Handle and render submodes

src/main.rs

@@ -111,6 +111,7 @@ pub struct State {
     pub cursor: Cursor,
     pub file: Option<OsString>,
     pub mode: Mode,
+    pub submode: Option<Key>,
     pub last_saved: Rope,
     pub scroll: Cursor,
     pub size: (usize, usize),
@@ -133,6 +134,7 @@ impl State {
             cursor: Cursor::default(),
             file: file_name,
             mode: Mode::default(),
+            submode: None,
             last_saved,
             scroll: Cursor::default(),
             size: (cols as usize, rows as usize),
@@ -179,6 +181,12 @@ impl State {
             .buffer
             .draw(cols, buffer_rows, self.scroll, self.cursor, out)?;
 
+        // draw submode
+        if let Some(submode) = self.submode {
+            out.queue(cursor::MoveTo(cols - 10, rows - 1))?;
+            write!(out, "{:?}", submode)?;
+        }
+
         // draw cursor
         let cursor_pos = set_cursor_pos.unwrap_or_else(|| {
             // calculate cursor position on buffer
@@ -222,9 +230,7 @@ impl State {
 
         match event {
             Event::Key(KeyEvent { code, .. }) => {
-                if let Some(keybind) = self.config.keybinds.visual.map.get(&code) {
-                    self.execute_keybind(keybind.clone());
-                }
+                self.on_key(code);
             }
             event => self.on_any_event(event),
         }
@@ -305,13 +311,28 @@ impl State {
             Mode::Command(_) => return false, // command mode is handled in [on_command_event]
         };
 
-        match keybinds.map.get(&key) {
-            None => false,
-            Some(keybind) => {
-                self.execute_keybind(keybind.clone());
-                return true;
-            }
+        if let Some(submode) = self.submode {
+            // if we're currently in a submode, try to run this submode's keybind
+            keybinds
+                .submodes
+                .get(&submode)
+                .and_then(|submode| submode.get(&key))
+                .cloned()
+                .map(|keybind| self.execute_keybind(keybind));
+            // whether or not there is a keybind we exit the submode
+            self.submode = None;
+        } else if keybinds.submodes.contains_key(&key) {
+            // enter a submode if available
+            self.submode = Some(key);
+        } else if let Some(keybind) = keybinds.map.get(&key) {
+            // run the keybind if available
+            self.execute_keybind(keybind.clone());
+        } else {
+            // key is not bound; don't handle
+            return false;
         }
+
+        true
     }
 
     fn on_any_event(&mut self, event: Event) {