Simple cursor movement, insertion, and deletion

src/action.rs

@@ -66,6 +66,7 @@ impl RawEvent {
                     Some(c)
                 }
                 KeyCode::Backspace if modifiers == KeyModifiers::NONE => Some('\x08'),
+                KeyCode::Delete if modifiers == KeyModifiers::NONE => Some('\x7F'),
                 KeyCode::Enter if modifiers == KeyModifiers::NONE => Some('\n'),
                 _ => None,
             },
@@ -109,19 +110,7 @@ impl RawEvent {
         }
     }
 
-    pub fn is_go(&self) -> bool {
+    pub fn to_open_prompt(&self) -> Option<Action> {
-        matches!(
-            &self.0,
-            TerminalEvent::Key(KeyEvent {
-                code: KeyCode::Enter,
-                modifiers: KeyModifiers::NONE,
-                kind: KeyEventKind::Press,
-                ..
-            })
-        )
-    }
-
-    pub fn to_open(&self) -> Option<Action> {
         if matches!(
             &self.0,
             TerminalEvent::Key(KeyEvent {
@@ -132,7 +121,13 @@ impl RawEvent {
             })
         ) {
             Some(Action::OpenPrompt)
-        } else if matches!(
+        } else {
+            None
+        }
+    }
+
+    pub fn to_open_switcher(&self) -> Option<Action> {
+        if matches!(
             &self.0,
             TerminalEvent::Key(KeyEvent {
                 code: KeyCode::Char('b'),

src/state.rs

@@ -1,5 +1,5 @@
 use crate::{
-    Action, Args, Color, Error, Event, theme,
+    Action, Args, Color, Dir, Error, Event, theme,
     ui::{self, Element as _, Resp},
 };
 use crossterm::event::{KeyCode, KeyEvent, KeyEventKind, KeyModifiers};
@@ -14,11 +14,58 @@ new_key_type! {
 #[derive(Copy, Clone, Default)]
 pub struct Cursor {
     pub pos: usize,
+    // Used to 'remember' the desired column when skipping over shorter lines
+    desired_col: isize,
+}
+
+impl Cursor {
+    fn reset_desired_col(&mut self, text: &Text) {
+        self.desired_col = text.to_coord(self.pos)[0];
+    }
+}
+
+pub struct Text {
+    chars: Vec<char>,
+}
+
+impl Text {
+    pub fn to_coord(&self, pos: usize) -> [isize; 2] {
+        let mut n = 0;
+        let mut i = 0;
+        for line in self.lines() {
+            if (n..n + line.len() + 1).contains(&pos) {
+                return [(pos - n) as isize, i as isize];
+            } else {
+                n += line.len() + 1;
+                i += 1;
+            }
+        }
+        [0, i as isize]
+    }
+
+    pub fn to_pos(&self, mut coord: [isize; 2]) -> usize {
+        if coord[1] < 0 {
+            return 0;
+        }
+        let mut pos = 0;
+        for (i, line) in self.lines().enumerate() {
+            if i as isize == coord[1] {
+                return pos + coord[0].clamp(0, line.len() as isize) as usize;
+            } else {
+                pos += line.len() + 1;
+            }
+        }
+        pos.min(self.chars.len())
+    }
+
+    pub fn lines(&self) -> impl Iterator<Item = &[char]> {
+        self.chars.split(|c| *c == '\n')
+    }
 }
 
 pub struct Buffer {
     pub path: PathBuf,
-    pub chars: Vec<char>,
+    pub text: Text,
     pub cursors: HopSlotMap<CursorId, Cursor>,
 }
 
@@ -32,21 +79,69 @@ impl Buffer {
         };
         Ok(Self {
             path,
-            chars,
+            text: Text { chars },
             cursors: HopSlotMap::default(),
         })
     }
 
+    pub fn move_cursor(&mut self, cursor_id: CursorId, dir: Dir) {
+        let Some(cursor) = self.cursors.get_mut(cursor_id) else {
+            return;
+        };
+        match dir {
+            Dir::Left => {
+                cursor.pos = cursor.pos.saturating_sub(1);
+                cursor.reset_desired_col(&self.text);
+            }
+            Dir::Right => {
+                cursor.pos = (cursor.pos + 1).min(self.text.chars.len());
+                cursor.reset_desired_col(&self.text);
+            }
+            Dir::Up => {
+                let mut coord = self.text.to_coord(cursor.pos);
+                cursor.pos = self.text.to_pos([cursor.desired_col, coord[1] - 1]);
+            }
+            Dir::Down => {
+                let mut coord = self.text.to_coord(cursor.pos);
+                cursor.pos = self.text.to_pos([cursor.desired_col, coord[1] + 1]);
+            }
+        };
+    }
+
     pub fn insert(&mut self, pos: usize, c: char) {
-        self.chars.insert(pos, c);
+        self.text.chars.insert(pos.min(self.text.chars.len()), c);
-        self.cursors.values_mut().for_each(|c| {
+        self.cursors.values_mut().for_each(|cursor| {
-            if c.pos >= pos {
+            if cursor.pos >= pos {
-                c.pos += 1
+                cursor.pos += 1;
+                cursor.reset_desired_col(&self.text);
             }
         });
     }
 
-    pub fn begin_session(&mut self) -> CursorId {
+    pub fn remove(&mut self, pos: usize) {
+        // TODO: Bell if false?
+        if self.text.chars.len() > pos {
+            self.text.chars.remove(pos);
+            self.cursors.values_mut().for_each(|cursor| {
+                if cursor.pos >= pos {
+                    cursor.pos = cursor.pos.saturating_sub(1);
+                    cursor.reset_desired_col(&self.text);
+                }
+            });
+        }
+    }
+
+    pub fn backspace(&mut self, pos: usize) {
+        if let Some(pos) = pos.checked_sub(1) {
+            self.remove(pos);
+        }
+    }
+
+    pub fn delete(&mut self, pos: usize) {
+        self.remove(pos);
+    }
+
+    pub fn start_session(&mut self) -> CursorId {
         self.cursors.insert(Cursor::default())
     }
 

src/terminal.rs

@@ -207,8 +207,11 @@ impl<'a> Rect<'a> {
         self.rect([0, 0], self.size())
     }
 
-    pub fn set_cursor(&mut self, cursor: [usize; 2], style: CursorStyle) -> Rect {
+    pub fn set_cursor(&mut self, cursor: [isize; 2], style: CursorStyle) -> Rect {
-        if self.has_focus {
+        if self.has_focus
+            && (0..=self.size()[0] as isize).contains(&cursor[0])
+            && (0..self.size()[1] as isize).contains(&cursor[1])
+        {
             self.fb.cursor = Some((
                 [
                     self.origin[0] + cursor[0] as u16,

src/theme.rs

@@ -27,7 +27,7 @@ impl Default for BorderTheme {
             bottom_right: '╯',
             join_left: '├',
             join_right: '┤',
-            fg: Color::DarkGrey,
+            fg: Color::AnsiValue(244),
         }
     }
 }

src/ui/input.rs

@@ -56,7 +56,7 @@ impl Visual for Input {
                 .rect([self.preamble.chars().count(), 0], frame.size())
                 .with(|frame| {
                     frame.text([0, 0], &self.text);
-                    frame.set_cursor([self.cursor, 0], CursorStyle::BlinkingBar);
+                    frame.set_cursor([self.cursor as isize, 0], CursorStyle::BlinkingBar);
                 });
         });
     }

src/ui/panes.rs

@@ -1,13 +1,17 @@
 use super::*;
 use crate::{
-    state::{BufferId, Cursor, CursorId},
+    state::{Buffer, BufferId, Cursor, CursorId},
     terminal::CursorStyle,
 };
+use std::collections::HashMap;
 
 #[derive(Clone)]
 pub struct Doc {
     buffer: BufferId,
-    cursor: CursorId,
+    // Remember the cursor we use for each buffer
+    cursors: HashMap<BufferId, CursorId>,
+    // x/y location in the buffer that the centre of pane is trying to focus on
+    focus: [isize; 2],
 }
 
 impl Doc {
@@ -15,7 +19,26 @@ impl Doc {
         Self {
             buffer,
             // TODO: Don't index directly
-            cursor: state.buffers[buffer].begin_session(),
+            cursors: [(buffer, state.buffers[buffer].start_session())]
+                .into_iter()
+                .collect(),
+            focus: [0, 0],
+        }
+    }
+
+    fn refocus(&mut self, state: &mut State) {
+        let Some(buffer) = state.buffers.get_mut(self.buffer) else {
+            return;
+        };
+        let Some(cursor) = buffer.cursors.get(self.cursors[&self.buffer]) else {
+            return;
+        };
+        self.focus = buffer.text.to_coord(cursor.pos);
+    }
+
+    pub fn close(self, state: &mut State) {
+        for (buffer, cursor) in self.cursors {
+            state.buffers[buffer].end_session(cursor);
         }
     }
 }
@@ -25,27 +48,42 @@ impl Element for Doc {
         let Some(buffer) = state.buffers.get_mut(self.buffer) else {
             return Err(event);
         };
-        let Some(cursor) = buffer.cursors.get(self.cursor) else {
-            return Err(event);
-        };
 
         match event.to_action(|e| {
             e.to_char()
                 .map(Action::Char)
                 .or_else(|| e.to_move().map(Action::Move))
                 .or_else(|| e.to_pane_move().map(Action::PaneMove))
+                .or_else(|| e.to_open_switcher())
         }) {
+            action @ Some(Action::OpenSwitcher) => Ok(Resp::handled(action)),
             Some(Action::SwitchBuffer(new_buffer)) => {
-                buffer.end_session(self.cursor);
                 self.buffer = new_buffer;
                 let Some(buffer) = state.buffers.get_mut(self.buffer) else {
                     return Err(event);
                 };
-                self.cursor = buffer.begin_session();
+                // Start a new cursor session for this buffer if one doesn't exist
+                self.cursors
+                    .entry(self.buffer)
+                    .or_insert_with(|| buffer.start_session());
+                self.refocus(state);
                 Ok(Resp::handled(None))
             }
             Some(Action::Char(c)) => {
-                buffer.insert(cursor.pos, c);
+                let Some(cursor) = buffer.cursors.get(self.cursors[&self.buffer]) else {
+                    return Err(event);
+                };
+                if c == '\x08' {
+                    buffer.backspace(cursor.pos);
+                } else if c == '\x7F' {
+                    buffer.delete(cursor.pos);
+                } else {
+                    buffer.insert(cursor.pos, c);
+                }
+                Ok(Resp::handled(None))
+            }
+            Some(Action::Move(dir)) => {
+                buffer.move_cursor(self.cursors[&self.buffer], dir);
                 Ok(Resp::handled(None))
             }
             _ => Err(event),
@@ -58,19 +96,16 @@ impl Visual for Doc {
         let Some(buffer) = state.buffers.get(self.buffer) else {
             return;
         };
-        let Some(cursor) = buffer.cursors.get(self.cursor) else {
+        let Some(cursor) = buffer.cursors.get(self.cursors[&self.buffer]) else {
             return;
         };
 
-        let mut n = 0;
+        // Set cursor position
-        for (i, line) in buffer.chars.split(|c| *c == '\n').enumerate() {
+        let cursor_coord = buffer.text.to_coord(cursor.pos);
+        frame.set_cursor(cursor_coord, CursorStyle::BlinkingBar);
+
+        for (i, line) in buffer.text.lines().enumerate() {
             frame.text([0, i], line);
-
-            if (n..=n + line.len()).contains(&cursor.pos) {
-                frame.set_cursor([cursor.pos - n, i], CursorStyle::BlinkingBar);
-            }
-
-            n += line.len() + 1;
         }
     }
 }

src/ui/root.rs

@@ -34,7 +34,9 @@ impl Element<CanEnd> for Root {
                 None => {
                     break match self.panes.handle(state, event) {
                         Ok(resp) => resp.action,
-                        Err(event) => event.to_action(|e| e.to_open().or_else(|| e.to_cancel())),
+                        Err(event) => {
+                            event.to_action(|e| e.to_open_prompt().or_else(|| e.to_cancel()))
+                        }
                     };
                 }
             };