From 8e125b8c7c7b3df8dd73d00a52edcec9fbd2d3af Mon Sep 17 00:00:00 2001
From: Timothy Warren <twarren@nabancard.com>
Date: Fri, 30 Aug 2019 11:20:52 -0400
Subject: [PATCH] Basic backspacing

---
 src/editor.rs | 72 ++++++++++++++++++++++++++++++++++++++++++++++-----
 src/main.rs   |  2 +-
 2 files changed, 67 insertions(+), 7 deletions(-)

diff --git a/src/editor.rs b/src/editor.rs
index d177f25..060d93b 100644
--- a/src/editor.rs
+++ b/src/editor.rs
@@ -11,6 +11,7 @@ use std::time::{Duration, Instant};
 use self::EditorKey::*;
 
 const KILO_TAB_STOP: usize = 4;
+const KILO_QUIT_TIMES: u8 = 3;
 
 /// A representation of a line in the editor
 #[derive(Debug, Default)]
@@ -40,10 +41,14 @@ pub struct Editor {
     screen_cols: usize,
     screen_rows: usize,
     rows: Vec<EditorRow>,
+    dirty: u64,
     filename: String,
     status_message: String,
     status_message_time: Instant,
+
+    // Properties not present in C version
     output_buffer: String,
+    quit_times: u8,
 }
 
 /// Keycode mapping enum
@@ -87,10 +92,12 @@ impl Default for Editor {
             screen_cols: 0,
             screen_rows: 0,
             rows: vec![],
+            dirty: 0,
             filename: String::new(),
             status_message: String::new(),
             status_message_time: Instant::now(),
             output_buffer: String::new(),
+            quit_times: KILO_QUIT_TIMES,
         }
     }
 }
@@ -126,6 +133,7 @@ impl Editor {
 
         for char in in_str.chars() {
             input.push(match char {
+                '\x08' => Backspace,
                 '\x7f' => Backspace,
                 '\x1b' => Escape,
                 '\r' => Enter,
@@ -285,6 +293,7 @@ impl Editor {
 
             match char {
                 Backspace => self._del_or_backspace(Backspace),
+                DeleteKey => self._del_or_backspace(DeleteKey),
                 Enter => {
                     // TODO
                 }
@@ -306,6 +315,11 @@ impl Editor {
                 OtherKey(c) => {
                     if c.is_ascii_control() {
                         if c == ctrl_key('q') {
+                            if self.dirty > 0 && self.quit_times > 0 {
+                                self.set_status_message(&format!("WARNING!!! File has unsaved changes. Press Ctrl-Q {} more times to quit.", self.quit_times));
+                                self.quit_times -= 1;
+                                return Some(OtherKey('\0'));
+                            }
                             print!("\x1b[2J");
                             print!("\x1b[H");
                             // Break out of the input loop
@@ -313,10 +327,10 @@ impl Editor {
                         }
 
                         if c == ctrl_key('s') {
-                            // @TODO show save success/error
+                            // Save success/error message handled by save method
                             match self.save() {
                                 Ok(_) => (),
-                                Err(e) => (),
+                                Err(_) => (),
                             }
                         }
 
@@ -330,6 +344,8 @@ impl Editor {
                 _ => (),
             };
 
+            self.quit_times = KILO_QUIT_TIMES;
+
             return key;
         }
 
@@ -338,7 +354,10 @@ impl Editor {
     }
 
     fn _del_or_backspace(&mut self, key: EditorKey<char>) {
-        // TODO
+        if key == DeleteKey {
+            self.move_cursor(&ArrowRight);
+        }
+        self.delete_char();
     }
 
     fn _page_up_or_down(&mut self, key: EditorKey<char>) {
@@ -457,7 +476,9 @@ impl Editor {
             &self.filename
         };
 
-        let mut left_message = format!("{:.80} - {} lines", filename, self.rows.len());
+        let modified = if self.dirty > 0 { "(modified}" } else { "" };
+
+        let mut left_message = format!("{:.80} - {} lines {}", filename, self.rows.len(), modified);
         let right_message = format!("{}/{}", self.cursor_y + 1, self.rows.len());
         let mut len = left_message.len();
         if len > self.screen_cols {
@@ -567,6 +588,8 @@ impl Editor {
     fn append_row(&mut self, row: &str) {
         self.rows.push(EditorRow::new(row));
         self.update_row(self.rows.len() - 1);
+
+        self.dirty += 1;
     }
 
     fn row_insert_char(&mut self, row_index: usize, char_index: usize, ch: char) {
@@ -580,6 +603,20 @@ impl Editor {
         row.chars.insert(at, ch);
 
         self.update_row(row_index);
+
+        self.dirty += 1;
+    }
+
+    fn row_delete_char(&mut self, row_index: usize, char_index: usize) {
+        let row = &mut self.rows[row_index];
+        if char_index >= row.chars.len() {
+            return;
+        }
+
+        row.chars.remove(char_index);
+        self.update_row(row_index);
+
+        self.dirty += 1;
     }
 
     // ------------------------------------------------------------------------
@@ -595,6 +632,17 @@ impl Editor {
         self.cursor_x += 1;
     }
 
+    fn delete_char(&mut self) {
+        if self.cursor_y == self.rows.len() {
+            return;
+        }
+
+        if self.cursor_x > 0 {
+            self.row_delete_char(self.cursor_y, self.cursor_x - 1);
+            self.cursor_x -= 1;
+        }
+    }
+
     // ------------------------------------------------------------------------
     // File I/O
     // ------------------------------------------------------------------------
@@ -624,18 +672,30 @@ impl Editor {
             self.append_row(&line);
         }
 
+        self.dirty = 0;
+
         Ok(())
     }
 
     fn save(&mut self) -> io::Result<()> {
         if self.filename.len() == 0 {
-            return Ok(())
+            return Ok(());
         }
 
         let mut file = File::create(&self.filename)?;
         let data = &mut self.rows_to_string();
 
-        file.write_all(data.as_bytes())?;
+        let res = file.write_all(data.as_bytes());
+
+        match res {
+            Ok(()) => {
+                self.dirty = 0;
+
+                self.set_status_message(&format!("{} bytes written to disk", data.len()));
+            }
+            Err(e) => self.set_status_message(&format!("Failed to save: {:?}", e)),
+        };
+
         file.sync_all()?;
 
         Ok(())
diff --git a/src/main.rs b/src/main.rs
index 393fd4e..9f5999f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -25,7 +25,7 @@ fn main() -> Result<(), Error> {
         editor.open(&args[1])?;
     }
 
-    editor.set_status_message("HELP: Ctrl-Q = quit");
+    editor.set_status_message("HELP: Ctrl-S = save | Ctrl-Q = quit");
 
     // Main input loop. Editor::process_keypress uses an Option Enum as a sentinel.
     // `None` is returned on a quit action, in other cases, `Some(())` is returned,