3 files changed, 71 insertions, 6 deletions

diff --git a/src/main.rs b/src/main.rs
index de25e9c..dd20c3f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -20,7 +20,7 @@ fn edit(file: &OsStr) -> Result<(), String> {
         }
     };
 
-    let r = match Rope::open(Path::new(file)) {
+    let mut r = match Rope::open(Path::new(file)) {
         Ok(r) => r,
         Err(err) => {
             return Err(format!("open file {}: {}", file.to_string_lossy(), err));
@@ -44,6 +44,7 @@ fn edit(file: &OsStr) -> Result<(), String> {
                 break;
             }
         };
+        // TODO: handle line-wrapping.
         let _ = line.print(&mut stdout);
     }
     let _ = stdout.write(b"\x1b[H");
@@ -113,15 +114,25 @@ fn edit(file: &OsStr) -> Result<(), String> {
                     .line(cursor_row)
                     .expect("cursor_row should always be valid")
                     .len();
-                if cursor_col == usize::from(size.ws_col - 1) || cursor_col >= len {
+                if cursor_col >= len {
                     continue;
                 }
                 cursor_col += 1;
                 move_cursor(&mut stdout, cursor_row, cursor_col);
             }
             Key::Char(c) => {
-                print!("{} ", c);
-                let _ = stdout.flush();
+                let line = r
+                    .line(cursor_row)
+                    .expect("cursor_row should always be valid");
+                cursor_col = std::cmp::min(cursor_col, line.len());
+                r = line.insert(cursor_col, c);
+                move_cursor(&mut stdout, cursor_row, 0);
+                let _ = r
+                    .line(cursor_row)
+                    .expect("cursor_row should always be valid")
+                    .print(&mut stdout);
+                cursor_col += 1;
+                move_cursor(&mut stdout, cursor_row, cursor_col);
             }
         }
     }
diff --git a/src/rope.rs b/src/rope.rs
index 3162e44..7d5ee28 100644
--- a/src/rope.rs
+++ b/src/rope.rs
@@ -132,6 +132,55 @@ impl Node {
             }
         }
     }
+
+    fn insert(&self, pos: usize, c: u8) -> Node {
+        match self {
+            Node::Leaf(v) => {
+                if v.len() < MAX_NODE_SIZE {
+                    let mut new_buf = vec![0; v.len() + 1];
+                    new_buf[..pos].copy_from_slice(&v[..pos]);
+                    new_buf[pos] = c;
+                    new_buf[pos + 1..].copy_from_slice(&v[pos..]);
+                    return Node::Leaf(new_buf);
+                }
+                let mut buf_left = vec![0; pos + 1];
+                buf_left[..pos].copy_from_slice(&v[..pos]);
+                buf_left[pos] = c;
+                let mut buf_right = Vec::new();
+                buf_right.extend_from_slice(&v[pos..]);
+                let mut lines = self.lines();
+                if c == b'\n' {
+                    lines += 1;
+                }
+                return Node::Branch(Branch {
+                    left: Rc::new(Node::Leaf(buf_left)),
+                    right: Rc::new(Node::Leaf(buf_right)),
+                    len: v.len() + 1,
+                    lines: lines,
+                });
+            }
+            Node::Branch(b) => {
+                let mut lines = self.lines();
+                if c == b'\n' {
+                    lines += 1;
+                }
+                if pos < b.left.len() {
+                    return Node::Branch(Branch {
+                        left: Rc::new(b.left.insert(pos, c)),
+                        right: b.right.clone(),
+                        len: b.len + 1,
+                        lines: lines,
+                    });
+                }
+                return Node::Branch(Branch {
+                    left: b.left.clone(),
+                    right: Rc::new(b.right.insert(pos - b.left.len(), c)),
+                    len: b.len + 1,
+                    lines: lines,
+                });
+            }
+        }
+    }
 }
 
 impl Display for Node {
@@ -251,4 +300,9 @@ impl Slice {
     pub fn len(&self) -> usize {
         return self.end - self.start;
     }
+
+    pub fn insert(&self, pos: usize, c: u8) -> Rope {
+        let Rope(buf) = &self.buf;
+        return Rope(Rc::new(buf.insert(self.start + pos, c)));
+    }
 }
diff --git a/src/term.rs b/src/term.rs
index 20098a0..2303fa2 100644
--- a/src/term.rs
+++ b/src/term.rs
@@ -67,7 +67,7 @@ pub enum Key {
     Down,
     Left,
     Right,
-    Char(char),
+    Char(u8),
 }
 
 pub fn read_key(stdin: &mut Stdin) -> Result<Key, String> {
@@ -83,7 +83,7 @@ pub fn read_key(stdin: &mut Stdin) -> Result<Key, String> {
             return Ok(Key::CtrlQ);
         }
         if buf[0] != ESC {
-            return Ok(Key::Char(char::from(buf[0])));
+            return Ok(Key::Char(buf[0]));
         }
         // Try to handle an escape sequence.
         let mut buf = vec![0; 2];