff --git a/src/main.rs b/src/main.rs
index 54b644d..139b4c3 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -140,6 +140,7 @@ impl State {
         } else {
             self.cursor_row -= 1;
         }
+        self.repaint_line_full()?;
         return Ok(());
     }
 
@@ -154,6 +155,7 @@ impl State {
         } else {
             self.cursor_row += 1;
         }
+        self.repaint_line_full()?;
         return Ok(());
     }
 
@@ -166,11 +168,11 @@ impl State {
         }
         if self.cursor_col == 0 {
             self.up()?;
-            self.repaint_line_full()?;
             self.cursor_col = self.line_cols;
         } else {
             self.cursor_col -= 1;
         }
+        self.repaint_line_full()?;
         return Ok(());
     }
 
@@ -185,6 +187,7 @@ impl State {
         } else {
             self.cursor_col += 1;
         }
+        self.repaint_line_full()?;
         return Ok(());
     }
 }
@@ -217,21 +220,31 @@ fn edit(file: &OsStr) -> Result<(), Box<dyn Error>> {
             }
             Key::Up => {
                 let _ = state.up();
-                let _ = state.repaint_line_full();
                 let _ = stdout().flush();
             }
             Key::Down => {
                 let _ = state.down();
-                let _ = state.repaint_line_full();
                 let _ = stdout().flush();
             }
             Key::Left => {
                 let _ = state.left();
-                let _ = state.repaint_line_full();
                 let _ = stdout().flush();
             }
             Key::Right => {
                 let _ = state.right();
+                let _ = stdout().flush();
+            }
+            Key::Backspace => {
+                if state.row_start == 0 && state.cursor_row == 0 && state.cursor_col == 0 {
+                    continue;
+                }
+                let offset = state.buf.line_idx(state.row_start+state.cursor_row)+state.line_offset;
+                let need_refresh_all = state.cursor_col == 0;
+                let _ = state.left();
+                state.buf = state.buf.slice(0, state.buf.floor_char_boundary(offset-1)).concat(&state.buf.slice(offset, state.buf.len()));
+                if need_refresh_all {
+                    let _ = state.repaint_all();
+                }
                 let _ = state.repaint_line_full();
                 let _ = stdout().flush();
             }
-- 
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